Mobile eye imaging system

Abstract

Disclosed here is a mount for a mobile eye imaging system, and the mobile eye imaging system itself. The mount includes a nose bridge portion and lateral members that inhibit rotation of the mobile eye imaging system relative to a subject's face, while the system is in use. The system comprises a visual guide for defining a viewing direction for image capture, the mount, and an alignment mechanism engaged with the mount and visual guide, for positioning the system on a mobile device such that the visual guide is aligned with an image capture device of the mobile device.

Description

[0001] MOBILE EYE IMAGING SYSTEM

[0002] Technical Field

[0003] The present invention relates, in general terms, to a mount for a mobile eye imaging system, and the mobile eye imaging system itself. More specifically, it relates to a mount for stably positioning the mobile eye imaging system on a subject's face, and a system, utilising the mobile eye imaging system, that can be attached to a portable image capture device to image the subject's eye.

[0004] Background

[0005] Ophthalmic conditions can take on a range of severities and occur over a range of durations. While some of these conditions are minor and may go away on their own, others may require a larger degree of medical intervention. Some of these conditions may occur suddenly and have intense or rapidly developing symptoms, while others may be long-lasting and have gradually developing symptoms.

[0006] Chronic eye conditions are typically long-lasting and do not go away without medical intervention. They may affect any of the components of the eye. As such, these conditions require regular monitoring to enable proactive management and early intervention. Some examples of chronic eye conditions include cataracts and glaucoma.

[0007] Conventionally, the monitoring of these chronic eye conditions has been limited to tertiary healthcare settings, as it relies heavily on bulky devices operated by highly trained ophthalmologists. This poses a challenge, especially in developing countries or at remote locations, where there exists a limited availability of ophthalmic diagnostic tools and where the tools are made available only to ophthalmologists. The scarcity of these diagnostic tools also leads to high costs of use.

[0008] As such, patients and their caregivers face difficulties in actively participating in the monitoring process and accessing timely information about the progression of their conditions. The limited accessibility of such monitoring methods to patients and their primary caregivers also restricts the convenience and flexibility of assessing eye health. Some devices exist to facilitate eye imaging in a more flexible setting using a mobile device. However, accurate imaging using a mobile device is difficult due to the instability of the operator's hand, and variations in angle between images. Angle variations change the direction at which light enters the eye and therefore changes the angle at which light reflects from features of the eye - e.g. the pupil, the iris, and the lens. Thus, a small change in angle can dramatically affect the amount of reflected light and resulting image quality.

[0009] There is hence now an urgent need for a user-friendly solution to enable patients and their caregivers to perform home or community-based, repeatable monitoring of eye conditions in non-medical settings. This will enable proactive management and early intervention.

[0010] Summary

[0011] In view of the abovementioned drawbacks of the prior art, a mount is taught herein, for stably mounting an imaging device, such as a smartphone, to a subject's face. The verb "mounting" includes "contacting", "resting against" and similar terms, as well as "actively engaging" such as pinching the nose.

[0012] Disclosed herein is a mount for a mobile eye imaging system. The mount comprises a nose bridge portion and a lateral portion or lateral extension. The nose bridge portion rests against, or mounts to, the nose bridge of the subject during imaging. The lateral portion is offset relative to a centre of the face of the subject. One or both of the nose bridge portion and the lateral portion may be elongate, thereby providing three non-collinear points of contact with the subject's face. Alternatively, if neither of the nose bridge portion nor the lateral portion is elongate, then a third point of contact may be provided such that, again, there are three non-collinear points of contact with the subject's face.

[0013] Advantageously, by providing three non-collinear points of contact, the mount greatly reduces, or entirely avoids, rotation of the imaging device relative to the subject's eye, during image capture. This provides a consistent, repeatable position for the image capture device relative to the eye, for imaging the eye. Disclosed herein is a mobile eye imaging system, the system comprising : a visual guide defining a viewing direction for image capture; a mount that is adjustable to align an eye of a subject with the viewing direction when the mount is mounted to a predetermined portion of the subject; and an alignment mechanism engaged with the mount and visual guide, for positioning the system on a mobile device such that the visual guide is aligned with an image capture device of the mobile device.

[0014] In some embodiments, the visual guide is an annular ring, configured to direct the subject's eye to a focal point of the optical system.

[0015] In some embodiments, the annular ring comprises an LED annular ring with adjustable brightness. Advantageously, adjusting a brightness of the LED annular ring may provide a dynamic visual guide for correct positioning of the eye.

[0016] In some embodiments, where the annular ring comprises an LED annular ring, the system may further comprise a mirror mounted at a predefined angle relative to the visual guide, to reflect incident light into the eye.

[0017] In some embodiments, the system may further comprise a light source emitting light towards the mirror, such that incident light in reflected into the eye.

[0018] In some embodiments, the system may be communicatively coupled to the mobile device when in use, such that activation of the light source to emit light towards the mirror is synchronised with image capture by the image capture device. Image capture by the image capture device may happen spontaneously upon activation of the light source, or it may happen via manual control upon activation of the light source.

[0019] In some embodiments, the system may comprise a potentiometer configured to adjust the brightness of the light source.

