Ophthalmic Headset

Abstract

A wearable headset 1 for performing eye tests comprising a light source 2, a screen 9 and means 10 to split an incident light into two or more separate beams. A lens assembly 6, 7 defines an optical path with an information processing means to control displays on the screen to create patterns downstream of the screen resulting from controllably blocking the transmitting light from the light source in defined regions of the screen. A sensor is disposed to capture images of an eye being tested wherein the means to split an incident light to two or more separate beams is disposed to direct light from the light source after it has passed through the screen to the eye and wherein the pattern projected onto the eye is captured by the sensor. A wearable head set for performing eye tests with a first and second part is also provided. The first part comprises a display means to generate patterns to be projected onto a single eye to be tested and the second part is wearable by a user having a pair of opening aligned to the user’s eye.

Description

The present disclosure relates to wearable headsets for performing eye tests. Typically, the health of a patient’s eye is tested using equipment such as bench mounted slit lamps or corneal topographers. The patient rests their chin on a rest and looks into a camera. These devices are large, unwieldy, and difficult to transport. In some cases, it is also difficult to hold the patient’s body still relative to the equipment. In particular older patients with mobility and posture issues tend to find it difficult and uncomfortable to stay on a chin rest for extended period of time. This is often compounded when patients have hearing difficulties which make it difficult for the patients to hear and / or understand instructions during the test. This underlines the need for a simple and transportable device for performing examinations of the eye which overcome the above issues. According to a first aspect of the invention there is provided a wearable headset for performing eye tests comprising a first part and a second part, the first part comprising a display means to generate patterns to be projected onto a single eye to be tested; the second part being wearable by a user and having a pair of openings aligned with both eyes of the user, wherein the first part is releasably couplable to the second part in a first position in which patterns from the display means are directed to a first eye of the user to test the first eye and a second position in which patterns from the display means are directed to a second eye of the user to test the second eye, the first part further comprising means to block the opening in the second part aligned with the eye not being tested. By using a headset worn by a patient, relative movement between the patient and test equipment is minimised, enabling capture of improved pictures or videos of the patent’s eyes. Furthermore, the same headset may be used to test both eyes of the patient without requiring extra parts to test the different eyes that must be stored and may be easily lost. The unit is also simple to make, easy to use and lightweight. The first part and second part may be releasably coupled by sliding rails. The sliding rails may be substantially vertical in relation to the horizontal plane in which the display means is two-dimensionally arrayed. The difference between the first and second positions may be a rotation of 180°, wherein the 180° rotation may be about an axis defined as being: coplanar with a line joining the eyes of the user, and perpendicular to the line joining the eyes, and passing at least through a point substantially at the midpoint of a segment joining the eyes of the user. The display means may comprise: a light source; a screen; a means to split incident light beam into two or more separate beams; a lens assembly defining an optical path from the light source through the screen to the means to split the incident light beam; an information processing means to control displays on the screen, to create patterns downstream of the screen resulting from controllably blocking and transmitting light from the light source in defined regions of the screen. The wearable headset may also comprise; a sensor disposed to capture images of an eye being tested; wherein the means to split the incident light beam may be disposed to direct light from the light source after it has passed through the screen to the sensor and the eye being tested, and wherein the pattern projected onto the eye may be compared to the pattern projected through the screen. The means to split the incident light beam into two or more light beams may be a mirror. This may be a two-way mirror. The means to split the incident light may be a beamsplitter. The means to split the incident light beam into two or more light beams may be a prism beam splitter, a cube beamsplitter, or