VCSEL arrays for OCT imaging

Abstract

The swept-source OCT system comprises multiple light beams from an array of VCSELs. The multiple light beams are imaged onto the retina of the eye, and an image of the multiple light beams formed on the retina is imaged onto a detector array. In some embodiments, a portion of the light from the multiple light beams is reflected off a reference mirror and combined with the multiple light beams returning from the retina and imaged onto the detector array to generate an interference signal. The wavelengths of the multiple light beams are swept to generate a swept-source signal on the detector and recorded to generate an interference signal for each of the multiple light beams. The interference signal can be processed to generate a reflectance signal for each of the multiple light sources.

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims the benefit under 35 U.S.C. Section 119(e) of U.S. Provisional Patent Application No. 63 / 268,254, filed February 18, 2022, which is incorporated by reference in its entirety herein.

[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 as WO / 2019 / 246412 on December 26, 2019, and U.S. Application No. 17 / 647,585, filed January 10, 2022, entitled "AXIAL LENGTH MASUREMENT MONITOR", now U.S. Patent No. 11,497,396, issued November 15, 2022 (the entire disclosures of which are incorporated herein by reference). [Background technology]

[0003] Optical coherence tomography (OCT) has been used in many fields to provide high-resolution tomographic images of tissues and other structures. One field in which OCT is often used is ophthalmic examination of tissues such as the cornea, lens, and retina. For example, it can be useful to monitor retinal thickness to diagnose and monitor the development of retinal disease. For example, OCT imaging of the eye lens can be useful to diagnose and treat cataracts, and OCT imaging to determine the axial length of the eye can be useful to monitor the progression of myopia. Although widely used in clinical applications, OCT has generally not been used for in-home monitoring, at least in some cases. In-home monitoring would be beneficial, as it could lead to earlier disease detection and improved monitoring and treatment.

[0004] Although useful, conventional approaches to OCT imaging may be sub-ideal in at least some respects. Research related to the present disclosure suggests that at least some of the approaches may be more complicated and have more moving parts than would be ideal. Also, conventional approaches are less suitable for in-home monitoring. Also, conventional approaches to OCT imaging may provide very good axial resolution along the path of the measurement beam, but the lateral resolution may be sub-ideal in at least some respects. Scanning mirrors may be used to scan the measurement beam, but this may lead to less spatial resolution lateral to the beam than would be ideal.

[0005] In light of the above, it would be useful to have improved systems and methods for OCT imaging that overcome at least some of the aforementioned limitations. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2019 / 246412 [Patent Document 2] U.S. Pat. No. 11,497,396 Summary of the Invention [Means for solving the problem]

[0007] The disclosed embodiments provide improved systems and methods for OCT imaging. The disclosed systems and methods allow for substantially simultaneous generation of A-scan measurements from multiple swept-source light beams, which can increase spatial resolution and, in some embodiments, reduce acquisition time for imaging an area. In some embodiments, an area can be measured without a moving mirror to scan the measurement beam, which can reduce the complexity of the system and provide imaging with fewer moving parts. Alternatively, a scanning mirror can be used to displace the area measured with multiple beams and provide increased spatial resolution with multiple swept-source light beams. The multiple light beams can be generated in many ways, and in some embodiments, the multiple light beams are generated using an array of vertical cavity surface emitting lasers (VCSELs).

[0008] In some embodiments, multiple light beams from multiple light sources, such as multiple VCSELs, are imaged onto the retina of the eye, and the images of the multiple light beams formed on the retina are imaged onto a detector array. In some embodiments, a portion of the light from the multiple light beams is reflected off a reference mirror and combined with the multiple light beams returning from the retina and imaged onto the detector array to generate an interference signal. The wavelengths of the multiple light beams are swept to generate a swept-source signal on the detector and recorded to generate an interference signal for each of the multiple light beams. The interference signal can be processed to generate a reflectance signal for each of the multiple light sources. Citation by reference

[0009] 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 disclosure will be obtained by reference to the following detailed description and accompanying drawings that set forth illustrative embodiments.

[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) system 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 system utilizing Bluetooth® communication, according to some embodiments.

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

[0016] [Figure 4] FIG. 4 shows a VCSEL array imaged into the eye using an OCT system according to some embodiments.

[0017] [Diagram 5] FIG. 5 shows the system of FIG. 4 in which one or more lenses comprise a lenslet array for forming multiple images of the retina, according to some embodiments.

[0018] [Figure 6]FIG. 6 shows a swept-source VCSEL configured to generate multiple light sources with a lenslet array and lenses according to some embodiments.

[0019] [Figure 7] FIG. 7 shows an etalon optically coupled to one or more lenses to generate a wavelength signal, according to some embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Detailed Description 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 the detailed description includes many specific embodiments, these are provided by way of example only and should not be construed as limiting the scope of the invention disclosed herein.

[0021] 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 focusing 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 surface. 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.

[0022] 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 by 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 fluid accumulation 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 OCT system and help identify fluid pockets or regions in the eye, as these may indicate changes in eye health.