[0020] In some embodiments, the alignment mechanism comprises an aperture configured to selectively permit or block light from passing through the aperture towards the eye. In some embodiments, the mount is removably attached to a rail of the alignment mechanism, and the rail has notches to provide for discrete movement of the mount relative to the alignment mechanism.

[0021] In some embodiments, the system comprises a stationary eye cup and a moveable eye cup, the movable eye cup moving relative to the stationary eye cup with adjustment of the mount.

[0022] In some embodiments, the mount comprises an adjustable nose bridge.

[0023] In some embodiments, the adjustable nose bridge is made of a flexible material is positioned to conform to contours of a nose of the subject.

[0024] In some embodiments, the alignment mechanism is a magnet-based alignment mechanism.

[0025] In some embodiments, the magnet-based alignment mechanism comprises a holder for the mobile device, the holder fitted with at least three magnets for engaging corresponding magnets, of respectively opposite polarity, of the mobile device.

[0026] In some embodiments, the at least three magnets are arranged to engage with the corresponding magnets in a single orientation only.

[0027] In some embodiments, the system may further comprise a rack for fixedly positioning the system above a surface during imaging.

[0028] In some embodiments, the rack comprises a motorised movement mechanism for moving the system relative to the surface to position the visual guide relative to the eye.

[0029] In some embodiments, the system further comprises a connector for wired connection the system and mobile device, for transfer of at least one of power and control signals during imaging.

[0030] In some embodiments, the image capture device is a mobile phone camera. Brief description of the drawings

[0031] Some embodiments of the systems and methods for this invention, in accordance with the present disclosure, will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

[0032] FIG. la illustrates the mobile eye imaging system, when viewed from a subject's point of view, and FIG. lb shows a mount of such an eye imaging system.

[0033] FIG. 2a illustrates the mobile eye imaging system, when viewed from the side, with an image capture device positioned below the mobile eye imaging system.

[0034] FIG. 2b illustrates the mobile eye imaging system, when viewed from the shorter end of the system and image capture device.

[0035] FIG. 3a illustrates one embodiment of the adjustable mount of the mobile eye imaging system and the various components of the alignment mechanism, wherein the adjustable mount is positioned on a rail with notches, permitting discrete movement, and wherein mounting to the subject comprises an adjustable nose bridge, a stationary and a moveable eye cup, and FIG. 3b illustrates the same embodiment as FIG. 3a, from the front view.

[0036] FIG. 4 illustrates the magnet-based alignment mechanism on the mobile eye imaging system, both when the image capture device is attached to the mobile eye imaging system and when the image capture device and the mobile eye imaging system are separate.

[0037] FIG. 5 illustrates the rack where the mobile eye imaging system could be attached through the magnets.

[0038] Detailed description

[0039] Embodiments of the present disclosure relate to systems for use in mobile eye imaging. In particular, embodiments relate to a mount for positioning a mobile eye imaging system on the face of the subject whose eye is being imaged. The mount inhibits rotation of the image capture device relative to the subject's face, and thus the eye, during imaging. Moreover, by using the nose as a landmark against which the mount rests, the mount also improves consistency of the position of the mount on the face of the user. The mobile eye imaging system taught herein itself is for use by patients and their caregivers to perform non-invasive assessments of the eye, as well as to conveniently monitor a variety of eye conditions at home or in communitybased settings. The invention set out in this disclosure aims to empower individuals to actively participate in their own eye health management, promote regular and personalised monitoring and seek timely intervention for improved outcomes, by providing a user-friendly mobile eye imaging system.

[0040] The present disclosure provides a mobile eye imaging system, an embodiment of which is indicated by numeral 100 in FIG. la. The mobile eye imaging system 100 comprises a visual guide 102, mount 104, and alignment mechanism 106. Also shown is a smartphone 108, used as the image capture device. The visual guide 102 defines a viewing direction (marked "X", and extending into the page) for image capture while the mount 104 is adjustable to align an eye of a subject with the viewing direction X when the mount 104 is mounted to a predetermined portion of the subject (e.g., when the mount 104 is resting on the bridge of the nose of the subject). The alignment mechanism 106 is engaged with the mount 104 and visual guide 102 and positions the system 100, in use, on a mobile device 108 such that the visual guide is aligned with an image capture device of the mobile device 108. As such, the mount 104 ensures the eye is positioned in the desired location for imaging of the eye, while the visual guide 102 guides the eye to look in the right direction during imaging - e.g., towards the image capture device.

[0041] Throughout this disclosure, unless the context states otherwise, the words "patient", "user", and "subject" may be used interchangeably to refer to an individual who presents with a chronic eye condition which requires frequent monitoring and intervention and who is the subject whose eye is imaged by the mobile eye imaging system as disclosed in this disclosure. Also, unless context dictates otherwise, the terms in each case also cover instances where the system is operated by a user, such as a healthcare professional or caregiver, for imaging the eye of a subject or patient who is different from the healthcare professional.

[0042] Throughout this disclosure, unless the context states otherwise, the words "brightness" and "intensity" may be used interchangeably as it should be understood by a skilled person that the intensity of a light source refers to a physical quantity corresponding to the power emitted by the light source per unit area, and brightness refers to a human perception of the intensity of light.

