Patent Application
20250235096
The present invention is related to improvements in systems for visual testing and imaging, and in particular a headset mounted aberrometer system.
Eye care is an important part of overall health and many specialized systems have been developed to allow ophthalmologists to examine a person's eyes. Many of these devices are expensive, limiting their availability. They are also bulky, often requiring a dedicated table or mounting a special stand. The size, weight, and general ungainliness of these devices also can require dedicated space in a doctor's office to be reserved for that equipment.
One device used for eye testing is an aberrometer, a diagnostic device that uses a laser and wavefront analysis to measure refractive aberrations of the eye for evaluating issues such as nearsightedness, farsightedness and astigmatism, as well as more complex visual defects. Conventional aberrometers are table top devices that can be expensive and heavy to move around. A patient must sit in front of the aberrometer system and press their head against a specially placed face bar or mask to position their eyes in front of the optical window. A doctor can control the system and monitor the results through a separate computer interface.
However, patients who have mobility limitations may not be able to easily make an office visit or be physically able to position themselves as required for examination using a particular optical tool. This can limit the ability to provide comprehensive eye examinations to these patients. Likewise, due to bulk and expense, it may be difficult or impossible to bring a variety of these specialized eye examination systems to a patient who is not able to travel to the doctor's office.
It is known to provide certain types of eye testing equipment in a portable form that can be integrated into a head mounted system. However, these systems can be limited. There is a need for a portable and inexpensive system for performing aberrometry in a variety of environments and that has an architecture that is well suited for use in a headset mounted implementation.
An improved aberrometer assembly suitable for integration a VR-style headset mount and that addresses the deficiencies with prior systems is disclosed herein.
In an embodiment, the aberrometer system comprises a headset frame configured to be worn on the face of a user. A first optical assembly is coupled the headset frame so the central optical axis of the optical assembly is in alignment with an eye of the user when the headset frame is worn. The optical assembly comprises a first beam splitter that defines an eye tracking channel having an eye tracking axis that substantially co-linear with the central optical axis. The first beam splitter also defines an aberrometer channel with an aberrometer optical axis that is off axis from the central optical axis.
The eye tracking channel comprises an IR imager with an imaging plane, an eyepiece, and a camera lens. An IR illuminator is provided to illuminate the eye of a user wearing the headset. The the eyepiece and camera lens configured to focus IR light reflected from the first eye of the user onto an imaging plane of the imager. The eye tracking channel further has a second beam splitter defining an off-axis display subchannel having a display optical axis. The display subchannel comprises adjustable display optics and an electronic display. The adjustable display optics are configured to relay an image output on the display to the eyepiece via the second beamsplitter so the image can be viewed by the user wearing the headset.
The aberrometer channel comprises an array camera, a plurality of lenses in alignment with the aberrometer optical axis and a third beam splitter defining a light source subchannel. The light source subchannel comprises a laser that emits the light used during aberrometry. The aberrometer channel is configured to direct laser light from the light source subchannel along the aberrometer optical axis to the first beamsplitter and to relay to the array camera laser light reflected by the first eye of the user when the user is wearing the headset frame and directed by the first beamsplitter into the aberrometer channel so the wavefront can be captured by the array camera.
In an embodiment, the adjustable display optics comprises a liquid lens with an electronically controlled spherical diopter power and a display lens assembly. Adjusting the spherical diopter power can change an apparent distance of an image output by the display as viewed through the eyepiece. Varying the liquid lens to move the apparent distance of an image far away can help the user put their eye into an unaccommodated state for imaging in the aberrometry process. The eye tracking camera can be used to verify that the eye is open and the user is looking straight ahead.
In an embodiment, the IR illuminator comprises a ring of IR emitters circling the central optical axis and on a side of the first beamsplitter furthest from the eyepiece. This placement allows for full IR illumination of the eye and so that substantially all of the IR light entering the eyepiece is reflected light from the user.
In the aberrometer channel, the light source subchannel can further comprise a focusing lens assembly between the laser and the beam splitter. The plurality of lenses in the aberrometer channel can comprise two set of lenses. The third beam splitter can be placed between the two lens sets. In an embodiment, to reduce the total length of the aberrometer channel along a single axis, the aberrometer channel can further comprise a diagonal which can be placed adjacent the third beam splitter and is operative to redirect the aberrometer optical axis.
