Automatic optical path adjustment in home OCT

Abstract

Retinal imaging systems and related methods employ user-specific approaches to control the reference arm length in an optical coherence tomography (OCT) imaging apparatus. One method involves restricting the user's head relative to the OCT imaging apparatus. A control reference arm length adjustment module alters the reference arm length to search for a user-specific reference arm length range, thereby identifying the reference arm length at which the OCT image detector generates an OCT signal corresponding to the user's retina. This user-specific reference arm length range covers a smaller range of reference arm lengths than the reference arm length adjustment range of the reference arm length adjustment module.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefits of U.S. Provisional Application No. 62 / 740,781, filed October 3, 2018, and U.S. Application No. 16 / 424,246, filed May 28, 2019, the entire contents of which are incorporated herein by reference. Background Technology

[0003] Age-related macular degeneration (AMD) is the leading cause of vision loss in the United States. In AMD, the central part of the retina (also known as the macula) deteriorates. When healthy, the macula collects and sends highly detailed images to the brain via the optic nerve. In its early stages, AMD typically does not significantly affect vision. If AMD progresses beyond the early stages, vision will become fluctuating and / or blurred. If AMD continues to progress to a late stage, central vision may be lost.

[0004] Although macular degeneration is currently considered incurable, treatments do exist that can slow its progression to prevent severe vision loss. Treatment options include: injections of anti-angiogenic drugs into the eye, laser therapy to destroy actively growing abnormal blood vessels (multiple vessels), and photodynamic laser therapy using photosensitizing drugs to destroy abnormal blood vessels (multiple vessels). Early detection of macular degeneration is crucial for preventing late-stage progression and inhibiting disease development before treatment.

[0005] Early detection of macular degeneration can be achieved using appropriate retinal imaging systems. For example, optical coherence tomography (OCT) is a minimally invasive imaging technique that relies on low-correlation interferometry that can be used to generate cross-sectional images of the macula. These cross-sectional images of the macula show whether the macular layer is deformed and can be used to monitor whether the macular layer deformation increases or decreases relative to earlier cross-sectional images to assess the impact of macular degeneration treatment. Summary of the Invention

[0006] The following is a simplified overview of some embodiments of the invention to provide a basic understanding of the invention. This content is not a broad overview of the invention. It is not intended to identify key / determining elements of the invention or to describe the scope of the invention. Its sole purpose is to present some embodiments of the invention in a simplified form as a prelude to the detailed implementation presented later.

[0007] Ophthalmic imaging systems and related methods employ an observer assembly to constrain a user's head in a substantially fixed position and orientation relative to an optical coherence tomography (OCT) imaging device, and employ a user-specific method to control the reference arm length in the OCT imaging device for imaging the user's retina. In many embodiments, the OCT imaging device includes a reference arm length adjustment module that is controlled to change the reference arm length. In many embodiments, the user engages their head with the observer assembly, thereby constraining the position of the user's retina relative to the OCT imaging device. Due to variations in the position of the user's retina relative to user facial features (e.g., forehead, cheeks) engaged with the observer assembly, and the possible variations in the relative position between the user's head and the observer assembly, the sample arm length to the retina of any particular user can be within a relatively large range. In many embodiments, a user-specific reference arm length range is used during imaging of the user's retina. The user-specific reference arm length range is substantially smaller than the reference arm adjustment range of the reference arm length adjustment module. Using a smaller user-specific reference arm length range during imaging the user's retina significantly reduces the amount of time spent scanning the reference arm length to find the reference arm length (at which the OCT image detector generates the OCT signal for the user's retina), thereby greatly reducing the total time required to image the user's retina. Furthermore, by employing a user-specific reference arm length range, the OCT imaging system can be simplified relative to more complex OCT imaging systems that include a positioning system for adjusting the distance between the OCT imaging device and the user's retina.

[0008] Therefore, in one aspect, an ophthalmic imaging system for imaging the retina includes an optical coherence tomography (OCT) imaging device, a housing to which the OCT imaging device is attached, an observer assembly coupled to the housing, and a control unit. The OCT imaging device includes a sample arm optical path, an OCT image detector, a reference arm optical path, and a reference arm length adjustment module. The reference arm optical path has a reference arm length. The reference arm length adjustment module is controllable to change the reference arm length within a reference arm length adjustment range. The observer assembly is configured to engage a user's head to restrict the user's head relative to the housing, such that the sample arm optical path extends to the user's retina. The control unit is operatively connected to the OCT image detector and the reference arm length adjustment module. The control unit is configured to store a user-specific reference arm length range that covers a smaller range of reference arm lengths than the reference arm length adjustment range. The control unit is configured to control the reference arm length adjustment module to change the reference arm length to search within the user-specific reference arm length range, thereby identifying a reference arm length for which the OCT image detector generates an OCT signal corresponding to the user's retina.

[0009] Any suitable method, such as those described herein, can be used to determine a suitable user-specific reference arm length range for use in an ophthalmic imaging system. For example, as described herein, a larger range of reference arm length adjustments for the adjustable reference arm module can be searched during initial imaging of the user's retina to identify the reference arm length at which the OCT image detector 38 generates the OCT signal corresponding to the user's retina. The identified reference arm length for the initial imaging of the user's retina can then be used to determine a suitable user-specific reference arm length range for use in subsequent imaging sessions of the user's retina. Alternatively, a suitable user-specific reference arm length range can be predetermined for any particular user. For example, the user-specific reference arm length range can be based on spatial information relating to one or more facial features of the user. In some embodiments, the user-specific reference arm length range may be based on one or more of the user's facial features, including the user's forehead, one or more of the user's cheeks, the cornea of ​​the user's eye including the user's retina, and the lateral orbital margin of the user. Spatial information relating to one or more facial features of a user is generated via one or more of the following: (a) a three-dimensional scan of one or more facial features of the user, (b) caliper measurement of one or more facial features of the user relative to the user's eye, including the user's retina, (c) a cast mask of one or more facial features of the user, (d) the axial length of the user's eye, including the user's retina, (e) an ultrasound measurement of the axial length of the user's eye, including the user's retina, and (f) an OCT measurement of the axial length of the user's eye, including the user's retina.

[0010] In many embodiments, the ophthalmic imaging system lacks a mechanism for adjusting the length of the optical path of the sample arm. For example, in many embodiments, the ophthalmic imaging system includes an objective lens assembly but does not include an adjustment mechanism configured to adjust the distance between the user's retina and the objective lens assembly.

[0011] The lack of an adjustment mechanism configured to adjust the distance between the user's retina and the objective lens assembly results in a reduced field of view on the retina for some users. To account for this reduced field of view, in some embodiments, the ophthalmic imaging system is configured to image a field of view equal to or less than 15 degrees on the user's retina for a reference arm length equal to any length within the reference arm length adjustment range. In some embodiments, the ophthalmic imaging system is configured to image a field of view equal to or less than 10 degrees on the user's retina for a reference arm length equal to any length within the reference arm length adjustment range.

[0012] OCT imaging devices can have a relatively small image depth. For example, in some embodiments, OCT imaging devices have an image depth of no more than 3 mm.

[0013] OCT imaging devices can have a relatively large sensitivity roll-off. For example, in some embodiments, OCT imaging devices have a sensitivity roll-off of no better than -3 dB at 2 mm.

[0014] The user-specific reference arm length range can be substantially smaller than the reference arm length adjustment range of the reference arm length adjustment module. For example, in many embodiments, the user-specific reference arm length range is less than half of the reference arm length adjustment range. In some embodiments, the user-specific reference arm length range is less than one-quarter of the reference arm length adjustment range.

[0015] The control unit can have any suitable configuration. For example, in many embodiments, the control unit is configured to receive input of a user-specific reference arm length range and store the user-specific reference arm length range in a memory device. In some embodiments, the control unit is configured to determine the user-specific reference arm length range by controlling a reference arm length adjustment module to change the reference arm length during imaging of the user's retina to search within the reference arm length adjustment range, thereby identifying the user-specific imaging reference arm length for which the OCT image detector generates an OCT signal corresponding to the user's retina. In some embodiments, the control unit determines the user-specific reference arm length range based on the user-specific imaging reference arm length.

[0016] The reference arm length adjustment range can include a relatively large reference arm length range. For example, in many embodiments, the reference arm length adjustment range includes a reference arm length range of at least 20 mm. The reference arm length adjustment range can include a reference arm length range of at least 30 mm. In some embodiments, the reference arm length adjustment range includes a reference arm length range of at least 40 mm.

[0017] User-specific reference arm length ranges can include relatively small reference arm length ranges. For example, in many embodiments, user-specific reference arm length ranges include reference arm length ranges of less than 10 mm. User-specific reference arm length ranges can include reference arm length ranges of less than 6 mm. In some embodiments, user-specific reference arm length ranges include reference arm length ranges of less than 4 mm.

[0018] In some embodiments, the ophthalmic imaging system includes a sensor that generates a signal indicating the position of features of the user's head relative to the housing. In such embodiments, the control unit can be configured to determine a user-specific reference arm length range based on the signal indicating the position of features of the user's head relative to the housing.