[0023] 1B shows a perspective view of a monocular optical coherence tomography (OCT) system 100 with an array of VCSELs for measuring a user's eye. The OCT system 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, in some embodiments, allows for articulation of the head 202. The head may be covered by a housing that encloses the optical module, the scanning module, and other associated circuitry and modules, and allows the OCT system 100 to measure the user's eyes, one eye at a time.

[0024] 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 to focus on the retina of the eye from within the head 202. 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 with respect to the OCT system 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 system 100 is configured to detect the 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 to 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 comprises a patient support. The patient support comprises a head rest or chin rest, either alternatively or in combination with the eyecup 212.

[0025] In some embodiments, the 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 the embodiment. In some cases, the coupling includes a threaded fastener and a threaded nut to tighten the head in a desired orientation relative to the neck. 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, or detents, alternatively or additionally can include friction increasing structures such as roughened surfaces, peaks and valleys, surface textures, and the like.

[0026] FIG. 2 shows a schematic diagram of a system that allows a patient to measure their eye with an OCT array at multiple time points and communicate the results. The patient looks into a handheld OCT device 100 and obtains measurements of AL. In some embodiments, the handheld OCT system 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 system 100 communicates the results via a wireless communication channel 110 to a mobile patient system 120, such as the patient's smartphone or other portable electronic system. In some cases, the wireless communication is via Bluetooth® communication. In some embodiments, the wireless communication is via Wi-Fi communication. In other embodiments, the wireless communication is via any other wireless communication known to those of skill in the art. Although wireless communication is referenced, in some embodiments, the OCT system is connected to the patient mobile system by wired communication, and the patient mobile system is wirelessly connected to a remote server, such as a cloud-based server.

[0027] In some cases, the result is a fully processed measurement of the OCT image of the eye. In some cases, all processing of the OCT data is performed on the handheld OCT system. For example, in some embodiments, the handheld OCT system includes hardware or software elements that allow the OCT light waveform to be converted into an electronic representation. In some cases, the handheld OCT system further includes hardware or software elements that allow processing of the electronic representation, for example, to extract measurements of axial length or retinal thickness.

[0028] 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 system 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 system for further processing, for example to extract a measurement of RT.

[0029] In some cases, the patient receives the results and analysis of the OCT measurement on the patient mobile app. In some embodiments, the results include an alert 122 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 measurements 124. For example, in some cases, the retinal or axial length measurement produces a result with a specific value in millimeters ("mm"), e.g., 23.6 mm. In some cases, the result corresponds to a change in length that is outside of a desired range. This causes the system to produce an alert and display the measurements 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 that shows a history of the patient's axial length and retinal thickness measurements over multiple time points.

[0030] In some cases, the patient mobile system 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 via Wi-Fi communication. In other cases, the wireless communication is via a cellular network. In still other cases, the wireless communication is via 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.

[0031] Once stored in the cloud, in specific embodiments, the results are then transmitted to other systems. In some cases, the results are transmitted to a patient system 150 on the patient's computer, tablet, or other electronic system via a first communication channel 132. In some embodiments, the results are transmitted to a physician system 160 on the patient's physician's computer, tablet, or other electronic device via a second communication channel 134. In some cases, the results are transmitted to an analysis system 170 on another user's computer, tablet, or other electronic system via a third communication channel 136. In some embodiments, the results are transmitted to a patient management system or hospital management system 180 via a fourth communication channel 138. In some cases, the systems each have appropriate software instructions to perform the associated functions as described herein.

[0032] In specific embodiments, the first communication channel is a wired or wireless communication channel. In some cases, the communication is via Ethernet. In other cases, the communication is via a local area network (LAN) or a wide area network (WAN). In still other cases, the communication is via Wi-Fi. In still other cases, the communication is via 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.

[0033] In some cases, the second communication channel is a wired or wireless communication channel. In some cases, the communication is via Ethernet. In specific embodiments, the communication is via a local area network (LAN) or a wide area network (WAN). In other embodiments, the communication is via Wi-Fi. In still other embodiments, the communication is via 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.

[0034] In specific cases, the third communication channel is a wired or wireless communication channel. In some cases, the communication is via Ethernet. In other cases, the communication is via a local area network (LAN) or a wide area network (WAN). In still other cases, the communication is via Wi-Fi. In still other cases, the communication is via 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.

[0035] In some embodiments, the fourth communication channel is a wired or wireless communication channel. In some cases, the communication is via Ethernet. In other cases, the communication is via a local area network (LAN) or a wide area network (WAN). In still other cases, the communication is via 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.

[0036] In some embodiments, the patient's physician receives the results and analysis of the OCT measurements on a physician system 160. In some cases, the results include an alert 162 that alerts the physician that the results of the measurements 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 that shows recent and historical measurements for each of the physician's patients. In specific cases, the physician system also displays contact and history information 168 for each of the physician's patients.

[0037] In some embodiments, other users receive the results and analysis of the OCT measurements on analysis system 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 outcomes for particular physicians or nursing facilities. To protect patient privacy, in some cases the analysis system is restricted to receiving only a subset of a given patient's information. For example, the subset is restricted to not include any personally identifiable information about a given patient. In some cases, the results include alert 172, which alerts 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.

[0038] 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 contains 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.