In an embodiment, the aberrometer optical axis and display optical axis are each substantially normal to the central optical axis. These two axes can also be substantially coplanar.
Any of the embodiments of the first optical assembly can be removably mounted to the headset frame and can be switched from being mounted in front of one eye or the other.
Any of the embodiments of the first optical assembly can also be mounted to the headset frame so they can be moved from a first position in front of a first eye to a second position in front of a second eye of the user. In an embodiment, the first optical assembly is mounted so it can be rotated from the first to the second position, and also thereby moving any component similarly mounted to the headset frame in front of the second eye. In another embodiment, the first optical assembly is slidably mounted so it can be moved from the first to the second position by lateral translation. An adjustable light baffle can be coupled to the first optical assembly so that when the first optical assembly is in the first position the baffle covers the second eye region and when the first optical assembly is in the second position the baffle covers the first eye region.
Any of the embodiments of the first optical assembly can also be integrally mounted to the headset frame. Where only one optical assembly is provided, the system can be used with either eye by configuring the headset so it can be use right-side up or upside down. In one embodiment, the headset frame has two nose channels, one on top and one on the bottom. An adaptor can be provided to cover up the unused nose channel and provide a top surface of the headset that can extend to the user's forehead.
With any of the embodiments of the first optical assembly, the headset frame can have an opening in front of the other eye. A user wearing the headset frame for aberrometry of one eye can see through the opening with the other eye so they can focus on a distant object, simplifying bringing the eye being measured into an unaccommodated state needed for accurate aberrometry.
Along with the first optical assembly, second optical assembly can be coupled to the headset in front of the second eye region. The second optical assembly can be removably mounted or integral to the headset and can be in its own housing or the first and second optical assemblies can be mounted within a common outer housing. The mounting can allow the user of the headset to switch which eye the first and second optical assemblies are positioned in front of, such as by rotation or translation. In an embodiment, the second optical assembly is an eye tracking and display system, such as the eye tracking channel component of the first optical assembly. In a further embodiment, the second optical assembly is the same as the first optical assembly, thereby allowing aberrometry of both eyes to be performed without having to modify the headset. Other types of optical assemblies could be used as the second optical assembly.
The aberrometer, eye tracking, and display channels can be controlled by a computer system to vary the stimulus shown on the displays, vary the power of the liquid lens, perform eye tracking and monitoring the a user's eye, and to control initiate the aberrometry process to measure refractive aberrations of the eye.
Further features and advantages, as well as structure and operation of various embodiments are disclosed in detail below with references to the accompanying drawings in which:
The eye tracking channel 140 comprises an eyepiece 142, an imaging camera 144, and a camera lens assembly 146 which is configured to focus incoming light onto the imaging plane 148 of the camera 144. The camera 144 can be a CMOS or other sensor with a rolling or global shutter. Various cameras known to those of skill in the art for eye tracking applications can be used. One suitable camera is a Basler daA3840-45 um camera that has a mono CMOS rolling sensor with 4K UHD resolution, a USB data interface, and a housing of about 20 mm (L)×29 mm (W)×29 mm (W) in size.
A second beam splitter 112 is positioned between the eyepiece 142 and camera lens assembly 146 and leads to a display channel 160 having a display optical axis 106 that is off axis from the central optical axis 102, such as by substantially 90 degrees, although other angles, such as 45 or 30 degrees could be used. The display channel 160 comprises adjustable display optics 162 and a display 164. Display 164 can be a conventional flat panel display, such as an LED, LCD, micro mirror or OLED display, with sufficient resolution to present adequate images to a user as part of aberrometry testing. In an embodiment, the display is a small display, such as between 30 to 40 mm and of the type commonly used in smart watch applications. One suitable display is the Kingtech model PV13904PY24G-C1 AMOLED display with a panel size of about 35 mm and a resolution of 454×454 pixels.