[0019] In some embodiments, the ophthalmic imaging system includes a sensor that generates a signal indicating the position of a feature of the user's forehead relative to the housing. In such embodiments, the control unit can be configured to determine a user-specific reference arm length range based on the signal indicating the position of the feature of the user's forehead relative to the housing.

[0020] In some embodiments, the ophthalmic imaging system includes a sensor that generates a signal indicating the position of features of a user's eye relative to the housing, wherein the eye includes the user's retina. In such embodiments, the control unit can be configured to determine a user-specific reference arm length range based on the signal indicating the position of features of the user's eye relative to the housing.

[0021] In many embodiments, the observer assembly includes a compliant member that adapts to the relative movement between the user's head and the OCT device. For example, in many embodiments, the observer assembly includes a compliant member whose thickness can vary by up to 10 mm in response to changes in pressure exerted by the user's head on the observer assembly. In some embodiments, the observer assembly includes a compliant member whose thickness can vary by up to 20 mm in response to changes in pressure exerted by the user's head on the observer assembly.

[0022] In many embodiments, the ophthalmic imaging system includes a focusing module controlled by a control unit to focus sample light transmitted through the sample arm optical path onto the user's retina. A focusing setting of the focusing module corresponding to a user-specific imaging reference arm length can be employed during imaging of the user's retina.

[0023] In many embodiments of ophthalmic imaging systems, the sample arm length for a particular user is substantially the same across imaging sessions of the user's retina. For example, in many embodiments, the observer assembly is configured to engage the user's head to constrain the user's head relative to the housing, such that the sample arm length is substantially the same across imaging instances of the user's retina.

[0024] In another aspect, a method for imaging the retina is provided. The method includes: restricting the user's head relative to the housing via an observer assembly coupled to a housing and engaged with the user's head, such that the optical path of a sample arm of an optical coherence tomography (OCT) imaging device attached to the housing extends to the user's retina. The method includes: controlling a reference arm length adjustment module of the OCT imaging device, via a control unit, to change the reference arm length of the reference arm optical path of the OCT imaging device to search a user-specific reference arm length range, thereby identifying the reference arm length at which the OCT image detector generates an OCT signal corresponding to the user's retina. The reference arm length adjustment module is controllable to change the reference arm length within a reference arm length adjustment range. The user-specific reference arm length range covers a reference arm length range smaller than the reference arm length adjustment range. The method includes imaging the user's retina using the OCT imaging device.

[0025] Any suitable method, such as those described herein, can be used to determine a suitable user-specific reference arm length range for use in methods of imaging the retina. For example, as described herein, a larger range of reference arm length adjustments for the adjustable reference arm module can be searched during initial imaging of the user's retina to identify the reference arm length at which the OCT image detector 38 generates the OCT signal corresponding to the user's retina. The identified reference arm length for the initial imaging of the user's retina can then be used to determine a suitable user-specific reference arm length range for use in subsequent imaging sessions of the user's retina. Alternatively, a suitable user-specific reference arm length range can be predetermined for any particular user. For example, the user-specific reference arm length range can be based on spatial information relating to one or more facial features of the user. In some embodiments, the user-specific reference arm length range may be based on one or more of the user's facial features, including the user's forehead, one or more of the user's cheeks, the cornea of ​​the user's eye including the user's retina, and the edge of the user's lateral orbit. Spatial information relating to one or more facial features of a user is generated via one or more of the following: (a) a three-dimensional scan of one or more facial features of the user, (b) caliper measurements of one or more facial features of the user relative to the user's eye, including the user's retina, (c) mask casting of one or more facial features of the user, (d) axial length of the user's eye, including the user's retina, (e) ultrasound measurement of the axial length of the user's eye, including the user's retina, and (f) OCT measurement of the axial length of the user's eye, including the user's retina.

[0026] In many embodiments, the method does not include adjusting the length of the sample arm optical path. For example, in many embodiments, the observer assembly includes an objective lens assembly, and the method does not include adjusting the distance between the user's retina and the objective lens assembly.

[0027] The lack of adjustment for the distance between the user's retina and the objective lens assembly results in a reduced field of view on the retina for some users. To account for this reduced field of view, in some embodiments, for a reference arm length equal to each of the lengths within the reference arm length adjustment range, imaging of the user's retina is limited to a field of view equal to or less than 15 degrees on the user's retina. In some embodiments, for a reference arm length equal to each of the lengths within the reference arm length adjustment range, imaging of the user's retina is limited to a field of view equal to or less than 10 degrees on the user's retina.

[0028] In some embodiments of this method, the OCT imaging device has a relatively small image depth. For example, the OCT imaging device may have an image depth of no more than 3 mm.

[0029] In some embodiments of this method, the OCT imaging device has a relatively large sensitivity roll-off. For example, the OCT imaging device may have a sensitivity roll-off of no better than -3 dB at 2 mm.

[0030] In many embodiments of this method, the user-specific reference arm length range is substantially smaller than the reference arm length adjustment range. For example, the user-specific reference arm length range may be less than half of the reference arm length adjustment range. In some embodiments of this method, the user-specific reference arm length range is less than one-quarter of the reference arm length adjustment range.

[0031] This method can be implemented using any suitable control unit. For example, in many embodiments, the method includes: (a) receiving input of a user-specific reference arm length range by the control unit, and (b) storing the user-specific reference arm length range in a tangible memory device by the control unit. In many embodiments, the method includes: (a) controlling a reference arm length adjustment module to change the reference arm length during imaging of the user's retina to search within the reference arm length adjustment range to identify a user-specific imaging reference arm length for which the OCT image detector generates an OCT signal corresponding to the user's retina; (b) determining the user-specific reference arm length range based on the user-specific imaging reference arm length by the control unit; and (c) storing the user-specific reference arm length range in a tangible memory device by the control unit.

[0032] The reference arm length adjustment range can include a relatively large reference arm length range. For example, in many embodiments of the method, the reference arm length adjustment range includes a reference arm length range of at least 20 mm. The reference arm length adjustment range can include a reference arm length range of at least 30 mm. In some embodiments of the method, the reference arm length adjustment range includes a reference arm length range of at least 40 mm.

[0033] The user-specific reference arm length range can include a relatively small reference arm length range. For example, in many embodiments of the method, the user-specific reference arm length range includes a reference arm length range of less than 10 mm. The user-specific reference arm length range can include a reference arm length range of less than 6 mm. In some embodiments of the method, the user-specific reference arm length range includes a reference arm length range of less than 4 mm.

[0034] Any suitable method can be used to determine the user-specific reference arm length range. For example, in some embodiments, the method includes: (a) receiving input of the user-specific reference arm length range by a control unit, and (b) storing the user-specific reference arm length range in a tangible memory device by the control unit. In some embodiments, the method includes: (a) controlling a reference arm length adjustment module to change the reference arm length during imaging of the user's retina to search within the reference arm length adjustment range to identify the user-specific imaging reference arm length for which the OCT image detector generates an OCT signal corresponding to the user's retina, (b) determining the user-specific reference arm length range based on the user-specific imaging reference arm length by the control unit, and (c) storing the user-specific reference arm length range in a tangible memory device by the control unit.

[0035] In some embodiments of the method, sensors are used to measure the user's position relative to the housing. For example, in some embodiments, the method includes: (a) generating a signal by a sensor indicating the position of features of the user's head relative to the housing, and (b) determining a user-specific reference arm length range by a control unit based on the signal indicating the position of features of the user's head relative to the housing. In some embodiments, the method includes: (a) generating a signal by a sensor indicating the position of features of the user's forehead relative to the housing, and (b) determining a user-specific reference arm length range by a control unit based on the signal indicating the position of features of the user's forehead relative to the housing. In some embodiments, the method includes: (a) generating a signal by a sensor indicating the position of features of the user's eye, including the user's retina, relative to the housing, and (b) determining a user-specific reference arm length range by a control unit based on the signal indicating the position of features of the user's eye relative to the housing.

[0036] In many embodiments of the method, the observer assembly includes a compliant member that adapts to the amount of relative movement between the user and the OCT device. For example, in many embodiments of the method, the observer assembly includes a compliant member whose thickness can change by up to 10 mm in response to changes in the pressure exerted by the user's head on the observer assembly. In some embodiments of the method, the observer assembly includes a compliant member whose thickness can change by up to 20 mm in response to changes in the pressure exerted by the user's head on the observer assembly.

[0037] In many embodiments of the method, the ophthalmic imaging system includes a focusing module that is controllable to focus sample light transmitted through the sample arm optical path onto the retina. The method may include: (a) storing, by a control unit, a focusing setting of the focusing module of the OCT imaging device corresponding to a user-specific reference arm length range, and (b) employing that focusing setting during imaging of the user's retina.

[0038] In many embodiments of this method, the sample arm length for a particular user is substantially the same throughout an imaging session of the user's retina. For example, in many embodiments, the observer assembly is configured to engage the user's head to constrain the user's head relative to the housing, such that the sample arm length is substantially the same for each imaging instance of the user's retina.

