Abstract
The invention provides a system for a patient to obtain quality eye tests results without other people's assistance. The system includes a wearable, head-mounted, ophthalmic device. With a head mounted structure, the patient's head position remains still relative to the ophthalmic device. One or more “iris” cameras and a display screen are used to help align the patient's eye on ocular lenses for optimal eye test results. The system includes a patient interface module that allows the patient to operate the device. Accessory features such as a microphone and earphones are used to communicate with a close by stander during and after the eye exam. Another key feature is a cloud service connection used to store test results for remote access by the patient or other authorized persons.
Claims
1. A wearable ophthalmic apparatus for a patient to conduct self-operable eye test, said wearable ophthalmic apparatus comprising a head-mounted structure and an interface device for the patient to control the eye test on his/her own, wherein said head-mounted structure comprises a pair of ocular lens, a pair of off-axis cameras, a pair of infrared illumination LEDs, each of said off-axis cameras and each of said LEDs being fixed close to one of said ocular lenses, a display screen fixed to an inner side of said head-mounted structure, wherein said off-axis cameras capture patient's pupil/iris images for automatically aligning the patient's eye to said head-mounted structure's optical axis.
2. The wearable ophthalmic apparatus of claim 1, wherein said display screen comprises two divided portions, one dedicated for the patient's right eye and another dedicated for the patient's left eye.
3. The wearable ophthalmic apparatus of claim 1, wherein said interface device is a hand-held push button operably coupled to said head-mounted structure wirelessly or via a cable.
4. The wearable ophthalmic apparatus of claim 1, wherein said interface device is an assembly of one or more sensors that collect the patient's various responses.
5. The wearable ophthalmic apparatus of claim 1, wherein each of said off-axis cameras can be an assembly of cameras, and each of said illumination LEDs can be an assembly of LEDs.
6. The wearable ophthalmic apparatus of claim 1, wherein visual field analysis is conducted when test stimuli are presented on said display screen and the patient responses are collected from said hand-held device, allowing the patient's non-testing eye remains open and optionally fixated to a fixation target.
7. The wearable ophthalmic apparatus of claim 1, further comprising a pair of on-axis cameras, a beam splitter placed between said ocular lenses and said display screen, wherein said pair of on-axis cameras are fixed to another side of said beam splitter so that each of said on-axis cameras being aligned to one of said ocular lenses and focused on patient's pupil/iris, wherein patient eye alignment can be performed with said on-axis cameras.
8. The wearable ophthalmic apparatus of claim 1, wherein the patient's gaze is determined by analyzing the images captured by said off-axis cameras or said on-axis cameras, and used for presenting the stimuli with improved accuracy during visual field analysis.
9. The wearable ophthalmic apparatus of claim 1, wherein said on-axis cameras can be switched to a retina mode with additional focusing and illumination optics for taking fundus images.
10. The wearable ophthalmic apparatus of claim 1, wherein the fundus images can be taken with said on-axis cameras simultaneously for both patient eyes.
11. The wearable ophthalmic apparatus of claim 1, wherein the patient's gaze is determined by analyzing the images captured by said off-axis cameras or said on-axis cameras, and used for stitching the fundus images.
12. A wearable ophthalmic apparatus for a patient to conduct self-operable eye test, comprising a head-mounted structure, an image processing device and an interface device for the patient to control the eye test on his/her own, wherein said head-mounted structure comprises a pair of ocular lenses, a pair of off-axis cameras being fixed adjacent to said ocular lenses, a pair of infrared illumination LEDs, each of said LEDs being fixed under one of said ocular lenses, a pair of laser deliver modules, a display screen fixed to an inner side of said head-mounted structure, and a beam splitter coupled between said ocular lenses and said display screen, wherein said pair of laser deliver modules is coupled to said beam splitter's other surface, each of said laser delivery modules being aligned to one of said ocular lenses, and wherein said off-axis cameras capture patient's pupil/iris images for aligning the patient's eye to the optical axis of the head-mounted structure automatically.
13. The wearable ophthalmic apparatus of claim 12, wherein said laser delivery modules comprises scanning and focusing optics that direct light beams to a target area on the patient's retina or cornea.
14. The wearable ophthalmic apparatus of claim 12, wherein each of said off-axis cameras can be an assembly of cameras, and each of said illumination LEDs can be an assembly of LEDs.
15. The wearable ophthalmic apparatus of claim 12, wherein said display screen is comprises two separate screens, one dedicated for the patient's right eye and another dedicated for the patient's left eye.