An illumination source 111 for the eye tracking camera 144 is provided to produces IR light, such as in a wavelength region of from 800 nm to 900 nm. The camera lens assembly 146 is configured for use in these wavelengths. Light from source 111 that is reflected from the eye 101 is received by eyepiece 142 which forms an image of the eye 101 on an intermediate image plane between the second beam splitter 112 and camera lens assembly 146. Camera lens assembly 146 conjugates the intermediate image plane with the camera sensor plane 148. The optical performances of camera lens assembly 146 and the eyepiece 142 are matched.
Illumination source 111 is positioned to provide sufficient illumination of the eye for eye tracking and imaging purposes. In an embodiment, illumination source 111 comprises a plurality of IR LEDs (850 nm wavelength) which are placed between the eye plane 108 and the first beam splitter 110 in a position that will illuminate the eye 101 without blocking the eye 101. The amount of illumination required can vary depending on factors including the sensitivity of the camera 144. In an embodiment, the LEDs are configured to provide an irradiance of approximately 225 W/m2. The adjustable display optics 162 operate as relay optics to transfer an image output on display 164 to the second beam splitter 112 to allow the user to see the display (through eyepiece 142). Adjustable display optics 162 comprises a relay lens and a liquid lens that can be driven electronically to adjust the spherical power provided, such as across a range+10 to −10 diopters or other diopter range as appropriate. A suitable lens is the Optotune model EL-16-40-TC. The relay lens is configured to correct for color aberration within a range of visual wavelengths, such as 480 nm to 640 nm. The second beam splitter 112 is configured to reflect visible light from the display channel and to pass IR wavelength light to the eye tracking camera 144.
In an embodiment, a technician or doctor can control the spherical power of the liquid lens in the display optics 162, such as through a remote computer interface coupled to system 100, to allow for a rapid and large diopter change to blur the image seen on the display. The blurring of the image is an important aspect of preparing the user's eye for wave front capturing. The liquid lens The liquid lens can also be autonomously controlled by software operative to change the spherical power and that monitors images from the eye tracking channel to determine when the user is looking straight ahead and not blinking so that the aberrometry process can be started
The aberrometer channel 120 comprises a Shack-Hartmann array camera 122, a light source channel 124 and a set of lenses 126, 128 which are configured to capture the reflected wave front from the user's eye 101 and provide it to the imaging plane 130 of the array camera 122. Light source channel 124 comprises and laser diode 132 and a focusing lens assembly 134 to collimate the laser light. A third beam splitter 136 is placed along the aberrometer optical axis 104 and is used to convey the light laser light into the aberrometer channel along its optical axis 104. The laser diode 132 can be a low power laser diode, such as 1 mw or less, and that generates 680 nm red laser light. The beam splitter 136 can be a precision cube beam splitter to minimize wave front distortions.
An eye cup 210 extends forward off the first beam splitter 110 for use in helping to position a user's eye along the central optical axis 102 and to reduce stray light entering the system. A glass cover plate 215 can be used to seal the internals of the system 200. The illuminators 111 can be configured as a circumferential ring of a plurality of IR LEDs 220 surrounding the central optical axis 102. Ring 220 can be placed in a variety positions. In
Advantageously, having the eye tracking channel 140 directly in line with the central optical axis 102, components of the camera lens assembly 146 can be placed close to the beam splitter 112 without interfering with the reflected image from the display channel 160. This allows for a larger field of view in the eye tracking camera. In addition, having the aberrometer channel 120 and display channel 160 off-axis from the central optical axis 102 also advantageously allows the length of the optical assembly 110 along the central optical axis 102 to be short relative to the width of the other channels. This form factor advantageously allows the assembly 110 be integrated with a wearable headset, such as discussed with respect to
In an embodiment, diagonal 250 is a mirror configured to reflect the laser light frequency and is optically flat to introduce minimal distortion to the wave front. In an embodiment, the lenses, beam splitter and diagonal of the aberrometer channel are configured so that introduced wave front deviation is within 1/10 λ of the illumination. The use of diagonal 250 in the configuration 240 of
Advantageously, the improved aberrometer system 100 can be configured to be small and light enough to be mounted within a housing coupled to a headset that can be worn on a person's face.
