A method of post-operative vision simulation and system implementing the same

Abstract

A near-eye ophthalmic simulation device comprising a microdisplay (101), a light source (102) forming an exit pupil (103) at an exit pupil plane (105), to create a projected pattern on viewer's retina (112) appearing at a virtual image plane (109) when the user's pupil (106) substantially coincides with the exit pupil plane (105). A variable focus lens (108) placed to substantially coincide with an optical conjugate plane (111) of exit pupil plane (105), to control the virtual image distance (110) and the virtual image plane (109) location is comprised. Projected pattern carries visual information to simulate post-operative vision, distance whereof independently controllable by the variable focus lens (108).

Description

[0001] A METHOD OF POST-OPERATIVE VISION SIMULATION AND SYSTEM IMPLEMENTING THE SAME

[0002] Technical Field of the Present Invention

[0003] The invention presented hereby generally concerns methods of determining the correct intraocular lens type to be used for surgical lens replacement. Disclosed invention more specifically relates to methods and systems used for assessing subjective post-operative vision and implementation of bespoke intraocular lenses (IOL) for cataract and refractive lens exchange (RLE) surgery candidates.

[0004] Prior Art / Background of the Present Invention

[0005] Cataracts is an ophthalmic disease in which a cloudy area is formed in the lens of the eye, resulting in blurred vision. Cataract is the world's most common cause of preventable blindness and is responsible for the loss of vision of 50 million people. Currently, primary prevention or medical treatment options are lacking, making surgical removal and replacement of eye lens the only treatment option. More than 100 million cataract surgeries (the most common surgery in the world) are performed each year mostly in developed countries. Furthermore, there are also people who would like to go through Refractive Lens Exchange (RLE) surgery, in order to improve their vision and eliminate the need for eyeglasses even though they don't suffer from cataracts, where patients generally being the ages of 40 and 60.

[0006] Cataract surgery evolved significantly within the last decade with several Intraocular Lens (IOL) options being available for cataract surgery. Since there are a wide variety of IOLS available in the market, it gets ever more difficult to match the right patient with the right type of IOL suitable to them. This technical problem itself relies on issues that need to be addressed, such as the level of possible visual acuity improvement in patients, whether they will stop using eyeglasses if they opt for IOLS, and whether they will experience side effects such as halo, glare around light sources and dysphotopsia. As such, there is a strong need for a vision simulator which will help patients visualize the post-operative performance of different IOL options before cataract surgery.

[0007] In known technique, there exist several imaging devices for diagnosis of cataract and pre-operative evaluation such as optical coherence tomography (OCT), adaptive optics imaging systems (aberrometry), cataract densitometer, corneal topography. However, those options do not work through dense hypermature cataractous lenses due to large scattering. Moreover, none of those imaging modalities can predict potential visual acuity and which IOL type is best for a given particular patient. For cataract patients, potential acuity meters (PAM) measure the visual acuity (VA) that the patient is likely to achieve once there are no more opacifications of the ocular media of the eye. The purpose of such devices is to detect patients who will not benefit from cataract surgery; for example, those with macular problems or neurological issues. To separate visual loss due to opacifications from other reasons, the method used for PAM devices takes advantage of the fact that the opacification is typically not homogeneous and there are typically some small, relatively clear areas in the otherwise opaque lens. These clear areas are used to project a target (numbers, letters or stripes) onto the retina using a narrow light beam. The method requires strong user cooperation to align the small beam with the desired section of the patient's pupil.

[0008] A pinhole occluder is an opaque disk with one or more small holes through it, used by ophthalmologists to test visual acuity. The occluder is a simple way to focus light, as in a pinhole camera. This can be used to distinguish visual defects caused by refractive error, which improve when the occluder is used, from other problems, which do not. Also, there is not enough light due to the small pinhole, pinhole size is not adjustable, not steerable (no eye tracker), field-of-view (FOV) is narrow since pinhole glass is 10-12 millimeters ahead of the cornea corresponding to a circular field of vision of about 4 degrees. Therefore, pinhole occluders are not very effective for cataract patients.