a plate beamsplitter. The means to split the incident light into two or more light beams may be a polarising beamsplitter or a non-polarising beamsplitter. The light source may emit into the infrared part of the electromagnetic spectrum. The light source may emit in any suitable part of the electromagnetic spectrum. There may more than one light source. The display means may further comprise two or more polarisers in use with the prism beam splitters. According to a second aspect of the invention there is provided a wearable headset for performing eye tests comprising: a light source; a screen; a means to split incident light beam into two or more separate beams; a lens assembly defining an optical path from the light source through the screen to the means to split the incident light beam into two or more separate beams; an information processing means to control displays on the screen, to create patterns downstream of the screen resulting from controllably blocking and transmitting light from the light source in defined regions of the screen; a sensor disposed to capture images of an eye being tested; wherein the means to split incident light beam into two or more separate beams is disposed to direct light from the light source after it has passed through the screen the eye being tested, and wherein the pattern projected onto the eye is captured by the sensor. The means to split the incident light beam into two or more light beams may be a mirror. This may be a two-way mirror. The means to split the incident light may be a beamsplitter. The means to split the incident light beam into two or more light beams may be a prism beam splitter, a cube beamsplitter, or a plate beamsplitter. The means to split the incident light into two or more light beams may be a polarising beamsplitter or a non-polarising beamsplitter. The headset provides a simple to use, lightweight and transportable way to test the eyes of a patient. Using the headset, a variety of different patterns may be generated in a simple, reproducible way. By using a headset worn by a patient, relative movement between the patient and the test equipment is minimised, enabling capture of improved pictures or videos of the patient's eyes. The unit is also simple to make with limited peripheral components. The screen may comprise an array of pixels, wherein each pixel may be independently controllable to block or transmit light. The amount of light transmitted may be controllably variable, wherein the light in the defined regions of the screen may be completely transmitted, completely blocked, or attenuated such that the intensity of the light may be reduced. The screen may be a transparent screen. The screen may be a colour screen. The screen may be an LCD screen. The light source may be a white LED source. The means to split the incident light beam into two or more light beams may be a mirror. The means to split the incident light beam may be a two-way mirror that may be transparent to the sensor. The lens assembly may comprise a condenser lens assembly arranged to convert a substantially divergent beam of light from the light source into a parallel or a converging beam. The lens assembly may comprise one or more focussing lenses arranged to focus light from the light source and / or from the screen. The headset may comprise a means of selectively transmitting light of different frequencies disposed in front of the sensor. The lens assemblies may comprise one or more lens. There may be provided one or more apertures between the LED source and the lens assemblies to controllably restrict the amount of light hitting the one or more lens. Filters may be provided between the light source and the screen to apply colour to the light. A first optical axis may be defined along a direction from the light source to the mirror, and a second optical axis may be defined along a direction from the mirror to the eye being tested, wherein the first optical axis and the second optical axis may be nonparallel. The first optical axis may be substantially perpendicular to the second optical axis. The sensor may be non-colinear with the first optical axis, and the mirror may be a beam splitter that directs a portion of the light from the light source to the eye being tested, and a portion of the light from the light source to the sensor. A means of selectively transmitting light of different frequencies may be disposed in front of the sensor. The sensor may be disposed along the second optical axis such that light passes from the eye, through the mirror, to the sensor along a straight line along second optical axis. The headset may further comprise a further light source arranged to project additional patterns on to the eye being tested. The further light source may be disposed along the second optical axis. Optical elements may be disposed along the second optical axis, between the further light source and the