In this embodiment, the headset frame 305 has left and right openings 330, 330′ which are positioned to be in front of the user's eyes when the headset system 300 is worn. Alternatively, a single opening can be provided and which is in front of both of the user's eyes. A housing 315 contains the aberrometer 200 and is mounted on one side of the headset frame 305 so that the central optical axis 102 passes through one opening 330. In
The housing 315 may be integral with the headset frame 305 or removably coupled thereto, such as with coupling hardware 325. Mechanisms for coupling an optics module to a headset and which can be adapted to the present use are disclosed in U.S. Pat. No. 11,504,000 entitled “Ophthalmologic Testing Systems and Methods”, the entire contents of which are expressly incorporated by reference. The housing 315 or aberrometer 200 within the housing can be mounted to allow the position of the central optical axis 102 to be laterally adjustable so it can be positioned in alignment with a user's eyes. A vertical adjustment may also be provided.
Various manual or automated adjustable mounting mechanisms known to those of skill in the art can be used, such as a track mounting driven by linear actuators or a stepper motor. In an embodiment with an electronically controllable adjustment mechanism, the eye tracking camera can be used to adjust the position of the central optical axis 102 relative to the headset frame 305, either under control of an operator who can view the images output from the eye tracking camera, e.g., on a remote computer, or automatically using software to analyze the images returned from the camera, to position the optical axis 102 correctly relative to the user's eye.
During use of this embodiment, when a first eye of a user is in alignment with the aberrometer for imaging, the user's other eye is aligned with the opening 330′ in the headset frame. The user can look through this opening 330′ to a distant point far away from the headset in order to bring the non-imaged eye into an unaccommodated state. Once the non-imaged eye is relaxed, the imaged eye will also be relaxed and thus in a state that is ready to be imaged. Blinders 320 can be provided in front of opening 330′ to help the user focus attention on the distant point.
In order to properly image the eye, the pupil needs to be as dilated as possible and therefore stray light from opening 330′ should be blocked. In an embodiment a divider 335 is positioned within the headset frame 305 between openings 330 and 330′. Divider 335 can extend sufficiently in the headset frame 305 so that when the frame is worn the divider will contact the user's face. Divider 335 can be made of a confirmable material that will adjust to the contours of the user's face to reduce the possibility of light leakage. Alternatively, instead of blinders 320, the opening 330′ can be completely covered or omitted entirely although this might make it more difficult for a user to bring their eyes to an unaccommodated state, even with the use of the adjustable liquid lens in the display optics to change the apparent distance of a displayed image viewed by the imaging eye.
According to a further embodiment, the aberrometer assembly 200 can moved to allow imaging of either of the user's eyes. In one configuration, the housing 315 is removably mounted to the headset frame 305 and can be connected in front of either of the eye openings 330, 330′. After one eye is imaged, the housing 315 can be disconnected from the headset frame 305 and reattached in front of the other eye opening and reoriented as necessary. Blinders 320 or other covering can also be removably mounted and switched from one eye opening to the other as needed.
Other embodiments are variations of the configuration of
In a particular configuration, a modular system is available for the headset frame where an operator can attach an aberrometer housing 315 to one eye opening and then select from a cover, blinders 325, an imaging and eye tracking system in housing 316, or even a second aberrometer and attach that to the opposing eye opening on the headset frame. Other components could also be attached for use in different types of eye examinations.
Instead of being removably attached and swappable from one side to the other, one or more of the aberrometer assembly and the alternate eye cover, blinders, eye tracking system, or second aberrometer system can be integrally attached to the headset 305. For example, a system can be provided with the aberrometer system in housing 315 integral to the headset with the second eye component removable and replaceable with one or more of the components discussed above.
In a further variation 302 shown in
Yet a further embodiment is shown in
In yet a further embodiment, the housing 315 with the aberrometer 200 within can be rotatably mounted to the front of the headset frame 305.