[0039] In another aspect, an ophthalmic imaging system for imaging a user's retina includes an optical coherence tomography (OCT) imaging device, a housing to which the OCT imaging device is attached, an observer assembly coupled to the housing, an objective lens assembly, and a control unit. The OCT imaging device includes a sample arm optical path, an OCT image detector, a reference arm optical path having a reference arm length, and a reference arm length adjustment module controllable to change the reference arm length within a reference arm length adjustment range. The observer assembly is configured to engage the user's head to restrict the user's head relative to the housing, such that the sample arm optical path extends to the user's retina. The ophthalmic imaging system does not include an adjustment mechanism configured to adjust the distance between the user's retina and the objective lens assembly. The control unit is operatively connected to the OCT image detector and the reference arm length adjustment module. The control unit is configured to control the reference arm length adjustment module to change the reference arm length to indicate the reference arm length at which the OCT image detector generates an OCT signal corresponding to the user's retina.

[0040] In many embodiments, the ophthalmic imaging system images a reduced visual field on the user's retina. For example, in many embodiments, the ophthalmic imaging system is configured to image a visual field of equal to or less than 15 degrees on the user's retina for a reference arm length equal to each of all lengths within the reference arm length adjustment range. In some embodiments, the ophthalmic imaging system is configured to image a visual field of equal to or less than 10 degrees on the user's retina for a reference arm length equal to each of all lengths within the reference arm length adjustment range.

[0041] In many embodiments of ophthalmic imaging systems, the sample arm length for a particular user is substantially the same throughout an imaging session of the user's retina. For example, in many embodiments, the observer assembly is configured to engage the user's head to constrain the user's head relative to the housing, such that the sample arm length is substantially the same for each imaging instance of the user's retina.

[0042] To gain a more complete understanding of the nature and advantages of this invention, reference should be made to the following detailed descriptions and accompanying drawings. Attached Figure Description

[0043] Figure 1 A user is shown engaging an observer component of an ophthalmic imaging system, including an OCT imaging device, according to an embodiment.

[0044] Figure 2 yes Figure 1 A simplified schematic diagram of the components and associated optical paths of an OCT imaging device in an ophthalmic imaging system.

[0045] Figure 3 This illustrates the field of view on the retina when the pupil is positioned at the focal length of an ophthalmic lens in an ophthalmic OCT imaging system.

[0046] Figure 4 This illustrates the reduced field of view on the retina when the pupil is positioned away from the focal length of the ophthalmic lens in an ophthalmic OCT imaging system.

[0047] Figure 5 yes Figure 1 A simplified schematic diagram of the components of an OCT imaging device in an ophthalmic imaging system.

[0048] Figure 6 This is a simplified schematic block diagram of the operation of a method for imaging the retina during an imaging session according to an embodiment.

[0049] Figure 7 An example search range for the reference arm path length for initial imaging and subsequent imaging of a particular user's retina, according to an embodiment, is shown.

[0050] Figure 8 This is a simplified schematic block diagram according to an embodiment of a method for determining a user-specific reference arm length range based at least in part on the user's position measured by sensors in order to search for actions for imaging the user's retina during a subsequent imaging session.

[0051] Figure 9 The example feature-based search range for the reference arm path length for initial imaging and subsequent imaging of the retina of a particular user, according to an embodiment, is shown. Detailed Implementation

[0052] In the following description, various embodiments of the invention will be described. Specific configurations and details are set forth for illustrative purposes to provide a thorough understanding of the embodiments. However, it will also be apparent to those skilled in the art that the invention may be practiced without these specific details. Furthermore, well-known features may be omitted or simplified so as not to obscure the described embodiments.

[0053] Referring now to the accompanying drawings, in which the same reference numerals denote the same parts in these views. Figure 1 A user 12 is shown viewing the observation port 14 of the observer assembly 16 of an ophthalmic imaging system 10, according to many embodiments. The ophthalmic imaging system 10 includes an optical coherence tomography (OCT) imaging device 18 to which the observer assembly 16 is coupled. The observer assembly 16 is configured to engage with the user's head to restrict the user's head relative to the OCT imaging device 18, thereby positioning one of the user 12's eyes substantially on the optical axis of the OCT imaging device 18. For example, in Figure 1 In the configuration shown, the observer assembly 16 is configured to approximately position the user 12's right eye on the optical axis of the OCT imaging device 18. In the illustrated embodiment, the observer assembly 16 may be rotated 180 degrees relative to the OCT imaging device 18 about pivot 20 to facilitate reconfiguration of the observer assembly 16 for approximately positioning the user 12's left eye on the optical axis of the OCT imaging device 18. Thus, each of the user 12's right and left eyes can be selectively and approximately positioned on the optical axis of the OCT imaging device 18 for imaging of the respective eye by the OCT imaging device 18. In many embodiments, the final positioning and alignment of the optical axis of the user 12's respective eye with the optical axis of the OCT imaging device 18 is achieved by the user 12 adjusting the position of the user's head relative to the observation port 14 in response to feedback provided to the user 12 by the ophthalmic imaging device 18.

[0054] In many embodiments, the OCT imaging device 18 automatically adjusts the reference arm path length as described herein during an imaging session (during which an OCT image is generated for the user's retina). The OCT imaging device 18 can have any suitable configuration to accommodate the automatic adjustment of the reference arm path length. For example, Figure 2 A simplified schematic diagram of the components and associated optical paths of an embodiment of the OCT imaging device 18 is shown. Figure 2The components of the OCT imaging device 18 shown include a broadband light source 22, a dual-mirror scanner 24, focusing lenses 26 and 28, dichroic mirrors 30, 32, and 34, an adjustable reference arm module 36, an OCT image detector 38, an eye illuminator 40, an eye camera 42, and a display device 44. In the illustrated embodiment, the OCT imaging device 18 is a spectral domain OCT imaging device operating in the wavelength range of 800 nm to 900 nm. The eye illuminator 40 uses light of a suitable wavelength (e.g., light with a wavelength greater than 920 nm) to illuminate the eyes 46 of the user 12. The display device 44 can project light of any suitable wavelength (e.g., from 400 nm to 700 nm). The dichroic mirror 30 transmits the OCT wavelength and the display wavelength range (400 nm to 900 nm) and reflects the illumination wavelength (e.g., greater than 920 nm) to the eye camera 40. The dichroic mirror 32 transmits the display wavelength range and reflects the OCT wavelength.

[0055] In operation, a broadband light source 22 generates OCT wavelength light. The OCT wavelength light propagates from the light source 22 to a dichroic mirror 34. The sample arm portion of the OCT wavelength light passes through the dichroic mirror 34 and continues propagating along the sample arm optical path 48 to the eye 46. The reference arm portion of the OCT wavelength light is reflected by the dichroic mirror 34 so that it propagates along the reference arm optical path extending into the adjustable reference arm module 36. The sample arm portion of the OCT wavelength light is focused onto the retina of the eye 46. The OCT wavelength light focused on the retina is scattered by the retina, causing the backscattered portion of the OCT wavelength light to propagate back along the sample arm optical path 48. The backscattered portion of the OCT wavelength light passes through a dichroic mirror 30 and is reflected back to the dichroic mirror 34 by the dichroic mirror 32 and the dual-mirror scanner 24. The dichroic mirror 34 reflects the backscattered portion of the OCT wavelength light to the OCT image detector 38. The adjustable reference arm module 36 includes a reference arm mirror 50 that reflects a reference arm portion of the OCT wavelength light back to a dichroic mirror 34. The returned portion of the reference arm portion of the OCT wavelength light passes through the dichroic mirror 34 and reaches an OCT image detector 38. In response to the combined incident of the returned sample arm OCT light and the returned reference arm OCT light onto the OCT image detector 38, the OCT image detector 38 generates and outputs an OCT image signal, which is processed using known techniques to construct a three-dimensional OCT image of the retinal layer. In many embodiments, the OCT image detector 38 detects interference between the returned sample arm light and the reference arm light only when the travel times of the light in the reference arm and the sample arm are approximately equal. In many embodiments, the reference arm mirror 50 is mounted to a motor mechanism that is controllable to change the position of the reference arm mirror 50, thereby controllably changing the optical path length of the reference arm. The ability to change the reference arm path length enables the OCT imaging device 18 to be used to generate OCT images of the retinas of any user group of the desired user population, even though the retinas of each user may be at different distances from the OCT imaging device 18 when the user's head is engaged with the observer assembly 16 due to corresponding anatomical variations between the user's head and variations in the relative position between the user's head and the observer assembly 16.

[0056] In many embodiments, the eye illuminator 40, eye camera 42, and display device 44 are used to provide feedback to the user 12, through which the user 12 self-aligns their eye 46 with the optical axis of the OCT imaging device 18. The display device 44 displays a fixed target observed by the user to align the eye 46. The eye camera 42 measures the current position of the eye relative to the optical axis of the OCT imaging device 18 by illuminating the eye 46 via the eye illuminator 40. Based on the measured position of the eye relative to the optical axis of the OCT imaging device 18, the display device 44 further displays feedback to the user 12, through which the user adjusts the position of their head relative to the observer assembly 16 to position the user's eye 46 within an acceptable distance of the optical axis of the OCT imaging device 18 for generating an OCT image of the user's retina.