16. The wearable ophthalmic apparatus of claim 12, wherein said interface device is a hand-held push button operably coupled to said laser delivery modules and said head mounted structure wirelessly or via a cable.
17. The wearable ophthalmic apparatus of claim 12, wherein said interface device is an assembly of sensors that collect the patient's various responses.
18. The wearable ophthalmic apparatus of claim 12, wherein said image processing device is operably coupled to said head-mounted structure through one or more optical cables and one or more electrical cables.
19. The wearable ophthalmic apparatus of claim 12, wherein said image processing device comprises either confocal scanning laser ophthalmoscopy (SLO) or optical coherence tomography (OCT).
20. The wearable ophthalmic apparatus of claim 12, wherein the patient's gaze is determined by analyzing the images captured by said off-axis cameras, and used for removing motion artifacts in said SLO and OCT images.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a perspective view illustration of the ophthalmic device platform according to the present invention.
[0023] FIG. 2 is a front view illustration of the ophthalmic device platform showing two designated screen areas for each eye.
[0024] FIG. 3 is a side view illustration of the ophthalmic device platform according to FIG. 1.
[0025] FIG. 4a is an illustration of a battery powered wearable ophthalmic device and is charged with a docking station while it is not in use.
[0026] FIG. 4b is an illustration of an ophthalmic device that consists of a wearable head-mounted module and a separated chassis to host bulky and heavy optical and electrical modules.
[0027] FIG. 5 is a top-level illustration of the wearable ophthalmic device and the accessory features such as the cloud based service connection ability which can be used to share test results with other permitted viewers.
[0028] FIGS. 6a and 6b are again a front view illustration of the two individual display screens used to present the fixation targets and the stimuli for each eye based on the detected gaze direction.
[0029] FIGS. 7a and 7b are illustrations of a wearable head-mounted fundus camera implemented with features in the present invention.
[0030] FIG. 8 is an illustration of a wearable head-mounted SLO and OCT imager that is implemented with features in the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0031] While the present invention may be embodied in many different forms, designs or configurations, for the purpose of promoting an understanding of the principles of the invention, reference will be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation or restriction of the scope of the invention is thereby intended. Any alterations and further implementations of the principles of the invention as described herein are contemplated as would normally occur to one skilled in the art to which the invention relates.
[0032] FIG. 1 is a perspective view illustration of the ophthalmic device platform according to the present invention. In this illustration, several key features inside the wearable ophthalmic device are shown including the head-mounted structure, on-axis cameras, ocular lenses, beam splitter, infrared illumination light emitting diodes (LEDs), display screen and patient interface module, etc. When a patient uses the wearable device, his or her eyes are aligned through the ocular lenses. A patient interface module is operably connected to the wearable device wirelessly or with a cable for the patient to operate the device by him or herself. The patient interface module can be an assembly of one or more sensors that collect the patient's various responses. The head mounted structure 107, which can be in a shape of a goggle or a helmet, is for the patient to wear on during an eye test. His or her head position remains still relative to the ophthalmic device. The components illustrated in FIG. 1 can be held still relative to the patient's head position. Inside of the head mounted structure 107 an ophthalmic device 100 shown in FIG. 1 contains a pair of on-axis cameras 101. The patient wears the head mounted structure and the patient's eyes are centered in the ocular lenses 104. Just under the ocular lenses 104, is the infrared illumination light emitting diode (LED) 105. Behind the ocular lenses 104, a visible or infrared beam splitter 103 is used. Behind the beam splitter 103 is the high definition display screen 102. The patient interface module 106 is communicatively connected to the device through a cable or wirelessly.
[0033] FIG. 2 is a front view of then ophthalmic device platform 100 described in FIG. 1 as if the patient is viewing the display screen 202 through his or her eyes. This is an improved and key feature of the wearable ophthalmic device. By having split display screen functionality, a dedicated screen area for each eye will help fixate and relax the non-tested eye and improve test reliability. Once the patient wears the head mounted device, there is a dedicated screen 201 for each eye. Fixation target, operation instructions, test stimuli or test results can be displayed on the screen 201. When one of the patient's eyes undergoes a test through the Ocular lenses 203, the other eye need not be closed or blocked with an eye patch. The screen dedicated to the non-tested eye can be completely dark or, even better, presents a fixation target to help stabilize this non-testing eye and minimize the influence on the tested eye. With the design described in FIG. 2, a comfortable test environment is created. The patient is completely immersed in the test device with only views to the test screen. There is no influence of ambient light on the test results, involuntary head movement related to the device is eliminated, and both eyes are relaxed but fixated to the target. Therefore, the eye exams can be executed with efficiency, quality and reliability.
