Axial length measurement monitor

Abstract

The OCT axial length measuring device is configured to measure an area of ​​the retina within a range of about 0.05 mm to about 2.0 mm. The area can be measured using a scanned measurement beam or multiple substantially fixed measurement beams. The OCT measuring device can include multiple reference optical path lengths, where a first optical path length corresponds to a first position of the cornea and a second optical path length corresponds to a second position of the retina, and the axial length is determined based on the difference between the first and second positions. An axial length map can be generated to determine alignment with the ocular measuring device and improve measurement accuracy and repeatability. In some embodiments, the OCT measuring device includes a swept-source vertical cavity surface emitting laser ("VCSEL").

Description

[Technical field]

[0001] (Related Applications) This application claims priority to U.S. Provisional Application No. 63 / 200,718, entitled "AXIAL LENGTH MEASUREMENT MONITOR," filed March 24, 2021, the entire disclosure of which is incorporated herein by reference.

[0002] The subject matter of this application is related to PCT / US2019 / 038270, filed June 20, 2019, entitled "MINIATURIZED MOBILE, LOW COST OPTICAL COHERENCE TOMOGRAPHY SYSTEM FOR HOME BASED OPHTHALMIC APPLICATIONS," and published on December 26, 2019 as WO / 2019 / 246412, the entire disclosure of which is incorporated herein by reference. [Background technology]

[0003] Recently developed phototherapies have been proposed to reduce and potentially reverse the increase in axial length of the eye. It would be helpful to have improved methods and devices for measuring refractive errors in order to determine appropriate therapies for treating the progression of refractive errors such as myopia.

[0004] Conventional approaches to measuring refractive error can be sub-ideal. Cycloplegia can be used to freeze the accommodative response in an attempt to provide a more reliable measurement of refractive error, but many patients do not like to be dilated, which can make daily measurements with cycloplegic agents an unrealistic goal. Subjective refraction is also based on visual acuity, which can be sub-ideal, as the eye's lens can accommodate, which reduces the accuracy and repeatability of apparent refraction. Objective refraction measurements from devices such as autorefractometers can automatically find hyperfocal corrections halfway between the plus and minus sides of the depth of field, but these devices are subject to the patient's accommodation and can provide sub-ideal results.

[0005] Although it has been proposed to measure axial length changes to determine changes to the refractive error of the eye, conventional approaches to measuring axial length may be sub-ideal in at least some respects. Some conventional approaches to measuring axial length may rely on optical coherence tomography systems that are more complicated than would be ideal. At least some of the conventional approaches to measuring axial length may also rely on differences in distance between a single point on the cornea and the retina. Research related to the present disclosure suggests that the retina may be less smooth than would be ideal, which may result in sub-ideal results. At least some conventional research indicates that the correlation between axial length changes and refractive error is reasonably good only when a large subject population (e.g., 50-100 subjects) is examined periodically over a period of 6-12 months. As a result, the axial length changes of certain children using conventional axial length monitors may correlate sub-ideally with myopic progression and may be less suitable for monitoring myopic progression and adjusting treatment.

[0006] Studies relevant to the present disclosure suggest that for the same subject, even for a population of subjects with similar intraocular biometry, conventional approaches to measuring axial length may measure an area of ​​approximately 50 microns at the fovea, and that retinal thickness may vary substantially (e.g., by amounts of approximately 50 microns or more) when measured over such a small area.

[0007] In light of the above, improved methods and devices are needed for determining refractive error and change in axial length of the eye. Summary of the Invention [Means for solving the problem]

[0008] The disclosed methods and systems provide improved measurement of the axial length of the eye. In some embodiments, an area of ​​the retina is measured to provide a more accurate axial length measurement. The area of ​​the retina may have a maximum diameter, e.g., diameter, in the range of about 0.05 mm to about 2.0 mm. The area can be measured using a scanned measurement beam or multiple substantially fixed measurement beams. In some embodiments, the OCT measurement device comprises multiple reference optical path lengths, a first optical path length corresponding to a first position of the cornea, a second optical path length corresponding to a second position of the retina, and an axial length is determined based on the difference between the first and second positions. In some embodiments, an axial length map is generated that can be used to determine alignment with the eye measurement device and improve measurement accuracy and repeatability. In some embodiments, the OCT measurement device comprises a swept-source vertical cavity surface emitting laser ("VCSEL").

[0009] (Incorporated by reference) All patents, applications, and publications referenced and identified in this specification are incorporated herein by reference in their entirety and shall be considered to be incorporated by reference in their entirety even if referenced elsewhere in this application. [Brief description of the drawings]

[0010] A better understanding of the features, advantages, and principles of the present invention will be obtained by reference to the following detailed description setting forth illustrative embodiments and the accompanying drawings and appended claims.

[0011] [Figure 1A] FIG. 1A shows a simplified diagram of the human eye.

[0012] [Figure 1B] FIG. 1B shows a perspective view of a monocular optical coherence tomography (OCT) device for measuring a user's eye according to some embodiments.

[0013] [Diagram 2] FIG. 2 shows a schematic diagram of a system that allows a patient to measure axial length at multiple time points and communicate the results according to some embodiments.

[0014] [Figure 3A] FIG. 3A illustrates a handheld optical coherence tomography device utilizing Bluetooth® communication according to some embodiments.

[0015] [Figure 3B] FIG. 3B illustrates a Global System for Mobile Communications (GSM) handheld OCT device according to some embodiments.

[0016] [Figure 4] FIG. 4 shows a perspective view of a binocular OCT device for measuring a user's eyes according to some embodiments.

[0017] [Diagram 5] FIG. 5 shows a block diagram of a binocular OCT device illustrating various components within the handheld unit body according to some embodiments.

[0018] [Figure 6]FIG. 6 shows a schematic diagram of an optical configuration that may be implemented with binocular OCT according to some embodiments.

[0019] [Figure 7] FIG. 7 illustrates a block diagram of an optical configuration configured on an optical layout substrate according to some embodiments.

[0020] [Figure 8] FIG. 8 shows a perspective view of a modular binocular OCT device according to some embodiments.

[0021] [Figure 9] FIG. 9 shows a perspective / cutaway internal view of a binocular OCT device according to some embodiments.

[0022] [Figure 10] FIG. 10 shows another perspective / cutaway internal view of a binocular OCT device according to some embodiments.

[0023] [Figure 11] FIG. 11 shows an overhead / cutaway view of a binocular OCT device with eye position sensors according to some embodiments.

[0024] [Figure 12] FIG. 12 shows an OCT device with two reference arms according to some embodiments.

[0025] [Figure 13A] FIG. 13A shows signal strength and frequency for an OCT device with two signals received simultaneously using one or more detectors, for example a balanced pair, according to some embodiments.

[0026] [Figure 13B] FIG. 13B shows the signal frequency broadening due to the chirp of the swept source.

[0027] [Figure 14]FIG. 14 illustrates the measurement depth of an axial length monitor according to some embodiments.

[0028] [Figure 15] FIG. 15 illustrates a fixation target configured to change color in response to user alignment according to some embodiments.

[0029] [Figure 16] FIG. 16 illustrates an array of VCSELs coupled to multiple optical fibers according to some embodiments.

[0030] [Figure 17] FIG. 17 shows a VCSEL array imaged into the eye according to some embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] The following detailed description provides a deeper understanding of the features and advantages of the invention described in this disclosure according to the embodiments disclosed herein. Although this detailed description includes many specific embodiments, these are provided only as examples and should not be interpreted as limiting the scope of the invention disclosed herein. For example, although reference is made to measuring the axial length of the eye, the methods and devices disclosed herein can be used to measure many types of samples, such as other tissues and non-tissue materials of the body. Although reference is made to generating a map of the axial length, the methods and devices disclosed herein can be used to generate images of intraocular tissues, such as cross-sectional or tomographic images of the eye, such as images of one or more of the retina, cornea, or lens.

[0032] In some embodiments, the term "axial length" refers to the distance between the corneal apex and the retinal pigment epithelium (RPE) of the eye. Measurement of the axial length along the optical axis of the eye can be used to determine the paraxial focal length and refractive power of a refractive device that can be provided to bring the eye into a state of emmetropia, moving the best focused image to the surface of the retinal pigment epithelium. The axial length can also be measured along any other suitable direction, and the axial length can be expressed as an average value that is the average of measurements of the axial length along multiple directions from the RPE, including the fovea, fovea, or even the entire macula, to the corneal apex. In some embodiments, the axial length can also be determined at least in part based on the curvature of the cornea, for example, multiple axial lengths are determined along an annular region of the cornea and a corresponding annular region of the macula.

[0033] The disclosed method, system, and device are highly suitable for measuring the axial length of the eye. Research related to the present disclosure suggests that the axial length can be used to measure the change in eye length caused by scleral remodeling, and an eye model has been developed to convert the axial length to refractive error. In some embodiments, the eye model is configured to include the anterior and posterior curvatures of the cornea, the corresponding corneal thickness, and the location and power of the eye's crystalline lens. In some embodiments, the power of the crystalline lens is substantially constant, and the variation in the anterior chamber depth can be assumed based on the eye model or measured directly. The eye model can be converted into a regression curve and included as an algorithm within the application.

[0034] The presently disclosed methods, systems, and devices are highly suitable for combination with PCT / US2019 / 038270, filed June 20, 2019, entitled "MINIATURIZED MOBILE, LOW COST OPTICAL COHERENCE TOMOGRAPHY SYSTEM FOR HOME BASED OPHTHALMIC APPLICATIONS," and published as WO / 2019 / 246412, the entire disclosure of which is incorporated by reference and is highly suitable for modification by the present disclosure. Such a system can be modified according to measuring axial length by modifying the light path to measure a change in OPD of up to + / - 3 mm (e.g., 21 + / - 3 mm).

[0035] Axial length measurements may be made over an area on the retinal surface that may have a diameter of 0.05-2.0 mm, preferably 0.10-1.5 mm. In some optical designs, a scanning system utilizing, for example, a movable mirror, may be deployed to perform multiple A-scans. An average axial length may be calculated from these individual measurements. Alternatively, or in combination, multiple substantially fixed beams may be used to measure axial length.

[0036] In some embodiments, the axial length measuring device is configured to monitor myopia progression. Research related to the present disclosure suggests that myopia progression is caused by a substantial deepening of the vitreous compartment, but that sometimes changes in corneal curvature may also contribute moderately. Research related to the present disclosure also suggests that axial length correlates significantly with myopia progression in children, and that the disclosed method and apparatus are highly suitable for monitoring myopia progression in children.

[0037] In some embodiments, the OCT device is equipped with an axial length monitor with an accuracy of + / - 25 microns, a resolution of 10 microns, and a repeatability of + / - 15 microns.

[0038] In some embodiments, the OCT device is configured to measure changes in spherocylinder equivalents of + / - 0.07 D and detect changes of 0.03 D based on the relationship between axial length and refraction as described herein. In some embodiments, this capability allows the device to monitor monthly changes in refraction in children, such as Asian children, whose myopia progression rates may average approximately 0.9 D / year.

[0039] In some embodiments, the OCT axial length measurement device is capable of rapidly detecting the effectiveness of myopia inhibition therapy, so that changes in therapy can be made before a patient's myopia approaches high myopia (>-5D) levels (in many embodiments, much lower levels of myopia, such as no more than 1.0D of myopia, e.g., a -1.0D refraction).

[0040] In some embodiments, the OCT AL measurement device has one or more of the following features, as shown in Table 1:

[0041] [Table 1]

[0042] In some embodiments, the OCT AL measurement device includes a monocular configuration in which the axial length is measured from the corneal apex to the retinal pigment epithelium (RPE) layer, allowing the patient to fixate and auto-align or self-align based on visual cues.

[0043] The disclosed systems, devices and methods are highly suitable for incorporation with previous OCT approaches. The OCT interferometer may comprise one or more of a time domain OCT interferometer, a swept source OCT interferometer, a spectral domain OCT interferometer, or a multi-reflectance OCT interferometer. Although a swept source VCSEL with limited range sweep and use of multiple VCSELs is referenced, the light source may comprise any suitable light source, such as a MEMS tunable VCSEL capable of sweeping over a range of wavelengths from about 20 nm to about 100 nm or more. Although an axial length map is referenced, in some embodiments, the OCT measurement system and device are configured to generate 3D tomographic images of the cornea and retina. In some embodiments, the 3D tomographic images of the retina include a high-resolution image of the retina with a spatial resolution along the OCT measurement beam in the range of 4 to 25 microns (e.g., with a resolution in the range of 2 to 10 microns).

[0044] The disclosed systems and methods can be configured in many ways. In some embodiments, the OCT system comprises a binocular device in which one eye is measured and the other eye is provided with a stimulus, such as a fixation stimulus. Alternatively, the OCT system may comprise, for example, a monocular device in which one eye is measured at a time and only the measured eye is provided with a fixation stimulus and the other eye is covered with an occluder.

[0045] The miniature OCT system disclosed herein is well suited for use with many previous clinical tests, such as measuring axial length. In some cases, the OCT system is used by the patient or by the healthcare provider. In many cases, the patient can align themselves with the system, but another user can also align the patient with the system and take the measurement. In some embodiments, the OCT system can be integrated with previous software and systems to provide additional information to the healthcare provider and provide alerts in response to changes in axial length. Alerts are optionally sent to patients, caregivers, and healthcare providers when corrective action should be taken (such as changes in eye therapy, visual stimulation therapy, medication, dosage, or reminders to take medication).

[0046] As used herein, the term "axial length" ("AL") refers to the axial distance of the eye from the cornea of ​​the eye to the retina of the eye. In some embodiments, the AL is measured as the distance from the anterior surface of the cornea to the retinal pigment epithelium ("RPE").

[0047] As used herein, the term "corneal thickness" ("CT") refers to the corneal thickness between the anterior corneal layer, e.g., the tear film, and the ultimate layer, e.g., the corneal endothelium.

[0048] As used herein, the term "retinal thickness (RT)" refers to the interlaminar retinal thickness used to assess the retinal thickness of a patient. RT may, for example, correspond to the retinal thickness between the anterior surface of the retina and the outer limiting membrane.

[0049] As used herein, the term "retinal layer thickness (RLT)" refers to the thickness of one or more optically detectable layers of the retina. An optically detectable layer of the retina may, for example, comprise the retinal thickness extending between the outer limiting membrane and the retinal pigment epithelium.

