Automatic optical device for generating data useful for screening an opening of the irido-corneal angle

Abstract

An automatic optical device comprises a structured light source configured to project a predetermined pattern, an optical split group, preferably a prism, configured to divide the pattern into a first pattern for a right eye and a second pattern for a left eye, a right mirror and a left mirror, arranged opposite the optical split group and respectively receiving the first and second pattern, a support configured to carry the optical split group, the right mirror, and the left mirror so as to define respective windows for framing, in use, the right and left eyes and the corresponding optical axes by means of an image acquisition unit and to capture an image of the right and left eyes while the corresponding first and second patterns are projected thereon.

Description

[0001] “AUTOMATIC OPTICAL DEVICE FOR GENERATING DATA USEFUL FOR SCREENING AN OPENING OF II IE I RIDO-CORNE AL ANGLE”

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to a device for generating screening data of an opening of the iridocorneal angle and contributing to the assessment of the risk of ocular disorders caused by poor drainage of ocular fluid; in particular, the screening data are one or more images of the eyes reflecting a predefined light pattern.

[0004] STATE OF HIE ARI'

[0005] It is known to measure the irido-corneal angle through gonioscopic examinations using a Goldman lens and optical coherence tomography. However, such diagnostic techniques are invasive and require expensive equipment.

[0006] SUMMARY AND OBJECTS OF THE INVENTION

[0007] The object of the present invention is to generate data useful for measuring the irido-corneal angle in a non-invasive manner and without requiring physical contact, thereby making it suitable also for uncooperative patients, such as elderly individuals and children.

[0008] The object of the present invention is achieved by means of a device comprising: a structured light source, both RGB and with wavelength intervals of predefined width, for projecting a predetermined pattern, e.g. a line or a grid; an optical split assembly, preferably a prism or a galvanometnc mirror group, for splitting the pattern into a first pattern for a right eye and a second pattern for a left eye; a right mirror and a left mirror, positioned opposite the optical split assembly and receiving the first and second patterns, respectively; a support for holding the optical split assembly, the right mirror, and the left mirror m such a way as to define respective windows for framing, in use, the right eye and the left eye, and the corresponding optical axes via an image acquisition unit, and to capture an image of the right eye and the left eye while the respective first and second paterns are projected onto the latter.

[0009] In particular, this is achieved by spacing the right mirror and the left mirror from the optical split assembly in such a way that the optical split assembly and the right and left mirrors do not at least partially obstruct the right and left irises as framed by the image acquisition device.

[0010] A device as above, also coupled with a pre-existing acquisition unit suitably provided with image processing software, allows for non-mvasive and rapid generation of data, preferably one or more images, simultaneously for both eyes, thus reducing patient engagement time, and the required components are readily available. Furthermore, the structured light source is detachably connected to the optical devices so that it can be replaced, e.g. in case of malfunction.

[0011] According to a preferred embodiment, an angular orientation of each of the right and left mirrors is adjustable.

[0012] In this manner, the conditions for executing the optical measurement can be adapted. This can be achieved, for example, by means of micro-mirror arrays and / or galvanometnc mirrors and / or translation, rotation / translation, or rotation mechanisms of monolithic rigid mirrors.

[0013] According to a preferred embodiment, the mirrors and / or the optical split device are configured to control the projection of the pattern along a predefined direction, preferably linear and more preferably along a lateral direction considering a triplet of coronal, sagittal, and transverse planes. In this way, time sequences of images representative of the movement of the pattern on the eyeball are generated. According to a preferred embodiment, the device further comprises the optical acquisition unit for capturing images of the right and left iris that are free from, i.e., not overlapping with, the right and left mirrors and the optical split assembly.

[0014] In this manner, the device can be configured either as a block to be mounted on a frame with a chin rest whose relative position and / or angular orientation with the mirrors and the optical split device is adjustable either manually or in a motorized way. Alternatively, a head-worn support can be implemented for a patient who therefore has the chin free, i.e., not resting on the chin rest, comprising the block and appropriate adjustments, e.g. for stabilizing the relative position between the mirrors etc. and the patient's head.

[0015] According to a preferred embodiment, the optical acquisition unit is in data exchange with an electronic processing device comprising a processor and a memory, e.g. a computer, for receiving: a first time sequence relating to the patterns projected by the structured light source; and / or a second time sequence relating to the acquisitions of the right and left eye while the first time sequence was being projected; or a second time sequence of the right eye and a third time sequence of the left eye, wherein the first time sequence is synchronized with the second time sequence or with the second and third time sequences.

[0016] Based on the above, an electronic control of the acquisition unit captures an image when the patern changes position. In this way, the second and, if present, the third time sequence comprise images captured when, based on the first time sequence, the pattern changes position.

[0017] BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will now be described according to one or more non-limiting embodiments, the description of which is supported by the following drawings: Fig. 1 : is a schematic view of a first embodiment of an optical measuring device according to the present invention;

[0019] Fig. 2: is a further embodiment of the present invention;

[0020] Fig. 3: is an image of an eye reflecting a diffracted linear pattern to enable subsequent assessment of the opening of the irido-corneal angle; such image is a frame contained in a time sequence of images generated using the device of the present invention.

[0021] DETAILED DESCRIPTION OF THE INVENTION

[0022] Figure 1 schematically illustrates a first embodiment of an optical measuring device 1 comprising a structured light source 2 for projecting a static or dynamic pattern, an optical split device 3, e.g. a prism or a galvanometric mirror group, configured to receive a structured light beam from source 2 and split it to duplicate the pattern in a mirror-symmetric fashion towards a right eye and a left eye, and a right mirror and a left mirror 4, 5 for receiving each the pattern from the source 2 and reflecting it towards the corresponding eye of a user or patient.