[0034] FIG. 3 is a side view of then ophthalmic device platform 100 described in FIG. 1. In this illustration, again, several key features inside the wearable ophthalmic device are shown including the on-axis cameras, ocular lenses, beam splitter, infrared LED, and display screen. When the patient uses the wearable device, his or her eyes are aligned through the ocular lenses. Off-axis cameras and coupled focusing adjustment mechanism are also introduced as options to the device. All key components for an ophthalmic device in FIG. 1 are shown in FIG. 3 for the purpose of clarity and simplicity. Patient's eyes 308 are aligned and centered in the ocular lenses 305 and focuses on the display screen 300. A pair of on-axis cameras 303 (only one is shown), combined with the optical beam splitter 302, can be used to capture the iris image of the patient, as illustrated with the solid ray traces 306. The on-axis cameras 303 can also be designed to focus on the patient's retina, as illustrated with the dotted ray traces 307. With appropriate optical design, the on-axis cameras 303 can be switched to operate in iris mode or in retina mode as needed. While the on-axis cameras 303 operate in retina mode, the focus adjustment mechanism can be coupled with that of the display screen 300 as illustrated by the dotted line 301, so that as soon as the on-axis cameras 303 are focused on the patient's retina, the display screen 300 is also on focus to the patient's eyes, and vice versa. If continuous iris monitoring is needed for the application, an additional pair of off-axis iris cameras 304 are used, and can be placed just next to the ocular lenses 305. The on-axis camera 303 can then be configured to operate in constant retina mode. If there is no need for a retina mode operated cameras in some applications, for simplicity, only one set of on-axis cameras 303 or off-axis cameras 304 are used. The beam splitter 302 can also be removed if the on-axis cameras 303 are removed.
[0035] Key functionalities supported by the platform and components described in FIG. 1, FIG. 2 and FIG. 3 allow a patient to align him or herself to the optical system of the device, operate the device using the patient interface module and obtain quality test results without any medical staff or another person's assistance.
[0036] Patient's eye position, gaze direction and the device working distance (i.e., the distance between the ocular lens and the eye) are all detected with the on-axis iris cameras 101 described in FIG. 1 or the off-axis iris cameras 304 described in FIG. 3. Combined with the head-mounted structure 107, a very stable and precise eye to device alignment can be automated and maintained throughout the exam. The distance between the two ocular lenses 104 can be adjusted to fit the patient's pupil distance. The eye to ocular lenses 104 distance can be set based on the iris image contrast (clear and sharp). Patient's gaze direction can be reliably monitored in real time with an initial gaze calibration step (giving sufficient computation power of the control unit).
[0037] The patient's eye refractive error need to be corrected for many ophthalmic exams. For example, the patient eye should be able to focus on the display screen of a visual field analyzer where test stimuli are presented; the illumination light and the camera sensor of a fundus camera should be focused on the patient's retina surface to take a retina photograph; the laser beam and the detection optics in an SLO and OCT imaging system should also be focused on the patient's retina to capture a retina image.
[0038] With the device described in FIG. 1, refractive error correction can be performed manually with the patient's cooperation and judgment if appropriate visual guidance is presented on the display screen 102 and/or additional audio guidance is provided through the device earphone (not shown). For example, present an image (or his or her own iris image) on the display screen 102, the patient can adjust the distance between the ocular lenses 104 and the display screen 102 until the image on the display screen 102 is on focus (clear and sharp) to his or her eyes. The refractive error is then corrected and the display screen 102 is at the patient's retina conjugate.
[0039] With the device described in FIG. 3, if the on-axis cameras 303 are operated in the retina mode and there is a coupled focusing adjustment mechanism 301 between the on-axis cameras 303 and the display screen 300, the manual refractive error correction procedure described above can also place the on-axis cameras 303 at the patient's retina conjugate at the same time.
[0040] The refractive error correction can also be automated with the device described in FIG. 1 or FIG. 3, if the on-axis cameras 101 or 303 can be operated in retina mode. Similar to the auto focus function in a common camera, the contrast of the captured retina images can be used to set the cameras focus on the retina surface. If the coupled focusing adjustment mechanism 307 is employed, the display screen 300 is also automatically focused to the patient's eye when the on-axis cameras 304 are focused on the retina.