mirror, the optical elements arranged to perform condensing and focusing operations. There may be one or more apertures disposed in the second optical axis. There may be provided one or more double aspheric lens to allow imaging of the retina. The distances between the various optical components may be suitably adjusted as required. The headset may further comprise one or more onboard power sources. The display means may further comprise any of the features of the wearable headset as described in the first aspect of the invention. It will be appreciated that any feature described in relation to a particular aspect may be applied mutatis mutandis to any other aspect, unless mutually exclusive. Embodiments of the inventions will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1A illustrate a top down view of a cross-section of the components of the headset; Figure IB illustrates a top down view of the headset of Figure 1A in a first configuration; Figure IC illustrates a top down view of the headset of Figure 1A in a different, second configuration; Figure 2 illustrates a front view of the first part of the headset of Figure 1A; Figure 3 is a rear view of the second part of the headset of Figure 1 A; Figure 4A is a user point of view of the first and second part of the headset of the first embodiment, engaged in a first configuration; Figure 4B is a user point of view of the first and second part of the headset of the first embodiment, engaged in a second configuration; Figure 5A illustrates an alternative embodiment of the headset shown in Figure 1, with the camera offset from the optical axis; Figure 5B is a user point of view of the first and second part of the headset of the second embodiment, engaged in a first configuration; Figure 5C is a user point of view of the first and second part of the headset of the second embodiment, engaged in a second configuration; and Figure 6 illustrates various patterns generated by the headset of either embodiment, overlaid on an eye being tested and captured by the headset. Figure 1A shows the optical components of a headset 1 for examining the eye of a patient. Figure 1 shows the optical components from above. The headset 1 comprises a white LED light source 2, provided with a heat sink 3. There is also provided a printed circuit board (PCB) 4 connected to a colour liquid crystal display (LCD) 9. The PCB 4 has a microprocessor or other controller (not shown) to control the LCD 9 to display various patterns. The patterns may be displayed in black and white or in colour. The LED light source 2 is mounted to the same PCB 4 and may be controlled by the same microprocessor or controller. Alternatively, there may be provided separate, independent PCBs and / or separate controllers for the LED 2 and the LCD 9. The light from the white LED light source 2 propagates through a condenser lens system 8. The light from the white LED source 2 is then propagated trough the LCD 9. Different patterns on the LCD 9 result in the white light from the LED 2 to be blocked, giving rise to shadows in specific regions of the light beam. The LCD 9 comprises a planar array of pixels. Each pixel of the LCD 9 may be independently controllable via a combination of software and hardware. This allows the creation of different patterns depending on the instantaneous characteristic of each pixel at any given time. In this configuration the LCD 9 performs the functions of a filter. In one embodiment, the LCD 9 may act as a binary filter, either blocking light or allowing it to transmit at a fixed amount. In other embodiments, by controlling the strength (contrast) of the pixels on the LCD 9 the amount of light transmitted through the LCD 9 can be varied. In this way the light may be transmitted, partially transmitted, or completely blocked in specific regions. The light beam, having propagated through the LCD 9, is then propagated through a focusing lens assembly 6. The light may also optionally be propagated through a magnifying lens assembly 7. After the lens assemblies 6, 7 the light is propagated through a two-way mirror 10. The display means may further comprise polarisers provided along the path of the light beam from the light source 2 to the two-way mirror 10. The series of optical elements from the light source 2 to the two-way mirror 10 and the intervening elements (lens assemblies 6, 7. 