[0039] 3A shows a handheld OCT system with an array of VCSELs that utilizes 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, communication is via a Bluetooth® wireless communication channel 110. In some instances, the handheld OCT system communicates results via the Bluetooth® channel to a mobile patient system 120 on the patient's smartphone or other portable electronic system.

[0040] In some instances, the results include an alert 122 that alerts the patient that the results of the measurement are outside of a desired range. In a specific embodiment, the results also include a display of the measurements 124. In a specific embodiment, the results also include a chart 126 that shows a history of the patient's OCT measurements over multiple time points.

[0041] In some cases, the patient mobile system application communicates the results of the measurements via wireless communication means 130 to a cloud-based or other network-based storage and communication system 140.

[0042] FIG. 3B illustrates a handheld OCT system with an array of VCSELs that can communicate directly with a cloud-based storage and communication system without relying on a user system such as a smartphone, according to some embodiments. In some embodiments, the handheld OCT system 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 system. In some cases, the GSM transmitter establishes wireless communication with a cloud-based or other network-based storage and communication system 140 via a wireless communication channel 114. In a specific case, the wireless communication is via 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 via a 3G or 4G communication channel.

[0043] In a specific embodiment, the patient mobile system 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.

[0044] Once retrieved from the cloud-based or other network-based storage and communication system, the results of the OCT measurement are viewed in a patient mobile application in some cases. In some cases, the results include an alert 122 that alerts the patient that the results of the measurement are outside of a normal or healthy range. In some cases, the results also include a display of the measured value 124.

[0045] In some cases, the handheld OCT device of Figures 3A and 3B is configured to be held in close proximity to the eye. For example, in a specific embodiment, the system is configured to be held in front of the eye with the detector and VCSEL array at a distance of 200 mm or less from the eye. In other embodiments, the system 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 system further comprises a housing for supporting the light source, optical elements, detector, and circuitry. In some cases, the housing is configured to be held in a user's hand. In some cases, the user holds the system in front of the eye and directs the light beam into the eye. In some cases, the system includes a sensor for measuring the eye being measured. For example, in a specific embodiment, the system includes an accelerometer or gyroscope for determining the eye being measured in response to an orientation of the housing. The system optionally includes a shielding structure coupled to the housing and a sensor for determining the eye being measured. The occlusion structure occludes one eye while the other eye is being measured. In some cases, the system includes a viewing target for aligning the light beam with a portion of the retina. For example, in specific embodiments, the system includes a viewing target for aligning the light beam with the fovea 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, as would be known to one of skill in the art.

[0046] In some embodiments, the handheld OCT system of FIGS. 3A and 3B is small enough and lightweight enough to be easily operated by a user with one hand.

[0047] 4 illustrates a system 100 comprising a VCSEL array 405 imaged into the eye using one or more lenses 430, for example after being combined with a reference beam using a Mach-Zehnder configuration, to provide multiple OCT interferograms at multiple locations of the eye, and light received from the eye imaged onto a detector array using one or more lenses. The VCSEL array 405 comprises a plurality of light sources 402. The plurality of light sources 402 comprises a first light source 402-1, a second light source 402-2, a third light source 402-3, and an Nth light source 402-N. In some embodiments, the array of light sources comprises a two-dimensional array of light sources.

[0048] Light from the VCSEL array 405 is directed towards one or more lenses 430, which may substantially collimate the light from the multiple VCSELs. The light from the one or more lenses 430 is directed towards a beam splitter 460. The beam splitter 460 reflects a portion of the light along a reference path and transmits a second portion of the light along a measurement path. The beam splitter 460 may comprise any suitable beam splitter, such as, for example, a partially reflecting mirror or a polarizing beam splitter. A first portion of the light from the beam splitter 460 is directed along the reference path towards a mirror 440. The light reflected from the mirror 440 is directed towards the beam splitter 440 and transmitted through the beam splitter 460 towards the detector 410. In some embodiments, one or more lenses 450 are located between the beam splitter 460 and the mirror 440. In some embodiments, additional optional mirrors are added to scan the image of the multiple light beams along the retina, such as mirrors coupled to galvanometers, which may be used in combination with multiple light beams as described herein.

[0049] Detector 410 may include any suitable detector. In some embodiments, detector 410 includes an array detector, such as, for example, a complementary metal oxide semiconductor (CMOS) array or a charge-coupled system (CCD) array. In some embodiments, detector 410 includes a plurality of pixels, each pixel having a width in the range of about 0.5 micrometers (μm) to about 5 μm, for example, in the range of about 1 μm to about 3 μm. In some embodiments, detector 410 includes a clock speed of at least about 1 MHz.

[0050] Detector 410 may comprise any suitable light sensing elements, such as silicon light sensing elements. The multiple light sensing elements can be arranged in any suitable manner, such as with a rectangular array. In some embodiments, detector 410 comprises multiple light sensing elements, for example at multiple locations corresponding to the location of the VCSEL imaged on the retina and thus onto the sensing elements. In some embodiments, detector 410 comprises an ASIC in which multiple light sensing elements each comprise a location corresponding to the location of the VCSEL imaged onto detector 410.