[0041] FIG. 4a describes a battery powered wearable ophthalmic device. The head-mounted structure 400 is recharged on a docking station 401 when not in use. FIG. 4b describes a wearable ophthalmic device that uses an external DC or AC power source so that no batteries are included in the head-mounted structure 402 in order to keep the device lightweight and comfortable for the patient. The DC or AC power source is packaged in a separated chassis 403 and connected to the wearable device. For the same purpose, some bulky or heavy components can be packaged into the separated chassis 403 as appropriate.
[0042] FIG. 5 describes a wearable ophthalmic device 500 is wirelessly connected to a remote Cloud server 501. A software application 502 that runs on computers or mobile devices can be used to assign test protocol, access test results and monitor test progress. Additional services and advanced features can be provided through the Cloud server 501. For example, the patient's test results and reports can be stored on the server and shared with other authorized viewers anytime and anywhere. Test results are grouped in chronological order and progressive change analysis can be performed on Cloud based server. Computationally intensive algorithms can also be applied to the test data on the Cloud server 501 without increasing the complexity of the wearable device 500. A software application 502 installed and run on a computer or any mobile devices can remotely connect to the wearable ophthalmic device 500 and the Cloud server 501. Medical professionals or the patient him- or herself can use the software application 502 to assign test protocols to the patient in advance, review test results after the test is complete. During the test, another person or a medical professional can also use the software application 502 to monitor the test progress and interact with the patient through the windows 503 and 504 and other patient management applications 505.
[0043] A further benefit of the present invention is to build a wearable visual field analyzer with real-time gaze detection and feedback function. FIG. 6a is a front view illustration of the two individual display screens 600 in the said wearable visual field analyzer, where the fixation targets 601 are presented for each eye. The detected gaze direction can be displayed on screen as a feedback to the patient, such as circles 602 as described in FIG. 6a. If the patient's gaze is detected off from the fixation targets 601, instructions are given to the patient to adjust his or her gaze so that the circles 602 are moved back to the fixation targets 601. FIG. 6b describes another strategy to take advantage of the real-time gaze detection and feedback function in the wearable visual field analyzer. If the patient's gaze is detected off from the fixation targets 601, the visual representation of the patient's gaze direction 602 is not displayed on the screen 600 (shown as dotted lines in the figure for explanation). Instead, the stimulus 605 to be presented at a target visual field angle 604 according to the fixation target position 601 is re-calculated and adjusted according to the patient's current gaze direction 602. This strategy ensures that the stimuli are always presented at the intended visual angles and every test is a valid test. It also essentially eliminates the need to validate the test results based on the blind spot monitoring or gaze monitoring (but no adjustment on the stimulus position 604 according to the gaze direction changes). Because the gaze feedback correction is performed in the background without the patient's notice, the test is thus more efficient and the test duration is reduced. Patient's sudden eye movements, such as blinks and saccades, etc., can also be detected with the real-time gaze detection function. Stimuli presented when these involuntary eye movements happen can be automatically re-tested to improve the test reliability.
[0044] In another embodiment, improved test results from a Fundus Camera can be achieved by using the present invention. A wearable head-mounted fundus camera 700 as described in FIG. 7a enables the user to easily capture high-quality fundus photographs all by him or herself without any medical staff or another person's assistance. Such device is more assessable and useful by a larger population and in more diverse use scenarios. The included patient interface module allows self-operation of the device and improved image quality. Two sets of the on-axis cameras 701 with focusing optics for each eye are configured in retina mode to capture the fundus photographs. Two sets of the off-axis cameras 702 for each eye are used as iris cameras. A head-mounted or goggle-like structure 704 is used to hold all components still relative to the patient's head position. Finally, a push button or touch sensor 703 is implemented for the patient to control the device and capture the fundus images by him or herself. The push button or touch sensor 703 may be connected to the device with a cable such as USB connection or wirelessly such as Bluetooth connection. FIG. 7b illustrates the wearable fundus camera 705 according to another embodiment of the invention, in which all other components are the same as described in FIG. 7a except that the on-axis cameras are able to switch between the iris mode and the retina mode, and thus the off-axis cameras are not included.
[0045] The wearable fundus camera as described in FIGS. 7a and 7b incorporate all the benefits as described above for the current invention, including (a) manual or automatic eye to device alignment supported by the iris-mode operated on-axis cameras and iris image analysis, and (b) manual or automatic refractive error correction supported by the retina-mode operated camera and a coupled focusing adjustment mechanism with the display screen.