[0050] FIG. 1A shows a simplified diagram of the human eye. Light enters the eye through the cornea 10. The iris 20 controls the amount of light allowed to pass by varying the size of the pupil 25, which allows the light to pass to the lens 30. The anterior chamber 40 contains aqueous humor 45, which determines the intraocular pressure (IOP). The lens 30 focuses light for imaging. The focal properties of the lens are controlled by muscles that reshape the lens. The focused light passes through the vitreous cavity, which is filled with vitreous humor 55. The vitreous humor maintains the overall shape and structure of the eye. The light then reaches the retina 60, which has a light-sensitive region. In particular, the macula 65 is the area of ​​the retina responsible for receiving light at the center of the visual plane. Within the macula, the fovea 70 is the area of ​​the retina that is most sensitive to light. The light that reaches the retina generates electrical signals that are passed to the optic nerve 80 and then to the brain for processing.

[0051] Several disorders result in reduced optical performance of the eye. In some cases, the axial length of the eye is undesirably long, which is associated with the patient's myopia. In some cases, the intraocular pressure (IOP) is either too high or too low. This is caused, for example, by too high or too low production rate of aqueous humor in the anterior chamber, or, for example, drainage of aqueous humor from the anterior chamber. In other cases, the retina is too thin or too thick. This occurs, for example, due to accumulation of fluid in the retina. Diseases associated with abnormal retinal thickness (RT) include, for example, glaucoma, macular degeneration, diabetic retinopathy, macular edema, and diabetic macular edema. In some cases, the healthy range of RT is 175 μm thick to 225 μm thick. In general, abnormalities in either or both IOP or RT indicate the possible presence of one of several ophthalmic diseases. In addition, IOP or RT fluctuate in response to ophthalmic treatment or other procedures. Therefore, it is desirable to have a means for measuring IOP and / or RT for diagnosing ophthalmic diseases and assessing the effectiveness of treatment for a given patient.In some cases, it is desirable to measure the thickness of one or more retinal layers, for example the thickness of multiple layers.In addition, it is desirable to process the data obtained from the OCT system and help identify fluid pockets or regions in the eye, as these may indicate changes in eye health.

[0052] The systems and methods disclosed herein relate to the use of optical coherence tomography (OCT) to measure AL at multiple time points. For example, a patient measures their AL at multiple time points to track the progression of an ophthalmic disease, such as myopia, over time. As another example, a patient measures their AL at multiple time points to track their response to light therapy or other treatments. In some cases, the system generates an alert when one or more recent measurements of AL deviate significantly from previous measurements. In some cases, the system alerts the patient or the patient's physician to the change. In some cases, this information is used to schedule a follow-up appointment between the patient and physician (e.g., to attempt treatment of an ophthalmic condition, to discontinue a prescribed treatment, or to perform additional testing).

[0053] 1B shows a perspective view of a monocular optical coherence tomography (OCT) device 100 for measuring a user's eye according to some embodiments. The OCT device 100 includes a head 202, a base 204, and a neck 206 therebetween. The head 202 is connected to the neck 206 by a coupling 208 that allows for articulation of the head 202 in some embodiments. The head is covered with a housing that encloses an optical module, a scanning module, and other associated circuitry and modules that may allow the OCT device 100 to measure the user's eyes, one eye at a time.

[0054] In some embodiments, the head 202 further includes a lens 210, an eyecup 212, and one or more LED lights 214. The lens 210 may be configured to direct one or more light sources from within the head 202 to focus on the retina of the eye. The eyecup 212 may be configured to position the patient's head, and thereby position the patient's eye, for scanning and examination. The eyecup 212 may be rotatable such that the protruding portion 216 is positioned adjacent the patient's eye and may extend along the side of the head (e.g., adjacent the patient's temple) when the patient's head is properly oriented relative to the OCT device 100. The eyecup 212 may be coupled to a sensor configured to detect a rotational orientation of the eyecup 212. In some embodiments, the OCT device 100 is configured to detect a rotational orientation of the eyecup 212, and thereby determine whether the patient is presenting their right or left eye for scanning and measurement. More specifically, in some embodiments, the protruding portion 216 of the eyecup 212 extends adjacent either the patient's right temple or left temple, thereby allowing determination of the patient's eye being measured. In some embodiments, the eyecup 212 includes a patient support. The patient support includes a head rest or chin rest, either alternatively or in combination with the eyecup 212.

[0055] In some embodiments, a coupling 208 connects the head 202 to the neck 206 and allows for pivotal movement about the coupling. The coupling 208 can be any suitable coupling, which can be fixed, articulating, rotating, or pivoting according to an embodiment. In some cases, the coupling includes a threaded fastener and a threaded nut to tighten the head relative to the neck in a desired orientation. The threaded nut can be operable by hand and can include a knurled knob, a wing nut, a star nut, or some other type of manually operated tightening mechanism. The coupling can alternatively or additionally include any suitable member that allows for adjustment of the angle of the head relative to the neck and can include cams, levers, detents, or alternatively or additionally include friction increasing structures such as roughened surfaces, peaks and valleys, surface textures, etc.

[0056] FIG. 2 shows a schematic diagram of a system that allows a patient to measure AL at multiple time points and communicate the results according to some embodiments. The patient looks into a handheld OCT device 100 and obtains measurements of AL. In some embodiments, the handheld OCT device includes an optical system 102, electronics 104 for controlling and communicating with the optical system, a battery 106, and a transmitter 108. In some cases, the transmitter is a wired transmitter. In some cases, the transmitter is a wireless transmitter. In some cases, the handheld OCT device 100 communicates the results to a mobile patient device 120, such as the patient's smartphone or other portable electronic device, over a wireless communication channel 110. In some cases, the wireless communication is by Bluetooth® communication. In some embodiments, the wireless communication is by Wi-Fi communication. In other embodiments, the wireless communication is by any other wireless communication known to those of skill in the art. Although wireless communication is referenced, in some embodiments, the OCT device is connected to the patient mobile device by wired communication, and the patient mobile device is wirelessly connected to a remote server, such as a cloud-based server.

[0057] In some cases, the result is a fully processed measurement of AL. In some cases, all processing of the OCT data is performed on the handheld OCT device. For example, in some embodiments, the handheld OCT device includes hardware or software elements that allow the OCT light waveform to be converted into an electronic representation. In some cases, the handheld OCT device further includes hardware or software elements that allow processing of the electronic representation, for example to extract a measurement of AL.

[0058] In some cases, the result is an electronic representation of the raw optical waveform obtained from the OCT measurements. For example, in some embodiments, the handheld OCT device includes hardware or software elements that allow the OCT optical waveform to be converted into an electronic representation. In some cases, these electronic representations are then passed to a mobile patient device for further processing, for example to extract a measurement of RT.

[0059] In some cases, the patient receives the results and analysis of the AL measurement on the patient mobile app. In some embodiments, the results include an alert 122 that alerts the patient that the result of the measurement is outside of a normal or healthy range. In some cases, the results also include a display of the measurement value 124. For example, in some cases, the AL measurement generates a result with a particular value in millimeters (mm), e.g., 23.6 mm. In some cases, this result corresponds to a change in axial length outside of a desired range. This causes the system to generate an alert and display the measurement value on the patient mobile app. In some embodiments, the alert is transmitted to a healthcare provider, such as a treating physician. In some embodiments, the results also include a chart 126 showing the history of the patient's AL over multiple time points.

[0060] In some cases, the patient mobile device communicates the results of the measurements to a cloud-based or other network-based storage and communication system 140 via a communication means 130. In some embodiments, the communication means is a wired communication means. In some embodiments, the communication means is a wireless communication means. In some cases, the wireless communication is by Wi-Fi communication. In other cases, the wireless communication is by a cellular network. In still other cases, the wireless communication is by any other wireless communication known to those of skill in the art. In specific embodiments, the wireless communication means is configured to enable transmission to or reception from a cloud-based or other network-based storage and communication system.

[0061] Once stored in the cloud, in specific embodiments, the results are then transmitted to other devices. In some cases, the results are transmitted to a patient device 150 on the patient's computer, tablet, or other electronic device by a first communication channel 132. In some embodiments, the results are transmitted to a physician device 160 on the patient's physician's computer, tablet, or other electronic device by a second communication channel 134. In some cases, the results are transmitted to an analysis device 170 on another user's computer, tablet, or other electronic device by a third communication channel 136. In some embodiments, the results are transmitted to a patient management system or hospital management system 180 by a fourth communication channel 138. In some cases, each of the devices has appropriate software instructions to perform the associated functions as described herein.

[0062] In specific embodiments, the first communication channel is a wired or wireless communication channel. In some cases, the communication is by Ethernet. In other cases, the communication is by a local area network (LAN) or a wide area network (WAN). In still other cases, the communication is by Wi-Fi. In still other cases, the communication is by any other wired or wireless communication channel or method known to those skilled in the art. In some embodiments, the first communication channel is configured to allow transmission to or reception from a cloud-based or other network-based storage and communication system. In some cases, the first communication channel is configured to allow reception only from a cloud-based or other network-based storage and communication system.

[0063] In some cases, the second communication channel is a wired or wireless communication channel. In some cases, the communication is by Ethernet. In specific embodiments, the communication is by a local area network (LAN) or a wide area network (WAN). In other embodiments, the communication is by Wi-Fi. In still other embodiments, the communication is by any other wired or wireless communication channel or method known to those skilled in the art. In some cases, the second communication channel is configured to allow transmission to or reception from a cloud-based or other network-based storage and communication system. In some embodiments, the second communication channel is configured to allow reception only from a cloud-based or other network-based storage and communication system.

[0064] In specific cases, the third communication channel is a wired or wireless communication channel. In some cases, the communication is by Ethernet. In other cases, the communication is by a local area network (LAN) or a wide area network (WAN). In still other cases, the communication is by Wi-Fi. In still other cases, the communication is by any other wired or wireless communication channel or method known to those skilled in the art. In some embodiments, the third communication channel is configured to allow transmission to or reception from a cloud-based or other network-based storage and communication system. In some cases, the third communication channel is configured to allow only reception from a cloud-based or other network-based storage and communication system.

[0065] In some embodiments, the fourth communication channel is a wired or wireless communication channel. In some cases, the communication is by Ethernet. In other cases, the communication is by a local area network (LAN) or a wide area network (WAN). In still other cases, the communication is by Wi-Fi. In still other cases, the communication is any other wired or wireless communication channel or method known to those skilled in the art. In some cases, the fourth communication channel is configured to allow transmission to or reception from a cloud-based or other network-based storage and communication system. In other cases, the fourth communication channel is configured to allow only reception from a cloud-based or other network-based storage and communication system.

[0066] The determination of AL can be performed in many locations. For example, the determination of AL can be performed on the handheld OCT device. In some cases, the determination of AL is performed at a location close to the handheld OCT device, such as by a smartphone or other portable electronic device. In some embodiments, the determination of AL is performed on a cloud-based storage and communication system. In some cases, the handheld OCT device is configured to compress the measurement data and transmit the compressed measurement data to the cloud-based storage and communication system. Alternatively, or in combination, other components of the OCT system, such as a mobile device operably coupled to the OCT device, can be configured to, for example, compress the measurement data and transmit the compressed measurement data to the cloud-based storage and communication system.

[0067] In some embodiments, the patient receives the results and analysis of the AL measurement on the patient device 150. In some cases, the results include an alert 152 that alerts the patient that the results of the measurement are outside of normal or healthy ranges. In some cases, the results also include a display of the measurement value 154. For example, in one case, the AL measurement produces a result of 23.6 mm. This result corresponds to an increase in axial length indicating an increase in myopia. Outside of normal or healthy ranges. In some cases, it causes the system to generate an alert and display the measurement of 23.6 mm on the patient device. In a specific case, the results also include a chart 156 showing the history of the patient's AL over multiple time points. In some cases, the patient device also displays instructions 158 for the patient to follow. In some cases, the instructions instruct the patient to visit their physician. In some embodiments, the instructions include, for example, the patient's name, the date of the most recent AL measurement, and the next scheduled visit to the physician.

[0068] In some embodiments, the patient's physician receives the results and analysis of the AL measurement on the physician device 160. In some cases, the results include an alert 162 that alerts the physician that the results of the measurement correspond to a potentially significant change from baseline. In some cases, the results also include an alert 164 that notifies the physician of the patient's measurements. In some embodiments, the alert includes a suggestion for the physician to call the patient and schedule an appointment or provide medical assistance. In some embodiments, the results also include a display 166 showing the most recent and historical measurements for each of the physician's patients. For example, in some cases, the measurement of the AL produces a result of 23.6 mm. This result corresponds to a change from the baseline value indicating a possible progression of myopia. Outside of normal or healthy ranges. In some cases, this causes the system to generate an alert and display on the physician app the measurement of 23.6 mm, or the amount of increase in axial length from the previous measurement. In a specific case, the physician device also displays contact and history information 168 for each of the physician's patients.

[0069] In some embodiments, other users receive the results and analysis of the AL measurements on the analysis device 170. In some cases, the other users are researchers investigating the effectiveness of new forms of treatment. In other cases, the other users are auditors monitoring the results of a particular doctor or nursing facility. To protect patient privacy, in some cases the analysis device is limited to receiving only a portion of a given patient's information. For example, some are limited to not include any personally identifiable information about a given patient. In some cases, the results include an alert 172 that warns or indicates that a large number of abnormal or undesirable measurements have been taken within a particular time period. In some cases, the results include one or more graphical representations 174 of the measurements across a population of patients.

[0070] In some cases, the results and analysis on the analysis device include disease information such as a physician-confirmed diagnosis. In some cases, the results and analysis include anonymous patient data such as age, sex, genetic information, information about the patient's environment, smoking history, other diseases the patient has suffered from, etc. In some cases, the results and analysis include anonymous treatment plans for the patient such as a list of light therapy, prescribed medications, and treatment history. In some cases, the results and analysis include measurement results such as results of AL measurements, patient refraction (glasses prescription), visual function tests, or patient compliance with a course of treatment. In some cases, the results and analysis include data from an electronic medical record. In some cases, the results and analysis include diagnostic information from a visit to a patient's health care provider such as results of an axial OCT scan obtained by the patient's health care provider.

[0071] In some embodiments, the patient's clinical, hospital, or other healthcare provider receives the results and analysis of the AL measurement on a patient management system or hospital management system 180. In some cases, the system includes the patient's electronic medical record. In some cases, the results and analysis provide the patient's healthcare provider with data that allows the provider to update the treatment plan for the patient. In some cases, the results and analysis allow the provider to decide to refer the patient for early outpatient care. In some cases, the results and analysis allow the provider to decide to postpone outpatient care.

[0072] In some embodiments, one or more of the patient device, physician device, and analysis device include a software application that includes instructions for performing the functions of the patient device, physician device, or analysis device, respectively, as described herein.