[0043] Visual guide defining a viewing direction of image capture

[0044] The visual guide 102 ensures the subject looks in the direction of the image capture device during imaging, or otherwise in a desired direction. While a subject may properly position their eye with respect to an image capture device (hereinafter used interchangeably with the term "camera" for illustration purposes, though an infrared imaging device or other imaging device may be used as appropriate), the subject may look in any direction. Unless the eye is looking in the right direction - i.e., direction "X" - some features of the eye may be obscured by other features. Moreover, it is more difficult to assess progression of a medical condition of an eye from a temporal distribution of images of the eye, if the individual images show the eye looking in inconsistent directions. Therefore, guiding the eye to look in a consistent direction assists with repeatability of imaging, identification of diseases, as well as temporal analysis of disease progression.

[0045] The visual guide 102 may have any shape, such as an annular ring, oval shape, one or more arcs or other visual features intended to make clear the viewing direction (through the focal point) along which the subject should look for image capture. In general, the shape of the visual guide 102 will have a closed loop with the image capture device within the closed loop. For illustrative purposes only, an annular ring 110 embodiment is adopted in the description below, though an arcuate shaped visual guide, arrows (pointing to a common location in space through which the viewing direction should pass for accurate imaging - e.g., such that the viewing direction of the eye, the common location in space and the imaging axis are all collinear) and other designs may be appropriate. The annular ring 110 or other visual guide 102 is configured to direct the subject's eye to an imaging axis, also "X", of the image capture device, where the imaging axis passes through a focal point of the image capture device. Although not limited in this regard, the term "annular ring" may be used throughout the present disclosure to term a component shaped like a ring and occupying the region between two concentric circles. The annular ring 110 is attached to, is part of or is integral with, the alignment mechanism 106 so that the annular ring 110 is positioned over a lens of the image capture device of the mobile device 108, when in use. The visual guide 102 provides a clear visual cue indicating the direction to which a subject should direct the eye during imaging - the viewing direction, such as along the line of "X". The annular ring 110 may optionally correspond to the position at which a subject should place the eye during imaging - e.g., the viewing direction will be through a centre of the annular ring 110 during imaging, through a centre of rotation of an arc, through a point of convergence in space of directions defined by arrows, or through a location otherwise made evident from the visual guide 102.

[0046] When the subject's eye is looking in a desired direction as predetermined by the placement of the annular ring 110, the image capture process is advantageously enhanced as the positioning and alignment of the eye is optimised. In particular, the visual guide 102 is located relative to the image capture device such that images of the subject's eye are taken along a consistent direction, and from a consistent location, relative to the image capture device. As such, progression of eye conditions can be readily monitored in general without image transformation that may otherwise be required to normalise images captured from different angles and distances into a common plane and common size.

[0047] In another one or more embodiments, the visual guide 102 comprises a light source. For example, the visual guide 102 may comprise a bright annular ring 110. The annular ring 110 may be illuminated by a light source, such as by comprising a mirrored surface to reflect light directed at the annular ring 110 or may itself be a light source. The light source is designed to emit a standard brightness level that ensures visibility without causing discomfort or distraction to the subject. The light source also ensures lighting conditions at which images are captured are consistent across images. This avoids feature distortion arising from varying lighting conditions at the time of image capture in a temporal sequence of images. The consistent brightness level may ensure a reliable and uniform visual guide for the subject, simplifying positioning and alignment of the eyes for accurate assessment.

[0048] In another one or more embodiments, the visual guide 102 may comprise a lightemitting diode (LED). The LED may have controllable brightness and / or controllable colour. By controlling the brightness and / or colour of the LED, the LED advantageously serves as a dynamic visual guide during the imaging process. For example, the LED may be a first brightness or first colour (e.g., orange) during positioning of the eye relative to the image capture device and may take on a second brightness or second colour (e.g., green) upon correct positioning of the eye (i.e., in the position required for image capture, with the viewing direction aligned with the image capture device). The location and viewing direction of the eye may be determined by image analysis performed in a manner evident to the skilled person in light of the present disclosure - e.g., through a machine learning model adapted to identify features of the eye, or other image features, from an image or continuous image feed or visual feed (i.e., a continuous sequence of images taken over time) from the image capture device, determine from those features the viewing direction of the eye (e.g., based on a location of image features, such as a centre of the image, and / or eye features relative to each other) and estimate a degree of alignment between the viewing direction of the eye and the viewing direction as prescribed by the visual guide (e.g., that alignment is exact, or is within a predetermined threshold such as ± 10°). That analysis may be performed by software integrated into the mobile device or the present system with control signals for controlling the LED being generated by the same software. The analysis may also be performed manually by a user. In the case of the software being in the mobile device, the control signals are transmitted via wireless connection or wired connection as discussed below, to the present system for controlling the LED.

[0049] The LED annular ring 110 may have an adjustable intensity - however, though possible in some embodiments, the LED annular ring will not be used to illuminate the eye during image capture. Instead, this illumination function will be afforded by a further light source, discussed below. Adjustment can be manual, e.g., using a potentiometer or other controller, or automatic and based on image analysis. Image analysis can be performed in software as set out above. To that end, the image capture device may provide a visual feed for analysis by the software to determine a position and viewing direction of the eye. The software generates a control command to control illumination of the LED based on how close the eye is to the correct position and viewing direction. Where the software is in the mobile device, the control command can be transmitted wirelessly to the present system (e.g., using near-field communication (NFC) or Bluetooth®), or through a wired connection (e.g., into the charging port of the mobile device). Where the software is in the present system, the visual feed may be supplied wirelessly or via wired connection from the mobile device to the present system, the present system then analysing the visual feed and determining and issuing a control signal for controlling illumination of the LED.