[0057] like Figure 3 As shown, by minimizing the amount of iris obstruction in the sample arm portion of the OCT wavelength light, the pupil is positioned at the focal length of ophthalmic lens 28 to maximize the imageable area on the retina. Conversely, as Figure 4 As shown, positioning the pupil away from the focal length of the ophthalmic lens 28 reduces the area on the retina that can be imaged. Therefore, in order to image the entire macula (approximately 20 degrees), existing ophthalmic OCT systems include a device for adjusting the distance between the pupil and the ophthalmic lens of the OCT system. In some existing ophthalmic OCT systems, the distance between the entire ophthalmic OCT system and the user's pupil is adjustable. In some other existing ophthalmic OCT systems, the position of the ophthalmic lens relative to the rest of the ophthalmic OCT system is adjustable to adjust the distance between the ophthalmic lens and the user's pupil. In some other existing ophthalmic OCT systems, the position of the user's head is moved relative to the ophthalmic OCT system to adjust the distance between the ophthalmic lens and the user's pupil.

[0058] In existing ophthalmic OCT systems, eliminating the ability to reposition the pupil relative to the ophthalmic lens would severely degrade performance. For example, in existing ophthalmic OCT systems, eliminating the ability to reposition the pupil relative to the ophthalmic lens could result in: (a) a significantly reduced field of view on the retina due to iris obstruction, and / or (b) the inability to adjust the reference arm path length to the length required for retinal imaging in the absence of sufficient adjustment range for the reference arm path length in existing ophthalmic OCT systems.

[0059] In contrast to existing ophthalmic OCT systems, in many embodiments of the ophthalmic OCT system described herein, the distance between the user's pupil and the ophthalmic lens is substantially fixed, and the ophthalmic OCT system does not include an adjustment mechanism configured to adjust the distance between the user's pupil and the objective lens assembly. To accommodate the lack of an adjustment mechanism configured to adjust the distance between the user's pupil and the objective lens assembly, an adjustable reference arm module 36 is configured to be controllable to change the reference arm path length within a range significantly larger than that in current ophthalmic OCT systems. For existing ophthalmic OCT imaging systems, the adjustment of the reference arm path length only needs to accommodate variations in the axial length of the eye for different users. For (+ / - 6 diopters), the typical axial length of the eye can vary by + / - 3 mm. As a result, the adjustment of the reference arm path length in existing OCT imaging systems does not need to exceed approximately 6 mm. In contrast, the position of a facial landmark relative to the eye varies much more significantly. A facial landmark can vary within a range of + / - 30 mm. Therefore, in many embodiments, the reference arm length adjustment range includes a relatively large range of reference arm lengths. For example, in many embodiments of this method, the reference arm length adjustment range includes a reference arm length range of at least 20 mm. The reference arm length adjustment range may include a reference arm length range of at least 40 mm. In some embodiments of this method, the reference arm length adjustment range includes a reference arm length range of at least 60 mm.

[0060] However, a larger reference arm path length adjustment range itself increases the time spent searching within that range to identify the reference arm length for which the OCT image detector 38 generates the OCT signal corresponding to the user's retina. Increased search time significantly increases chair time, leading to fixation loss and increased technician costs. To limit search time, in many embodiments described herein, a user-specific reference path arm length range is employed to restrict the search for identifying the reference arm length for which the OCT image detector generates the OCT signal corresponding to the user's retina to a suitably small range for the specific user.

[0061] Any suitable method, such as those described herein, can be used to determine a suitable range of user-specific reference path arm lengths for a particular user. For example, as described herein, a larger range of reference arm path length adjustments for the adjustable reference arm module 36 can be searched during initial imaging of the user's retina to identify the reference path length for which the OCT image detector 38 generates the OCT signal corresponding to the user's retina. The identified reference path length for the initial imaging of the user's retina can then be used to determine a suitable range of user-specific reference path arm lengths for use in subsequent imaging sessions of the user's retina. Alternatively, a suitable range of user-specific reference path arm lengths for any particular user can be predetermined based on spatial information relating to the user's facial features (e.g., forehead, cheeks, cornea, lateral orbital margins, and / or any other suitable facial features) and the relationships between them. Spatial information relating to the user's facial features can be captured / measured in any suitable manner, including but not limited to any suitable virtual method, any suitable physical method, and any suitable combination of virtual and physical methods. For example, spatial information related to the user's facial features and / or a suitable range of user-specific reference path arm lengths can be determined based on: (a) a three-dimensional scan of the user's face, (b) caliper measurements of specific landmarks on the user's face relative to the user's eyeballs, (c) mask casting of the user's face, (d) combining (a) to (c) with the axial length of the eye (e.g., measured via ultrasound, OCT, etc.), combining the axial length of the eye with measurements of the distance to the facial landmarks to determine the distance from the facial landmarks to the retina, and / or (e) OCT measurements via OCT image detector 38.

[0062] Furthermore, in the absence of an adjustment mechanism for adjusting the distance between the user's pupil and the objective lens assembly, for some users, such as those with smaller pupils positioned far from the focal length of the ophthalmic lens 28, this can result in a reduced field of view on the user's retina. To accommodate the variability in the resulting field of view for different users, in some embodiments, the ophthalmic imaging system 10 images a fixed reduced field of view for all users. For example, in some embodiments, the ophthalmic imaging system 10 is configured to image a field of view equal to or less than 15 degrees on the user's retina for a reference arm length equal to any length within the reference arm length adjustment range. In some embodiments, the ophthalmic imaging system 10 is configured to image a field of view equal to or less than 10 degrees on the user's retina for a reference arm length equal to any length within the reference arm length adjustment range.

[0063] In many embodiments, the OCT imaging device 18 is configured to automatically control components / modules of the OCT imaging device 18 during an imaging session (during which an OCT image of the user's retina is generated). In many embodiments, the OCT imaging device 18 includes a suitable control unit operatively connected to and configured to communicate with and / or control the component / module. For example, Figure 5 This is a simplified schematic diagram illustrating components / modules of an embodiment of an OCT imaging device 18, which includes a control unit 30 operatively coupled to the components / modules. The control unit 30 includes a processor 33 and a data storage device 34. The data storage device 34 stores program instructions executable by the processor 33 to perform the actions described herein. The data storage device 34 also stores user-specific data as described herein, which is used by the processor 33 to customize control of the operation of the OCT imaging device 18 for a specific user, as described herein.

[0064] The control unit 30 is operatively connected to the user interface 32 to receive input from the user and / or display output to the user via the user interface 32. Any suitable user interface 32 may be used, including but not limited to one or more buttons, a display, a touch display, one or more indicator lights, and / or a speaker. The user interface 32 may be configured to allow the user to input an identifier for the imaging session, enabling the control unit 30 to use scan parameters stored in the data storage device 34 when controlling components / modules of the OCT imaging device 18 during the user's imaging session.

[0065] The control unit 30 is operatively connected to the eye illuminator 40, the eye camera 42, and the display device 44. The control unit 30 can turn on the eye illuminator 40 at the start of an imaging session and turn it off at the end of the imaging session. In many embodiments, the control unit 30 turns on the eye camera 42 at the start of an imaging session, receives image data from the eye camera 42, processes the image data to track the position of the optical axis of the eye 46 relative to the optical axis of the OCT imaging device 18, and turns off the eye camera 42 at the end of the imaging session. In many embodiments, the control unit 30 turns on the display device 44 at the start of an imaging session, generates feedback on the display device 44 and displays the feedback to the user, enabling the user to reposition their head relative to the observer assembly 16 so that the user's eye 46 is fully aligned with the optical axis of the OCT imaging device 18 for generating an OCT image of the user's retina, and turns off the display device 44 at the end of the imaging session.

[0066] Control unit 30 is operatively connected to broadband light source 22, dual-mirror scanner 24, reference arm length adjustment module 36, OCT image detector 38, and focusing module 52 to control the operation of these components / modules during the OCT imaging portion of an imaging session. Control unit 22 can turn on broadband light source 22 at the beginning of the OCT scanning portion of the imaging session to initiate the transmission of OCT wavelength light across the sample and reference arm, and can turn off light source 22 at the end of the imaging session. Control unit 30 can control reference arm length adjustment module 36 to change the reference arm length to search for user-specific reference arm lengths(s) as described herein, for which OCT image detector 38 generates appropriate OCT signals for use in generating OCT images of the user's retina. Control unit 30 can also control reference arm length adjustment module 36 to change the reference arm length to search within a previously determined range of user-specific reference arm lengths for the corresponding user, thereby identifying a reference arm length for which OCT image detector 38 generates appropriate OCT signals for use in generating OCT images of the user's retina. The control unit 30 may also control the reference arm length adjustment module 36 to optimize the OCT signal generated by the OCT image detector 38 and / or adjust the reference arm length in response to movement of the eye 46 relative to the OCT imaging device 18. In many embodiments, the control unit 30 stores in the data storage device 34 one or more reference arm lengths and / or one or more settings of the reference arm length adjustment module 36 that the OCT image detector 38 is found to generate suitable OCT signals during a user's imaging session, for use in conjunction with control of the reference arm length adjustment module 36 during subsequent imaging sessions of the user, as described herein. In many embodiments, the control unit 30 stores in the data storage device 34 a previously determined user-specific reference arm length range for a given user, which is searched during imaging of the user's retina to identify a reference arm length for which the OCT image detector 38 generates suitable OCT signals for use in generating OCT images of the user's retina. The control unit 30 may control the focusing module 52 to change the settings of the focusing module 52 to focus the sample arm OCT wavelength light onto the target surface of the retina of the eye 46. The control unit 30 can store appropriate settings for the focusing module 52 used during an imaging session for a user in the data storage device 34 for use as settings for the focusing module 52 during subsequent imaging sessions for the user, as described herein.In many embodiments, the control unit 30 turns on the OCT image detector 38 at the beginning of the OCT scanning portion of the imaging session, receives the OCT detector output signal generated by the OCT image detector 38, processes the OCT detector output signal to generate an OCT image of the retina and determines how to control the reference arm length adjustment module 36 and the focusing module 52 during the imaging session, and turns off the OCT image detector 38 at the end of the imaging session. In many embodiments, the control unit 30 controls the operation of the dual-mirror scanner 24 during the imaging session. During the initial portion of the imaging session, the control unit 30 may control the dual-mirror scanner 24 to perform a limited two-dimensional scan of the sample arm OCT wavelength light, which is suitable for searching for suitable settings for the reference arm length adjustment module 36 and / or the focusing module 52, for which the OCT image detector 38 generates a suitable OCT detector output signal for the generation of an OCT image of the retina. Once the control unit 30 determines the suitable settings for the reference arm length adjustment module 36 and / or the focusing module 52, the control unit 30 may control the operation of the dual-mirror scanner 24 to perform a two-dimensional scan of the sample arm OCT wavelength light suitable for generating an OCT image of the retina.