8, LCD 9) define a first optical axis A. Defined on Figure 1 are two directions which are perpendicular to the first optical axis A. These two directions are a first direction C, defined as a vector pointing 90° from the first optical axis A, and a second direction D, pointing -90° from the first optical axis A. The first optical axis A divides Figure 1 into an anterior region comprising the subregion extending from the first optical axis A in the direction C, and a posterior region comprising the subregion extending from the optical axis in the direction D. In use, the posterior region is proximal to the user’s face, whereas the anterior region is distal to the user’s face. There may be provided one or more apertures along the first optical axis A to constrict light. The two-way mirror 10 is disposed at an angle of substantially 45° to the first optical axis A. The axis of incidence of the light beam from the light source will be taken as the x-axis of a 3D cartesian coordinate systems. In this coordinate system, the second optical axis may be considered to fall on the y-axis. A vertical line perpendicular to both the x-axis and the y-axis then corresponds to the z-axis of the coordinate system. The above defined angle of 45° is the angle defined between the xz plane and a vertical plane defining the mirror 10. In some embodiments, the mirror 10 may be adjusted in a yaw motion, i.e., rotated about the vertical axis (z-axis) in this coordinate system. Additionally, the mirror 10 may be adjusted in a pitch motion, i.e., rotated about the y-axis. The two adjustment controls defined above correspond to the Z-control and the K-control (tilt and rotation controls) of standard optical mirror mounts, respectively. This allows to accommodate for patients of different eye spacing and / or eye topologies, as the clinician can direct the beam of light to the desired position. Coarse adjustment as well as fine adjustment of the above controls may be provided. The two-way mirror 10 may be adjusted by any suitable control means. Such control means may be any of the widely used, well known control means known in the art. The two-way mirror 10 is provided such that the light incident upon it along the optical axis A is split into two beams. The first beam is reflected at substantially -90° to the optical axis A, into the posterior region, where it is incident on a patient’s eye. The second beam is reflected at substantially 90° to the optical axis A, into the anterior region. The two reflected beams are collinear along a second optical axis B that is substantially perpendicular to the first optical axis A, and parallel to second and third directions C and D. At a pre-determined distance from the two-way mirror 10 and alongside the second optical axis B, in the anterior region, there is provided a camera 12. Substantially collinear with the camera 12 and the two-way mirror 10, there is provided in the posterior region a viewpoint 18 to which may be in line with either eye port 14a, 14b which accommodates an eye to be tested. The headset 1 is provided such that the LCD 9 and the light source 2 are used to create a pattern, and this pattern is projected via the two-way mirror 10 into the eye via the eye port 14a,b. The two-way mirror 10 is provided such that the camera 12 sees through the two-way mirror 10. Arriving at the camera 12 are the following signals: 1) The pattern directly from the LCD 9, via the two-way mirror 10; and 2) The pattern from the LCD 9, via the two-way mirror 10, to the eye via the eye port 14a,b, and back to the camera 12. The camera 12 is used to record either still images or videos of the behaviour of the pattern after being projected onto the eye (signal 2), which can be compared to the original pattern (signal 1). Focusing and magnification lens assemblies 6, 7 are provided in the optical path between the mirror 10 and the camera 12 to magnify the view of the eye. A polariser 30 may be present. Polarisers may be disposed in the optical path of all light sources. Polarisers may be provided only in the optical paths of some light sources. There may also be provided a carousel of filters in front of the camera 12 to allow for fluorescein viewing. The filters may additionally comprise infrared filters to provide for IR viewing in embodiments where the light source is capable of emitting into the infrared region of the electromagnetic spectrum. This would be advantageous for instance for meibomian gland viewing. This arrangement allows different aspects of the eye to be measured, including for example corneal topography or dry eye symptoms, meibomian gland viewing in the infrared and / or viewing of different dyes such fluorescein. There may be provided an aspherical lens along the second optical axis B to allow imaging of the retina. There may be provided one or more apertures along the second optical axis B. There may be provided one or more lens assemblies along the second optical axis B. Such lens assemblies may be magnification lenses. Such lens assemblies may be any suitable type of lenses. An additional array of LEDs 25 may be positioned near the camera 12, in the section of the anterior region in-between the two-way mirror 10 and the camera 12, or near the camera as shown in Figure 1A. The additional, secondary LED array 25 may be white LEDs. This secondary LED array 25 may comprise discrete colours, RGB, far red and infrared LEDs. The additional array of LEDs 25 may be positioned