[0050] This dynamic feature of the LED may provide real-time visual feedback of the position and viewing direction of the subject's eye relative to the desired position and viewing direction. The visual feedback may be obtained using real-time software analysis of specific anatomical features - e.g., using a machine learning model trained to identify specific anatomical features of the eye, in a known manner in view of the teaching set out above, and then determine from those features whether the eye is aligned with the imaging direction. The features may be the iris, the pupil, the limbus, or they may be any other anatomical features on the subject's eye. Moreover, the intensity of the LED on the annular ring may be varied according to a subject's response to the illumination. For example, the intensity of the LED annular ring may be decreased to accommodate sensitive eye conditions or specific user preferences of the subject.

[0051] In one embodiment, the intensity of the LED annular ring may be increased to guide the subject's eye to the desired focal point. This may provide for precise and reliable alignment of the eye with the image capture device for high-quality image capture. For example, the LED annular ring (i.e., the visual guide) may provide stronger illumination as the user's eye (i.e., the viewing direction thereof) becomes more aligned with the viewing direction.

[0052] Advantageously, a dynamic feedback loop between the intensity of the LED on the LED annular ring and how a subject responds to the illumination of the LED ensures a precise and reliable placement of an eye of a subject for high-quality image capture, and at the same time enhances user experience.

[0053] In some embodiments, the system comprises a light source or further light source 112, as also shown in FIG. 2a. The further light 112 source may illuminate the anterior segment of a subject's eye, ensuring optimal visibility and clarity during image capture. This enables the image capture device to capture detailed and high- resolution images of the eye's anterior segment. The further light source 112 may have an adjustable intensity. Adjustment can be manual, e.g., using a potentiometer 114 or other controller, or automatic and based on image analysis - e.g. once the machine learning model set out above (for determining alignment of the viewing direction and imaging direction) identifies that the subject's eye is aligned with the image capture device, the system 100 may trigger the image capture device of the smartphone 108 to capture an image of the subject's eye.

[0054] In some embodiments, the visual guide and the further light source may be a single entity or unitary device. In other embodiments, the visual guide 102 and the further light source 112 are two separate components. Moreover, the visual guide 102 may simply guide the viewing direction but otherwise provide no illumination.

[0055] In one or more embodiments, the mobile eye imaging system 100 also comprises a mirror 116 mounted at a predefined angle 0 (see FIG. 2a) relative to the visual guide 102 (or surface normal thereof). In the embodiment shown, the mirror 116 is mounted in a projection extending away from the visual guide 102 at the predefined angle 0 relative to the visual guide 102. The mirror 116 reflects incident light into the eye - that incident light being light emitted from the further light source 112 or, in some embodiments, from the visual guide 102 (e.g., through an LED in the annular ring). The predefined angle 0 may be between about 35 ° to about 55 °, with respect to the plane of the annular ring. It may also be between about 40 ° to about 50 °, or between about 44 ° to about 46 °.

[0056] In use, the mobile eye imaging system 100 is communicatively coupled with the image capture device, wherein the image capture device may be on (or within) a mobile device. The coupling may deliver power to the further light source 112 of the present system 100 and / or visual guide 102. The further light source 112 is directed at the mirror 116, at an angle that ensures light emitted from the further light source is reflected into the eye. Thus, while the mobile eye imaging system 100 and the image capture device are communicatively coupled, the further light source 112 may be activated to emit light towards the mirror 116. Activation of the further light source 112 may be continuous or may be in sync with the instant when image capture occurs on the image capture device. For example, the mobile device 108 may issue a control command to the present system 100, the control command specifying that an image is to be captured, the present system then activating the further light source 112 for a predetermined duration so that the eye is illuminated during image capture.

[0057] The further light source 112 for illuminating the eye during image capture will generally be different from the visual guide 102 and any light source therein - e.g., the LED light source. The system may comprise a controller, presently embodied by a potentiometer 114, configured to adjust the intensity of light from the further light source 112. The brightness may be adjusted to suit a subject's specific preferences or to illuminate different structures in the eye. The potentiometer 114 may be a sliding contact point that forms a voltage divider, varying the amount of voltage that reaches the further light source and hence varying the intensity of the further light source 112. The potentiometer 114 may also be a rotating contact point in the form of an adjustment knob. In other embodiments, where the further light source 112 forms part of the visual guide 102, the controller may similarly adjust the intensity of light from the visual guide 102.

[0058] In one or more embodiments, the system 100 comprises an aperture 118 configured to selectively permit light through from the further light source 112 towards another eye of the subject. The aperture 118 thus has a first condition in which light from the further light source 112 is blocked and a second condition in which light from the further light source 112 is emitted through the aperture 118 towards another eye of the subject - i.e., the eye that is not being imaged. The aperture 118 may comprise a slide and an opening, the slide being slidable relative to the opening, to open and close the opening and thereby open (permit light to escape from) the aperture 118 and close (prevent light from escaping) the aperture 118 and may permit partial closure to control the amount of light emitted through the aperture 118. Directing light at both eyes reduces visual discomfort during imaging, resulting from inconsistent lighting levels between the subject's eyes. This may make it easier for the subject to focus along the viewing direction with the eye being imaged.