[0009] A recent study by Vinas et al. titled "Visual simulators replicate vision with multifocal lenses" compares performance of real IOLS, spatial light modulator-based adaptive optics simulators, and opto-tunable lens-based adaptive simulators using a phantom eye (i.e., artificial eye). Such adaptive optics simulators are useful as a research device and can be effective in replicating the performance of multifocal IOLs using an artificial eye. However, such simulators are not suitable for subjective evaluations with patients.

[0010] Cataract surgery can be performed only once, is irreversible, and carries high-risk as it impacts the most vital sense, the vision. Selection of suitable IOLs is difficult for both doctors and patients. There exists an objective need to develop a diagnostic device for use before cataract surgeries to help match the right patient to right IOL and reduce the anxiety of both patients and doctors.

[0011] Objects of the Present Invention

[0012] Primary object of the disclosed invention is to present a method of in vivo post-operative vision simulation before lens replacement surgeries for cataract and other. Another object of the disclosed invention is to present a method of postoperative vision simulation with the aid of a computational holographic display and pupil tracker.

[0013] Another object of the disclosed invention is to present a method of postoperative vision simulation that takes advantage of a variable focus lens for rendering images at different distances to a user.

[0014] Another object of the disclosed invention is to present a method of postoperative vision simulation that takes advantage of a variable focus lens for rendering images in the near, far and intermediate planes whereby the assessment of visual acuity can be performed in a simulated manner.

[0015] Another object of the disclosed invention is to present a method of postoperative vision simulation whereby IOL selection module is comprised to guide cataract patients about IOL options and corresponding visual performance, which will lead to better expectation management and shortening decision times by more than 50%.

[0016] Summary of the Present Invention

[0017] Present invention discloses a novel method that addresses aforementioned problems using CGH display technology, which enables to shape and steer the beam of light through the relatively clear areas of the cataractous lens of a patient who is a candidate for lens replacement proedure. A programmable exit pupil and holographic pupil formation help patients see crisp images even through cataractous lenses. One can form single or multiple pupils, which help create images at different focal depths simultaneously without a conflict between the vergence and accommodation (VAC). Eye box controlling method in the disclosed invention allows scanning capabilities over the occluded parts of the pupil and detects as well as directs the optical beam through the non-cataractous regions on the crystalline lens. The adjustable depth of holographic displays allows to test accommodation response and the virtual image can be replaced at the desired depth to correct the refractive errors.

[0018] Disclosed invention incorporates a pupil tracker and automatic algorithmic adjustments using patient's diagnostics data, reducing the measurement times, and making the technology more accessible for patients. Once the device is aligned and the position is calibrated with the aid of the pupil tracker cameras and inter-pupillary distance adjustments, multiple small regions on the pupil were dynamically addressed, through which virtual images are sent to the retina, granting a unique ability to make use of non- cataractous parts of the lens efficiently.

[0019] Disclosed invention also takes advantage of a variable focus lens, enabling different images to be formed in the near, far and intermediate planes whereby the assessment of visual acuity can be performed in a simulated manner. With the approach in the present disclosure, location and the information carried in the images cast and generated by the optical system can be digitally controlled, helping the patients see crisp images created in different focal lengths even through cataractous lenses.

[0020] Brief Description of the Figures of the Present Invention

[0021] Accompanying figures are given solely for the purpose of exemplifying a a method and system of in vivo post-operative vision simulation using varifocal display, whose advantages over prior art were outlined above and will be explained in brief hereinafter. The figures are not meant to delimit the scope of protection as identified in the claims nor should they be referred to alone in an effort to interpret the scope identified in said claims without recourse to the technical disclosure in the description of the present invention.

[0022] Figure 1 illustrates the optical architecture of the display module configured to show virtual images at different depths.

[0023] Figure 2 illustrates the electronic modules and control signals of the claimed device.

[0024] Figure 3 illustrates the formed virtual objects corresponding to near, intermediate and far planes which allows for ophthalmic tests for a monofocal lens, natural or IOL.

[0025] Figure 4 illustrates the visual artifacts that can simulated which are formed as virtual objects.