Detents or other mechanisms (not shown) can be used to secure the mounting plate 505 in a fixed position. Various rotatable mounting mechanisms known to those of ordinary skill in the art can be used. In one embodiment, the rotatable mounting assembly comprises a spring that urges the mounting plate 505 against the headset frame. To switch the position of the aberrometer and blinder 320 from one eye to the other, the mounting plate 505 can be pulled outward from the headset frame, rotated 180 degrees and released. Instead of a spring, a screw mechanism can be used and that is configured to hold the mounting plate 505 rigidly against the headset frame 305 when it is tightened and to allow for rotational motion when listened. Latches or other similar mechanisms (not shown) can be used to secure the mounting plate 505 in position on the headset frame 305 during eye imaging operations.
Returning to
The wave front sensor 122 is proceeded by an aspherical lens 604 for capturing collimated wave fronts at a distance D1. Another aspherical lens 603.2 is located a distal position of D2 away from the aspherical lens 604. A beam splitter 608 is used to direct light from an off-axis laser diode onto the aberrometer optical axis 104. This light is used to illuminate the user's eye 101. An aspheric lens 603.1 is positioned between the beam splitter 608 on-axis with the first beam splitter 110 and is also positioned within a fixed distance D3 of a larger aspherical lens 602 that is adjacent to the first beam splitter 110. A polarizer 620 is included in the optical path, such as between the cube beam splitter 608 and lens 603.2. An aperture 622 is placed after lens 604 and in front of the wave front camera 122. In an embodiment, aspheric lens 602 has a 25 mm diameter and 0.4 numerical aperture. Aspheric lenses 603.1 and 603.1 are 6.33 mm diameter and lens 604 is 25 mm in diameter with a 0.3 numerical aperture.
Turning to
In a particular embodiment, the lenses in the aberrometer channel can be configured to provide a compact system with the element distances substantially as set forth in Table 1 below:
In operation, light from the laser diode 132 is focused by the aspherical lenses 606 and 605.2 on the glass aperture 607. The aperture 607 forms point source beam which is collimated by aspherical lens 605.1 and then reflected by the cubic beam splitter 608 into the aberrometer optical channel 104. The beam passes through aspherical lenses 603.1 and 602 where it is reflected by the first beam splitter 110 to the eye 101 being tested. Light reflected from the eye 101 is redirected by the first beam splitter 110 into the aberrometer channel 102, passes through lenses 602, 603.1, beam splitter 608 and continues through additional aspherical lenses 603.2 and 604, finally landing on the imaging surface 130 of the wave front camera 122.
In an embodiment of
Lens 715 is a distance D7 from the imaging plane 148 and the imaging plane 148 is a distance D6 from the second beam splitter 112. The first and second beam splitters 110, 112 are distance D8 apart. Lens 708 in the eyepiece 142 is a distance D9 from the eye plane 108. In the display channel, the relay lens 716 is a distance D10 from the beam splitter 112. Liquid lens 721 is a distance D11 from the display image plane 166. The first beam splitter 110 is a distance D12 from the eye plane 108. In a particular embodiment, the lenses in the eyepiece 142, camera lens assembly 146, and display optics are configured to provide a compact system with the element distances substantially as set forth in Table 2 below:
In this specific embodiment, the 5-element camera lens assembly has NA substantially equal to 0.1, a FOV substantially equal to 20 mm, and a weight of about 30 g. The display optics projection lens is a 5-element group providing a pupil diameter Dp of substantially 6 mm and a FOV of substantially 40 degrees with a weight of about 25 g. The total length of the display channel is about 138 mm from the central optical axis 102 to the display image plane 166.
A position adjustment mechanism for the aberrometry optical module can be included to allow for lateral adjustment to allow alignment with the eye of different users that have different intraocular spacings. When two optical modules are provided on the headset, the adjustment mechanism can be configured to move the assemblies symmetrically towards or away from each other to adjust the intraocular spacing. Various adjustment mechanisms known to those of ordinary skill in the art can be used for these purposes.
Various aspects, embodiments, and examples of the invention have been disclosed and described herein. Modifications, additions and alterations may be made by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
This application claims priority to U.S. Provisional Patent Application No. 63/362,866, filed Apr. 12, 2022, the entire contents of which is incorporated by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2023/018205 | 4/11/2023 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63362866 | Apr 2022 | US |