[0051] In some embodiments, the detector 410 is configured to sample, for example, at least about 100 A-scan measurements in parallel. The number of A-scan measurements obtained substantially simultaneously, for example in parallel, may be related to the number of VCSELs in the array and can be any suitable number of parallel A-scan measurements, for example, at least about 1,000 A-scan measurements, at least about 10,000 A-scan measurements, or at least about 100,000 A-scan measurements. The number of VCSELs in the array may include any suitable number, such as at least about 100 VCSELs, at least about 1,000 VCSELs, at least about 10,000 VCSELs, or at least about 100,000 VCSELs. The VCSELs can be arranged in any suitable manner, such as, for example, a 10×10 array, a 30×30 array, a 64×64 array, a 128×128 array, a 256×256 array, a 300×300 array, or a 512×512 array. The VCSELs of the array can be configured to sweep at a rate that provides the detector 410 with sufficient time to capture an intensity profile over time for each VCSEL element for a complete sweep across a wavelength range, e.g., a sweep time across a complete wavelength range in the range of about 0.1 seconds to about 1 second, even though the sweep time could be more rapid.

[0052] In some embodiments, the detector 410 comprises an application specific integrated circuit (ASIC). Alternatively, or in combination, the detector 410 comprises a CMOS detector array coupled to an ASIC for signal acquisition.

[0053] A portion of the light transmitted through the beam splitter 460 is directed along a measurement optical path toward a lens 480 and the eye. The lens 480 may comprise one or more of a variable focus lens, a multifocal lens, or a bifocal lens, for example, to compensate for refractive error of the eye. The light transmitted through the mirror is imaged inside the eye, and the optical power of the eye and the lens 480 is used to form an image 402I1 of the light source from the VCSEL array 405 within the eye. In some embodiments, the image 402I1 formed inside the eye comprises a plurality of corresponding first images of individual VCSEL light sources of the VCSEL array, e.g., an image 402I1-1 corresponding to light source 402-1, an image 402I1-2 corresponding to light source 402-2, an image 402I1-3 corresponding to light source 402-3, and an image 402I1-N corresponding to light source 402-N.

[0054] Light returned from the retina is transmitted through lens 480 and reflected off mirror 460 towards one or more lenses 420 and detector 410. Light reflected from mirror 460 is transmitted through one or more lenses 420 to form an image 402I2 of light returned from inside the eye on detector array 410. In some embodiments, an image 405I1 of the VCSEL array 405 formed inside the eye is imaged onto detector array 410 using one or more lenses 420 to form image 402I2. In some embodiments, components of image 402I2 correspond to components of image 405I1 and multiple light sources of VCSEL array 405, e.g., VCSELs of VCSEL array 405. In some embodiments, image 402I2 includes image 402I2-1 corresponding to image 402I1-1 and light source 402-1, image 402I2-2 corresponding to image 402I1-2 and light source 402-2, image 402I2-3 corresponding to image 402I1-3 and light source 402-3, and image 402I2-N corresponding to image 402I1-N and light source 402-N.

[0055] As each of the VCSELs of the array varies in wavelength, the intensity of a corresponding image varies and is captured using detector 410. One or more VCSELs can be configured to sweep the wavelength of light emitted from one or more VCSELs in many ways. In some embodiments, the VCSELs generate light and sweep the wavelength substantially simultaneously. In some embodiments, each of the VCSELs is driven with a common voltage, and each VCSEL independently sweeps its output wavelength in response to the common voltage, for example, based on individual heating and wavelength output characteristics. Alternatively, or in combination, the VCSELs may be swept sequentially, for example, with sequential activation of each of the multiple VCSELs. In some embodiments, each of the multiple VCSELs is powered independently of the other VCSELs to provide independent wavelength sweeping.

[0056] A detector 410 is coupled to a processor, and image intensity signals from each VCSEL are captured and processed. In some embodiments, the detector 410 generates a time-varying signal for each of the multiple VCSELs, e.g., from the image from each VCSEL of the array. In some embodiments, the time-varying signal comprises a time-varying interferogram that can be transformed using a suitable transformation, such as a Fourier transform, to generate reflectance signals from different depths, such as an A-scan. In some embodiments, the time-varying signal is adjusted in response to the wavelength-swept characteristics of each of the one or more VCSELs prior to being transformed to provide a time-varying signal that is more suitable for transformation. In some embodiments, an A-scan is generated for each of the multiple light sources, such as an A-scan for each of the multiple VCSELs. The multiple A-scans can be combined to generate an image of the eye corresponding to the location of each VCSEL imaged onto the retina.

[0057] In some embodiments, one or more lenses 450 focus the light onto a mirror 440 to form an image of the multiple light sources 402 from the VCSEL array 405 on the mirror 440. In some embodiments, the light is focused into an image 402R, which comprises multiple reference beams that form an illumination spot on the mirror 440. In some embodiments, the image 402R includes an image 402R-1 corresponding to the light source 402-1, an image 402R-2 corresponding to the light source 402-2, an image 402R-3 corresponding to the light source 402-3, and up to an image 402R-N corresponding to the light source 402-N. Each of these images is imaged onto the detector array 410 such that the location of the detector array includes the corresponding reference image 402R and image 402I1 from the eye. In some embodiments, image 402I2-1 includes an image of image 402I1-1 and an image of 402R-1 that overlap at a first location of array 410, image 402I2-2 includes an image of image 402I1-2 and an image of 402R-2 that overlap at a second location of array 410, image 402I2-3 includes an image of image 402I1-3 and an image of 402R-3 that overlap at a third location of array 410, and image 402I2-N includes an image of image 402I1-N and an image of 402R-N that overlap at an Nth location of array 410.