[0026] Figure 5 illustrates the cataraoct densitometer results that is provided by the pupil tracker unit.

[0027] Figure 6 illustrates a block diagram chart of the control signals of the electronic modules, tunable lens driver and microdisplay.

[0028] Figure 7 illustrates light combiner module using dichoric mirrors

[0029] Figure 8 illustrates light combiner module using fiber optics.

[0030] Figure 9 demonstrates light combiner module using waveguide optics.

[0031] Figure 10 demonstrates the optical conjugate planes of the claimed device. Detailed Description of the Present Invention

[0032] 101) Microdisplay

[0033] 102) Light source

[0034] 103) Exit pupil

[0035] 104) Variable aperture

[0036] 105) Exit pupil plane

[0037] 106) Pupil

[0038] 107) Exit pupil beam

[0039] 108) Variable focus lens

[0040] 109) Virtual image plane

[0041] 110) Virtual image distance

[0042] 111) Optical conjugate plane a. Image conjugate planes b. Pupil conjugate planes

[0043] 112) Retina

[0044] 113) Photodetector

[0045] 114) Control unit

[0046] 115) Frame synchronization signal

[0047] 116) Control signals

[0048] 117) Lens driver

[0049] 118) Response time

[0050] 119) Waveform

[0051] 120) PID controller

[0052] 121) Combiner

[0053] 122) Fiber

[0054] 123) Dichroic mirror

[0055] 124) Waveguide

[0056] 125) Diffuser

[0057] 126) Halo

[0058] 127) Glare 128) Perspective image

[0059] 129) Temporal multiplexing

[0060] 130) Cataract densitometry

[0061] 131) Pupil tracking unit

[0062] 132) Lens

[0063] 133) Visual artefacts

[0064] 134) Fiber moving actuator

[0065] 135) Infrared LED

[0066] Present disclosure concerns a post-operative vision simulator for candidates of cataract or refractive lens exchange (RLE) surgery. The proposed instrument as part of the present disclosure is a holographic display integrated with a real-time pupil tracker and transmits a holographic image through the patient's pupil. Said instrument incorporates a microdisplay and a varifocal lens (varifocal lens and variable focus lens being used interchangeably) to digitally control the location of the images and digital information of the light beams that are entering through the patients' pupils.

[0067] Present disclosure also concerns a method that addresses aforementioned problems using varifocal display technology. Disclosed invention enables to shape and steer the beam of light through the relatively clear areas of the cataractous lens. A controllable exit pupil formation helps patients see crisp images even through cataractous lenses. One can create images in different focal depths simultaneously without a conflict between the vergence and accommodation (VAC).

[0068] According to the present disclosure, a device is proposed comprising a varifocal display module according to at least one embodiment. According to several embodiments, said varifocal display module is configured to display relevant predetermined sets of images to the user. One such set of images may comprise Snellen chart images, while another set may comprise LogMAR chart images. According to different embodiments, said images may correspond to images representing different focal distances, i.e. objects at near, intermediate, and far proximity.

[0069] According to the present disclosure, different focal depths, namely near, intermediate and far vision are targeted using a varifocal lens which can be configured to render near objects as focused image and the others as defocused images. Disclosed invention is as such capable of simulating conditions for at least a monofocal lens, which is analogous to the general properties of a normal, organic lens that is found by default in humans. Such focal depths, inasmuch as their difference is a result of spatial positioning in a real world case, may be generated such that they refer to at least one near object, one intermediate object and one far object.

[0070] According to the present disclosure, images are generated for targeting different focal depths, namely near, intermediate and far vision superimposed and, according to at least one embodiment, all may be focused images. When, as an example, a bright light source is located at far distance, the corresponding retinal image can have ring-like colored artefacts, i.e., halo visual artefacts around the image of the bright light source. Furthermore, the diffractive multifocal or trififocal IOLS or cataractous lenses can create varying degrees of scattered light and background glare, which are duly and effectively simulated by the teaching of the present disclosure.