[0067] Figure 6 This is a simplified schematic block diagram of the operation of a method 100 for imaging the retina by an ophthalmic imaging system during an imaging session, according to an embodiment. Any suitable ophthalmic imaging system (such as the ophthalmic imaging system 10 described herein) can be used to practice method 100.

[0068] In action 102, the user's identifier for the ophthalmic imaging system is input into the ophthalmic imaging system for use in controlling the OCT imaging device of the ophthalmic imaging system during an imaging session. For example, the user's identifier may be used to retrieve user-specific reference arm length data and / or user-specific focus data for use in controlling the OCT imaging device during an imaging session. The user's identifier may also be used to store user-specific reference arm length data and / or user-specific focus data determined during an imaging session for use in one or more subsequent imaging sessions for the identified user.

[0069] In action 104, the identifier of the user used for the imaging session can be used to determine the appropriate reference arm search range for the imaging session. If reference arm length data is not stored for the identified user, the reference arm search range for the imaging session can be set to a default initial search range suitable for a target user group that includes the identified user. For example, Figure 7An example search range for the reference arm path length of an OCT imaging device is shown for initial imaging and subsequent imaging of the user's retina. The search range for the reference arm path length for subsequent imaging of the user's retina is typically smaller than the search range for the reference arm path length for initial imaging of the user's retina because the search range for subsequent imaging is determined based on the reference arm path length used to generate OCT images of the user's retina during (multiple) earlier imaging sessions. During the identified initial imaging session of the user's retina, the reference arm search range for that imaging session can be limited between two options: a maximum reference arm length 130 suitable for the target user group and a minimum reference arm length 132. During the identified subsequent imaging session of the user's retina, the reference arm search range for that imaging session can be limited between two options: a user-specific maximum reference arm length 134 and a user-specific minimum reference arm length 136 based on the reference arm length used to image the user's retina during one or more previous imaging sessions. For example, a user-specific maximum reference arm length 134 can be set by adding an appropriate path length increment to the initial imaging maximum reference arm length 138, which is used during the initial imaging session for the identified user to generate an OCT image of the user's retina. Similarly, a user-specific minimum reference arm length 136 can be set by subtracting an appropriate path length increment from the initial imaging minimum reference arm length 140, which is used during the initial imaging session for the identified user to generate an OCT image of the user's retina.

[0070] In action 106, the user's head engages with the observer assembly to limit the position of the user's head relative to the OCT imaging device during the imaging session. In many embodiments, the OCT imaging device provides feedback to the user, enabling the user to reposition their head to position the user's eye, to be imaged, within a suitable distance from and properly aligned with the optical axis of the OCT imaging device for generating an OCT image of the user's retina.

[0071] In action 108, while appropriately restricting the user's eye relative to the optical axis of the OCT imaging device, the reference arm length of the OCT imaging device is changed to search within the reference arm search range used for this imaging session, identifying a suitable reference arm length for generating an OCT image of the user's retina. For example, in OCT imaging device 18, the position of the reference arm mirror 50 is controlled by control unit 30 to change the reference arm length within the reference arm search range used for this imaging session. The OCT image detector output signal is monitored by control unit 30 to identify the reference arm length, for which the OCT image detector output signal indicates that the reference arm length is sufficiently close to the sample arm length to generate an OCT image of the user's retina. To expedite the search for a suitable reference arm length for this imaging session, the extent to which the sample arm OCT light is scanned in a two-dimensional manner during the search for a suitable reference arm length can be limited compared to a two-dimensional scan for generating an OCT image of the retina. When the reference arm search range used for this imaging session is based on the length of (multiple) reference arms used to generate the user's OCT images during one or more previous imaging sessions, the time required to search for the user-specific reference arm search range can be significantly reduced compared to the time required to search for a larger reference arm search range for the user's initial imaging session.

[0072] In action 110, the sample arm OCT wavelength light is focused onto the retina, and, if necessary, the reference arm length is adjusted to optimize the OCT image detector output signal. For example, in OCT imaging device 18, control unit 30 can control focusing module 52 to change the optical power of focusing module 52 to change the focusing of sample arm OCT wavelength light on the target surface of the retina, while monitoring the OCT image detector output signal to identify the setting of focusing module 52, which optimizes the OCT image detector output signal at an appropriate position on the target surface of the retina. Once the optimal setting of focusing module 52 is identified, control unit 30 can control reference arm length adjustment module 36 to finely change the reference arm length, while monitoring the OCT image detector output signal to identify the setting of reference arm length adjustment module 36, which optimizes the OCT image detector output signal for the optimal setting of focusing module 52.

[0073] In action 112, the identified reference path length and the identified focus setting are used during the generation of the OCT image of the user's retina. In some embodiments, the reference path length is controlled during the generation of the OCT image to optimize the OCT image detector output signal throughout the entire generation period of the OCT image.

[0074] In action 114, the lengths of multiple reference arms used to generate OCT images during an imaging session are stored in a memory device (e.g., data storage device 34 of control unit 30) to be associated with the identified user for determining the reference arm search range for subsequent imaging sessions of the identified user. If the reference arm path length is changed during OCT image generation to optimize the OCT image detector output signal throughout the entire OCT image generation period and / or in response to eye movement relative to the OCT imaging device, the maximum and minimum reference arm lengths used during OCT image generation can be stored in the memory device to be associated with the identified user for determining the reference arm search range for subsequent imaging sessions of the identified user.

[0075] In action 116, the focusing settings used during the generation of the OCT image can be stored in a memory device for association with the identified user, for use in subsequent imaging sessions of the identified user. For example, in OCT imaging device 18, control unit 30 can store the settings of focusing module 52 in data storage device 34 for association with the identified user, for use as settings of focusing module 52 in subsequent imaging sessions of the identified user.

[0076] Figure 8 This is a simplified schematic diagram of the additional actions that can be performed in method 100 to determine the reference arm search range for a subsequent imaging session for the identified user. In action 118, a sensor generates a signal indicating the position of a feature of the user's head relative to the OCT imaging device. For example, in ophthalmic imaging system 10, a sensor may be mounted to observer assembly 16 and generate a signal indicating the position of a feature of the user's head relative to OCT imaging device 18. In action 120, the control unit uses the measured position of the feature of the user's head relative to the OCT imaging device to determine the reference arm search range for the imaging session. For example, in embodiments where observer assembly 16 includes a compliant member that deforms by different amounts in response to different interfacial force amplitudes applied to observer assembly 16 by the user's head, the measured position of the feature of the user's head relative to the OCT imaging device can be used to determine the reference arm search range for the imaging session to take into account the actual overall position of the user's head relative to the OCT imaging device. By taking into account the actual overall position of the user's head relative to the OCT imaging device, the reference arm search range for the imaging session can cover a smaller range of reference arm lengths compared to when the actual overall position of the user's head relative to the OCT imaging device is unknown. For example, Figure 9The diagram illustrates: an example of a non-feature-based initial reference arm search range 142 suitable for an initial imaging session of a user, for which the overall position of the user's head relative to the OCT imaging device is unknown; an example of a feature-based initial reference arm search range 144 suitable for an initial imaging session of a user, for which the overall position of the user's head has been measured via a sensor that generates a signal indicating the position of the user's head features relative to the OCT imaging device; and an example of a feature-based user-specific reference arm search range 146 suitable for a subsequent imaging session of the user, for which the overall position of the user's head has been measured via a sensor that generates a signal indicating the position of the user's head features relative to the OCT imaging device. The non-feature-based initial reference arm search range 142 can be selected as a suitable range for a target user group and for the expected overall position of the head relative to the OCT imaging device for each member of the target user group. The feature-based initial reference arm search range 144 can be selected based on the measured overall position of the user's head and the target user group. By measuring the actual overall position of the user's head relative to the OCT imaging device, the feature-based initial reference arm search range 144 covers a smaller range of reference arm lengths than the non-feature-based initial reference arm search range 142, which accommodates possible variations in the overall position between the user's head and the OCT imaging device. The feature-based user-specific reference arm search range 146 covers a smaller range of reference arm lengths than the feature-based initial reference arm search range 144 because it is based on both the measured overall position of the specific user's head relative to the OCT imaging device and the reference arm lengths used during the generation of OCT images of the specific user's retina during one or more previous imaging sessions. In action 122, data defining the relationship between the reference arm lengths suitable for generating OCT images of the user's retina and the position of features of the user's head during the generation of OCT images of the user's retina is stored in memory for use during subsequent imaging of the user's retina. In action 124, the following signals and data are used to determine the feature-based user-specific reference arm search range 146 for the imaging session: signals generated by the sensor during subsequent imaging sessions of the user, and data defining the relationship between the reference arm length suitable for the generation of OCT images of the user's retina and the position of features of the user's head during the previous generation of OCT images of the user's retina.