[0058] In some embodiments, each reference light source is combined with a corresponding image of a VCSEL on the retina and swept with the corresponding VCSEL to generate a corresponding image of the light source from the VCSEL on the detector. For example, image 402I2-1 may include a combination of image 402I1-1 from the eye and image 402R-1 from the reference mirror 440 such that image 402I2-1 is modulated while the VCSEL corresponding to light source 402-1 is swept. Image 402I2-2 may include a combination of image 402I1-2 from the eye and image 402R-2 from the reference mirror 440 such that image 402I2-2 is modulated while the VCSEL corresponding to light source 402-2 is swept. Image 402I2-3 may include a combination of image 402I1-3 from the eye and image 402R-3 from the reference mirror 440 such that image 402I2-3 is modulated while the VCSEL corresponding to light source 402-3 is swept. Images 402I2-N may include a combination of images 402I1-N from the eye and images 402R-N from reference mirror 440 such that images 402I2-N are modulated while the VCSEL corresponding to light source 402-N is swept. Each of the VCSEL light sources may be swept, for example, independently or synchronously or a combination thereof.

[0059] The mirror 440 can be configured in many ways according to the present disclosure. In some embodiments, the mirror 440 comprises a substantially flat reflective surface. Alternatively, the mirror 440 may comprise a deformable mirror to provide compensation for the optical path difference between the mirror surface and the surface of the retina. The deformable mirror may include any suitable deformable mirror, such as a deformable membrane mirror or a segmented mirror with discrete displacement elements to compensate for the optical path difference.

[0060] The VCSEL array 405 can be configured in a number of ways according to the present disclosure. In some embodiments, the array comprises a plurality of VCSELs configured to sweep the wavelength emitted from each VCSEL using heating of the VCSEL. The number of VCSELs may include any suitable number (N) of VCSELs, where the number N can be, for example, from about 10 to about 10,000 VCSELs, optionally from about 100 to about 1,000 VCSELs. The VCSELs may be arranged in an array of rows and columns, such as, for example, an I×J array, where I corresponds to the number of rows and J corresponds to the number of columns. For example, the number of columns I can be in the range of about 10 to about 100 (or more), and the number J can be in the range of about 10 to about 100. The range of the sweep can be any suitable range, for example, from about 5 nm to about 20 nm, for example, from about 5 nm to about 10 nm. Examples of suitable VCSELs and associated signal processing are described in "MINIATURIZED MOBILE, LOW COST OPTICAL COHERENCE TOMOGRAPHY SYSTEM FOR HOME BASED OPHTHALMIC APPLICATIONS," published as WO / 2019 / 246412 on December 26, 2019, and U.S. Application No. 17 / 647,585, filed January 10, 2022 and entitled "AXIAL LENGTH MASUREMENT MONITOR," the entire disclosure of which is incorporated herein by reference. VCSEL arrays can be fabricated in many ways, for example, with VCSELs formed on a semiconductor die. In some embodiments, the VCSEL array 405 comprises an application specific integrated circuit (ASIC).

[0061] In some embodiments, an array of VCSELs comprises a plurality of VCSELs where a mirror, such as a MEMS mirror, moves to sweep the wavelength, and the sweep range can be any suitable range, such as from about 10 nm to about 100 nm or more. The mirrors of one or more VCSELs may be driven synchronously to provide substantially simultaneous wavelength sweeps, or independently to provide independent wavelength sweeps, and combinations thereof.

[0062] FIG. 5 illustrates the system of FIG. 4 with a lenslet array for forming multiple images of the retina. In some embodiments, one or more lenses 420 comprise a lenslet array 425. The lenslet array 425 comprises multiple lenses, such as a first lens 422 and a second lens 424. In some embodiments, the second image 402I2 of the multiple light sources from the VCSEL array includes a first image 402I2-1 from a first lenslet and a second image 402I2-2 from a second lenslet. Each lens of the lenslet array forms an image of the light from the retina and the light from the reference mirror on the detector array, which can provide additional information about the interference signal measured with the detector array 410. In some embodiments, the lenslet array forms a first image 402I2-1, a second image 402I2-2, and up to an Nth image of the light from the retina on the detector array 410. Each of these images includes an image of the light from the VCSEL elements imaged onto the retina and re-imaged onto the detector array 410, such as images 402I2-1, 402I2-2, 402I2-3, 402I2-N. This approach increases the number of images of the VCSEL array proportionately. For example, for a 10×10 VCSEL array with 100 VCSEL light sources and a 10×10 lenslet array with 100 lenses, the total number of images of the light sources from the VCSELs is 10,000, which can provide additional information. For example, with 100 lenslets, each VCSEL in the array is imaged simultaneously 100 times while the VCSEL is swept, which provides additional information to reconstruct an A-scan for the VCSEL at a location on the retina. In some embodiments, the number of lenses in the array multiplies the number of images of the VCSEL elements by the number of lenslets, for example, by 100 in the above embodiment. Although reference is made to each lenslet imaging the entire multiple light sources from the VCSEL array, in some embodiments each lenslet images a portion of the light from the VCSEL array.