[0071] According to many embodiments of the present disclosure, virtual images in the form of perspective holograms are generated at different depths, one embodiment of such using said image generation based on depth quantization rendering software that is utilized with varifocal display with respect to visual acuity tests known in the practice. In several embodiments, such a visual acuity test may take advantage of a LogMAR chart or Snellen chart. Different depth images are configured to correspond to upper, middle and lower sections of a LogMAR chart or Snellen chart.

[0072] An exemplary embodiment comprises a configuration with a varifocal display unit and the pupil tracking unit housing a visible camera and near infrared camera (NIR). NIR camera can detect eye pupil position, determine its size, and align it with the other data such as Scheimpflug cataract densitometer data. Visible camera can detect the exit pupil location using corneal reflections from the regions outside the eye pupil or using purkinje reflections. Those can be used to align the computer generated holography generated beams with the pupil of the viewer.

[0073] The optical unit can also include an additional beam splitter to make the outside world visible such that virtual objects and real objects can be seen together simultaneously. In another embodiment, varifocal display can use the optical relay lenses used in augmented reality or virtual reality glasses archtecture such as waveguides, freeform mirrors and lenses. One such lens is a varifocal lens according to various embodiments.

[0074] According to an embodiment wherein the ophthalmic benchtop simulator device is taught, the present disclosure houses the varifocal display unit, pupil tracking unit, mechanical adjustments for aligning the left and right eye pupils of the user or patient with the exit pupil plane of the beanchtop simulator device. The user's head can be immobilized with respect to the device.

[0075] In another configuration, the device can be made binocular and present holographic stereograms to the viewer to stimulate three-dimensional vision. According to at least one embodiment, disclosed invention utilizes a pupil tracking unit that automatically identifies the relatively clear areas of the cataractous lens using a visible camera, a near-infrared camera, and / or cataract densitometry data. This invention does not require patient cooperation, as the locations and sizes of the exit pupils can be controlled mechanically by the device's steerable housing unit.

[0076] Present invention also addresses the problem of existing simulators not having multifocal IOL assessment capability with patients; since they can only emulate a multifocal IOL design using an artificial eye. Disclosed invention employs multiple programmable pinhole generation techniques to simultaneously render content at multiple depths with proper focus cues. Moderate cataracts and refractive lens exchange (RLE) candidates are as such expected to greatly benefit from the disclosed simulator, albeit severe hypermature dense cataracts could have limited success due to serious scattering.

[0077] A phantom eye or an artificial eye with an artificial lens, such as an artificial cataractous lens, monofocal IOL, or multifocal / trifocal IOL, can be used to train the algorithms employed in the present invention. During such tests, the contrast of the displayed Snellen chart or other visual acuity test patterns can be adjusted. Similarly, halo patterns and other diffractive visual artifacts, similar to those produced by multifocal and trifocal IOLS, can be added to the displayed patterns using algorithms, with different levels of glare also adjustable. Another feature of the disclosed invention is the ability to adjust the distribution of energy along the axial axis. This allows the display of defocus curves matching different multifocal designs and the creation of new custom lens designs. Training the algorithms with the artificial eye enhances the post-surgery visual performance predictions of the disclosed invention. The present invention includes a computation unit that allows operating persons (e.g. ophthalmologists) to selectively adjust virtual distances of the depth images during testing. The visual parameters that can be configured include visual acuity, side effects such as halos and glare, contrast, defocus curves, and depth perception.

[0078] RLE patients do not suffer from cataracts but would like to lead a life without eyeglasses. Varifocal display can present true 3D with all the depth and focus cues. Therefore, a disclosed simulator can be used for the healthy eye and present information that has trifocal, EDOF, or other functions and the associated defocus curves. Disclosed simulator has the potential to impact RLE surgery market as it reduces the anxiety of patients who prefer a glasses free lifestyle.

[0079] The most prominent reason for patient dissatisfaction after surgery is the side effects of IOLS, for simulating which there is no simulator available in the market. Dislcosed simulator will have software modules for contrast sensitivity, halo and glare artefacts that form around the light sources, and dysphotopsia (unwanted images), which are mainly due to diffractive effects and edge effects of the multifocal lens surface profile. The algorithms used to simulate the side effects can be trained using machine learning algorithms using the artificial eye (30) models.