[0073] FIG. 3A illustrates a handheld OCT device utilizing near field wireless communication according to some embodiments. In some embodiments, the handheld OCT device 100 includes an optical system 102, electronics for controlling and communicating with the optical system 104, a battery 106, and a wireless transmitter 108. In some cases, the wireless transmitter is a Bluetooth® transmitter. In some cases, the results from one or more AL measurements are stored on the handheld OCT device until an authorized user, such as the patient or another person designated by the patient, opens the patient mobile device on a smartphone or other portable electronic device. Once opened, the patient mobile device application establishes wireless communication with the handheld OCT device. In some cases, the communication is by a Bluetooth® wireless communication channel 110. In some cases, the handheld OCT device communicates the results by a Bluetooth® channel to a mobile patient device 120 on the patient's smartphone or other portable electronic device.

[0074] In some instances, the results include an alert 122 that alerts the patient that the result of the measurement is outside of a desired range. In a specific embodiment, the results also include a display of the measurement value 124. For example, a measurement of AL may in one case produce a result of 23.6 mm. This result is outside of the desired range. In one case, this causes the system to generate an alert and display a measurement of 23.6 mm on the patient mobile app. In a specific embodiment, the results also include a chart 126 that shows the history of the patient's AL over multiple time points.

[0075] In some cases, the patient mobile device application communicates the results of the measurements to a cloud-based or other network-based storage and communication system 140 via wireless communication means 130. In some cases, the wireless communication is Wi-Fi communication. In other cases, the Wi-Fi communication is over a secure Wi-Fi channel. In still other cases, the wireless communication is over a cellular network. In a specific embodiment, the cellular network is a secure cellular network. In other embodiments, the transmitted information is encrypted. In some cases, the communication channel is configured to allow transmission to or receipt from a cloud-based or other network-based storage and communication system. In some cases, the data is stored on the smartphone or other portable electronic device until the smartphone or other portable electronic device connects to a Wi-Fi or cellular network.

[0076] In some cases, the Patient Mobile Device Application has a feature that notifies the patient, or another person designated by the patient, when too much time has passed since the Patient Mobile Device Application was last opened. For example, in some cases, this notification occurs because the patient has not obtained AL measurements as recently as required by the measurement schedule set by their physician or other healthcare provider. In other cases, the notification occurs because the handheld OCT device has stored the results of too many measurements and needs to transmit the data to the patient's smartphone. In specific embodiments, the Patient Mobile Device Application communicates with a cloud-based or other network-based storage and communication system to display the complete set of patient data.

[0077] FIG. 3B illustrates a handheld OCT device capable of communicating directly with a cloud-based storage and communication system without relying on a user device such as a smartphone according to some embodiments. In some embodiments, the handheld OCT device 100 includes an optical system 102, electronics for controlling and communicating with the optical system 104, a battery 106, and a wireless transmitter 108. In some cases, the wireless transmitter is a GSM transmitter. In some cases, results from one or more AL measurements are stored on the handheld OCT device. In some cases, the GSM transmitter establishes wireless communication with a cloud-based or other network-based storage and communication system 140 over a wireless communication channel 114. In certain cases, the wireless communication is over a GSM wireless communication channel. In other embodiments, the system utilizes third generation (3G) or fourth generation (4G) mobile communication standards. In such cases, the wireless communication is over a 3G or 4G communication channel.

[0078] In specific embodiments, the patient mobile device 120 receives the results of the measurements from a cloud-based or other network-based storage and communication system 140 via wireless communication means 130. In some cases, the wireless communication is by Wi-Fi communication. In some cases, the Wi-Fi communication is by a secure Wi-Fi channel. In other cases, the wireless communication is by a cellular network. In some cases, the cellular network is a secure cellular network. In specific cases, the transmitted information is encrypted. In some embodiments, the communication channel is configured to allow transmission to or reception from a cloud-based or other network-based storage and communication system.

[0079] Once retrieved from the cloud-based or other network-based storage and communication system, the results of the AL measurement are, in some cases, viewed within the patient mobile application. In some cases, the results include an alert 122 that alerts the patient that the result of the measurement is outside of a normal or healthy range. In some cases, the results also include a display of the measurement value 124. For example, in one case, the measurement of the AL produces a result of 23.6 mm, which is outside of a desired range as described herein. In a specific embodiment, this causes the system to generate an alert and display the measurement of 23.6 mm on the patient mobile application. In some embodiments, the results also include a chart 126 showing the history of the patient's AL over multiple time points.

[0080] In some cases, the Patient Mobile Device Application has a feature that notifies the patient, or another person designated by the patient, when too much time has passed since the Patient Mobile Device Application was last opened. For example, in some cases, this notification occurs because AL measurements have not been obtained as recently as required by the measurement schedule set by the physician or other healthcare provider. In other cases, the notification occurs because the handheld OCT device has stored the results of too many measurements and needs to transmit the data to the patient's smartphone. In specific embodiments, the Patient Mobile Device communicates with a cloud-based or other network-based storage and communication system to display the complete set of patient data.

[0081] In some cases, the handheld OCT device includes both a near-field transmitter and a GSM, 3G, or 4G transmitter. In some cases, the near-field transmitter is a Bluetooth transmitter. In some cases, the handheld OCT device communicates directly with a patient mobile device application on a smartphone or other portable electronic device through a Bluetooth wireless communication channel. In some embodiments, the handheld OCT also communicates with a cloud-based or other network-based storage and communication system through a GSM, 3G, or 4G wireless communication channel. In specific cases, the cloud-based system then communicates with the patient mobile device application through Wi-Fi, cellular, or other wireless communication channel. Alternatively, the Bluetooth transmitter is built into the docking station. In some cases, it allows for the use of older devices for patients who do not have smartphones. In some cases, the docking station also includes a means for charging the battery of the handheld OCT device.

[0082] In some cases, the handheld OCT device of FIGS. 3A and 3B is configured to be held in close proximity to the eye. For example, in a specific embodiment, the device is configured to be held in front of the eye with the detector at a distance of 200 mm or less from the eye. In other embodiments, the device is configured to be held in front of the eye with the detector at a distance of 150 mm or less, 100 mm or less, or 50 mm or less from the eye. In specific cases, the handheld OCT device further comprises a housing for supporting the light source, the optical elements, the detector, and the circuitry. In some cases, the housing is configured to be held in a user's hand. In some cases, the user holds the device in front of the eye and directs the light beam into the eye. In some cases, the device includes a sensor for determining which eye is being measured. For example, in a specific embodiment, the device includes an accelerometer or gyroscope for determining the eye being measured in response to an orientation of the housing. The device optionally includes a shielding structure coupled to the housing and a sensor for determining the eye being measured. The shielding structure occludes one eye while the other eye is being measured. In some cases, the device includes a viewing target for aligning the light beam with a portion of the retina. For example, in specific embodiments, the device includes a viewing target for aligning the light beam with the orbit of the eye. In some cases, the viewing target is a light beam. In some cases, the viewing target is a light emitting diode. In other cases, the viewing target is a vertical cavity surface emitting laser (VCSEL). In still further cases, the viewing target is any suitable viewing target that would be known to one of skill in the art.

[0083] The optical components described herein can be miniaturized to provide a handheld OCT device with a reduced physical size and mass as described herein, as will be understood by one of ordinary skill in the art.

[0084] In some embodiments, the handheld OCT device of FIGS. 3A and 3B is small enough and lightweight enough to be easily operated by a user with one hand. For example, in some embodiments, the device has a mass in the range of about 100 grams to about 500 grams, although the device can be heavier, for example, having a mass in the range of about 500 grams to about 1,000 grams. In some embodiments, the device has a mass in the range of about 200 grams to about 400 grams. In some embodiments, the device has a mass in the range of about 250 grams to about 350 grams. In specific embodiments, the device has a maximum transverse dimension in the range of about 80 mm to about 160 mm. In specific embodiments, the device has a maximum transverse dimension in the range of about 100 mm to about 140 mm. In specific embodiments, the device has a width in the range of about 110 mm to about 130 mm. In some embodiments, the maximum transverse dimension comprises a length. In some embodiments, the device has a width that is less than the length. In specific embodiments, the device has a width in the range of about 40 mm to about 80 mm. In a specific embodiment, the device has a width in the range of about 50 mm to about 70 mm.In a specific embodiment, the device has a width in the range of about 55 mm to about 65 mm.

[0085] FIG. 4 shows a perspective view of a binocular OCT device 4900 for measuring a user's eye according to some embodiments. The binocular OCT device 4900 comprises a first adjustable lens 4916-1 optically coupled to an OCT measurement system and a first fixation target configured in a handheld unit body 4903 (e.g., housing), both of which are hidden from view in this view. Similarly, a second adjustable lens 4916-2 may be optically coupled to the OCT measurement system and a second fixation target (hidden). The first adjustable lens 4916-1 may be part of a first free-space optical system configured to provide a fixation target and measure the axial length of the user's eye, while the second adjustable lens 4916-2 may be part of a second free-space optical system configured to provide only a fixation target so as to reduce the number of components in the binocular OCT device 4900. For example, both free space optics provide a fixation target for the user, but the binocular OCT device 4900 is turned upside down, i.e., inverted, after the user has measured the first eye, so that only one of the free space optics is used to measure axial length so that the user may measure the other eye.

[0086] The binocular OCT device 4900, in this embodiment, includes an interpupillary distance (IPD) adjustment mechanism 4905 that is accessible on the exterior of the handheld unit body 4903. In this embodiment, the IPD adjustment mechanism 4905 includes two components, a first component 4905-1 that adjusts the distance between lenses 4916-1 and 4916-2 to match the IPD of a user's pupils when the user places the binocular OCT device 4900 in front of the user's eyes when the eyecups 4901-1 and 4901-2 are positioned on the user's face.

[0087] The IPD can be set by a medical professional and locked into position for a user to measure one or more of AL, corneal thickness, or retinal thickness at home. Alternatively, the IPD can be user adjustable. A switch 4904 can be used to adjust the lenses 4916-1 and 4916-2 to match the user's refraction, i.e., eyeglass prescription. Alternatively, a mobile device such as a tablet can be used to program the refraction of each eye of the patient. For example, a user can fixate a first fixation target with one eye and a second fixation target with the other eye, and the movable lens can be adjusted to the user's refraction. The switch 4904 can selectively adjust the assembly of the lenses 4916-1 and 4916-2 in the handheld unit body 4903 to change the positioning of the lenses 4916-1 and 4916-2. These positions can be entered into the device by a medical professional and stored in the processor in addition to the orientation from the orientation sensor as described herein. The device can be reversed and the process can be repeated. Alternatively, or in addition, prescriptions for each eye can be stored in the processor and the lenses can be adjusted to the appropriate refraction for each eye in response to the orientation of the orientation sensor.

[0088] Both components 4905-1 and 4905-5 may be implemented as one or more wheels that are rotated manually by a healthcare professional. Alternatively, the IPD adjustment mechanism 4905 may be motorized. In this regard, components 4905-1 and 4905-5 may be configured as directional switches that activate a motor within the handheld unit body 4903, which rotates gears within the handheld unit body 4903 based on the direction the user orients the switch.

[0089] The switch 4904 can be used to adjust the focus of the binocular OCT device 4900. For example, because the focus change caused by the adjustment of the lenses 4916-1 and 4916-2 can be measured in customary units of refractive power (e.g., diopters) by adjusting the lenses 4916-1 and 4916-2. The diopter switch 4906 may also include a direction switch that activates a motor in the handheld unit body 4903 to rotate a gear in the handheld unit body 4903 based on the direction in which the medical practitioner orients the switch, adjusting the refractive power of the binocular OCT device 4900. Because the binocular OCT device 4900 may include an electronic device, the binocular OCT device 4900 may include a power switch 4906 for controlling the power supply of the binocular OCT device 4900.

[0090] Each of the eyecups 4901-1 and 4901-2 can be threadably mounted and coupled to the housing to allow adjustment of the eye position during measurement. Research related to the present disclosure suggests that the eyecups can be adjusted by a medical professional and locked into place to allow for sufficiently reproducible positioning of the eye for AL measurements as described herein. Alternatively, or in combination, an eye position sensor such as a Purkinje image sensor can be used to determine the distance from the eye to the OCT measurement system.

[0091] The binocular OCT device 4900 may have suitable dimensions and weights for in-home measurements and for a user to take the binocular OCT system on a trip. For example, the binocular OCT system may have a suitable length, a suitable width, and a suitable height. The length may extend along an axis corresponding to a user viewing direction. The length may be in a range of about 90 mm to about 150 mm, for example, about 130 mm. The width may extend laterally relative to the length and may be in a range of about 90 mm to about 150 mm, for example, about 130 mm. The height may be in a range of about 20 mm to about 50 mm. In some embodiments, the length is in a range of about 110 mm to about 210 mm, the width is in a range of about 100 mm to about 200 mm, and the height is in a range of about 50 mm to about 110 mm. In some embodiments, the maximum distance across the device is in a range of about 200 mm to about 350 mm, for example, about 300 mm.

[0092] The weight of the binocular OCT system can be in the range of about 1 pound to 2 pounds, for example, 0.5 kg to about 1 kg.

[0093] The binocular OCT device 4900 can be configured to be dropped and still function properly. For example, the binocular OCT device can be configured to be dropped from a height of about 30 cm and still function to perform accurate AL measurements, e.g., with changes in measured AL less than or equal to the repeatability of the measurements. The binocular OCT system can be configured to be dropped from a height of about 1 meter, e.g., without posing a safety hazard from glass breakage.

[0094] 5 shows a block diagram of a binocular OCT device 4900 illustrating various components within a handheld unit body 4903 according to some embodiments. For example, the binocular OCT device 4900 includes free space optics 4910-1 and 4910-2. Each of the free space optics 4910-1 and 4910-2 includes a fixation target 4912 for its respective eye that allows the user to fixate / gaze on the target while the user's AL is being measured, allowing fixation with the other eye to provide binocular fixation. The fixation target may include an aperture (e.g., a circular aperture to form a disk-shaped illumination target) that is back-illuminated using a light source such as an LED, although a cross or other suitable fixation stimulus may also be used. The free space optics 4910-1 and 4910-2 may also include refractive error (RE) correction modules 4911-1 and 4911-2, respectively, which include lenses 4916-1 and 4916-2. These lenses can be moved to preprogrammed positions corresponding to the refractive error of the appropriate eye. Peripheral boards 4915-1 and 4915-2 in the free space optics modules 4910-1 and 4910-2 provide electronic control to motorized stages 4914-1 and 4914-2, respectively, to correct the refractive error of each eye viewing the fixation target of the binocular OCT device 4900.