[0063] The lenslet array may comprise any suitable number of lenses, such as in the range of about 4 to about 100 lenses. In some embodiments, the lenslet array comprises a two-dimensional array of lenslets, such as an array of M×N lenslets, where M can be in the range of about 2 to about 10 lenses, and N can be in the range of about 2 to about 10 lenses, and M and N can have the same or different values, depending on the configuration. In some embodiments, the lenslet array comprises, for example, a 2×2 array, a 4×4 array, an 8×8 array, a 10×10 array, a 16×16 array, or a 32×32 array. The lenslet array may comprise any suitable lenslet array, such as, for example, a gradient index (GRIN) lenslet array, a crossed cylindrical lenslet array, a diffractive lenslet array, or a holographic lenslet array.

[0064] Although multiple light sources 602 from a VCSEL array 405 are referenced, the multiple light sources may be generated by any suitable optical configuration.

[0065] The lenslet array 425 can be configured to image light from the retina in a number of ways. In some embodiments, the lenses of the lenslet array comprise a phased, matched configuration, in which the lenslets are phase matched to one another.

[0066] 6 shows a swept-source VCSEL 610 configured to generate multiple light sources 602 with a lenslet array 630 and a lens 620. The VCSEL 610 may include any suitable VCSEL as described herein. In some embodiments, light 615 from the VCSEL 610 is directed toward a lens 620, which substantially collimates the light. The lenslet array 630 receives and focuses the light 615 to generate multiple light sources 602, which can be incorporated into the system 100 and the light from the swept VCSEL as described herein.

[0067] FIG. 7 shows one or more etalons 710 optically coupled to one or more lenses 420 to generate a signal that varies with wavelength from one or more VCSELs. In some embodiments, the one or more etalons 710 are configured to transmit wavelengths of light corresponding to constructive interference through the etalon and reduce transmission of light over wavelengths corresponding to destructive interference of light. As the VCSEL sweeps the output wavelength over a range of wavelengths, the etalon selectively transmits a first portion of the wavelengths and attenuates a second portion of the wavelengths to generate a time-varying intensity signal corresponding to the output wavelength. The time-varying intensity signal can be used to adjust a reconstructed reflectance signal from a tissue layer. In some embodiments, the time-varying intensity signal includes a clock signal corresponding to each emission wavelength of the one or more VCSELs.

[0068] In some embodiments, the one or more lenses 420 comprise a lenslet array 425, and the one or more etalons 710 include a plurality of etalons optically coupled to a portion of the plurality of lenslets to provide an etalon-modulated signal to the detector array. In some embodiments, each lenslet generates an image of a plurality of light beams reflected from the retina, and the intensity-modulated signal through the etalon and corresponding lenslet can be used to reconstruct an A-scan for signals transmitted through the lenslet without the use of an etalon. In some embodiments, the first lenslet 422 is not optically coupled to the one or more etalons 710, and the second lenslet 424 is optically coupled to the one or more etalons 710 and generates a signal corresponding to the wavelength at the array detector 410, and both signals can be used to construct a reflectance signal.

[0069] As described herein, the computing systems and systems described and / or illustrated herein broadly represent any type or form of computing system or system capable of executing computer-readable instructions such as those contained within the modules described herein. In their most basic configurations, these computing systems may each include at least one memory system and at least one physical processor.

[0070] As used herein, the term "memory" or "memory system" generally refers to any type or form of volatile or non-volatile storage system or medium capable of storing data and / or computer-readable instructions. In one embodiment, a memory system may store, load, and / or maintain one or more of the modules described herein. Examples of memory systems 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 of these, or any other suitable storage memory.

[0071] Additionally, as used herein, the term "processor" or "physical processor" generally refers to any type or form of hardware-implemented processing unit capable of interpreting and / or executing computer-readable instructions. In one embodiment, the physical processor may access and / or modify one or more modules stored in the memory system described above. Examples of physical processors include, but are not limited to, microprocessors, microcontrollers, central processing units (CPUs), field programmable gate arrays (FPGAs) implementing soft-core processors, application specific integrated circuits (ASICs), one or more portions thereof, variations or combinations of one or more of these, or any other suitable physical processor. The processor may include, for example, a distributed processor system running parallel processors, or remote processors such as servers, and combinations thereof.

[0072] 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 system, may cause the computing system to perform one or more tasks, such as method steps.

[0073] In addition, one or more of the systems described herein may transform representations of data, physical devices, and / or physical systems 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 system from one form of computing system to another form of computing system by executing on the computing system, storing data on the computing system, and / or otherwise interacting with the computing system.

[0074] As used herein, the term "computer-readable medium" generally refers to any form of system, 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.

[0075] 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, although the steps illustrated and / or described herein may be shown or discussed in a particular order, these steps do not necessarily have to be performed in the order illustrated or discussed.

[0076] The various exemplary methods described and / or illustrated herein may also 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.

[0077] 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.