along or adjacent to the second optical axis B. The additional array of LEDs 25 may be connected and controllable by a separate PCB or may be connected and controllable by the PCB 4. In addition to this additional array of LEDs 25, there may be provided additional separate optical elements 30 to focus and / or direct light from the additional array of LEDs 25 onto the eye of the patient. Polarising optical elements may also be present in front of the additional array of LEDs 25. The light from this secondary LED array 25 is not propagated through the LCD 9, and propagates directly to the eye and may serve as the basis for a different set of tests and testing functions, enabling the viewing of both the anterior and posterior parts of the eye, for example including the retina. The eye may also additionally be tested by using various filters which can be placed in front of the camera 12. The filters may be used alone or in tests requiring the instillation of dyes onto the eye. The filters may be removable into and out of the optical axis. Any suitable optical component, such as a lens for retinal viewing may be removable into and out of the optical axis. The filters may enhance reflections from the eye, helping uncover hidden details that are not normally detectable. Any suitable components may be modularly placed in or removed from the assembly. In the embodiments shown in Figures 1A to IC, the headset 1 is provided as a two-parts headset assembly disposed to be positioned on the head of a patient. The first part is a lighting and camera assembly 22 housing the optical components described in relation Figures 1A to IC and also shown in Figure 2. The lighting and camera assembly 22 has a rigid housing 15 enclosing its components. This prevents light bleeding into or out of the assembly 22. The lighting and camera assembly 22 is shown on its own in Figure 2, front on (facing the patient in use). The camera 12 is dashed as the view of the embodiment in Figure 2 results in only the two-way mirror 10 being visible. The rigid housing 15 may comprise slots or openings to add or remove filters and other optional components. The rigid housing 15 has an opening 18 along the second optical axis B, through which light is directed to the eye of the patient. The second part is a head mount piece 16, which is wearable by a user. The head mount piece 16 is arranged such that it is received onto the user’s face similarly to ski goggles or a virtual reality headset. The head mount piece 16 is shown on its own in Figure 3, front on (facing the patient in use). The head mount piece 16 comprises a front portion 13 comprising a rigid, flat surface with two openings 14a,b forming the eye ports. The openings 14a,b are provided such that they are of substantially the same size as the opening 18 on the lighting and camera assembly 22 as described in relation to Figure 1 and generally align with the eyes of a patient. Alternatively, the eye openings 14a,b may be larger in size than the opening 18 on the rigid enclosure 15. The openings 14a,b may be smaller than the opening 18 on the rigid enclosure 15 of the camera and lighting assembly 22. The head mount piece 16 comprises four rigid walls 19a,b,c,d extending substantially perpendicularly from the edges of the front portion 13 in the direction D as shown in Figures 1A-C. The walls 19a,b are the side walls, and the walls 19c,d (not shown) are the top and bottom walls, defining an enclosed space within the head mount piece. Only the side walls 19a,b can be seen in the figure due to its being a top view illustration. The rear edge of the walls forms a curved back portion 20 which joins the two walls 19a,b,c,d such that the walls 19a,b,c,d extend between the front portion 13 and the curved back portion 20. The back portion 20 of the head mount piece 16 is curved to conform to the shape of a user’s face and is open in the enclosed space. The back portion 20 is open and is bounded by the walls 19a,b,c,d. There may be cushioning provided on the back portion 20. The head mount piece 16 is held firmly on the user’s face by straps 17 around the head of the user. The straps 17 may be disposed such that they pass behind the head of the user, holding the head mount piece 16 firmly in place when in use. The straps 17 may be adjustable. When in use, the head mount piece 16 is provided such that the walls 19a,b,c,d and front portion 13 enclose a space which is optically sealed around the patient’s face, with light only entering through the openings 14a,b. The camera and lighting assembly 22 and the head mount piece 16 engage with each other such that in use the camera and lighting assembly 22 is removably connected to the head mount piece 16. The head mount piece 16 has vertical slide rails 21a,b on the forward facing surface 13. The camera and lighting assembly 22 comprises features 28a,b complementary with the rails 21a,b, such that the