[0095] As discussed herein, the binocular OCT device 4900 may include eyecups 4901-1 and 4901-2 that may be used to comfortably position the binocular OCT device 4900 on a user's face. They may also be configured to block external light when a user gazes into the binocular OCT device 4900. The eyecup 4901 may include eyecup adjustment mechanisms 4980-1 and 4980-2 that allow a healthcare professional, and optionally a user, to move the eyecups 4901-1 and 4901-2 back and forth relative to the handheld unit body 4903 to comfortably position the eyecups on the user's face and properly position each eye for measurement.

[0096] In some embodiments, the binocular OCT device 4900 comprises a fiber interferometer module 4950 comprising a single VCSEL or a plurality of VCSELs 4952. One or more VCSELs 4952 are optically coupled to a fiber distribution module 4953, which is optically coupled to a fiber Mach-Zehnder interferometer 4951. In embodiments comprising a plurality of VCSELs 4952, each of the VCSELs may comprise a different range of wavelengths than the other VCSELs 4952 in the plurality to extend the spectral range of light. For example, each VCSEL 4952 may pulse laser light that is swept over a range of wavelengths for a duration as described herein. The sweep range of each VCSEL 4952 may overlap an adjacent sweep range of another VCSEL 4952 in the plurality as described herein. Thus, the overall sweep range of wavelengths of the plurality of VCSELs 4952 may be extended to a larger wavelength sweep range. In addition, the emission of laser light from the plurality of VCSELs 4952 may be continuous. For example, a first VCSEL of the plurality of VCSELs 4952 may sweep a laser pulse across a first wavelength for a duration, then a second VCSEL of the plurality of VCSELs 4952 sweeps a laser pulse across a second wavelength for a similar duration, then a third VCSEL, etc.

[0097] The laser light from the one or more VCSELs 4952 is optically transmitted to a fiber distribution module 4953 where a portion of the laser light is optically transmitted to a fiber connector 4960 for analysis in the main electronics board 4970. The fiber connector 4960 may connect multiple optical fibers from the fiber distribution module 4953 to the fiber connector module 4960. Another portion of the laser light is optically transmitted to an optical path distance correction (OPD) module 4940 and ultimately transmitted to the free space optics 4910-1 for delivery to the user's eye and measurement of the user's eye with a portion of the measurement arm of the Mach-Zehnder interferometer. For example, the OPD correction module 4940 may include a peripheral board 4943 controlled by the main electronics board 4970 to actuate a motorized stage 4942 to vary the optical path distance between the user's eye, a coupler of the Mach-Zehnder interferometer, and the one or more VCSELs 4952. The OPD correction module 4940 may also include a fiber collimator 4941 that collimates the laser light from the VCSEL 4952 before delivery to the user's eye, and the fiber collimator can be translated using the OPD correction module 4940.

[0098] A controller interface 4930 may be used to receive user input and control the binocular OCT measurement system. The controller interface may comprise a first controller interface 4930-1 and a second controller interface 4930-2. The controller interface 4930 may comprise a trigger button mechanism that allows a user to initiate a series of steps to align the eye and measure the retina as described herein. Alternatively, or in combination, the device may be configured with an auto-capture feature such that data is automatically acquired once the device is aligned to the eye within appropriate tolerances.

[0099] In an embodiment, the binocular OCT device 4900 includes a scanner module 4990 that scans laser light from one or more VCSELs 4952 in a pattern (e.g., a stop-and-go scan pattern, a star scan pattern, a continuous scan pattern, a Lissajous scan pattern, or a flower scan pattern (rose curve)). For example, a peripheral board 4991 of the scanner module 4990 may be communicatively coupled to the main electronics board 4970, the peripheral board 4991 receiving control signals that instruct the scanner module 4992 to scan pulsed laser light from the VCSELs 4952 in a pattern to perform optical coherence tomography (OCT) measurements on the user's eye. The scanning module 4990 may include a sealing window 4992 that receives the laser light from the fiber collimator 4941 and optically transmits the laser light to a free-space two-dimensional scanner 4993, which provides the scanning pattern of the laser light. The two-dimensional scanner may comprise a scanner as described herein, such as, for example, a two-axis galvanometer or a two-axis electrostatic scanner. When present, a sealing window 4992 may be used to keep the internal components of the binocular OCT device 4900 free of dust and / or moisture. The laser light is then optically transmitted to relay optics 4994 such that the scanning laser light may be input to the user's eye by free-space RT optics 4910-1. In this regard, the scanning laser light may be transmitted to a hot mirror 4913 such that the infrared light may be reflected back towards the hot mirror, the scanning mirror, and focused into an optical fiber tip that is coupled to a collimation lens. The hot mirror 4913 generally transmits visible light and reflects infrared light, and the hot mirror 4913 may comprise, for example, a dichroic short-pass mirror.

[0100] The scanner and associated optics can be configured to scan any suitably sized region of the retina, such as the region comprising the fovea. In some embodiments, the scanner and associated optics are configured to scan the cornea while the retina is scanned. In some embodiments, the scanner is configured to scan the retina with a scan pattern, such as a predefined scan pattern, in response to instructions stored on a processor, such as a controller. For example, the scanner can be configured to scan the retina over an area having a maximum dimension, for example, in the range of about 0.05 to 2.0 mm. The maximum diameter can comprise a diameter and can be in the range of about 0.1 mm to about 1.5 mm. The dimensions of the corneal scan can be similar. The scanned region of the retina can comprise an area larger than the map of the AL, for example, to account for slight errors in alignment of up to 0.5 mm in the lateral positioning of the eye relative to the OCT system, for example, to compensate for alignment errors, for example, by aligning the map based on the measured position of the eye. The size of the OCT measurement beam on the retina can be in the range of about 25 microns to about 75 microns. In some embodiments, the mirror is moved with a continuous trajectory corresponding to a scan rate on the retina in the range of about 10 mm per second to about 200 mm per second, and the scan rate can be in the range of about 50 mm per second to about 200 mm per second. The displacement of the beam during the A-scan can be, for example, in the range of about 2 to 10 microns. The beams of each of the multiple A-scans can overlap. In some embodiments, the mirror moves continuously with one or more revolutions corresponding to the trajectory of the scan pattern, and the swept source VCSEL is turned on and off at a suitable frequency related to the size of the beam and the speed of the beam on the retina. In some embodiments, each of the multiple A-scans overlaps on the retina during at least a portion of the scan pattern.

[0101] In embodiments where the one or more VCSELs comprise multiple VCSELs, the multiple VCSELs can be scanned sequentially for each A-scan such that a measurement beam from each of the multiple VCSELs overlaps with a previous scan on the retina, and the cornea can be scanned similarly. For example, each of the sequentially generated beams from each of the multiple VCSELs from a first A-scan can overlap with each of the sequentially generated beams from each of the multiple VCSELs from a second A-scan along the trajectory.

[0102] As described herein, the binocular OCT device 4900 may include IPD adjustment by components 4905-1 and / or 4905-2. These components may be communicatively coupled to a manual translation stage IP adjustment module 4982, which effects actuation of free space optics modules 4910-1 and 4910-2 to change the separation distance between the free space optics modules and adjust the IPD.

[0103] The main electronics board 4970 may comprise various components. For example, a photodetector 4972 may be used to receive the laser light directed from the VCSEL 4952 through a fiber connector 4960 and the interference light reflected from the user's eye. The fiber connector 4960 may comprise a module 4961 that couples multiple optical fibers, for example, four optical fibers, to multiple detectors (e.g., five detectors). The fiber connector 4960 may also comprise an interferometer clock box 4962 (e.g., an etalon) that may be used in phase wrapping the light reflected back from the user's eye as shown and described herein. Once received by the photodetector 4972, the photodetector 4972 may convert the light into an electronic signal to be processed on the main electronics board 4970 and / or another processing device. The multiple photodetectors may comprise, for example, two detectors of a balanced detector pair coupled to a fiber Mach-Zehnder interferometer, a clock box detector, and a pair of power measurement detectors.

[0104] The main electronics board 4970 may include a communications power module 4973 (e.g., a universal serial bus, or "USB") that may communicatively couple the binocular OCT device 4900 to another processing system, provide power to the binocular OCT device 4900, and / or charge a battery of the binocular OCT device 4900. Of course, the binocular OCT device 4900 may include other modules that may be used to communicate information from the binocular OCT device 4900 to another device, including, for example, Wi-Fi, Bluetooth, Ethernet, FireWire, etc.

[0105] The main electronics board 4970 may also include VCSEL drive electronics 4971 that dictate how and when the VCSEL 4952 is fired towards the user's eye. Other components on the main electronics board 4970 include an analog block 4974 and a digital block 4975, which may be used to process and / or generate analog and digital signals, respectively, that are transmitted to the binocular OCT device 4900 (e.g., from an external processing system), received from various components within the binocular OCT device 4900, and / or received from various components within the binocular OCT device 4900. For example, the peripheral feedback button 4932 may generate an analog signal that is processed by the analog block 4974 and / or the digital clock 4975, which may then generate a control signal used by the peripheral board 4943 to stimulate the motorized stage module 4942. Alternatively, or in addition, analog block 4974 may process analog signals from photodetector 4972 so that they may be converted to digital signals by digital block 4975 for subsequent digital signal processing (e.g., FFT, phase wrapping analysis, etc.).

[0106] FIG. 6 shows a schematic diagram of an optical configuration 5100 that may be implemented with a binocular OCT 4900 according to some embodiments. The optical configuration 5100 includes one or more VCSELs 4952 that are fiber coupled by an optical coupler 5126. As discussed above, the one or more VCSELs 4952 may be swept over a range of wavelengths when launched. For embodiments with multiple VCSELs 4952, the wavelength may overlap the wavelength sweep range of another VCSEL 4952 in the plurality to increase in the overall sweep range of the VCSELs 4952. In some cases, this overall sweep range is centered around 850 nm. The laser light from the one or more VCSELs 4952 is propagated through the fiber coupler 5126 to an optical fiber line 5127 where another optical coupler 5118 splits a portion of the optical energy from the one or more VCSELs 4952 along two different paths.

[0107] In the first path, about 95% of the optical energy is optically transmitted to another optical coupler 5119, and about 5% of the optical energy is optically transmitted to an optical coupler 5120. In the second path, the optical energy is split once more by the optical coupler 5120. In this regard, about 75% of the optical energy from the optical coupler 5120 is transmitted to the phase correction detector 5101-1 through an interferometer, such as a Fabry-Perot interferometer comprising an etalon. The etalon and detector may comprise components of an optical clock 5125. The optical clock 5125 may comprise, for example, a single etalon. The etalon may comprise a substantially parallel plane and be tilted with respect to the propagation direction of the laser beam. The surface may comprise a coated or uncoated surface. The material may comprise any suitable optically transparent material with a suitable thickness. For example, the etalon may have a thickness in the range of about 0.25 mm to about 5 mm, e.g., about 0.5 mm to about 4 mm. The reflectivity of the etalon surface may be in the range of about 3% to about 10%. The etalon may be tilted with respect to the laser beam propagation direction, e.g., at an angle in the range of about 5 degrees to about 12 degrees. The finesse of the etalon may be in the range of about 0.5 to about 2.0, e.g., about 0.5 to 1.0. The etalon may comprise any suitable material, such as optical glass. The etalon thickness, refractive index, reflectivity, and tilt angle may be configured to provide a substantially sinusoidal optical signal at the clock box detector. A finesse in the range of about 0.5 to 2.0 can provide a substantially sinusoidal detector signal that is well suited for phase compensation as described herein, although embodiments with higher finesse values ​​can be effectively utilized.

[0108] In some embodiments, the clock box may include multiple etalons. This approach may be useful in embodiments where one or more VCSELs include multiple VCSELs and multiple etalons provide additional phase and clock signal information. The clock box may include a first etalon and a second etalon arranged such that light is sequentially transmitted through the first etalon and then the second etalon (e.g., in a series configuration), which may provide frequency mixing of the clock box signal and reduce the number of detectors and associated circuitry used to measure the phase of the swept source. Alternatively, multiple etalons may be arranged in a parallel configuration with multiple etalons coupled to multiple detectors.

[0109] The phase correction detector 5101-1 may use an optical signal from the optical clock 5125 to correct the phase of the light reflected from the user's eye 5109-1 by matching the phase of the one or more VCSELs 4952 by phase wrapping the light from the one or more VCSELs 4952 as described herein. The remaining 25% of the optical energy from the optical combiner 5120 may be optically transmitted to the detector 5101-2 for optical safety. For example, the detector 5101-2 may be used to determine the amount of optical energy being transmitted to the user's eye 5109-1 or 5109-2 depending on the orientation of the device. If the binocular OCT device 4900 determines that the detector 5101-2 is receiving too much optical energy that may damage the user's eye, the binocular OCT device 4900 may operate as a "kill switch" that deactivates the one or more VCSELs 4952. Alternatively, or in addition, the binocular OCT device 4900 may monitor the detector 5101-2 and increase or decrease the optical energy from one or more VCSELs 4952 as deemed necessary for laser safety and / or signal processing. The OCT device may include a second safety detector 5101-3 to provide a redundant measurement for improved eye safety.

[0110] The optical energy transmitted to the optical combiner 5119 (e.g., about 95% of the optical energy from the one or more VCSELs 4952) is also split along two paths, with about 99% of the remaining optical energy optically transmitted along the fiber to the optical combining element 5122, and about 1% of the remaining optical energy optically transmitted to the detectors 5101-3 for laser safety of the binocular OCT device 4900. A portion of the optical energy transmitted to the optical combiner 5122 may be split by the optical combiner 5122 between the two optical path loops 5110 and 5111 of the Mach-Zehnder interferometer, for example, at about 50% each. The reference optical path loop 5110 comprises a portion of the reference arm of the interferometer and may provide a reference optical signal (e.g., a measurement signal reflected from the user's retina through the measurement optical path loop 5111) for one or more of an AL measurement, a corneal thickness measurement, or a retinal thickness measurement of the user's eye 5109-1.

[0111] In some embodiments, the reference arm comprises multiple reference arms of different distances and corresponding different optical path lengths. For example, the reference optical path may comprise multiple optical fibers to provide multiple different optical path lengths in a parallel optical configuration. Although a parallel configuration is referenced, one skilled in the art will understand that it refers to the coupled arrangement of the fibers and not necessarily the orientation along the length of the fibers, which may be arranged in any suitable non-parallel configuration, for example, with a loop. In some embodiments, the reference optical path loop 5110 comprises a portion of the first reference optical path with a first reference optical path length for measuring the location of the cornea of ​​the eye. The second reference optical path comprises a different reference length. The second reference optical path loop 6110 comprises a portion of the second reference optical path with a second reference optical path length for measuring the location of the retina of the eye. In some embodiments, the reference optical path is split into the first reference optical path using a coupler 6122 coupled to the first reference optical path loop 5110 and the second optical path loop 6110 to split the reference beam into a first reference beam and a second reference beam. The first and second reference beams may be combined with combiner 6121 to combine the first and second reference beams prior to being combined with the measurement beam using combiner 5121. Although reference is made to an optical fiber for splitting the reference beam, one skilled in the art will recognize that this may also be done using a beam splitter.