[0059] Adjustable mount to align eye of subject with viewing direction

[0060] With reference to FIG. lb, the mount 104 may include a nose bridge portion 120 and lateral portion 122. In the embodiment shown, the mount 104 comprises a single body 124 of generally fixed shape, the nose bridge portion 120 and the lateral portion 122 forming part of that body 124. The nose bridge portion 120 rests against, or mounts to, the nose bridge of the subject during imaging. The nose bridge portion 120 thereby provides a fixed point of reference common to all subjects. The adjustment mechanism may be used to accommodate changes in the spacing between the eyes, and thus between the nose bridge and each eye, without requiring changes in position of the nose bridge portion 120 or mount 102. Where a single point of contact between an imaging device and the subject's face is provided, the imaging device will be able to pivot or roll on that point. This reduces consistency of the angle at which the eye is imaged and thus reduces imaging repeatability and quality. The same applies to mounts positioned on the eye socket - the shape and size of the eye socket varies greatly between individuals and thus the number or location of contact points and their orientations relative to the eye similarly greatly varies.

[0061] The present mount leverages on the general symmetry between the nose bridge and eyes of most subjects, providing three points of contact to stably position mount 102 on the face of the subject. The nose bridge portion 120 and lateral portion 122 each provide at least one point of contact. In some embodiments, one or both of the nose bridge portion and the lateral portion is elongate, thereby providing at least a third point of contact - i.e. each elongate body provides a line of contact comprising at least two spaced apart point of contact, such as points on the elongate body towards opposite ends of the elongate body. Alternatively, if neither of the nose bridge portion and lateral portion is elongate, then at least a third point of contact may be provided such that, again, there are three or more points of contact with the subject's face.

[0062] Where points of contact form a line, the mount, and thus the imaging device, can still pivot about the line of contact. This reduces stability of the imaging system 100 during imaging, thus reducing the quality of the images. To inhibit rolling or pivoting, at least three points of contact are used, and those points are non-collinear. In the three-point example, each point is distanced laterally relative to a line passing between the other two points, that rolling or pivoting is inhibited. By providing three, non-collinear points of contact, the mount greatly reduces, or entirely avoids, rotation of the imaging device relative to the subject's eye, during image capture. This provides a consistent, repeatable position for the image capture device relative to the eye, for imaging the eye.

[0063] In use, the nose bridge portion 120 is position on the nose bridge of the subject and is thus general centrally disposed on the subject's face, during use. In some embodiments, the nose bridge comprises the portion of the nose between the tip of the nose and glabella and, in other embodiments, also comprises one or both of the tip of the nose and glabella. The mount thus contacts the nose bridge, being a typical midpoint between the subject's eyes. Contrastingly, the lateral portion is offset relative to a centre of the face of the subject. The lateral portion may be positioned to sit above or below one of the subject's eyes, or on the forehead.

[0064] In the embodiment shown in FIG. lb, there are multiple further lateral portions 126, 128 and 130. The nose bridge portion 120, and any two of lateral portions 122, 126, 128, 130 may provide the three points of contact. The present mount 102 may alternatively comprise the nose bridge portion 120, and three lateral portions - one above and one below the eye being imaged and disposed on the opposite side of the face relative to the other two lateral portions, thereby to broaden support and thus increase stability of the mobile imaging system 100 when in use.

[0065] Where a lateral portion is provided above and below the eye - e.g. portions 122 and 126 - those portions may, together with the nose bridge portion 102 form a curved shape that at least partially bounds the eye being imaged.

[0066] The mount 102 of FIG. lb is symmetrical about the nose bridge portion 102. This provides consistent pressure across the subject's face during imaging.

[0067] In some embodiments, the body 124 comprises a rigid backing layer 132, formed e.g. from plastic, and a padding layer 134 overlying the rigid backing layer 132. The rigid backing layer 132 provides a stable body to which the alignment mechanism 106 and visual guide 104 can connect. The padding layer 134 provides a comfortable interface with the subject's face, while also permitting a small degree of lateral (left or right, relative to the subject's face) movement to align the image capture device with the eye. The padding layer 134 also provide a damping or cushioning effect, enhancing the stability of the position of the device on the face when looking at a subject's eye. This minimises potential confounding factors, such as the variation in the angle, and distance of lens to the eye. This allows consistent image capture, enabling more accurate software-based image analysis.

[0068] Now with reference to FIG. 3a, the system 301 comprises an adjustable mount 300 for locating the subject's eye relative to the visual guide. When the mount 300 is mounted to the subject, the eye of the subject is aligned, or is able to be aligned, with the desired viewing direction or focal point, as predetermined by the position of the annular ring (not identified, but the same as annular ring 110 of FIG. la). In this sense, being "mounted" to the subject comprises resting on a predetermined portion of the subject. In other embodiments, the mount 300 may physically attach to, or engage, part of the user's head. For illustration purposes, the mount 300 will be described in the context of a nose bridge or nose bridge portion 302 that is mounted to the nose (i.e., positioned on the nose) during use, though other embodiments are envisaged such as a mount for fitting about the ears of a subject. The mount is, in any case, designed to contact the subject at a predetermined location (e.g., bridge of the nose or around the ears) to reduce movement of the system 301 while positioning the system 301 close to the eyes of the subject. In this context, the word "when" includes the mount 300 being adjustable once it has been mounted to (e.g., positioned on) the nose of the subject and being adjustable prior to being mounted to the nose of the subject.