[0080] The disclosed invention introduces a vision simulator in the form of a table- top device. The architecture for one eye module of this device includes a point light source, a phase-only spatial light modulator (SLM), optical components, an exit pupil plane, pupil tracking cameras, and a computation unit. The simulator utilizes a partially coherent point light source to illuminate the spatial light modulator. A spatially coherent diverging beam generated by the point source is collimated by a lens before reaching the spatial light modulator. The spatial light modulator modulates the light, creating a phase-modulated beam and at least one exit pupil beam at the exit pupil plane, which substantially overlaps with the user's eye pupil. The propagated light rays are reflected from the beam splitter and reach the eye (pupil plane). This optical architecture ensures the correct ray angles from virtual objects encoded in the phase-only holograms. The modulated waves reflected by the beam splitter propagate into the eye pupil, forming the retinal image of the virtual object.

[0081] Disclosed invention proposes a more accurate post-operative visual accuracy (VA) prediction. Present invention employs a pupil tracker, which will automatically find the relatively clear areas of the cataractous lens using the cataract densitometry data. Disclosed invention does away with the need for patient cooperation, wherein locations and size of exit pupils can be controlled by mechanical movements / adjustments effectuated on the body of the device, and provides a wide field-of-view and is much less affected from scattering.

[0082] The disclosed invention enables highly accurate assessment of multifocal intraocular lenses (IOLS) before cataract surgery. Current solutions in the field lack the capability to assess multifocal IOLs in patients and can only emulate a multifocal IOL design using an artificial eye. This invention can effectively make use of a varifocal lens to generate content simultaneously at various depths with accurate focus cues. Even in cases of hypermature dense cataracts, the exit pupil in the varifocal display architecture can be configured as small as 1 millimeters and therefore experiences less severe scattering artifacts compared to other standard displays.

[0083] Disclosed invention also allows for the simulation of potential side effects from cataract surgery. One of the primary reasons patients may feel dissatisfied after cataract surgery is the side effects of intraocular lenses. Disclosed simulator includes software modules to simulate contrast sensitivity, halos and glare around light sources, and dysphotopsia (unwanted images), all of which being side effects primarily caused by diffractive effects and edge effects of the multifocal lens surface profile.

[0084] The prevalence of refractive problems among patients raises difficulties to profile the clear spots on the cataractous lens. It is imperative to eliminate the effect of the first-order aberrations caused by the crystalline lens shape since these problems prevent disclosed invention's instrument from providing a sharp virtual image for the patient. The most common aberrations among refractive errors are hyperopia (farsightedness) and myopia (nearsightedness).

[0085] Hyperopia and myopia are conditions that cause an image of an object to become unfocused on the retina. Myopia is a condition in which, opposite of hyperopia, an image of a distant object becomes focused in front of the retina. These refractive errors may be corrected with various prescription glasses or contact lenses specifically designed to counteract their effects. Nearsightedness (myopia) is corrected using a concave lens which is placed in front of a myopic eye, moving the image back to the retina and making it clearer. On the other hand, long-sightedness (hyperopia) is corrected using a convex lens, which is placed in front of a hypermetropic eye, moving the image forward and focusing it correctly on the retina. In other words, the focal planes of the environments are adjusted according to patients' measured diopter values of the refractive problems.

[0086] Refractive errors are represented in a specific notation in the eyeglass prescription, e.g., +2.00 + 1.50 x 180. The first number represents the spherical correction in diopters. A positive sign in front of the first number indicates farsightedness, whereas the negative sign indicates nearsightedness. The second number represents the cylindrical correction in diopters, which indicates the amount of lens power needed for astigmatism. The last number indicates the orientation of astigmatism. 90 corresponds to the vertical meridian of the eye, whereas 180 corresponds to the horizontal meridian.