lighting and camera assembly 22 and the head mount piece 16 can slide respective to each other along the rails 21a,b. The rails 21a,b are provided with stops or similar suitable feature to help set the correct vertical height of the head mount piece 16 with respect to the lighting and camera assembly 22, such that in a first configuration the eye ports 14a in the head mount piece 16 align with the opening 18 in the camera and lighting assembly 22. The camera and lighting assembly 22 is provided such that it can engage with the head mount piece 16 in two different configurations / orientations. This is shown in Figures IB and IC. In Figure IB the camera and lighting assembly 22 and the head mount piece 16 are connected in the first configuration, and the camera and lighting assembly 22 is a first way up. In Figure IC the camera and lighting assembly 22 and the head mount piece 15, 23 are connected a second configuration, with the lighting and camera assembly 22 rotated and a second way up. In the first configuration in Figure IB, the right eye port 14a of the head mount piece 16 is aligned with the opening 18 on the lighting and camera assembly 22 such that the right eye is tested. In the second configuration shown in Figure IC, the left eye port 14b of the head mount piece 16 is aligned with the opening of 18 on the lighting and camera assembly 22 such that the left eye is tested. In both configurations, the eye port corresponding to the eye not being tested is blocked out by the opaque housing 15 of the light and camera assembly 22. The change between configurations is achieved by removing the lighting and camera assembly 22 along the rails 21a,b and rotating it as detailed below. The operation to swap between testing a first eye and the other is performed as follow: In the initial configuration, the headset assembly is provided such that one eye is tested via an eye port 14 of the head mount piece 16 which is aligned with the opening 18 of the lighting and camera assembly 22. The lighting and camera assembly 22 is then removed from the head mount piece 16 and rotated 180° about an axis coplanar with the eyes of the patient, perpendicular to the line joining the eyes of the patient and passing at least through a point substantially at the midpoint of a segment joining the eyes of the patient. The lighting and camera assembly 22 is then reconnected to the head mount piece 16 such that the other eye can be tested. The axis of rotation 24 is shown as a dashed line in both figures IB and IC. The result of such rotation is that if the opening 18 of the camera and lighting assembly 22 was aligned with the first eye port 14a and was thus facing the left eye in the first configuration, it becomes aligned with the other eye port 14b and now faces the right eye after the rotation. In this example, the LED light source 2 providing the light to generate the pattern would be disposed proximal to the (not tested) right eye and after rotation, the LED light source 2 providing the light to generate the pattern through the LCD is proximal to the left eye. This operation would be swapped if the right eye is tested first. Figure 2 shows a front view of the lighting and camera assembly 22 , depicted from the point of view of a user if the head mount piece 16 was removed. Figure 3 shows a rear view (user point of view) of the head mount piece 16, without the lighting and camera assembly 22 being present. The figure shows the vertical rails 21a,b as well as the eye ports 14a,b. Figure 4A shows a user point of view of the lighting and camera assembly 22 and the head mount piece 16 engaged in the first configuration, with the light and camera assembly according to the first embodiment. In this configuration the right eye is tested and thus the right eye port 14a of the head mount piece 16 and the opening 18 of the lighting and camera assembly 22 are aligned. The left eye port 14b is blocked. Figure 4B shows a user point of view of the lighting and camera assembly 22 and head mount piece 16 engaged in the second configuration, with the light and camera assembly according to the first embodiment. In this configuration the left eye is tested and thus the left eye port 14b and the opening 18 of the lighting and camera assembly 22 are aligned, with the lighting and camera assembly 22 having been removed and rotated. The right eye port 14a is blocked. Figure 5A illustrates an alternative embodiment of the headset 1. This embodiment is the same as the embodiment discussed above, unless explicitly stated otherwise. In the embodiment illustrated in Figure 5, the two-way mirror 10 is offset from the camera 12 along the first optical axis A, such that the camera 12 is not on the optical axis B (comprising the two-way mirror 10 and the opening 18 of the camera and lighting assembly 22). Instead, the camera 12 views the eye of the patient along a second optical axis E parallel to but