[0077] Other variations are also within the spirit of this invention. Thus, while the invention is readily adaptable to various modifications and alternative constructions, certain illustrated embodiments are shown in the accompanying drawings and have been described in detail above. However, it should be understood that this is not intended to limit the invention to the one or more specific forms disclosed, but rather to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention, as defined in the appended claims.

[0078] In the context of describing the invention (especially in the context of the following claims), the terms “a,” “an,” and “the,” and similar designations are intended to cover both singular and plural forms, unless otherwise stated herein or obviously contradicted by the context. The terms “comprising,” “having,” “consisting of,” and “including” should be interpreted as open-ended terms (i.e., meaning “including, but not limited to”), unless otherwise noted. The term “connected” should be interpreted as being partially or wholly included, attached to, or combined, even in the presence of some intermediary. The recitation of value ranges herein is intended only as a shorthand method for individually referring to each individual value falling within that range, unless otherwise stated herein, and each individual value is incorporated into this specification as if it were separately recited herein. All methods described herein may be performed in any suitable order, unless otherwise stated herein or obviously contradicted by the context. The use of any and all examples or exemplary language (e.g., “such as”) provided herein is intended only to better illustrate the invention and does not constitute a limitation on the scope of the invention, unless otherwise required. The language in this specification should not be construed as indicating that any unclaimed element is necessary for practicing the invention.

[0079] Preferred embodiments of the invention have been described herein, including the best modes known to the inventors for carrying out the invention. Variations of these preferred embodiments will become apparent to those skilled in the art upon reading the prior description. The inventors expect those skilled in the art to adopt these variations as appropriate, and the inventors intend for the invention to be practiced in forms other than those specifically described herein. Correspondingly, the invention includes all modifications and equivalents to the subject matter set forth in the appended claims, as permitted by applicable regulations. Furthermore, any combination of the foregoing elements in all possible variations is covered by the invention unless otherwise stated herein or clearly contradicted by the context.

[0080] All references cited in this document (including publications, patent applications and patents) are incorporated herein by reference as if each reference were individually and specifically indicated to be incorporated by reference and to be presented in its entirety in this document.

[0081] Examples of embodiments of this disclosure can be described from the perspective of the following terms:

[0082] Clause 1. An ophthalmic imaging system for imaging a user's retina, the ophthalmic imaging system comprising: an optical coherence tomography (OCT) imaging device including a sample arm optical path, an OCT image detector, a reference arm optical path having a reference arm length, and a reference arm length adjustment module controllable to change the reference arm length within a reference arm length adjustment range; a housing to which the OCT imaging device is attached; an observer assembly coupled to the housing, the observer assembly being configured to engage a user's head to restrict the user's head relative to the housing such that the sample arm optical path extends to the user's retina; and a control unit operatively connected to the OCT image detector and the reference arm length adjustment module, the control unit being configured to: store a user-specific reference arm length range covering a reference arm length range smaller than the reference arm length adjustment range; and control the reference arm length adjustment module to change the reference arm length to search within the user-specific reference arm length range, thereby identifying the reference arm length at which the OCT image detector generates an OCT signal corresponding to the user's retina.

[0083] Clause 2. The ophthalmic imaging system of Clause 1, wherein the range of user-specific reference arm lengths is predetermined.

[0084] Clause 3. Ophthalmic imaging systems of Clause 1 or 2, wherein the user-specific reference arm length range is based on spatial information relating to one or more facial features of the user.

[0085] Clause 4. The ophthalmic imaging system of Clause 3, wherein one or more facial features of the user include one or more of the following: the user's forehead, one or more cheeks of the user, the cornea of ​​the user's eye including the user's retina, and the edge of the user's lateral orbit.

[0086] Clause 5. Clause 3's ophthalmic imaging system, wherein spatial information relating to one or more facial features of a user is generated via one or more of the following: a three-dimensional scan of one or more facial features of the user; caliper measurement of one or more facial features of the user relative to a user's eye including the user's retina; mask casting of one or more facial features of the user; axial length of a user's eye including the user's retina; ultrasound measurement of the axial length of a user's eye including the user's retina; and OCT measurement of the axial length of a user's eye including the user's retina.

[0087] Clause 6. Clause 1's ophthalmic imaging system includes an objective lens assembly, wherein the ophthalmic imaging system does not include an adjustment mechanism configured to adjust the distance between the user's retina and the objective lens assembly.

[0088] Clause 7. An ophthalmic imaging system of Clauses 1, 2 or 6, wherein the ophthalmic imaging system is configured to: image a visual field of equal or less than 15 degrees on the user's retina for a reference arm length equal to any length within the range of reference arm length adjustment.

[0089] Clause 8. Clause 7's ophthalmic imaging system, wherein the ophthalmic imaging system is configured to: image a visual field of equal to or less than 10 degrees on the user's retina for a reference arm length equal to any length within the reference arm length adjustment range.

[0090] Clause 9. Clause 1's ophthalmic imaging system, wherein the OCT imaging device has an image depth of not more than 3 mm.

[0091] Clause 10. An ophthalmic imaging system of Clauses 1, 2, 6 or 9, wherein the OCT imaging device has a sensitivity roll-off of no more than -3 dB at 2 mm.

[0092] Clause 11. The ophthalmic imaging system of Clause 1, wherein the user-specific reference arm length range is less than half of the reference arm length adjustment range.

[0093] Clause 12. Ophthalmic imaging systems of Clauses 1, 2, 6, 9 or 11, wherein the user-specific reference arm length range is less than one-quarter of the reference arm length adjustment range.

[0094] Clause 13. An ophthalmic imaging system of Clauses 1, 2, 6, 9 or 11, wherein the control unit is configured to: receive input of a user-specific reference arm length range; and store the user-specific reference arm length range in a tangible memory device.

[0095] Clause 14. An ophthalmic imaging system of Clauses 1, 6, 9, or 11, wherein: the control unit is configured to determine a user-specific reference arm length range by: controlling a reference arm length adjustment module to change the reference arm length during imaging of the user's retina to search within the reference arm length adjustment range, thereby identifying a user-specific imaging reference arm length for which the OCT image detector generates an OCT signal corresponding to the user's retina; and the control unit determining the user-specific reference arm length range based on the user-specific imaging reference arm length.

[0096] Clause 15. The ophthalmic imaging system of Clause 1, wherein the reference arm length adjustment range includes a reference arm length range of at least 20 mm.

[0097] Clause 16. The ophthalmic imaging system of Clause 15, wherein the reference arm length adjustment range includes a reference arm length range of at least 30 mm.

[0098] Clause 17. The ophthalmic imaging system of Clause 16, wherein the reference arm length adjustment range includes a reference arm length range of at least 40 mm.

[0099] Clause 18. The ophthalmic imaging system of Clause 1, wherein the user-specific reference arm length range includes a reference arm length range of less than 10 mm.

[0100] Clause 19. The ophthalmic imaging system of Clause 18, wherein the user-specific reference arm length range includes a reference arm length range of less than 6 mm.

[0101] Clause 20. Clause 19 of the ophthalmic imaging system, wherein the user-specific reference arm length range includes a reference arm length range of less than 4 mm.

[0102] Clause 21. An ophthalmic imaging system of Clauses 1, 6, 9, 11, 15, 16, 17, 18, 19 or 20, further includes a sensor that generates a signal indicating the position of a feature of a user's head relative to the housing, and wherein a control unit determines a user-specific reference arm length range based on the signal indicating the position of a feature of a user's head relative to the housing.

[0103] Clause 22. Clause 21 of the ophthalmic imaging system, wherein the observer assembly includes a compliant member whose thickness can change up to 10 mm in response to changes in pressure applied to the observer assembly by the user's head.

[0104] Clause 23. Clause 22's ophthalmic imaging system, wherein the observer assembly includes a compliant member whose thickness can change by up to 20 mm in response to changes in pressure applied to the observer assembly by the user's head.

[0105] Clause 24. Clause 21's ophthalmic imaging system, wherein the signal indicates the position of a feature of the user's forehead relative to the housing.