[0078] 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 usage, 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."

[0079] A processor as disclosed herein may be configured with instructions to perform any one or more steps of any method as disclosed herein.

[0080] 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.

[0081] As used herein, the term "or" is used inclusively to refer to items in alternative and combination.

[0082] As used herein, letters such as numbers refer to similar elements.

[0083] This disclosure includes the following numbered appendices:

[0084] Appendix 1. An OCT system for measuring reflectivity of a tissue layer, comprising: an array of VCSELs configured to generate an array of light beams and sweep the wavelength of each of the light beams; an interferometer coupled to the VCSEL array, the interferometer comprising a measurement optical path for generating a plurality of interference signals and a reference optical path; an array detector coupled to the interferometer and receiving the plurality of interference signals; and a processor coupled to the array detector, the processor configured with instructions for determining a reflectivity of the tissue layer in response to the plurality of interference signals.

[0085] Addendum 2. The system of Addendum 1, wherein the processor is configured to generate a plurality of A-scans of the tissue layer at a plurality of locations, the plurality of locations corresponding to locations of an array of light beams imaged onto the tissue layer.

[0086] Addendum 3. The system of any of Addendums 1-2, wherein each of the plurality of A-scans corresponds to a location of a VCSEL of the VCSEL array imaged onto the tissue layer.

[0087] Addendum 4. The system of any of Addendums 1-3, further comprising one or more lenses arranged to form a reference image of the array of VCSELs on a reference mirror and a measurement image of the array within the eye, combine the measurement image and the reference image, and generate a plurality of interferograms.

[0088] Addendum 5. The system of any of Addendums 1-4, wherein the reference image of the array includes multiple reference beams at multiple locations on the reference mirror corresponding to the locations of the multiple VCSELs, and the measurement image includes multiple measurement beams at multiple locations on the retina corresponding to the locations of the multiple VCSELs, and the multiple reference beams overlap with the multiple reference beams at multiple corresponding locations on the detector to generate multiple interferograms.

[0089] Addendum 6. The system of any of Addendums 1-5, wherein each of the multiple interferograms corresponds to one of the multiple VCSELs, one of the multiple locations on the reference mirror, and one of the multiple locations on the retina.

[0090] Addendum 7. The system of any of Addendums 1-6, wherein the one or more lenses comprise an array of lenslets for generating a plurality of images of the measurement image and the reference image, each of the plurality of lenslets generating an image of the measurement image and the reference image.

[0091] Addendum 8. The system of any of Addendums 1-7, wherein the mirror comprises a deformable mirror, optionally comprising one or more of a deformable membrane mirror or a segmented mirror, to compensate for an optical path difference between the tissue layer and the reference mirror.

[0092] Addendum 9. The system of any of Addendums 1-8, wherein the detector array is configured to sample a plurality of interference signals at a plurality of locations at a rate of at least about 1,000 Hz, the array of VCSELs comprises at least about 100 VCSELs, and the array detector comprises at least about 10,000 pixels.

[0093] Clause 10. The system of any of clauses 1-9, further comprising one or more lenses configured to image the array of VCSELs inside the eye and generate a plurality of interference signals.

[0094] Addendum 11. The system of any of Addendums 1-10, wherein each VCSEL of the array is configured to vary wavelength using one or more heating or refractive index modifications of the gain medium within each VCSEL.

[0095] Addendum 12. The system of any of Addendums 1-11, wherein each VCSEL of the array is configured to vary wavelength without the use of a MEMS mirror.

[0096] Addendum 13. The system of any of Addendums 1-12, 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.

[0097] Addendum 14. The system of any of Addendums 1-13, further comprising a lenslet array for imaging the array of light beams returned from the retina.

[0098] Addendum 15. The system of any of Addendums 1-14, wherein each lens of the lenslet array forms an image of the array of light beams on the array detector.

[0099] Addendum 16. A system as described in any of Addendums 1-15, wherein the number of lenses in the lenslet array corresponds to a multiplier of the number of images of the array of light beams onto the array detector, and optionally, the number of elements of the VCSEL array imaged onto the detector is multiplied by the number of lenslets.

[0100] Addendum 17. The system of any of Addendums 1-16, wherein each lens of the lenslet includes a phase that is matched to the phase of other lenslets of the array.

[0101] Addendum 18. A system according to any of Addendums 1-17, wherein the OCT system does not include a scanning mirror for scanning the array of light beams laterally along the tissue layer.

[0102] Addendum 19. A system according to any of Addendums 1-18, wherein the OCT system comprises a scanning mirror for scanning the array of light beams laterally along the tissue layer.

[0103] Appendix 20. A method for measuring the reflectance of a tissue layer using OCT, comprising: generating an array of light beams from a plurality of light sources; sweeping the wavelength of each of the plurality of light sources; generating a plurality of interference signals using an interferometer coupled to the array of light beams, the interferometer comprising a measurement optical path and a reference optical path; receiving the plurality of interference signals using an array detector coupled to the interferometer; and determining the reflectance of the tissue layer in response to the plurality of interference signals using a processor.