offset form the second optical axis B. Both the second and third optical axes B, E extend through the opening 18 in the light and camera assembly 22 and whichever eye port 14a,b of the head mount piece 16 is aligned with the opening 18. Figure 5B shows a user point of view of the lighting and camera assembly 22 and the head mount piece 16 engaged in the first configuration, with the light and camera assembly according to the second embodiment. In this embodiment the camera 12 is offset from the two-way mirror 10. In the configuration shown in Figure 5A the right eye is tested and thus the right eye port 14a of the head mount piece 16 and the opening 18 of the lighting and camera assembly 22 are aligned. The left eye port 14b is blocked. Figure 5C shows a user point of view of the lighting and camera assembly 22 and head mount piece 16 engaged in the second configuration, with the light and camera assembly according to the second embodiment. In this configuration the left eye is tested and thus the left eye port 14b and the opening 18 of the lighting and camera assembly 22 are aligned, with the lighting and camera assembly 22 having been removed and rotated. The right eye port 14a is blocked. Figure 6 shows various patterns which can be generated by the display, recreated onto the eye and captured by the camera. Any suitable sensor may be used instead of the camera 12. The means for generating the patterns may be any suitable filtering means which blocks and / or attenuates the light from the light source 2. Instead of filtering light from a source, patterns may be generated by a single display, such as an array of switchable LEDs. The LED light source 2 may be coloured to provide different colours of light. In addition to emitting white light, the light source 2 may emit into the infrared part of the electromagnetic spectrum. The light source 2 may emit in any suitable part of the electromagnetic spectrum. There may more than one light sources. The two-way mirror 10 described herein is just one example of a means to split or redirect light. In place of the mirror 10 any suitable means to split an incident light beam into two or more light beams may be used. The means to split the incident light may be a beam-splitter. The means to split the incident light beam may be a prism beam splitter, a cube beam splitter, or a plate beam splitter. The means to split the incident light into two or more light beams may be a polarising beam splitter or a non-polarising beam splitter. The optical arrangement described herein is by w ay of examples only, and it must be understood that any suitable components, including the filters, lenses and any of the components described, may be varied to achieve the described function. The additional LED array 25 may be any suitable light source. The second LED array 25 may be omitted. There may be provided buttons or any other suitable controls on the outer enclosure 15 of the camera and lighting assembly 22 for controlling the intensity of the light, the colour of the light, whether the light is on or off. The buttons may also control the display 9 or filters, to vary the amount of light blocked or modulate the attenuation levels. The controls may provide controls of the LCD 9 as a whole or may provide control of individual parts thereof. The buttons may also provide controls of the camera 12, to select capture modes and other camera settings. The controls may provide means to adjust the alignment, tilt, and positioning of all the optical components. There may be provided a screen on the front portion 29 of the housing 15 of the camera and lighting assembly 22, to allow an operator to see the eye and the patterns created thereon. Additional viewports may be provided such as to allow the operator to see the patterns formed on the eye. The camera 12 may be omitted. Any suitable means may be used to connect the lighting and camera assembly 22 and the head mount piece 16. This may comprise the rails 21a,b and complementary features 28a,b as described above. It may be any suitable alternative to rails. Wired or wireless connections to local or remote devices may be used for selecting tests, viewing camera output, and saving images or videos. There may be provided an onboard power source 26. The onboard power source 26 may be a battery or any other suitable means of supplying power. The onboard power source 26 may allow hands free operation of the handset 1. The onboard power supply 26 may comprise rechargeable batteries. The onboard power supply 26 may be rechargeable and / or removable. The power may instead be supplied via a connection to the mains. The distances between all components along all optical axes may be adjustable. Means to fixedly position the optical components along all optical axes may be provided. Means to move optical components in and out of the optical axes while the wearable headset is in use may be provided.