[0106] Clause 25. Clause 24 of the ophthalmic imaging system wherein the control unit determines a user-specific reference arm length range based on a signal indicating the position of a feature of the user's forehead relative to the housing.

[0107] Clause 26. Clause 21 of the ophthalmic imaging system, wherein the signal indicates the position of a user’s eye, including the user’s retina, relative to the housing.

[0108] Clause 27. Clause 26 of the ophthalmic imaging system wherein the control unit determines a user-specific reference arm length range based on a signal indicating the position of the user's eye relative to the housing.

[0109] Clause 28. An ophthalmic imaging system of Clauses 1, 6, 9, 11, 15, 16, 17, 18, 19 or 20, further comprising a focusing module controlled by a control unit to focus sample light transmitted through the sample arm optical path onto the user's retina, wherein a focusing setting of the focusing module corresponding to a reference arm length for which the OCT image detector generates an OCT signal corresponding to the user's retina is employed during imaging of the user's retina.

[0110] Clause 29. An ophthalmic imaging system of Clauses 1, 6, 9, 11, 15, 16, 17, 18, 19 or 20, wherein: the sample arm optical path has a sample arm length; and the observer assembly is configured to engage the user's head to restrict the user's head relative to the housing, such that the sample arm length is substantially the same for each imaging instance of the user's retina.

[0111] Clause 30. A method for imaging a user's retina, the method comprising: restricting the user's head relative to the housing via an observer assembly coupled to a housing and engaged with the user's head, such that a sample arm optical path of an optical coherence tomography (OCT) imaging device attached to the housing extends to the user's retina; controlling a reference arm length adjustment module of the OCT imaging device by a control unit to change the reference arm length of the reference arm optical path of the OCT imaging device to search a user-specific reference arm length range, thereby identifying a reference arm length for which the OCT image detector of the OCT imaging device generates an OCT signal corresponding to the user's retina, the reference arm length adjustment module being controllable to change the reference arm length within a reference arm length adjustment range, the user-specific reference arm length range covering a reference arm length range smaller than the reference arm length adjustment range; and imaging the user's retina by the OCT imaging device.

[0112] The method of Clause 31. Clause 30, wherein the user-specific reference arm length range is predetermined.

[0113] Clause 32. The method of Clause 30 or 31, wherein the user-specific reference arm length range is based on spatial information relating to one or more facial features of the user.

[0114] Clause 33. The method of Clause 32, wherein one or more facial features of the user include one or more of the following: the user's forehead, one or more cheeks of the user, the cornea of ​​the user's eye including the user's retina, and the edge of the user's side eye socket.

[0115] Clause 34. The method of Clause 32, wherein spatial information relating to one or more facial features of a user is generated by one or more of the following: a three-dimensional scan of one or more facial features of a user; caliper measurement of one or more facial features of a user relative to a user's eye including the user's retina; mask casting of one or more facial features of a user; axial length of a user's eye including the user's retina; ultrasound measurement of the axial length of a user's eye including the user's retina; and OCT measurement of the axial length of a user's eye including the user's retina.

[0116] Clause 35. The method of Clause 30, wherein the observer assembly includes an objective lens assembly, and the method does not include adjusting the distance between the user's retina and the objective lens assembly.

[0117] Clause 36. The method of Clauses 30, 31 or 35, wherein, for a reference arm length equal to each of the lengths within the range of reference arm length adjustment, the imaging of the user's retina is limited to a field of view equal to or less than 15 degrees on the user's retina.

[0118] The method of Clause 37. Clause 36, wherein, for a reference arm length equal to each of all lengths within the range of reference arm length adjustment, the imaging of the user's retina is limited to a field of view equal to or less than 10 degrees on the user's retina.

[0119] Clause 38. The method of Clause 30, wherein the OCT imaging device has an image depth of not more than 3 mm.

[0120] Clause 39. The methods of Clauses 30, 31, 35 or 38, wherein the OCT imaging device has a sensitivity roll-off of no more than -3 dB at 2 mm.

[0121] The method of Clause 40. Clause 30, wherein the user-specific reference arm length range includes less than half of the reference arm length adjustment range.

[0122] Clause 41. The method of Clauses 30, 31, 35 or 38, wherein the user-specific reference arm length range includes less than a quarter of the reference arm length adjustment range.

[0123] The methods of Clause 42, Clause 30, 31, 35, 38, or 40 include: receiving input of a user-specific reference arm length range by a control unit; and storing the user-specific reference arm length range in a tangible memory device by the control unit.

[0124] The method of Clause 43. Clauses 30, 35, 38, or 40 includes: controlling a reference arm length adjustment module to change the reference arm length during imaging of a user's retina by a control unit to search within the reference arm length adjustment range to identify a user-specific imaging reference arm length for which the OCT image detector generates an OCT signal corresponding to the user's retina; determining a user-specific reference arm length range based on the user-specific imaging reference arm length by the control unit; and storing the user-specific reference arm length range in a tangible memory device by the control unit.

[0125] Clause 44. The method of Clause 30, wherein the reference arm length adjustment range includes a reference arm length range of at least 20 mm.

[0126] Clause 45. The method of Clause 44, wherein the reference arm length adjustment range includes a reference arm length range of at least 30 mm.

[0127] Clause 46. The method of Clause 45, wherein the reference arm length adjustment range includes a reference arm length range of at least 40 mm.

[0128] Clause 47. The method of Clause 30, wherein the user-specific reference arm length range includes the range less than 10 mm in the reference arm length adjustment range.

[0129] The method of Clause 48. Clause 47, wherein the user-specific reference arm length range includes the range less than 6 mm in the reference arm length adjustment range.

[0130] Clause 49. The method of Clause 48, wherein the user-specific reference arm length range includes the range less than 4 mm in the reference arm length adjustment range.

[0131] The methods of Clause 50, Clause 30, 35, 38, 40, 44, 45, 46, 47, 48 or 49 include: generating a signal by a sensor indicating the position of a feature of a user's head relative to the housing; and determining a user-specific reference arm length range by a control unit based on the signal indicating the position of a feature of a user's head relative to the housing.

[0132] Clause 51. The method of Clause 50, wherein the observer assembly includes a compliant member whose thickness can change up to 10 mm in response to changes in pressure applied to the observer assembly by the user's head.

[0133] Clause 52. The method of Clause 51, wherein the observer assembly includes a compliant member whose thickness can change by up to 20 mm in response to changes in pressure applied to the observer assembly by the user's head.

[0134] The method of Clause 53.30 includes: generating a signal by a sensor indicating the position of a feature of the user's forehead relative to the housing; and determining a user-specific reference arm length range by a control unit based on the signal indicating the position of the feature of the user's forehead relative to the housing.

[0135] The method of Clause 54. Clause 30 includes: generating a signal by a sensor indicating the position of a feature of a user's eye relative to the housing, the eye including the user's retina; and determining a user-specific reference arm length range by a control unit based on the signal indicating the position of the feature of the user's eye relative to the housing.

[0136] The methods of Clause 55, Clause 30, 35, 38, 40, 44, 45, 46, 47, 48, 49, 53 or 54 include: storing, by a control unit, a focusing setting of the focusing module of the OCT imaging device corresponding to a user-specific reference arm length range; and employing the focusing setting during imaging of the user's retina.

[0137] Clause 56. The methods of Clauses 30, 35, 38, 40, 44, 45, 46, 47, 48, 49, 53 or 54, wherein: the sample arm optical path has a sample arm length; and the observer assembly is configured to engage the user's head to limit the user's head relative to the housing, such that the sample arm length is substantially the same for each imaging instance of the user's retina.

[0138] Clause 57. An ophthalmic imaging system for imaging a user's retina, the ophthalmic imaging system comprising: an optical coherence tomography (OCT) imaging device including a sample arm optical path, an OCT image detector, a reference arm optical path having a reference arm length, and a reference arm length adjustment module controllable to change the reference arm length within a reference arm length adjustment range; a housing to which the OCT imaging device is attached; an observer assembly coupled to the housing, the observer assembly being configured to engage a user's head to restrict the user's head relative to the housing such that the sample arm optical path extends to the user's retina; an objective lens assembly, wherein the ophthalmic imaging system does not include an adjustment mechanism configured to adjust the distance between the user's retina and the objective lens assembly; and a control unit operatively connected to the OCT image detector and the reference arm length adjustment module, the control unit being configured to: control the reference arm length adjustment module to change the reference arm length to indicate the reference arm length at which the OCT image detector generates an OCT signal corresponding to the user's retina.

[0139] Clause 58. Clause 57 of the ophthalmic imaging system, wherein the ophthalmic imaging system is configured to: image a field of view equal to or less than 15 degrees on the user's retina for a reference arm length equal to each of all lengths within the range of reference arm length adjustment.

[0140] Clause 59. Clause 58 of the ophthalmic imaging system, wherein the ophthalmic imaging system is configured to: image a field of view equal to or less than 10 degrees on the user's retina for a reference arm length equal to each of all lengths within the range of reference arm length adjustment.