[0046] The advantages of the wearable fundus camera are numerous. For examples, first, the patient is allowed to operate the device and trigger the capture button whenever he or she is ready, therefore any chance of involuntary eye movements (such as blinks, saccades, etc.) at the time the image is captured can be greatly diminished. Second, because the eye to device alignment remains unchanged, the patient can repeat the capture immediately at the same fixation targets to increase the success rate of obtaining a defect-free high-quality fundus image. Third, the patient can also repeat the capture as the fixation target moves to different locations so that a collection of the patient's fundus images covering a large retina area can be taken. Fourth, with the real-time gaze direction function, each fundus camera image can be associated with the actual visual field angle, not with the field angle of the presented fixation target position. It can further help stitch precisely the collection of the fundus images captured above into a larger field view. Fifth, With the design including two sets of the on-axis cameras and the illumination light sources, the fundus images can be taken for both eyes simultaneously. In fact, for cost sensitive applications, the wearable fundus camera can also be implemented with only one set of the imaging components so that the fundus image is captured for one eye at a time. The head-mounted structure is designed so that the imaging components can be flipped or translated to be able to align with the other eye.
[0047] FIG. 8 illustrates a wearable head-mounted SLO and OCT imager that is implemented with features in the present invention. The wearable (head-mounted) SLO and OCT imager 800 enables the user to easily capture high-quality SLO and OCT images all by him or herself without any medical staff or another person's assistance. The patient interface module allows self-operation of the device and improved image quality. Due to the complexity of the imaging system, it is preferable to keep most functional components and modules in a separated chassis. The improved test results from an SLO and OCT imager can be achieved by this implementation. The SLO and OCT imager provides simultaneous confocal SLO and OCT. Due to the point or line scanning nature of the SLO and OCT technologies, the on-axis cameras are replaced with laser (or light source) delivery module 802, which consists of scanning and focusing optics that direct the light beam to the target area on the patient's retina or cornea. The automated refractive error correction can be achieved by maximizing the detected light intensity as the focusing optics for the laser delivery module 802 is swept over a small range from the nominal position. There can be only one set of the laser delivery module 802 for the purpose of simplicity or cost-saving. The optical components in the laser delivery module 802 can be arranged so that the laser beam is delivered to one of the eyes and then switched to the other eye as needed. The implementation of the optical signal detection module for the SLO and the OCT imagers can vary widely depending on the technologies and techniques involved. In the present invention, in order to keep the head-mounted module lightweight, it is preferable to keep most functional components and modules in a separated chassis 804, which may include the light source, the signal detection module, computer, control unit and power supply, etc. The chassis 804 and the head-mounted module 800 are connected through electrical and optical cables 801. It is important that a patient interface module 803 is included so that the patient can trigger the image acquisition when he or she is ready. The off-axis cameras 806 are also included to support eye to device alignment, blinks and/or saccades detection and monitor the gaze direction during the image scans. Due to the scanning nature of the SLO and OCT imaging technology, it is usually take seconds to complete the image acquisition. Motion artifacts are almost inevitable in the acquired images due to the head and/or eye movements in traditional SLO and OCT imagers.
[0048] With the wearable SLO and OCT imagers described in present invention, however, the head to device alignment remains unchanged throughout the test, and the device has essentially unlimited time window to keep scanning and acquiring data points. Data points acquired during an eye movement, such as a blink or a saccade, are detected and rejected until every data point within the targeted scan area are validated as motion-free.
[0049] Another advantage with the present invention is that the data acquisition can be paused and resumed because the same eye to device alignment can be restored and maintained.
[0050] A fast iris and pupil detection algorithm can also be implemented to track the patient's gaze and the gaze direction can then be fed back to the optical scan controller in real time. If the patient's gaze is shifted away from the fixation target, the optical scanner applies with appropriate offsets accordingly to make sure the laser beam is projected to the correct locations on the retina. With recorded gaze data, post-acquisition analysis can also be implemented to reveal the physical locations of the laser beam on the patient's retina, which is then used to register each frame or pixel in the image. This is very useful to remove motion artifacts that are common in SLO and OCT images.
[0051] Although one or more embodiments of the ophthalmic device have been described in detail, one of ordinary skill in the art will appreciate the modifications to the component selection, and design of the individual high definition screens with on-axis “iris” cameras, beam splitter, etc. orientation. It is acknowledged that obvious modifications will ensue to a person skilled in the art. The claims which follow will set out the full scope of the invention.