Claims

1. A wearable headset for performing eye tests comprising a first part and a second part,the first part comprising a display means to generate patterns to be projected onto a single eye to be tested;the second part being wearable by a user and having a pair of openings aligned with both eyes of the user,wherein the first part is releasably couplable to the second part in a first position in which patterns from the display means are directed to a first eye of the user to test the first eye and a second position in which patterns from the display means are directed to a second eye of the user to test the second eye,the first part further comprising means to block the opening in the second part aligned with the eye not being tested.

2. The wearable headset of claim 1 wherein the first part and second part are releasably coupled by sliding rails.

3. The headset of claim 2 wherein the sliding rails are substantially vertical in relation to the horizontal plane in which the display means is two-dimensionally arrayed.

4. The headset of any of claims 1 to 3 wherein the difference between the first and second positions is a rotation of 180°, wherein the 180° rotation is about an axis defined as being:coplanar with a line joining the eyes of the user, andperpendicular to the line joining the eyes, andpassing at least through a point substantially at the midpoint of a segment joining the eyes of the user.

5. The headset of any of claims 1 to 4 wherein the display means comprises:a light source;a screen;a means to split an incident light into two or more separate beams;a lens assembly defining an optical path from the light source through the screen to the means to split the incident light beam; andan information processing means to control displays on the screen, to create patterns downstream of the screen resulting from controllably blocking and transmitting light from the light source in defined regions of the screen;the headset further comprising: a sensor disposed to capture images of an eye being tested;wherein the means to split the incident light beam is disposed to direct light from the light source after it has passed through the screen to the sensor and the eye being tested,and wherein the pattern projected onto the eye is compared to the pattern projected through the screen.

6. A wearable headset for performing eye tests comprising:a light source;a screen;a means to split an incident light into two or more separate beams;a lens assembly defining an optical path from the light source through the screen to the means to split the incident light beams;an information processing means to control displays on the screen, to create patterns downstream of the screen resulting from controllably blocking and transmitting light from the light source in defined regions of the screen;a sensor disposed to capture images of an eye being tested;wherein the means to split an incident light into two or more separate beams is disposed to direct light from the light source after it has passed through the screen to the eye being tested, and wherein the pattern projected onto the eye is captured by the sensor.

7. The headset of claim 6 wherein the screen comprises an array of pixels, whereineach pixel is independently controllable to block or transmit light.

8. The headset of claim 6 or claim 7 wherein the amount of light transmitted is controllably variable, wherein the light in the defined regions of the screen iscompletely transmitted, completely blocked, or attenuated such that the intensity of the light is reduced.

9. The headset of any of claims 6 to 8 wherein the screen is a transparent screen.

10. The headset of any of claims 6 to 8 wherein the screen is a colour screen.

11. The headset of any of claims 6 to 8 wherein the screen is an LCD screen.

12. The headset of any of claims 6 to 11 wherein the light source is a white LEDsource.

13. The headset of any of claims 6 to 12 wherein the means to split an incident light beam is a two-way mirror that is transparent to the sensor.

14. The headset of any of claims 6 to 13 wherein the lens assembly comprises a condenser lens assembly arranged to convert a substantially divergent beam of light from the light source into a parallel or a converging beam.

15. The headset of any of claims 6 to 14 wherein the lens assembly comprises one or more focussing lenses arranged to focus light from the light source and / or from the screen, and optionally wherein a means of selectively transmitting light of different frequencies is disposed in front of the sensor.

16. The headset of any of claims 6 to 15 wherein filters are provided between the light source and the screen to apply colour to the light.

17. The headset of any of claims 6 to 16 in which a first optical axis is defined along a direction from the light source to the mirror, and a second optical axis is defined along a direction from the mirror to the eye being tested, wherein the first optical axis and the second optical axis are non-parallel.

18. The headset of claim 17, wherein the first optical axis is substantially perpendicular to the second optical axis.

19. The headset of claim 17 or claim 18 wherein the sensor is non-colinear with the first optical axis, and the mirror is a beam splitter that directs a portion of the light from the light source to the eye being test, and a portion of the light from the light source to the sensor, and optionally wherein a means of selectively transmitting light of different frequencies is disposed in front of the sensor.

20. The headset of any of claims 17 to 19 wherein the sensor is disposed along the second optical axis such that light passes from the eye, through the mirror, to the sensor along a straight line along second optical axis.

21. The headset of any of claims 6 to 20 also comprising a further light source arranged to project additional patterns on to the eye being tested.

22. The headset of claim 21, when dependent on claim 17 or any claim dependent thereon, wherein the further light source is disposed along the second optical axis.

23. The headset of claim 22 wherein optical elements are disposed along the second optical axis, between the further light source and the mirror, the optical elements arranged to perform condensing and focusing operations.

24. The headset of any of claims 6 to 23 further comprising one or more onboard power sources.

25. The headset of claim 5 wherein the display means further comprises the features of any of claims 7 to 24.

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