[0141] Clause 60. An ophthalmic imaging system of Clauses 57, 58 or 59, wherein: the sample arm optical path has a sample arm length; and the observer assembly is configured to engage the user's head to restrict the user's head relative to the housing, such that the sample arm length is substantially the same for each imaging instance of the user's retina.

Claims

1. An ophthalmic imaging system for imaging a user's retina, the ophthalmic imaging system comprising: The OCT imaging device includes a sample arm optical path, an OCT image detector, a reference arm optical path with a reference arm length, and a reference arm length adjustment module, which can be controlled to change the reference arm length within a reference arm length adjustment range. The housing to which the OCT imaging device is attached; An observer assembly coupled to the housing, the observer assembly being configured to engage with a user's head to restrict the user's head relative to the housing, such that the optical path of the sample arm extends to the user's retina; as well as A control unit, operatively connected to the OCT image detector and the reference arm length adjustment module, is configured to: During the initial imaging of the user's retina, the reference arm length adjustment module is controlled to change the reference arm length within the reference arm length adjustment range to identify the initial imaging reference arm length at which the OCT image detector generates an OCT signal corresponding to the user's retina; A user-specific reference arm length range is determined based on the initial imaging reference arm length, and the user-specific reference arm length range covers a reference arm length range that is smaller than the reference arm length adjustment range. and During the imaging of the user's retina after the initial imaging of the user's retina, the reference arm length adjustment module is controlled to change the reference arm length to search within the user-specific reference arm length range, thereby identifying the subsequent imaging reference arm length for which the OCT image detector generates an OCT signal corresponding to the user's retina.

2. The ophthalmic imaging system of claim 1, wherein, Includes an objective lens assembly, wherein the ophthalmic imaging system does not include an adjustment mechanism configured to adjust the distance between the user's retina and the objective lens assembly.

3. The ophthalmic imaging system as described in claim 1 or 2, characterized in that, The ophthalmic imaging system is configured to image a visual field of equal to or less than 15 degrees on the user's retina.

4. The ophthalmic imaging system as described in claim 3, characterized in that, The ophthalmic imaging system is configured to image a visual field of 10 degrees or less on the user's retina.

5. The ophthalmic imaging system as described in claim 1, characterized in that, The OCT imaging device has an image depth of no more than 3 mm.

6. The ophthalmic imaging system as described in claim 1, characterized in that, The span of the user-specific reference arm length range is less than half the span of the reference arm length adjustment range.

7. The ophthalmic imaging system as described in claim 6, characterized in that, The span of the user-specific reference arm length range is less than one-quarter of the span of the reference arm length adjustment range.

8. The ophthalmic imaging system as described in claim 1, characterized in that, The reference arm length adjustment range includes a reference arm length range of at least 20 mm.

9. The ophthalmic imaging system as described in claim 8, characterized in that, The reference arm length adjustment range includes a reference arm length range of at least 30 mm.

10. The ophthalmic imaging system as described in claim 9, characterized in that, The reference arm length adjustment range includes a reference arm length range of at least 40 mm.

11. The ophthalmic imaging system as described in claim 1, characterized in that, The user-specific reference arm length range includes reference arm lengths less than 10 mm.

12. The ophthalmic imaging system as described in claim 11, characterized in that, The user-specific reference arm length range includes reference arm lengths less than 6 mm.

13. The ophthalmic imaging system as described in claim 12, characterized in that, The user-specific reference arm length range includes reference arm lengths less than 4 mm.

14. The ophthalmic imaging system as described in claims 1, 2, 5, 6, 8, 9, 10, 11, 12, or 13, characterized in that, The system further includes a position sensor that generates a position signal indicating the position of a feature of the user's head relative to the housing, and wherein the control unit determines a user-specific reference arm length range based on the initial imaging reference arm length and the position signal indicating the position of a feature of the user's head relative to the housing.

15. The ophthalmic imaging system as described in claim 14, characterized in that, The position signal indicates the position of a feature of the user's forehead relative to the housing.

16. The ophthalmic imaging system as described in claim 15, characterized in that, The control unit determines the user-specific reference arm length range based on the initial imaging reference arm length and the position signal indicating the position of the user's forehead features relative to the housing.

17. The ophthalmic imaging system as described in claim 14, characterized in that, The position signal indicates the position of the user's eye features relative to the housing, the eye including the user's retina.

18. The ophthalmic imaging system as described in claim 17, characterized in that, The control unit determines the user-specific reference arm length range based on the initial imaging reference arm length and the position signal indicating the position of the user's eye relative to the housing.

19. The ophthalmic imaging system as described in claims 1, 2, 5, 6, 8, 9, 10, 11, 12, or 13, characterized in that, The system further includes a focusing module controlled by the control unit to focus sample light transmitted through the sample arm optical path onto the user's retina, wherein a focusing setting of the focusing module corresponding to the reference arm length for which the OCT image detector generates an OCT signal corresponding to the user's retina is employed during imaging of the user's retina.

20. The ophthalmic imaging system as described in claim 1, 2, 5, 6, 8, 9, 10, 11, 12 or 13, characterized in that: The optical path of the sample arm has a sample arm length; and The observer assembly is configured to engage the user's head to suppress movement of the user's head relative to the housing.

21. A method for imaging a user's retina, the method comprising: The user's head is restricted relative to the housing via an observer assembly coupled to the housing and engaged with the user's head, such that the optical path of the sample arm of the OCT imaging device attached to the housing extends to the user's retina; During the initial imaging of the user's retina, the control unit controls the reference arm length adjustment module of the OCT imaging device to change the reference arm length of the reference arm optical path of the OCT imaging device within the reference arm length adjustment range, thereby identifying the initial imaging reference arm length at which the OCT image detector of the OCT imaging device generates the OCT signal corresponding to the user's retina. The control unit determines a user-specific reference arm length range based on the initial imaging reference arm length, and the user-specific reference arm length range covers a reference arm length range smaller than the reference arm length adjustment range; as well as The control unit controls the reference arm length adjustment module to change the reference arm length during the imaging of the user's retina after the initial imaging of the user's retina, in order to search within the user-specific reference arm length range, thereby identifying the subsequent imaging reference arm length for which the OCT image detector generates an OCT signal corresponding to the user's retina.

22. The method as described in claim 21, characterized in that, The observer assembly includes an objective lens assembly, and the method does not include adjusting the distance between the user's retina and the objective lens assembly.

23. The method as described in claim 21 or 22, characterized in that, Imaging of the user's retina is limited to a field of view of 15 degrees or less on the user's retina.

24. The method as described in claim 23, characterized in that, Imaging of the user's retina is limited to a field of view of 10 degrees or less on the user's retina.

25. The method as described in claim 21, characterized in that, The OCT imaging device has an image depth of no more than 3 mm.

26. The method as described in claim 21, characterized in that, The span of the user-specific reference arm length range is less than half the span of the reference arm length adjustment range.

27. The method as described in claim 21, 22, or 25, characterized in that, The span of the user-specific reference arm length range is less than one-quarter of the span of the reference arm length adjustment range.

28. The method as described in claim 21, characterized in that, The reference arm length adjustment range includes a reference arm length range of at least 20 mm.

29. The method as described in claim 28, characterized in that, The reference arm length adjustment range includes a reference arm length range of at least 30 mm.

30. The method as described in claim 29, characterized in that, The reference arm length adjustment range includes a reference arm length range of at least 40 mm.

31. The method as described in claim 21, characterized in that, The user-specific reference arm length range includes the range less than 10 mm within the reference arm length adjustment range.

32. The method as described in claim 31, characterized in that, The user-specific reference arm length range includes the range less than 6 mm within the reference arm length adjustment range.

33. The method as described in claim 32, characterized in that, The user-specific reference arm length range includes the range less than 4 mm within the reference arm length adjustment range.

34. The method as described in claims 21, 22, 25, 26, 28, 29, 30, 31, 32 or 33, characterized in that, This includes generating a position signal by a position sensor indicating the position of a feature of the user's head relative to the housing, and wherein the control unit determines a user-specific reference arm length range based on the initial imaging reference arm length and the position signal indicating the position of a feature of the user's head relative to the housing.

35. The method as described in claim 21, characterized in that, This includes generating a position signal by a position sensor indicating the position of a feature of the user's forehead relative to the housing, and wherein the control unit determines a user-specific reference arm length range based on the initial imaging reference arm length and the position signal indicating the position of the feature of the user's forehead relative to the housing.

36. The method as described in claim 21, characterized in that, This includes generating a position signal by a position sensor indicating the position of the user's eye features relative to the housing, the eye including the user's retina, and wherein the control unit determines a user-specific reference arm length range based on the initial imaging reference arm length and the position signal indicating the position of the user's eye features relative to the housing.

37. The method as described in claims 21, 22, 25, 26, 28, 29, 30, 31, 32, 33, 35, or 36, characterized in that, include: The control unit stores the focusing settings of the focusing module of the OCT imaging device corresponding to the user-specific reference arm length range; as well as The focusing settings are used during imaging of the user's retina.

38. The method as described in claims 21, 22, 25, 26, 28, 29, 30, 31, 32, 33, 35, or 36, characterized in that: The optical path of the sample arm has a sample arm length; and The observer assembly is configured to engage the user's head to suppress movement of the user's head relative to the housing.

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