[0112] A portion of the optical energy transmitted through the optical loop 5111 is transmitted along the measurement arm of the Mach-Zehnder interferometer to the user's left eye 5109-1. For example, the optical energy being transmitted to the user's eye 5109-1 may pass through an OPD correction module 4940 to implement any optical path distance corrections to the interferometer appropriate for the binocular OCT device 4900. This light may then be scanned over the user's eye 5109-1 by a scanning mirror 5113 of the scanner module 4990 to measure the retinal thickness of the user's eye 5109-1 while the user's eye 5109-1 fixates (e.g., along a fixation path 5106-1) on a fixation target 4912-1.

[0113] Fixation target 4912-1 can be back-illuminated using LED 5102-1, and light can be propagated along optical path 5106-1 through dichroic mirror 5115, which includes optical elements 5103-1 and 5105-1 and a hot mirror. In some cases, the fixation target can also include an illumination stop 5104 to provide relief to the user's eye 5109-1 while fixating the target.

[0114] Light impinging on the user's cornea and retina of eye 5109-1 may be reflected back along a path established by OPD correction module 4940, scanning mirror 5113, focusing element 5114, dichroic mirror 5115, and optical element 4916-1, through optical loop 5111, and back to optical combiner 5122. In this case, optical combiner 5122 may optically transmit the reflected optical energy to optical combiner 5121, which may combine the optical energy reflected from the measurement arm with reference optical energy split into multiple reference optical paths along loops 5110 and 6110. Optical combiner 5121 may then optically transmit the optical energy to balanced detectors 5101-4 and 5101-5 so that axial length measurements may be performed. In an embodiment, the measurements include corneal thickness measurements and retinal thickness measurements. In performing measurements with balanced detectors, optical combiner 5121 may split the optical energy approximately 50% for each of detectors 5101-1 and 5101-4 such that the interference signals arrive out of phase on the balanced detectors.

[0115] The light may be focused through multiple optical elements 5112 and 5114, directed to the user's eye 5109-1 by a dichroic mirror 5115, and focused onto the user's retina by optical element 4916-1. Both the light from the scanning mirror 5113 and the light reflected from the user's eye 5109 are shown reflecting from a dichroic mirror 5115, which may generally comprise a hot mirror 4913 configured to reflect infrared light and transmit visible light.

[0116] As can be seen from this example, the user's right eye 5109-2 does not receive any optical energy from the one or more VCSELs 4972 in the orientation shown. Rather, the user's right eye 5109-2 is used for binocular fixation with a target 4912-2, which may be back-illuminated with another LED 5102-2. The target 4912-2 is similar in size and shape to the target 4912-1, and can be provided to the eye with similar optics to provide binocular fixation. In this regard, the user's right eye 5109-2 can also fixate the target 4912-2 along an optical path 5106-2 through optical elements 4916-2, 5105-2, 5103-2, and illumination stop 5104-2, which has similar refractive power, separation distance, and dimensions as the optics along optical path 5106-1.

[0117] The binocular OCT system 4900 can be configured to move the optical components to a customized configuration for the user being measured. The lens 4916-1 can be adjusted along the optical path 5106-1 according to the refraction, e.g., eyeglass prescription, of the eye being measured. The lens 4916-1 can be moved under computer, user, or other control to adjust the lens 4916-1 to focus on the fixation target 4912-1 and to focus the measurement beam of the OCT interferometer on the user's retina. For example, the lens can be translated as shown by arrow 5146. In one embodiment, lens 4916-1 comprises an objective lens (e.g., the lens along the optical path closest to the corresponding eye). Lens 4916-2 can be moved under computer, user, or other control to adjust lens 4916-2 and focus fixation target 4912-2 on the user's retina. For example, the lens can be translated as shown by arrow 5144. In one embodiment, lens 4916-2 comprises an objective lens (e.g., the lens along the optical path closest to the corresponding eye). OPD correction module 4940 can be translated axially toward and away from mirror 5113 as shown by arrow 5146. OPD correction module 4940 can be moved under computer control to properly position the optical path difference between the measurement arm and the reference arm for the user's eye being measured. The interpupillary distance can be adjusted by translating optical path 5106-2 toward and away from optical path 5106-1.

[0118] The free space optics module 4910-2 may include one or more components along the optical path 5106-2, such as LED 5101-2, fixation target 4912-2, lens 5103-2, aperture 5104-2, lens 5105-2, or lens 4916-2. The free space optics module 4910-2 may be translated laterally toward and away from optical components located along the optical path 5106-1 to adjust the interpupillary distance, as indicated by arrow 5142. The free space retinal thickness optics module 4910-1 may include one or more components along the optical path 5106-1, such as LED 5102-1, fixation target 5103-1, aperture 5104-1, mirror 5116, lens 5105-1, mirror 5115, or lens 4916-1. The OPD correction module 5146 may include an optical fiber in the measurement arm of the interferometer and a lens 5112 for substantially collimating light from the optical fiber and focusing light from the retina into the optical fiber.

[0119] FIG. 7 shows a block diagram of an optical configuration 5100 configured on an optical layout substrate 5150 according to some embodiments. For example, a binocular OCT device 4900 may be configured with multiple layers extending generally along a plane, each of which may be configured to perform a specific function. In this case, the optical layout substrate 5150 provides support for the optical configuration 5100, which may be used to reduce vibration of the optical components. The optical substrate 5150 may include multiple components that are enclosed within a housing of a fiber optic module as described herein. The multiple components that are enclosed within the housing 5153 and supported on the substrate may include one or more of a coupler 5118, a coupler 5119, a coupler 5120, a coupler 5121, a coupler 5122, a reference arm comprising an optical fiber 5110, and any combination thereof. One or more VCSELs 4952 may be enclosed within the housing. A number of optical fibers extending from the coupler 5120 may extend through the housing to appropriate detectors, for example coupled to the clock box detector 5101-1 and the safety detector 5101-2. The optical fiber extending from the coupler 5119 may be coupled to a second safety detector 5101-3 and extend through the housing 5153. A second optical fiber extending from the coupler 5119 may be coupled to an interferometer to measure the sample using an optical coupler 5122. The optical fiber portion of the sample measurement arm may extend from the coupler 5122, for example, through the housing 5153 to the optical path difference correction module 4940.

[0120] The printed circuit board may provide a support layer extending along the electronics side, where several processing devices (e.g., main electronics board 4970 including drive electronics 4971) may be coupled to an optical layout board 5150 through cables 5151 which connect to connectors 5152 configured on the optical layout board 5150 to drive one or more VCSELs 4952.

[0121] 8 shows a perspective view of a modular embodiment of a binocular OCT 4900 according to some embodiments. For example, the main electronics board 4970 of the binocular OCT 4900 may be implemented as a printed circuit board (PCB) 5160 mounted to a housing 4953 that encapsulates the optical components on the optical layout board 5150. The PCB 5160 may provide power and electronics and control the optical configuration 5100 of the optical layout board 5150. The PCB 5160 may also include or be communicatively coupled to the peripheral boards 4932-1, 4932-2, 4943, 4914-1, and 4914-2. The binocular OCT device 4900 may also include a free space optics module mounted on the optical layout board 5150 and communicatively coupled to the main electronics board 4970. The free space optics modules mounted on the optics substrate may comprise one or more of module 4910-1, module 4910-2, or OPD correction module 4940 as described herein. The free space module 4910-2 can be configured to move with respect to the optical layout substrate 5150 to adjust the interpupillary distance. The OPD correction module can be configured to move with respect to the optical layout substrate 5150.

[0122] The interferometer module 4950 may include an optical fiber coupler as described herein and one or more VCSELs 4952. The main electronics board 4970 or one of the peripheral boards may include electronics to drive the VCSELs 4952. The one or more VCSELs 4952, optically coupled to optical fibers on the optical layout board 5150, propagate laser light to the optical fibers on the optical layout board 5150. Laser light reflected from the user's eye 4910-1 may propagate to the PCB 5160, where a photodetector 4972 detects the reflected laser light and converts the light to an electrical analog signal for processing by the analog block 4974.

[0123] In some embodiments, the optical layout substrate 5150 provides damping to the binocular OCT 4900. For example, if the binocular OCT 4900 were to be dropped, the damping mechanism configured in the optical layout substrate 5150 can compensate for any vibration effects on the impact of the binocular OCT 4900 and protect its components (e.g., the optical layout substrate 5150, the PCB 5160, the interferometer module 4950, and the respective components). The mounting plate 5150 can include a similar damping mechanism.

[0124] 9 shows a perspective / cutaway internal view of a binocular OCT 4900 according to some embodiments. In this view, the optical layout board 5150, PCB 5160, and interferometer module 4950 are mechanically coupled together in a compact form configured within the housing 4903 of the binocular OCT 4900. As can be seen from this view, fixation targets 4912-1 and 4912-2 (e.g., LED lights) are visible to a user through lenses 4916-1 and 4916-2, respectively, when the user places the binocular OCT 4900 close to the user's eyes. The laser light from the VCSEL propagates along part of the same optical path as the fixation target 4912-1. Thus, when a user gazes at fixation targets 4912-1 and 4912-2, laser light from one or more VCSELs as described herein is operable to propagate through the user's eye and be reflected back to the optical layout substrate 5150 for subsequent processing to determine the user's retinal thickness.

[0125] 10 shows another perspective / cutaway internal view of a binocular OCT device 4900 according to some embodiments. In this view, an optical layout substrate 5150 is illustrated showing the arrangement of one or more VCSELs 4952, fiber couplers 5126, detectors 5105-1-5105-5, a Fabry-Perot optical clock 5125, and optical couplers 5118-5122. The optical layout substrate 5150 may also include a splice 5170.

[0126] FIG. 11 illustrates a binocular OCT system 4900 including an eye position sensor according to some embodiments. FIG. 11 illustrates an overhead / cutaway internal view of a binocular OCT 4900 including an eye position sensor 5610 according to some embodiments. The eye position sensor 5610 may include one or more of an array sensor, a linear array sensor, a one-dimensional array sensor, a two-dimensional array sensor, a complementary metal oxide semiconductor (CMOS) two-dimensional array sensor, a quadrant detector, or a position-sensitive detector. The eye position sensor 5610 can be combined with a lens to form an image of the eye on the sensor, such as a Purkinje image from reflection of light from the cornea of ​​the eye. The eye position sensor can be incorporated into any of the embodiments disclosed herein, such as the binocular OCT system described with reference to FIG. 41B-10.

[0127] In the illustrated view, optical configuration 5100 is mounted on an optical layout substrate 5150 above optical fiber couplings (e.g., fiber loops 5110 and 5111 in FIG. 6) and optical couplers 5118-5122, and other fiber components as described herein. Thus, one or more free space optical components as described herein can be optically coupled to the fiber components below them.

[0128] As shown, the free space optics modules 4910-1 and 4910-2 are generally aligned with the user's eyes 5109-1 and 5109-2, respectively. The distance between the free space optics modules 4910-1 and 4910-2 may be adjusted according to the user's IPD, as described herein. In some embodiments, this adjustment is maintained for the user while the binocular OCT 4900 is held by the user. For example, the user may be a patient who uses the binocular OCT 4900 for home use over a period of time. To ensure that correct axial length, corneal thickness, and retinal thickness measurements are performed while held by the user, the binocular OCT 4900 may prevent the user from adjusting the IPD. Similarly, the binocular OCT 4900 may also prevent the user from adjusting the OPD via the OPD correction module 4940.

[0129] As can be seen from this diagram (FIG. 11), fixation targets 4912-1 and 4912-2 (e.g., LED light targets) pass through various optical elements of their respective free space optics modules 4910-1 and 4910-2. OPD correction module 4940 receives laser light from one or more VCSELs 4952 as described herein and directs the light towards scanning mirror 4990. Light from scanning mirror 4990 passes through a lens and is reflected by dichroic mirror 5115 through lens 4916-1 to the user's eye 5109-1.

[0130] In some embodiments, the OCT measurement beam remains substantially fixed relative to the position sensor at each of a plurality of positions of the fixation target.

[0131] In some embodiments, the axial length map comprises multiple regions corresponding to multiple locations of the fixation target.

[0132] In some embodiments, the axis length map comprises between 5 and 20 regions and the multiple locations of the fixation target comprise between 5 and 20 regions.

[0133] In some embodiments, the OCT system includes a scanner for scanning the OCT beam to a plurality of locations of the patient's retina for each of a plurality of fixation target locations, for example, the scanner can be configured to scan an area of ​​the retina at a plurality of retinal locations for each of a plurality of fixation target locations, where the area of ​​the cornea and retina scanned at each of the plurality of fixation target locations is less than an area of ​​one or more of the axial length map, the retinal image, or the corneal image.

[0134] In some embodiments, the OCT measurement beam is transmitted to a scanning mirror mounted on a piezoelectric drive motor to compensate for the optical path distance. For example, a hot mirror configured to reflect and transmit the OCT measurement beam to a fixation target can be configured to translate to adjust the optical path difference while the position of the XYZ translation stage remains substantially fixed. In some embodiments, the translation of the mirror reflects the OCT measurement beam and adjusts the OPD while the path of the transmitted light remains substantially unaltered, such as the path of the light from the fixation target, and optionally the light transmitted through the mirror to the position sensor.

[0135] In some embodiments, the OCT beam is routed through a micromirror / microlens assembly where both the direction and OPD can be adjusted. In some embodiments, the beam radius can also be varied. The micro-optics assembly can be mounted on a set of linear drives including piezoelectric drives with sub-micron resolution. Such drives are commercially available from DTI motors, as described on the internet at dtimotors.com.

[0136] Such a system may rely on reduced driving forces, and according to some embodiments a driving force of 1 N may be sufficient.

[0137] In some embodiments, the driving force is in the range of 0.5 Newtons (N) to 2.5 N, and the resolution does not exceed 0.5 microns. In some embodiments, the response time is 1 mm per 0.1 seconds or faster. The lens assembly can be controlled with a processor, such as a microcontroller or FPGA, to increase the signal-to-noise ratio, as described herein. In some embodiments, the lens assembly is configured to dither the OCT measurement beam on the retina.