[0069] In other embodiments, the adjustable mount 300 that rests on a predetermined portion of the subject may be a chin rest, designed for the subject to place a chin on. It may also take the form of a forehead strap or support.

[0070] In one or more embodiments, the mount 300 is attached to a movement mechanism of the alignment mechanism 307 thereby permitting adjustment of the mount 300. In FIG. 3a, the movement mechanism comprises rail 304, connected to two cups

[0071] 306, 308, and a slide 305 that slides along the rail 304 to position the mount 300 relative to the alignment mechanism 307. The alignment mechanism 307 comprises the movement mechanism 304, 305 and a body 309 that engages the mobile device comprising the image capture device. The body 309 of the embodiment in FIG. 3a, comprises magnetic points 310 for attaching to the mobile device. Thus, body 309 holds the mobile device on the system 301, while the movement mechanism controls the relative position between the mobile device (and thus the image capture device) and the mount 300.

[0072] The mount 300 and movement mechanism 304, 305 control relative movement between the mount 300 and alignment mechanism 307, to ensure the visual guide can be located relative to a subject's eye regardless of the size of the subject's face, depth of eye sockets or distances between facial features. The mount 300 may be adjustable based on its interaction with the movement mechanism. Moreover, a first end of the mount 300 may be in a fixed position relative to the alignment mechanism

[0073] 307, the mount 300 being adjustable by moving a second, opposite end of the mount towards and away from the fixed end. To facilitate this function, the mount 300 of FIG. 3a may be flexible.

[0074] The movement mechanism 304, 305 may comprise any desired arrangement of parts, such as a pin and socket arrangement positioned so that the mount 300 can be in various, discrete locations on the alignment mechanism 307. In other embodiments, the movement mechanism comprises a rail 304 permitting continuous movement of the mount 300 relative to the alignment mechanism along a length of the rail 304. Alternatively, the rail 304 may have notches or another device to provide for discrete movement of the mount relative to the alignment mechanism (e.g., protrusions on one of the rail 304 and slide 305, and notches on the other of rail 304 and slide 305). When protrusions of one of the slide 305 and rail 304 engage notches on the other of the slide 305 and rail 304, friction resists relative motion between the slide 305 and rail 304 and thus between the mount 300 and the alignment mechanism 307. The friction may be manually overcome to move the mount relative to the alignment mechanism - e.g. to engage a different pair of protrusions and notches. The notches on the rail 304 or slide 305 may decrease the occurrences of slipping or sliding of the mount 300 during the image capture process. The provision for discrete movement of the mount 300 relative to the alignment mechanism may also allow for seamlessly switching the use of the mobile eye imaging system between two or more than two subjects, wherein a first notch setting (i.e., protrusions are engaged with a first pair of notches on opposite sides of the slide 305, or notches are engaged with a first pair of protrusions on opposite sides of the slide 305) may correspond to the depth of an eye socket or depth of a nose bridge of a first subject, or the spacing between the nose bridge and the eye of the first subject, and a second notch setting (i.e., protrusions are engaged with a second pair of notches on opposite sides of the slide 305, or notches are engaged with a second pair of protrusions on opposite sides of the slide 305) may correspond to the depth of an eye socket or depth of a nose bridge of a second subject, or the spacing between the nose bridge and the eye of the second subject. To that end, the mount 300 may comprise a flexible member and the two ends of the mount 300 can be moved towards each other (including one end being brought towards the other end) to bend the flexible member to accommodate subjects with deeper eye sockets, or away from each other to straighten the flexible member to accommodate subjects with shallower eye sockets. The rigid backing layer 132 may be replaced by the flexible member to afford this bending function. In one or more embodiments, the mobile image capture system comprises a stationary eye cup 306 and a moveable eye cup 308. The moveable eye cup 308 may move relative to the stationary eye cup 306 as the mount is adjusted. The moveable cup 306 may comprise part of the mount 300. The ends of the mount 300 may coincide with or comprise the moveable cup 308 and stationary cup 306 such that, as mentioned above, movement of the moveable cup 308 towards or away from the stationary cup 306 causes bending of the mount 300. In this regard, the mount 300 may be shaped as a bar with a semicircle or circle on each end, the semicircle or circle at least partially defining a peripheral edge of the respective cup.

[0075] The mount 300 may include a flexible member 302, the flexible member 302 being an adjustable nose bridge in some embodiments. The adjustable nose bridge may be made of a flexible polymer. The adjustable nose bridge may be made of polydimethylsiloxane (PDMS). The adjustable nose bridge may be positioned and shaped to conform to the contours of a nose of the subject. The depth of the nose bridge can also be customised to allow for use in subjects with varying depths of eye sockets, by varying the distance between the opposite ends of the nose bridge. Thus, the nose bridge may be optionally extended or retracted, depending on the subject's specific anatomical requirements. As the moveable eye cup 308 moves relative to the stationary eye cup 306, the nose bridge is extended or retracted.