[0023] As illustrated in the drawing, in use, the optical axes Al , A2 of the user’s eyes are transverse, either on the same plane or on different planes, to the corresponding right and left optical paths Pl and P2 of the patterns between the split device 3 and the corresponding mirrors 4, 5.

[0024] The structured light source 2 comprises, for example, LED or laser sources coupled with appropriate optical devices for both focusing the light beam (e.g., lenses) and generating patterns (e.g., diffractive optical elements capable of generating, from a point-shaped beam, one or more vertical lines, i.e., lines parallel to the sagittal plane and perpendicular to the transverse plane), as well as for moving the pattern, preferably linearly in a lateral direction, in the transition zone between the iris and the pupil. As illustrated in the figure, an optical axis A3 of the structured light source 2 is movable and / or also the mirrors 4, 5 are movable. Preferably, the optical axis A3 and / or the mirrors 4, 5 are movable both during the execution of the measurement and prior to the measurement, in order to adapt the configuration and ensure that the patterns reach the eyeballs of the user in the correct direction. For example, the optical path of each pattern from the corresponding mirror 4, 5 to the eye is at an angle of 60° with respect to the optical axis of the eye, preferably while the latter is gazing at a fixed frontal target during the movement of the pattern from right to left (or vice versa) on the eyeball. The shape, intensity, color, and movement dynamics of the pattern can be set manually or automatically to account for the different reflectivity of the patient's iris, and its position is controlled so as to scan the surface of the eye from the temporal to the nasal region or vice versa.

[0025] The inclination of the optical path between the mirrors 4, 5 and the optical axes of the eyes is such that, in the case of a vertical line pattern moving in a direction perpendicular to itself, a first reflection is obtained due to the outer surface of the cornea, a second reflection due to the inner surface (i.e., wetted by the aqueous humor) — normally, since the thickness of the cornea can be considered fixed and relatively low, the first and second reflections are very close to each other — and a third reflection located at the inner edge of the iris (Figure 3). By processing the image showing these three lines (in the case where the pattern is a vertical line), it is subsequently possible to estimate a degree of opening, typically on a scale of four levels, and / or to calculate the iridocorneal angle according to known methods.

[0026] According to one embodiment not shown, the device 1 is mounted on a support structure for medical use comprising a chin rest on which a patient rests their head; the medical personnel perform the calibration of the vertical and / or angular position of the mirrors 4, 5 in order to obtain the correct angle of the optical path of the patterns toward the eyeballs, e.g., the 60° illustrated in the figure; the calibration also includes the focusing of the pattern on the eyeballs, e.g., via the edge optics of the structured light source 2. Alternatively, in another embodiment not shown in the figure, the device 1 is integrated into a head-wearable support.

[0027] When the light patterns strike the corresponding irises, an image recording is performed via an optical acquisition unit 6 to generate a time sequence representative of the iris during the projection of the patterns by the structured light source 2. The latter also stores, e.g., via an electronic controller, a time sequence of the pattern projection. These time sequences are synchronized in a known manner so that each frame of the projection time sequence corresponds to a frame of the iris representative time sequence.

[0028] In the embodiment of Figure 1, a single acquisition unit 6 frames the eyeballs through an additional optical split device 7, e.g., a prism and corresponding right and left mirrors 8, 9. In this way, a single time sequence is generated in which the frames comprise images of both eyes.

[0029] In the embodiment of Figure 2, differently from Figure 1, each eye is framed by a corresponding acquisition unit 6, 6', preferably comprising a matrix of CMOS optical sensors, each of which generates a time sequence of acquisition of its respective eye, resulting in a time sequence for the right eye and a time sequence for the left eye. According to another embodiment, only the second and third time sequences of captured images, each from the respective acquisition unit 6, 6', are synchronized with each other.

[0030] In both embodiments, the images of the eyes in the frames of the acquired time sequences do not exhibit any interference from mirrors 4, 5 and, if present, 8, 9, nor from the structured light source 2, the optical split device 3, and, if present, the optical split device 7. Preferably, the optical projection path of the patterns and the optical axes of the eyeballs are coplanar.

Claims

CLAIMS1. An automatic optical device (1) comprising: a structured light source (2) configured to project a predetermined light pattern, an optical split group (3) configured to divide said pattern into a first pattern for a right eye and a second pattern for a left eye, a right mirror and a left mirror (4, 5), positioned opposite the optical split group (3) and receiving the first and second pattern respectively, a support configured to carry the optical split group (3), the right mirror, and the left mirror so as to define respective windows for framing, in use, the right and left eyes and the corresponding optical axes (Al , A2) by means of an image acquisition unit, and to capture an image of the right and left eyes while the corresponding first and second patterns are projected thereon.

2. The automatic optical device (1) according to claim 1, further comprising an electronic controller programmed to control at least one among the optical split group (3), the right and left mirrors (4, 5), and edge optics of the structured light source (2), in order to move the first and second pattern over the corresponding right and left corneas along a predefined direction, preferably linear.

3. The automatic optical device (1) according to claim 1 or 2, further comprising an electronic image acquisition group (6; 6, 6') configured to frame the right and left eyes while the first and second patterns are projected thereon.

4. The automatic optical device (1) according to claims 2 and 3, wherein the electronic image acquisition group (6; 6, 6') is programmed to generate a time sequence of images of both the right and left eyes or, synchronised with one another, a time sequence of images of the righteye and a time sequence of images of the left eye, wherein the device is programmed, via synchronisation of the electronic controller and the electronic image acquisition group, to capture images of the eyes when the pattern changes position.

5. The automatic optical device (1) according to any one of the preceding claims, wherein the pattern is a line or a grid.

6. The automatic optical device (1) according to any one of the preceding claims, characterised in that it is wearable on the head of a user.

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