[0138] As described, the disclosed OCT system includes a scanner that can be controlled to move a measurement beam in a scan pattern over the patient's cornea and retina. The scan pattern can be one of a variety of types, including a stop-and-go scan pattern, a star scan pattern, a continuous scan pattern, a Lissajous scan pattern, or a flower pattern (sometimes referred to as a rose curve). The flower pattern or rose curve can be used to generate measurement data that can be processed to generate data representative of data that would be obtained from a different scan pattern. Additionally, the flower pattern or rose curve can be used to generate measurement data that can be processed to generate interferometric data that improves the ability to detect fluid or pockets of fluid in areas of the retina.

[0139] FIG. 12 illustrates an OCT device 4900 with multiple reference arms, e.g., two reference arms, according to some embodiments. The OCT device includes a light source, such as one or more VCSELs 4952. The light source may include any suitable light source, such as a broadband source, a superluminescent diode (SLD), a single VCSEL, a MEMS-based VCSEL, multiple VCSELs, multiple VCSELs without MEMS mirrors where the wavelength is swept using overdrive of the VCSELs, an array of VCSELs, or an array of MEMS VCSELs. The OCT device may include multiple reference optical paths, such as a first reference optical path in a first reference arm for measuring the position of the cornea, and a second reference optical path in a second reference arm for measuring the position of the retina. The first reference optical path may include a first loop 5110 along the first reference optical path and a second loop 6110 along the second reference optical path, as described herein. The OCT system may include multiple couplers for coupling optical fibers, as described herein. The first and second reference optical paths allow for simultaneous measurement of the retina and cornea positions as described herein. A measurement optical path 1210 along the measurement arm of the OCT system may include a measurement optical path loop 1211. A portion of the measurement path 1210 that extends into the eye may include a measurement beam 1212.

[0140] The light from the reference path 1220 and the measurement path 1210 can be combined in many ways. In some embodiments, a combiner 6122 splits the reference optical path into a first reference optical path and a second reference optical path, and a combiner 6121 combines the two reference optical paths. As described herein, a combiner 5121 combines the reference optical path and the measurement optical path, and multiple combiners extend from the combiner 5121 to the balanced detectors 5104-4 and 5104-5.

[0141] In some embodiments, the OCT device is configured to measure the axial length at one location along the eye, for example, with a single OCT measurement beam configured to scan the eye without moving a scanning mirror. Alternatively, the OCT system can be configured to scan the measurement beam along the eye, as described herein.

[0142] In some embodiments, the OCT system is configured to measure the axial length of the eye using a plurality of optical fibers arranged in a substantially fixed configuration. Each of the plurality of optical fibers can be configured to scan a first location of the cornea and a second location of the retina. For example, the OCT device 4900 can include a plurality of light sources, interferometers, and detectors in which the configuration shown in FIG. 12 is replicated for each of the plurality of measurement beams. In some embodiments, the one or more light sources 4952 include an array of VCSELs coupled to a plurality of optical fibers, couplers, and detectors, each of which is similar to the configuration of FIG. 12.

[0143] FIG. 13A shows signal strength and frequency for an OCT device with two signals received simultaneously using one or more detectors, e.g., a balanced pair, according to some embodiments. In some embodiments, the frequency of the interference signal is related to the optical path difference between the reference arm and the sample location along the measurement arm. In some embodiments, the zero optical path difference location is set at a suitable position between the cornea and the lens to generate two different frequency bands for the cornea and the lens. By positioning the zero optical path difference location such that the distance to the cornea and the distance to the retina are different, two different distributions of frequencies can be obtained, for example, with a single reference arm optical path. By positioning the zero optical path difference location closer to the cornea and further away from the retina, the two distributions of frequencies will comprise a first lower frequency corresponding to the location of the cornea at a first location along the measurement optical path, and a second higher frequency corresponding to the location of the retina at a second location along the measurement optical path. In some embodiments, the first peak 1310 can occur for a first distribution of frequencies corresponding to a first optical path difference along the sample measurement arm, e.g., a corneal frequency, and the second peak 1320 can occur for a second distribution of frequencies corresponding to a second optical path difference along the sample measurement arm, e.g., a retinal frequency. Alternatively, the optical path difference for the cornea can be greater than the retina, such that the corneal frequency is greater than the retinal frequency. These signals can be generated using an OCT system that includes a single reference arm or multiple reference arms, as described herein, e.g., with reference to FIGS. 6 and 12. In some embodiments, the optical path differences for the cornea and retina are sufficiently different to provide a separation between the distribution of frequencies of the first peak 1310 and the distribution of frequencies of the second peak 1320. In some embodiments, the first reference fiber comprises a first length configured to provide a first measurement frequency for the cornea, and the second reference optical fiber comprises a second length configured to provide a second measurement frequency for the retina, where the first frequency is resolvable from the second frequency.

[0144] 13B shows the signal frequency spread 1330 of a single frequency distribution due to chirp of the swept source. In some embodiments, the swept source VCSEL is driven with a nonlinear current ramp to narrow the distribution of frequencies 1330 towards an ideal distribution 1340 having a narrower distribution of frequencies. This approach is well suited for use with VCSELs that rely on heat buildup from overdriving current into the VCSEL to sweep the wavelength of the VCSEL.

[0145] In some embodiments, the reference arms have different polarizations to separate the signals, which has the advantage of reducing interference between the reference signals.

[0146] In some embodiments, one or more lenses, e.g., the objective lens closest to the eye, is equipped with a bifocal configuration to focus light simultaneously onto the retina and cornea to increase the optical signal.

[0147] FIG. 14 illustrates the measurement depth of an axial length monitor according to some embodiments. In some embodiments, the axial length monitor has a measurement depth that exceeds that utilized for retinal measurements. In some embodiments that measure retinal thickness, the measurement depth is in the range of about 8-10 mm. The axial length monitor can be configured to measure a suitable distance corresponding to the axial length of the eye, which may correspond to a range of about 29 mm to about 34 mm in air. The coherence length of the light source can be sufficiently long to provide interference of the light source as described herein. In some embodiments, the location of the zero optical path difference 1430 is located between the cornea and the retina, e.g., between the lens and the retina, when the eye is aligned with the OCT measurement system to simultaneously measure the cornea and the retina. In some embodiments, the measurement beam 1212 is focused to a waist near the zero OPD location, e.g., within about 1 mm of the zero OPD location. Alternatively, a bifocal lens can be used to focus the measurement beam on the retina and cornea. A first distance 1410 between the zero optical path difference 1430 and the cornea is measured, and a second distance 1420 between the zero optical path difference ("OPD") between the cornea and the retina is measured simultaneously in response to the generated frequency. This approach has the benefit of reducing the measurement depth used to perform the measurement, for example, by reducing the coherence length and the number of sampling points used for each A-scan wavelength sweep of the measurement beam. In some embodiments, the first distance 1410 and the second distance 1420 correspond to non-overlapping mirrored interference terms that appear in the image at different distances that correspond to distances from the zero OPD position of both the corneal surface and the retinal surface. In some embodiments, the non-overlapping mirrored interference terms allow each A-scan to be acquired using fewer sampling points compared to non-mirrored interference terms.

[0148] In some embodiments, the reference optical paths are adjusted to set a first zero OPD for the first reference optical path at a first location corresponding to a first frequency from the cornea and a second zero OPD for the second reference optical path at a second location corresponding to a second frequency from the retina, the first frequency being different from the second frequency to be resolved separately. The combined, simultaneously generated signals can be separated based on the frequency of the corresponding reference optical path difference as described herein. This approach reduces the sampling and coherence length of the OCT system and can measure the position of the cornea and retina simultaneously.

[0149] In some embodiments, the characteristics of the interference signal from the cornea are different from the characteristics of the interference signal from the retina, and the difference in these characteristics can be used to determine the frequencies corresponding to the cornea and the frequencies corresponding to the retina. These characteristics may comprise, for example, one or more of the sharpness of the peaks in the distribution of interference signal intensity or frequency. In some embodiments, the anterior surface of the cornea provides an interference signal with sharper peaks in the distribution of intensity and frequency that are stronger than, for example, the distribution of intensity and frequency from the surface of the retina.

[0150] The measurement beam 1212 can be focused in any suitable manner to measure the cornea and retina and provide measurement signals from the cornea and retina. For example, the measurement beam can be focused between the cornea and the retina. Alternatively, or in combination, the measurement beam can be focused using a variable lens that changes the focus of the measurement beam between the cornea and the retina, (e.g., using sequential activation of the lens to a first configuration for focusing the measurement beam on the cornea and a second configuration for focusing the measurement beam on the retina). A multifocal lens, such as a bifocal lens or a diffractive lens, can be used to focus the beam simultaneously on the cornea and the retina. In some embodiments, the lens focuses the measurement beam simultaneously on the cornea and the retina, and the reference arm includes multiple reference paths as described herein.

[0151] (Physical measurement considerations) a. Measurement depth in swept-source OCT relates to the following aspects: i. the coherence length of the light source; ii. Sampling points per wavelength sweep range, and b. For retinal thickness measurement systems, (ii) may be a limiting factor.

[0152] (Methods for increasing measurement depth) a. Increasing the sampling points per wavelength sweep range is by: i. Increasing the sampling rate (at a constant wavelength sweep rate), or ii. Decreasing the wavelength sweep rate (at constant sampling rate).

[0153] In some embodiments, the OCT system is configured to switch between measurement configurations to measure two or more of the following: axial length by measuring the distance between the corneal surface and the retinal surface; retinal thickness; or corneal thickness. In some embodiments, the processor comprises instructions to switch between axial length measurement, retinal thickness measurement, and corneal thickness measurement. Tables 2 and 3 describe measurement parameters that may be used for retinal thickness measurement or axial length measurement, and the processor can be configured to switch between these measurement configurations. Although reference is made to an OCT system that can switch between the configuration axial length and retinal thickness configuration, in some embodiments, the OCT measurement system is configured to measure axial length without being configured to switch to a retinal thickness measurement configuration.

[0154] Table 2 shows measurement parameters for retinal thickness measurement system configuration and axial length measurement system configuration. Although approximate parameters are shown in Tables 2 and 3, these values ​​can be reduced by 50% from the values ​​shown or increased by amounts of 100% or more to perform proper measurements. For example, Table 2 shows performing axial length measurements as described herein by increasing the sampling frequency from 20 MHz to 80 MHz and the number of sampling points per A-scan from 1,000 to about 4,000.

[0155] [Table 2]

[0156] Table 3 shows parameters that can be used to measure retinal thickness and measure axial length by using a reduced wavelength sweep rate. In some embodiments, each wavelength sweep corresponds to one A-scan measurement. The duration of the sweep can be increased according to the reduced sweep rate to increase the number of sampling points per A-scan. The A-scan repetition rate is reduced, but the number of A-scan sampling points increases proportionally for a fixed sampling frequency, e.g., 20 MHz. In some embodiments, the length measured along the optical path of the measurement beam, e.g., along the A-scan, is proportional to the number of sampling points per A-scan, such that the measured length of the A-scan along the measurement optical path increases proportionally.

[0157] [Table 3]

[0158] In some embodiments, the retinal location is detected by OCT measurements.

[0159] In some embodiments, the corneal position is detected by a position sensor, such as a first Purkinje reflectance measurement, as described herein.

[0160] Both measurements can be nearly simultaneous, eg, within 100 ms, to reduce measurement inaccuracies related to, eg, movement.

[0161] FIG. 15 illustrates a fixation target 1500 configured to change color in response to user alignment to provide feedback to a user according to some embodiments. The fixation target 1500 comprises an outer region, such as a ring 1510, for indicating coarse alignment, and an inner region, such as a central dot 1520, for indicating fine alignment. The outer region may comprise a first color, e.g., red, when the eye is not coarsely aligned with the measurement system, and a second color, e.g., green, when the eye is coarsely aligned with the measurement system. Alignment of the eye with the measurement system can be measured in many ways, e.g., by measuring the position of the eye, as described herein. The fixation target 1500 may comprise a first configuration 1500-1, in which the outer region comprises the ring 1510 and the inner region comprises the central dot 1520, each comprising a first color, such as red, for indicating the absence of any coarse alignment or any fine alignment. The fixation target 1500 may comprise a second configuration 1500-2 for indicating coarse alignment and for indicating the absence of any fine alignment. In the second configuration, the outer region may have a second color, such as green, to indicate coarse alignment, and the inner region may have a first color, such as red, to indicate the absence of fine alignment. A third configuration 1500-3 of the fixation target 1500 may indicate that the coarse alignment and fine alignment conditions are met. In the third configuration, the outer region and the inner region each have a second color, for example, green. The user may self-align with the system in response to the color of the fixation target. In some embodiments, once the user is aligned with the OCT measurement system as shown with the third configuration 1500-3, the OCT system will automatically measure the axial length of the eye as described herein.

[0162] The fixation target can also be used to provide device status information to the user, for example, by providing a blink or other color. Alternatively, or in combination, the OCT system may include one or more external indicator lights for providing device status information. Battery status information indicated by the one or more external indicator lights may include one or more of battery status, alignment status, or device status. Battery status information may include one or more of charged, currently charging, or low battery level. Alignment status provided by the one or more external lights may include unaligned, coarsely aligned, or finely aligned, similar to the fixation light. Device status provided by the one or more lights may include one or more of ready for use, successful acquisition, data processing, or error.

[0163] Although a fixation target is referenced to indicate alignment, other approaches such as one or more of a visual display, audio feedback, or audio acquisition may also be used.

[0164] FIG. 16 shows a system 1600 comprising a VCSEL array 1605 coupled to a plurality of optical fibers 1610 for measuring axial thickness at a plurality of corneal and retinal locations. The plurality of optical fibers 1610 are coupled to a second plurality of optical fibers 1630 with distal ends arranged in a pattern to measure the cornea and retina at a plurality of locations as described herein. The plurality of optical fibers 1630 comprise a portion of the measurement arm 1210. The distal ends of the optical fibers 1630 are directed toward one or more lenses 1670 that focus light from the ends of the optical fibers to a plurality of locations within the eye. In some embodiments, the plurality of corneal and retinal locations are measured without using a scanning mirror to scan the beam to a plurality of locations. Light from the retina is focused back into the end of the optical fiber through the lens 1670. The lens 1670 may comprise a monofocal lens, a variable lens, a multifocal lens, or a bifocal lens for focusing light between the cornea and the retina, on the retina, or on the cornea, as described herein.