[0076] The adjustable nose bridge may be padded. The padding increases comfort during monitoring of a subject's eye condition. The padded nose bridge may provide a supportive platform for the system to comfortably and stably rest on the subject's nose during use. Stability of the position of the system increases the repeatability and consistency of the imaging process. The padded nose bridge may also minimise the discomfort that a subject may experience at pressure points arising from prolonged use of the mobile eye imaging system. Advantageously, increased user comfort further encourages the subject to remain in a steady position during eye assessment and reduces the likelihood of movement or repositioning of the eye. This increases the reliability of measurements taken from images of the eye.

[0077] The adjustable nose bridge may additionally be detachable - e.g., for cleaning and maintenance. This improves hygiene both over prolonged usage for a single subject, and when a single system is used for monitoring the eyes of more than one subject. The adjustable nose bridge may be fastened on the adjustable mount via an attachment mechanism, wherein the nose bridge, while removable, does not present any unintended movements during eye monitoring. Such attachment mechanisms will be known to the skilled person in view of the present teachings, such as a rubberised or elasticised member fitting over a plastic base of the mount, or reusable adhesive surfaces.

[0078] The adjustable nose bridge may be made from materials which are durable and hypoallergenic. The chosen materials may be skin-friendly, to provide for subjects with sensitive skins. The adjustable nose bridge may be made from skin-friendly materials such as PDMS.

[0079] In one or more embodiments, the mobile eye imaging system comprises an adjustable nose bridge which may include any one of, or more than one of, or all four of the above-described features, namely choice of a flexible material, inclusion of padding, detachable, and choice of a skin-friendly material.

[0080] Alignment mechanism

[0081] The present system comprises an alignment mechanism 400 that provides a fixed reference between the system and an image capture device (e.g., mobile device or smartphone) to which the system is attached when in use. The alignment mechanism is engaged with both the mount 401 and the visual guide. As such, the alignment mechanism 400 positions the system on a mobile device such that the visual guide is aligned with an image capture device of the mobile device.

[0082] To achieve this alignment, the alignment mechanism 400 should itself be located on the mobile device in a known, predetermined position. In some embodiments, the alignment mechanism 400 is magnet-based, to facilitate location of the alignment mechanism on the mobile device and for engaging the mobile device in a known configuration through magnetic attraction to the mobile device. The magnet-based engagement is afforded by one or more magnets 404, located on the alignment mechanism 400, and one or more opposite polarity magnets 406 in a holder 408 of the smartphone (e.g. a phone case designed to fit the relevant smartphone). The magnet-based embodiment provides one or more magnets on the alignment mechanism 400 that are arranged to magnetically attract corresponding magnets on the imaging device. In the case where one magnet is used, that magnet may comprise two poles to align with two poles (or two magnets) of opposite polarity on the mobile device. Similarly, where two magnets are used, they will connect to opposite poles (of the same magnet, or different magnets) on the imaging device. In the present embodiment, the holder 408 is fitted with multiple magnets for engaging corresponding magnets 404, of respective opposite polarity, of the mobile device. Presently, the holder comprises at least three such magnets. The locations of the magnets may be non-collinear. In some embodiments, the non-collinearity ensures the magnets 404, 406 of the present system engage with the corresponding magnets in the mobile device, in a single orientation only. By limiting the magnets and the corresponding magnets such that they properly engage in a single orientation only, the system advantageously reduces human error that may arise from inaccurate alignment between the mobile eye imaging system and the image capture device. It provides for a quick and accurate set up of the mobile eye imaging system.

[0083] In other embodiments, the alignment mechanism comprises a hook-and-loop fastener mechanism, to facilitate location of the alignment mechanism on the mobile device and for engaging the mobile device in a known configuration through the hook- and-loop fastening to the mobile device. Such an alignment mechanism may comprise at least three such hook-and-loop attachment points, or it may comprise one two-dimensional attachment point such that the hook and loop of the hook-and- loop fastener mechanism can properly engage in a single orientation only.

[0084] In other embodiments, the alignment mechanism comprises a series of adhesives, also to facilitate location of the alignment mechanism on the mobile device and for engaging the mobile device in a known configuration.

[0085] The abovementioned mount and alignment mechanism ensure efficient, consistent and repeatable setup of the present system relative to the eye of the subject, eliminating the need for tedious manual adjustments or complex alignment procedures. The same components can eliminate the need for a subject to perform fine adjustments to align the image capture device with the eye. Moreover, the mount increases stability as the mobile eye imaging system and the image capture device are positioned securely in place, removing unintended movement of the mobile eye imaging system with respect to the image capture device. In one or more embodiments, the mobile eye imaging system comprises a rack 502, with the alignment mechanism and / or image capture device being mounted on the rack 502. FIG. 5 provides an illustration of a possible setup of said rack 502. The rack 502 can be used so that a subject can move without moving the image capture device 504. The rack 502 may provide additional stability during the eye imaging process and eliminate the need for the setup, while remaining portable. The mobile eye imaging system 506 may be mounted on the rack 502 using any known mechanism - e.g., bolts and screws or friction fit. It may also be mounted on a rack 502 using a removable but secure adhesive or using any other secure assembly methods.