[0104] Addendum 21. An OCT system for measuring reflectivity of a tissue layer, comprising: a plurality of light sources configured to generate an array of light beams and sweep the wavelength of each of the light beams; an interferometer coupled to the array of light beams, the interferometer comprising a measurement optical path for generating a plurality of interference signals and a reference optical path; an array detector coupled to the interferometer and receiving the plurality of interference signals; and a processor coupled to the detector, the processor configured with instructions for determining a reflectivity of the tissue layer in response to the plurality of interference signals.

[0105] 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, changes, modifications, and substitutions without departing 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. 1. An OCT system for measuring reflectance of a tissue layer, comprising: an array of VCSELs configured to generate an array of light beams and sweep the wavelength of each of the light beams; an interferometer coupled to the VCSEL array, the interferometer comprising a measurement path for generating a plurality of interference signals and a reference path; an array detector coupled to the interferometer to receive the plurality of interference signals; a processor coupled to the array detector, the processor configured with instructions for determining a reflectivity of the tissue layer in response to the plurality of interference signals; An OCT system comprising:

2. 2. The system of claim 1, wherein the processor is configured to generate a plurality of A-scans of the tissue layer at a plurality of locations, the plurality of locations corresponding to locations of an array of the light beams imaged onto the tissue layer.

3. The system of claim 2 , wherein each of the plurality of A-scans corresponds to a location of a VCSEL of the VCSEL array imaged onto the tissue layer.

4. 10. The system of claim 1, further comprising one or more lenses arranged to form a reference image of the array of VCSELs on a reference mirror and a measurement image of the array within the eye, combining the measurement image and the reference image to generate a plurality of interferograms.

5. 5. The system of claim 4, wherein the reference image of the array includes a plurality of reference beams at a plurality of locations on the reference mirror corresponding to the locations of the plurality of VCSELs, and the measurement image includes a plurality of measurement beams at a plurality of locations on the retina corresponding to the locations of the plurality of VCSELs, the plurality of reference beams overlapping with the plurality of reference beams at a plurality of corresponding locations on the detector to generate a plurality of interferograms.

6. 6. The system of claim 5, wherein each of the multiple interferograms corresponds to one of the multiple VCSELs, one of the multiple locations on the reference mirror, and one of the multiple locations on the retina.

7. 5. The system of claim 4, wherein the one or more lenses comprise an array of lenslets for generating a plurality of images of the measurement image and the reference image, each of the plurality of lenslets generating an image of the measurement image and the reference image.

8. 5. The system of claim 4, wherein the mirror comprises a deformable mirror, optionally comprising one or more of a deformable membrane mirror or a segmented mirror, to compensate for an optical path difference between the tissue layer and the reference mirror.

9. 10. The system of claim 1 , wherein the detector array is configured to sample the plurality of interference signals at a plurality of locations at a rate of at least about 1,000 Hz, the array of VCSELs comprises at least about 100 VCSELs, and the array detector comprises at least about 10,000 pixels.

10. 10. The system of claim 1, further comprising one or more lenses configured to image the array of VCSELs inside the eye and generate the multiple interference signals.

11. 10. The system of claim 1, wherein each VCSEL of the array is configured to vary the wavelength using one or more heating or refractive index modifications of a gain medium within the each VCSEL.

12. The system of claim 11 , wherein each VCSEL of the array is configured to vary the wavelength without the use of a MEMS mirror.

13. The system of claim 1 , wherein each VCSEL of the array is configured to sweep the wavelength by an amount in a range from about 5 nm to about 20 nm.

14. The system of claim 1 , further comprising a lenslet array for imaging the array of light beams returned from the retina.

15. The system of claim 14 , wherein each lens of the lenslet array forms an image of the array of light beams onto the array detector.

16. 15. The system of claim 14, wherein the number of lenses in the lenslet array corresponds to a multiplier of the number of images of the array of the light beams onto the array detector, and optionally, the number of elements of the VCSEL array imaged onto the detector is multiplied by the number of lenslets.

17. 15. The system of claim 14, wherein each lens of the lenslet includes a phase that is matched to the phase of other lenslets of the array.

18. The system of claim 1 , wherein the OCT system does not include a scanning mirror for scanning the array of light beams laterally along the tissue layer.

19. The system of claim 1 , wherein the OCT system comprises a scanning mirror for scanning the array of light beams laterally along the tissue layer.

20. 1. A method for measuring reflectance of a tissue layer using OCT, comprising: generating an array of light beams from a plurality of light sources; Sweeping the wavelength of each of the plurality of light sources; generating a plurality of interference signals with an interferometer coupled to the array of light beams, the interferometer comprising a measurement path and a reference path; receiving the plurality of interference signals with an array detector coupled to the interferometer; determining, with a processor, a reflectivity of the tissue layer in response to the plurality of interference signals; A method comprising:

21. 1. An OCT system for measuring reflectance of a tissue layer, comprising: a plurality of light sources configured to generate an array of light beams and to sweep the wavelength of each of the light beams; an interferometer coupled to the array of light beams, the interferometer comprising a measurement path for generating a plurality of interference signals and a reference path; an array detector coupled to the interferometer to receive the plurality of interference signals; a processor coupled to the detector, the processor configured with instructions for determining a reflectivity of the tissue layer in response to the plurality of interference signals; An OCT system comprising:

Images