[0165] The plurality of optical fibers 1610 are coupled to a plurality of measurement optical fibers 1630 using a plurality of couplers 1620. The plurality of couplers 1620 receive light from the VCSEL array 1605 and split the light from the VCSEL array into a measurement path optical fiber 1630 and a reference path optical fiber 1640. The reference path comprises a plurality of reference path optical fibers 1645, which may comprise a plurality of split reference paths as described herein, each split reference path comprising a first distance corresponding to the cornea and a second distance corresponding to the retina. The plurality of reference path optical fibers comprise a plurality of reference path output optical fibers 1647.

[0166] Light from the plurality of reference optical fibers and the plurality of measurement optical fibers are combined with a plurality of couplers 1650 and directed to a plurality of detectors 1660, such as a plurality of balanced detectors, as described herein. In some embodiments, the plurality of measurement path optical fibers comprises optical fibers 1635 extending from the plurality of couplers 1620 to the plurality of couplers 1650. Output light from the plurality of couplers 1650 comprises a plurality of interference signals resulting from the combination of light from the plurality of measurement path optical fibers 1635 and the plurality of reference path output optical fibers 1647. The light from the plurality of couplers 1650 directed to the plurality of detectors 1660 comprises an interference signal responsive to a sweep of the VCSEL wavelength, as described herein, and can be processed to determine the location of the cornea and retina.

[0167] The VCSEL array can be coupled to the optical fiber and the detector in any suitable manner to generate an interference signal. In some embodiments, the VCSEL array comprises one or more light sources 4952 as described herein. The one or more light sources 4952 can comprise an array of VCSELs comprising a first VCSEL 4952-1, a second VCSEL 4952-2, a third VCSEL 4952-3, up to an Nth VCSEL 4952-N. The plurality of optical fibers 1610 can comprise any suitable number of optical fibers, such as a first optical fiber 1610-1, a second optical fiber 1610-2, a third optical fiber 1610-3, up to an Nth optical fiber 1610-N, etc. The multiple couplers 1620 coupled to the multiple optical fibers 1610 may comprise any suitable number of couplers, such as a first coupler 1610-1, a second coupler 1610-2, a third coupler 1610-3, up to an Nth coupler 1610-N.

[0168] The measurement optical path 1210 can be configured in any suitable manner. In some embodiments, the measurement optical path 1210 includes a first measurement optical fiber 1630 with a plurality of connectors 1620 coupling the measurement optical fibers, and a second measurement optical fiber 1635. In some embodiments, the first measurement optical fiber includes a first optical fiber 1630-1, a second optical fiber 1630-2, a third optical fiber 1630-3, and up to Nth optical fiber 1630-N. The second plurality of measurement optical fibers 1635 includes optical fibers coupled to each of the measurement optical fibers 1630 with a plurality of couplers 1620. The plurality of couplers 1620 may include a first coupler 1620-1, a second coupler 1620-2, a third coupler 1620-3, and up to Nth couplers 1620-N.

[0169] As described herein, the number of elements up to N may comprise any suitable number, and N may comprise 10, 20, 50, 100, or 200 or more elements.

[0170] The plurality of reference path optical fibers 1645 and the plurality of couplers 1650 can be configured in any suitable manner according to the present disclosure. In some embodiments, the plurality of reference path optical fibers 1645 comprises 2N reference paths, e.g., N reference paths with a first distance and N reference paths with a second distance, e.g., when the reference paths comprise a first distance corresponding to the cornea and a second difference corresponding to the retina. Alternatively, the plurality of reference path optical fibers 1645 may comprise N optical fibers, e.g., the plurality of reference optical fibers 1640, and the plurality of output optical fibers 1647 comprise the plurality of reference path optical fibers 1640. In some embodiments, the plurality of couplers 1650 comprises N couplers, each of the plurality of couplers coupled to one of the plurality of output reference optical fibers 1647 and one of the plurality of measurement optical fibers 1635.

[0171] FIG. 17 illustrates a system 1700 including a VCSEL array 1605 imaged into the eye using one or more lenses 1670 after being combined with a reference beam, for example using a Mach-Zehnder configuration, and light received from the eye imaged onto a detector array using one or more lenses. Light from the VCSEL array 1605 is directed to one or more lenses 1730 that can substantially collimate the light from the multiple VCSELs. The light from the one or more lenses 1730 is directed to a beam splitter 1760. The beam splitter 1760 reflects a portion of the light along a reference optical path and transmits a second portion of the light along a measurement optical path. The beam splitter 1760 may comprise any suitable beam splitter, such as, for example, a partially reflective mirror or a polarizing beam splitter. A first portion of the light from the beam splitter 1760 is directed along the reference optical path to a mirror 1740. Light reflected from mirror 1740 is directed towards beam splitter 1740 and transmitted through beam splitter 1760 towards detector 1710, which may comprise, for example, an array detector such as a complementary metal oxide semiconductor (CMOS) array or a charge coupled device (CCD) array. In some embodiments, one or more lenses 1750 are located between beam splitter 1760 and mirror 1740.

[0172] A portion of the light transmitted through the beam splitter 1760 is directed along a measurement optical path toward a lens 1780 and the eye. The lens 1780 may comprise, for example, one or more of a variable focus lens, a multifocal lens, or a bifocal lens. The light transmitted through the mirror is imaged inside the eye and uses the refractive power of the eye and the lens 1780 to form an image of the VCSEL array 1605 within the eye.

[0173] Light returned from the retina is transmitted through lens 1780 and reflected off mirror 1760 towards lens 1720 and detector 1710. Light reflected from mirror 1760 is transmitted through lens 1720 to form an image of the light from the eye on the detector array. In some embodiments, an image of the detector array formed inside the eye is imaged onto detector array 1710 using lens 1720 such that an image of the VCSEL array is imaged onto the detector. As each of the VCSELs in the array varies in wavelength, the intensity of the corresponding image varies and is captured using detector 1710. Detector 1710 is coupled to a processor and intensity signals for each VCSEL are captured and processed as described herein.

[0174] As described herein, the computing devices and systems described and / or illustrated herein broadly represent any type or form of computing device or system capable of executing computer-readable instructions such as those contained within the modules described herein. In their most basic configurations, these computing devices may each comprise at least one memory device and at least one physical processor.

[0175] As used herein, the term "memory" or "memory device" generally refers to any type or form of volatile or non-volatile storage device or medium capable of storing data and / or computer-readable instructions. In one example, a memory device may store, load, and / or maintain one or more of the modules described herein. Examples of memory devices include, but are not limited to, random access memory (RAM), read-only memory (ROM), flash memory, hard disk drive (HDD), solid-state drive (SSD), optical disk drive, cache, any variation or combination of one or more thereof, or any other suitable storage memory.

[0176] Additionally, as used herein, the term "processor" or "physical processor" generally refers to a processing unit implemented by any type or form of hardware capable of interpreting and / or executing computer-readable instructions. In one example, a physical processor may access and / or modify one or more modules stored in a memory device described above. Examples of physical processors include, but are not limited to, a microprocessor, a microcontroller, a central processing unit (CPU), a field programmable gate array (FPGA) implementing a soft-core processor, an application specific integrated circuit (ASIC), one or more portions thereof, one or more variations or combinations thereof, or any other suitable physical processor. A processor may include, for example, a distributed processor system running parallel processors, or remote processors such as a server, and combinations thereof.

[0177] Although illustrated as separate elements, the method steps described and / or illustrated herein may represent parts of a single application. Additionally, in some embodiments, one or more of these steps may represent or correspond to one or more software applications or programs that, when executed by a computing device, may cause the computing device to perform one or more tasks, such as method steps.

[0178] In addition, one or more of the devices described herein may transform data, physical devices, and / or representations of physical devices from one form to another. Additionally or alternatively, one or more of the modules listed herein may transform a processor, volatile memory, non-volatile memory, and / or any other portion of a physical computing device from one form of computing device to another form of computing device by executing on the computing device, storing data on the computing device, and / or otherwise interacting with the computing device.

[0179] As used herein, the term "computer-readable medium" generally refers to any form of device, carrier, or medium capable of storing or carrying computer-readable instructions. Examples of computer-readable media include, but are not limited to, transmission type media such as carrier waves, non-transitory type media such as magnetic storage media (e.g., hard disk drives, tape drives, and floppy disks), optical storage media (e.g., compact discs (CDs), digital video discs (DVDs), and BLU-RAY discs), electronic storage media (e.g., solid state drives and flash media), and other distribution systems.

[0180] Those skilled in the art will recognize that any process or method disclosed herein can be modified in many ways. The process parameters and sequence of steps described and / or illustrated herein are given as examples only and can be varied as desired. For example, the steps illustrated and / or described herein may be shown or discussed in a particular order, but these steps do not necessarily have to be performed in the order illustrated or discussed.

[0181] The various exemplary methods described and / or illustrated herein may omit one or more of the steps described or illustrated herein or may include additional steps in addition to those disclosed. Furthermore, the steps of any method as disclosed herein can be combined with any one or more steps of any other method as disclosed herein.

[0182] As described herein, the processor may be configured to perform one or more steps of any of the methods disclosed herein. Alternatively, or in combination, the processor may be configured to combine one or more steps of one or more methods as disclosed herein.

[0183] Unless otherwise noted, as used in this specification and the claims, the terms "connected to" and "coupled to" (and their derivatives) shall be interpreted as allowing for both direct and indirect (i.e., via other elements or components) connections. Additionally, as used in this specification and the claims, the terms "a" or "an" shall be interpreted as meaning "at least one of." Finally, for ease of use, as used in this specification and the claims, the terms "including" and "having" (and their derivatives) are intended to be synonymous and have the same meaning as the word "comprising."

[0184] A processor as disclosed herein may be configured with instructions to perform any one or more steps of any method as disclosed herein.

[0185] It should be understood that the terms "first," "second," "third," etc. may be used herein to describe various layers, elements, components, regions, or sections without referring to any particular order or sequence of events. These terms are only used to distinguish one layer, element, component, region, or section from another layer, element, component, region, or section. A first layer, element, component, region, or section as described herein could be referred to as a second layer, element, component, region, or section without departing from the teachings of the present disclosure.

[0186] As used herein, the term "or" is used inclusively to refer to items in alternative and combination.

[0187] This disclosure includes the following numbered appendices:

[0188] Appendix 1. A method of measuring a change in refractive error of an eye, the method comprising: measuring a first axial length of the eye from a first area of ​​the retina at a first time to determine a first axial length of the eye, the first area having a first maximum diameter within a first range of about 0.05 mm to about 2 mm; and measuring a second axial length of the eye from a second area of ​​the retina at a second time to determine a second axial length of the eye at the second time, the second area having a second maximum diameter within a range of about 0.05 mm to about 2.0 mm; and wherein the change in refractive error corresponds to a difference between the first axial length and the second axial length.

[0189] Appendix 2. The method of appendix 1, wherein the first maximum diameter is within a range of about 0.1 mm to about 1.5 mm, and the second maximum diameter is within a range of about 0.1 mm to about 1.5 mm.

[0190] Addendum 3. The method of Addendum 1, wherein the first area is measured using a first plurality of A-scans of the OCT measurement beam and the second area is measured using a second plurality of A-scans of the OCT measurement beam.

[0191] Clause 4. The method of clause 3, wherein each of the first area and the second area is measured using a scanning OCT measurement beam.

[0192] Clause 5. The method of clause 4, wherein the scanning OCT measurement beam moves along a first trajectory to measure a first plurality of A-scans and moves along a second trajectory to measure a second plurality of A-scans.

[0193] Clause 6. The method of clause 3, wherein the first area is measured using a first plurality of fixed measurement beams and the second area is measured using a second plurality of fixed measurement beams.

[0194] Clause 7. The method of clause 6, wherein a first plurality of fixed measurement beams are arranged to generate a first plurality of A-scans, and a second plurality of fixed measurement beams are arranged to generate a second plurality of A-scans.

[0195] Appendix 8. The method of Appendix 3, wherein the first plurality of A-scans measure a first plurality of corneal locations distributed over a first corneal area, the second plurality of A-scans measure a second plurality of corneal locations distributed over a second corneal area, the first axial length corresponding to a difference between the first plurality of retinal locations and the first plurality of corneal locations, and the second axial length corresponding to a difference between the second plurality of retinal locations and the second plurality of corneal locations.

[0196] Appendix 9. The method of Appendix 8, wherein a first plurality of axial lengths are determined, and a second plurality of axial lengths are determined, the first plurality of axial lengths corresponding to a first difference between each of the first plurality of corneal locations and a corresponding retinal location, and the second plurality of axial lengths corresponding to a second difference between each of the second plurality of axial locations and a corresponding retinal location.

[0197] Clause 10. The method of clause 1, wherein the first area substantially overlaps with the second area, optionally, the substantial overlap comprising at least about 50% overlap between the first area and the second area.

[0198] Clause 11. The method of clause 1, wherein one or more of the first maximum diameter or the second maximum diameter comprises a diameter.

[0199] Clause 12. The method of clause 1, wherein one or more of the first section or the second section comprises an annular portion.

[0200] Addendum 13. The method of Addendum 1, wherein one or more of the first region or the second region comprises an area.

[0201] Addendum 14. The method of Addendum 1, wherein the first axial length comprises a first axial length map, the second axial length comprises a second axial length map, and the change in refractive error corresponds to a difference between the first axial length map and the second axial length map.

[0202] Clause 15. A system for measuring changes in refractive error of an eye, the system comprising a processor configured with instructions for implementing a method according to any one of the preceding clauses.

[0203] Addendum 16. The system of Addendum 15, further comprising: a swept source for generating an OCT beam and varying a wavelength of the OCT beam; and an interferometer coupled to the swept source, the interferometer comprising a measurement optical path and a reference optical path, the reference optical path comprising a first reference path and a second reference path, wherein the first axial length corresponds to a first difference between a first position of the cornea of ​​the eye measured using the first reference path at a first time and a first position of the cornea of ​​the eye measured using the second reference path, and the second axial length corresponds to a second difference between a second position of the cornea measured using the first reference path at a second time and a second position of the retina measured using the second reference path.

[0204] Addendum 17. The system of Addendum 16, further comprising a detector, the detector coupled to the interferometer to receive a first interference signal and a second interference signal, the first interference signal resulting from light from the first reference path interfering with light from the measurement optical path, and the second interference signal resulting from light from the second reference path interfering with light from the measurement optical path.

[0205] Clause 18. A system for measuring an axial length of an eye, the system comprising: a swept source for generating a light beam and varying a wavelength of the light beam; an interferometer coupled to the swept source, the interferometer comprising a measurement optical path and a reference optical path, the reference optical path comprising a first reference path and a second reference path; the interferometer; a detector, the detector coupled to the interferometer to receive a first interference signal and a second interference signal, the first interference signal resulting from light from the first reference path interfering with light from the measurement optical path and the second interference signal resulting from light from the second reference path interfering with light from the measurement optical path; and a processor coupled to the detector, the processor configured with instructions for determining an axial length of the eye in response to the first interference signal and the second interference signal.