[0086] Advantageously, a setup mounted on a rack 502 decreases the occurrence of unintended movements or vibrations that may occur, and which may affect the quality of the images being captured. The setup mounted on a rack 502 also allows subjects who may have difficulty maintaining a steady position - e.g., patients suffering from tremors in the hands or fingers - to use the setup with ease.

[0087] Advantageously, the rack 502 on which the setup is mounted may further comprise a motorised movement mechanism for moving the system relative to the surface on which the rack is position, to locate the visual guide relative to the eye. The present rack 502 comprises a rail system, having two perpendicularly disposed rails, along which the mobile eye imaging system can be moved together with the image capture device. The user can therefore control movement of the mobile eye imaging system relative to their eye, in two dimensions. The mount may similarly be motorised so that the mount maintains contact with the user during movement of the mobile eye imaging system - e.g., the mount may counteract movements made along the rails of the rack. The motorised movement mechanism may be remote controlled, to provide the subject with fine control of the system. The rack may permit three degrees-of-freedom 508, namely in the x-, y- and z-directions, to provide fine control over the position of the setup. It may also offer three degrees-of-freedom following a polar coordinate system, and / or one or more additional degrees of rotational freedom.

[0088] In one or more embodiments, the mobile eye imaging system also comprises a connector 510 which may provide for a wired connection between the system and the mobile device. The wired connection may provide for transfer of at least one of power and control signals during imaging. In one or more embodiments, the image capture device may be a mobile phone camera.

[0089] It will be appreciated that many further modifications and permutations of various aspects of the described embodiments are possible. Accordingly, the described aspects are intended to embrace all such alterations, modifications, and variations that fall within the spirit and scope of the appended claims.

[0090] Throughout this disclosure and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps, but not the exclusion of any other integer or step or group of integers or steps.

[0091] The reference to any prior art in this disclosure is not, and should not be taken as, an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge.

Claims

1. Claims1. A mount for a mobile eye imaging system, the mount comprising a body having: a nose bridge portion for resting against a bridge of a nose of a subject; and at least one lateral portion offset from the nose bridge portion such that, in use, each lateral portion is positioned towards a left or right side of a face of the subject.

2. The mount according to claim 1, wherein the nose bridge portion and at least one lateral portion form three non-collinear points of contact with the subject.

3. The mount according to claim 1 or 2, comprising at least three said lateral portions, one of the lateral portions positioned to be above an eye of the subject, in use, another of the lateral portions positioned to be below the eye of the subject, in use, and a further one of the lateral portions positioned to rest on an opposite side of the face of the subject to the other two lateral portions, in use.

4. The mount of any one of claims 1 to 3, wherein the body comprises a first member for engaging the mobile eye imaging system, and a padding layer, disposed against the first member, for contacting the face of the subject.

5. A mobile eye imaging system, the system comprising: a visual guide defining a viewing direction for image capture; a mount that is adjustable to align an eye of a subject with the viewing direction when the mount is mounted to a predetermined portion of the subject; and an alignment mechanism engaged with the mount and visual guide, for positioning the system on a mobile device such that the visual guide is aligned with an image capture device of the mobile device.

6. The mobile eye imaging system, wherein the mount is a mount according to any one of claims 1 to 4.

7. The system according to claim 5 or 6, wherein the visual guide is an annular ring, configured to direct the subject's eye to a focal point of the optical system.

8. The system according to claim 7, wherein the annular ring comprises an LED annular ring with adjustable brightness.

9. The system according to any one of claims 5 to 8, comprising a mirror mounted at a predefined angle relative to the visual guide, to reflect incident light into the eye.

10. The system according to claim 9, further comprising a light source emitting light towards the mirror, such that incident light in reflected into the eye.

11. The system according to claim 10, being communicatively coupled to the mobile device when in use, such that activation of the light source to emit light towards the mirror is synchronised with image capture by the image capture device.

12. The system according to claim 11, comprising a potentiometer configured to adjust the brightness of the light source.

13. The system according to claim 11, wherein the alignment mechanism comprises an aperture configured to selectively permit or block light from passing through the aperture towards the eye.

14. The system according to claim 5, wherein the mount is removably attached to a rail of the alignment mechanism, wherein the rail has notches to provide for discrete movement of the mount relative to the alignment mechanism.

15. The system according to claim 5, comprising a stationary eye cup and a moveable eye cup, the movable eye cup moving relative to the stationary eye cup with adjustment of the mount.

16. The system according to claim 5, wherein the mount comprises an adjustable nose bridge.

17. The system according to claim 16, wherein the adjustable nose bridge is made of a flexible material and is positioned to conform to contours of a nose of the subject.

18. The system according to claim 5, wherein the alignment mechanism is a magnet-based alignment mechanism comprising three or more magnets arranged to engage with corresponding magnets of the mobile device in a single orientation only, wherein the at least three magnets are non-collinear.

19. The system according to claim 5, further comprising a rack for fixedly positioning the system above a surface during imaging, the rack comprising a motorised movement mechanism for moving the system relative to the surface to position the visual guide relative to the eye.

20. The system according to claim 5, wherein the image capture device is a mobile phone camera.

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