[0206] Clause 19. The system of clause 18, wherein the first reference path comprises a first reference optical fiber and the second reference path comprises a second reference optical fiber.

[0207] Clause 20. The system of clause 19, wherein the first reference optical fiber has a first length and the second reference optical fiber has a second length different from the first length.

[0208] Clause 21. The system of clause 20, wherein the first length corresponds to a first distance to a cornea of ​​the eye, and the second length corresponds to a second distance to a retina of the eye, the first distance being less than the second distance.

[0209] Addendum 22. The system of Addendum 21, wherein the processor is configured to generate an A-scan for each of a plurality of sweeps of the swept source, the A-scan comprising a first peak corresponding to a first distance and a second peak corresponding to a second distance.

[0210] Addendum 23. The system of Addendum 22, wherein the first interference signal and the second interference signal are received together at the detector for each of a plurality of sweeps, and a transformation of the time-varying intensity data sampled at the detector for each of the plurality of sweeps produces a first peak corresponding to the first distance and a second peak corresponding to the second distance.

[0211] Clause 24. The system of clause 23, wherein the detector comprises a balanced detector.

[0212] Clause 25. The system of clause 22, wherein a single sweep of the swept source generates the first peak and the second peak.

[0213] Clause 26. The system of clause 21, wherein the swept source generates a first frequency and a second frequency at the detector, the first frequency corresponding to a first reference path length and the second frequency corresponding to a second reference path length, and the first frequency is less than the second frequency.

[0214] Clause 27. The system of clause 21, wherein the first length remains substantially fixed and the second length remains substantially fixed while the swept source sweeps through a range of wavelengths to measure the first distance and the second distance.

[0215] Addendum 28. The system of Addendum 27, wherein the first length corresponds to a first optical path difference along the first reference optical fiber and the second length corresponds to a second optical path difference along the second reference optical fiber, the first optical path difference being less than the second optical path difference by an amount in the range of about 16 mm to about 26 mm, optionally in the range of about 18 mm to about 24 mm.

[0216] Clause 29. The system of clause 27, wherein the first distance of the first reference optical fiber is less than the second distance of the second reference optical fiber by an amount in the range of about 15 mm to about 25 mm.

[0217] Addendum 30. The system of Addendum 18, wherein the first interference signal comprises a first plurality of interference signals from a first plurality of corneal locations, and the second interference signal comprises a second plurality of interference signals from a second plurality of retinal locations.

[0218] Addendum 31. The system of Addendum 30, wherein the light beam comprises a plurality of measurement light beams at a first plurality of corneal locations and a second plurality of retinal locations.

[0219] Addendum 32. The system of Addendum 31, wherein each of the multiple measurement light beams illuminates a first corneal location and a second retinal location.

[0220] Clause 33. The system of clause 31, wherein the first plurality of corneal locations and the second plurality of corneal locations remain substantially fixed as the swept source sweeps over a range of wavelengths.

[0221] Addendum 34. The system of Addendum 33, wherein the multiple measurement light beams are positioned to measure the cornea at a first plurality of locations and to measure the retina at a second plurality of locations.

[0222] Addendum 35. The system of Addendum 31, wherein the swept source comprises a plurality of swept sources, and the plurality of measurement light beams are generated using the plurality of swept sources.

[0223] Clause 36. The system of clause 35, wherein the multiple swept sources comprise multiple VCSELs.

[0224] Clause 37. The system of clause 36, wherein the plurality of VCSELs comprises a two-dimensional array of VCSELs.

[0225] Addendum 38. The system of Addendum 18, further comprising a mirror configured to scan the measurement beam from the measurement optical path along the retina of the eye.

[0226] Addendum 39. The system of Addendum 38, wherein the mirror is configured to scan the measurement beam on the retina over an area having a maximum diameter in the range of about 0.05 mm to about 2.0 mm, optionally in the range of about 0.1 mm to about 1.5 mm, and optionally the maximum diameter has a diameter.

[0227] Addendum 40. The system of Addendum 38, wherein the processor is configured to generate a plurality of A-scans from the measurement path at a plurality of locations along the retina, and the processor is configured with instructions for determining an axial length in response to the plurality of A-scans.

[0228] Addendum 41. The system of Addendum 38, wherein the mirror is configured to scan the measurement beam along the cornea of ​​the eye while the measurement beam scans along the retina of the eye.

[0229] Addendum 42. The system of Addendum 41, wherein the processor is configured to generate a plurality of A-scans for locations along the cornea and the retina, each of the plurality of A-scans comprising a first peak corresponding to the cornea and a second peak corresponding to the retina.

[0230] Addendum 43. The system of Addendum 42, wherein the processor is configured with instructions for determining a location of the cornea responsive to the locations of the multiple corneal A-scan peaks and, optionally, an angular orientation of the eye relative to the measurement beam responsive to the locations of the multiple corneal A-scan peaks.

[0231] Addendum 44. The system of Addendum 43, wherein the processor is configured with instructions for determining an angular orientation of the eye responsive to locations of the plurality of corneal A-scan peaks and the plurality of retinal A-scan peaks.

[0232] Clause 45. The system of clause 44, wherein the processor is configured with instructions for determining an axial length of the eye in response to an angular orientation of the eye.

[0233] Addendum 46. The system of Addendum 41, wherein the processor is configured to generate the axial length in response to a plurality of A-scans.

[0234] Addendum 47. The system of Addendum 41, wherein the processor is configured to scan the measurement beam along the cornea in a substantially annular pattern.

[0235] Addendum 48. The system of Addendum 41, wherein for each of the plurality of A-scans, a retinal location of the measurement beam is on an opposite side of the optical axis of the eye from a corresponding corneal location of the measurement beam.

[0236] Addendum 49. The system of Addendum 48, wherein the objective lens is configured to form an image of the mirror at a location between the cornea and the retina, and the measurement beam moves in a first direction toward the cornea on a first side of the image of the mirror, and the measurement beam moves in a second direction toward the retina on a second side of the image of the mirror.

[0237] Addendum 50. The system of Addendum 38, further comprising an objective lens positioned between the mirror and the eye, the objective lens configured to focus the measurement light beam at a waist between the retina and a back surface of the eye's lens, the measurement light beam comprising a portion of the measurement beam.

[0238] Addendum 51. The system of Addendum 50, wherein the objective lens is configured to form an image of the mirror within the eye at a location between the cornea of ​​the eye and the retina of the eye, and optionally, the image of the mirror is formed anterior to the waist within the eye.

[0239] Addendum 52. The system of Addendum 18, wherein the processor is configured with instructions for generating an axial length map comprising distances between a plurality of corneal locations and a corresponding plurality of retinal locations.

[0240] Addendum 53. The system of Addendum 18, wherein the zero optical path difference of the measurement beam is located within the eye between the cornea of ​​the eye and the retina of the eye, and the mirror is configured to scan the location of the measurement beam at the zero optical path difference.

[0241] Addendum 54. The system of Addendum 18, wherein the first reference path corresponds to a first zero optical path difference and the second reference path corresponds to a second optical path difference.

[0242] Addendum 55. The system of Addendum 54, wherein a first location corresponding to a first zero optical path difference of the first reference path is located within approximately 10 mm of the cornea, and a second location corresponding to a second zero optical path difference of the second reference path is located within approximately 10 mm of the retina of the eye.

[0243] Clause 56. The system of clause 55, wherein the first location is scanned using a mirror and the second location is scanned using a mirror.

[0244] Addendum 57. The system of Addendum 50, further comprising one or more of a variable focus lens or a bifocal lens for focusing the measurement light beam onto the cornea and retina.

[0245] Addendum 58. The system of Addendum 18, wherein the swept source comprises one or more of a laser, a semiconductor laser, a movable mirror coupled to a laser, a micromechanical movable (MEMS) mirror coupled to a laser, a vertical cavity laser, or a vertical cavity surface emitting laser (VCSEL), or a tunable VCSEL with a MEMS mirror.

[0246] Clause 59. The system of clause 58, wherein the swept source comprises a VCSEL, the VCSEL being configured to sweep a range of wavelengths using overdrive of current to the VCSEL.

[0247] Addendum 60. The system of Addendum 58, wherein the VCSEL is configured to sweep a wavelength range of about 5 nm to about 20 nm, optionally about 5 nm to about 10 nm.

[0248] Clause 61. The system of clause 18, wherein the swept source comprises a plurality of VCSELs.

[0249] Addendum 62. The system of Addendum 18, further comprising a Purkinje imaging system for determining the location of the cornea of ​​the eye.

[0250] Addendum 63. A system for measuring an axial length of an eye, the system comprising: an array of VCSELs configured to generate an array of light beams and sweep a wavelength of each of the light beams; an interferometer coupled to the VCSEL array, the interferometer comprising a measurement optical path and a reference optical path for generating a plurality of interference signals; an array detector coupled to the interferometer for receiving the plurality of interference signals; and a processor coupled to the detector, the processor configured with instructions for determining an axial length of the eye in response to the plurality of interference signals.

[0251] Addendum 64. The system of Addendum 63, further comprising a plurality of optical fibers coupled to the array of VCSELs on a proximal end of the optical fiber, the distal end of the optical fiber being positioned to transmit the measurement light beam toward the eye.

[0252] Clause 65. The system of clause 63, further comprising a lens configured to image the array of VCSELs inside the eye and generate a plurality of interference signals.

[0253] Clause 66. The system of clause 63, wherein each VCSEL of the array is configured to vary wavelength using one or more heating or index changes of the gain medium within each VCSEL.

[0254] Clause 67. The system of clause 66, wherein each VCSEL of the array is configured to tune wavelength without the use of a MEMS mirror.

[0255] Clause 68. The system of clause 63, wherein each VCSEL in the array is configured to sweep the wavelength by an amount in the range of about 5 nm to about 20 nm.

[0256] The embodiments of the present disclosure are shown and described herein and are provided only as examples. Those skilled in the art will recognize numerous adaptations, modifications, variations, and substitutions that do not depart from the scope of the present disclosure. Several alternatives and combinations of the embodiments disclosed herein can be utilized without departing from the scope of the present disclosure and invention disclosed herein. Therefore, the scope of the present disclosure is to be defined only by the scope of the appended claims and their equivalents.

Claims

1. A system for measuring changes in refractive error of an eye, the system comprising a processor configured with instructions for implementing a method, the method comprising: measuring a first axial length of the eye from a first area of ​​the retina at a first time to determine a first axial length of the eye, the first area having a first maximum diameter within a first range of about 0.05 mm to about 2 mm; measuring a second axial length of the eye from a second area of ​​the retina at a second time to determine a second length of the eye at a second time; Including, the second region having a second maximum diameter in a range of about 0.05 mm to about 2.0 mm; The change in refractive error corresponds to a difference between the first axial length and the second axial length.

2. 1. A method for measuring a change in refractive error of an eye, the method comprising: measuring a first axial length of the eye from a first area of ​​the retina at a first time to determine a first axial length of the eye, the first area having a first maximum diameter within a first range of about 0.05 mm to about 2 mm; measuring a second axial length of the eye from a second area of ​​the retina at a second time to determine a second length of the eye at a second time; Including, the second region having a second maximum diameter in a range of about 0.05 mm to about 2.0 mm; The method, wherein the change in refractive error corresponds to a difference between the first axial length and the second axial length.

3. 2. The system of claim 1, wherein the first maximum diameter is within a range of about 0.1 mm to about 1.5 mm, and the second maximum diameter is within a range of about 0.1 mm to about 1.5 mm.

4. The system of claim 1 , wherein the first area is measured using a first plurality of A-scans of an OCT measurement beam and the second area is measured using a second plurality of A-scans of an OCT measurement beam.

5. The system of claim 4 , wherein each of the first area and the second area is measured using a scanning OCT measurement beam.

6. 6. The system of claim 5, wherein the scanning OCT measurement beam moves along a first trajectory to measure the first plurality of A-scans and moves along a second trajectory to measure the second plurality of A-scans.

7. The system of claim 4 , wherein the first area is measured using a first plurality of fixed measurement beams and the second area is measured using a second plurality of fixed measurement beams.

8. 8. The system of claim 7, wherein the first plurality of fixed measurement beams are positioned to generate the first plurality of A-scans and the second plurality of fixed measurement beams are positioned to generate the second plurality of A-scans.

9. 5. The system of claim 4, wherein the first plurality of A-scans measure a first plurality of corneal locations distributed over a first corneal area, the second plurality of A-scans measure a second plurality of corneal locations distributed over a second corneal area, the first axial length corresponds to a difference between the first plurality of retinal locations and the first plurality of corneal locations, and the second axial length corresponds to a difference between the second plurality of retinal locations and the second plurality of corneal locations.

10. 10. The system of claim 9, wherein a first plurality of axial lengths are determined and a second plurality of axial lengths are determined, the first plurality of axial lengths corresponding to a first difference between each of the first plurality of corneal locations and a corresponding first retinal location, and the second plurality of axial lengths corresponding to a second difference between each of the second plurality of axial locations and a corresponding second retinal location.

11. 2. The system of claim 1, wherein the first area substantially overlaps with the second area, optionally, the substantial overlap comprises at least about a 50% overlap between the first area and the second area.

12. 2. The system of claim 1, wherein one or more of the first maximum diameter or the second maximum diameter comprises a diameter and / or one or more of the first region or the second region comprises an annulus or area.

13. 2. The system of claim 1, wherein the first axial length comprises a first axial length map, the second axial length comprises a second axial length map, and the change in refractive error corresponds to a difference between the first axial length map and the second axial length map.

14. a swept source for generating an OCT beam and varying the wavelength of the OCT beam; an interferometer coupled to the swept light source; Further equipped with the interferometer comprises a measurement optical path and a reference optical path, the reference optical path comprising a first reference path and a second reference path; 14. The system of any one of claims 1 and 3 to 13, wherein the first axial length corresponds to a first difference between a first position of the cornea of ​​the eye measured using the first reference path measured at a first time and a first position of the cornea of ​​the eye measured using the second reference path, and the second axial length corresponds to a second difference between a second position of the cornea measured using the first reference path and a second position of the retina measured using the second reference path at a second time.

15. 15. The system of claim 14, further comprising a detector coupled to the interferometer to receive a first interference signal and a second interference signal, the first interference signal resulting from light from the first reference path interfering with light from the measurement optical path, and the second interference signal resulting from light from the second reference path interfering with light from the measurement optical path.

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