[0087] The elimination procedure in the disclosed invention for hyperopia and myopia can be described as a graphical replication of the effect of the prescribed eyeglasses. The near point of a human eye, defined to be 25 cm, is the shortest object distance that a healthy eye can accommodate or to image onto the retina. Depending on the refractive problem, virtual depth planes created by the varifocal lens can be adjusted by the disclosed invention's varifocal lens driver unit. Depth values that are retrieved from a rendering software are adjusted to replicate the patient's prescribed eyeglasses effect on these planes.

[0088] According to the disclosed invention, the microdisplay unit can be configured as a phase modulator. An embodiment comprising said phase modulator can display phase patterns in the form of computer generated holograms (CGH). CGHs offer the possibility of creating wave-optical display systems that are under complete computer control. CGH calculation in the disclosed invention involves four major steps: content generation, focal plane discretization, object wave computation, and 3D image reconstruction. The desired virtual content is formed, rendered perspective frames are discretized into multiple focal planes with respect to their depth map values. Once the optical properties of the system are defined, the next step computes the object wave of the scene planes with respect to Angular Spectrum Propagation. The complex valued objectwaves are calculated to represent the 3D scene. The CGH system generally uses three methods for encoding: the amplitude holograms where the amplitude of the reference wave is modulated, phase holograms which modulate its phase and complex holograms where both amplitude and phase are modulated. In order to display the computed holograms on the phase-only SLM, complex valued hologram frames are phase mapped in the disclosed invention. As a final step, once the encoded CGH has been acquired to reproduce the 3D image of the scene, it can be displayed on a beam shaping device that is explained hereinafter.

[0089] Disclosed invention takes advantage of three-dimensonal scenes generatable by rendering programs. Such a virtual scene is formed by two depth planes which provide the perspective and depth map data as raw rendered frames to the depth quantization algorithm. To comply with the real eye examination scenario, a graphically constructed Snellen chart is used for far-plane content whereas the near-plane only contains the surrounding box of the Snellen chart. In this way, the patient experiences an illusion of the real eye examination scenario. According to such an embodiment, far, mid and near planes are formed at 180 centimeters, 60 centimeters and 30 centimeters respectively, where these distances can be controlled freely by adjusting the varifocal lens driver.

[0090] Disclosed invention proposes a near-eye ophthalmic simulation device suitable for use before cataract and / or refractive lens exchange operations.

[0091] An embodiment according to the present disclosure concerns a near-eye ophthalmic simulation device, comprising a microdisplay and a light source capable of forming at least one exit pupil, said exit pupil being independently sized using a variable aperture coupled with said light source, an exit pupil plane coinciding substantially with a pupil of a user wherein, said exit pupil beam being configured to create a projected pattern on the retina of the user when the device is in use.

[0092] In another embodiment according to the present invention, a near-eye ophthalmic simulation device comprises a computer-generated holographic display that can form said at least one exit pupil in a manner that is independently sizable and positionable relative to the position of said eye pupil. Each of the at least one exit pupil is configured to create a projected pattern on the retina of a viewer and carries visual information configured to simulate post-operative vision, wherein the distance of said visual information is independently controllable by a variable focus lens, said lens being placed such that it substantially coincides with the optical conjugate of said light source.

[0093] The virtual image distance can be independently controlled using said variable focus lens that is placed at a substantially coincident location with the conjugate of the light source, such that the exit pupil substantially coincides with a conjugate image plane of the variable focus lens. In certain embodiments, the focal distance of the variable focus lens is modified to change the virtual image distance without substantially changing the location of the exit pupil plane. Optical conjugate planes may be configured to comprise: a light source (or aperture), variable focus lens, exit pupil, microdisplay, retina, virtual image planes.

[0094] In certain embodiments of the present disclosure, a beam splitter can be comprised in at least one location on the general optical path, whereby it becomes possible to superpose the virtual images generated by the device with images present at real world scenes, i.e. physical surroundings of the person. Concurrently, according to at least one embodiment, the optical setup is configured such that three-dimensional scenes, i.e. volumetric scenes can be rendered in real-time.

[0095] In certain embodiments, a microcontroller can be comprised such that signal handling and processing can be accomplished. An example would be wherein a frame synchronization signal is established between said microcontroller and the micro-display, and based on this frame synchronization signal, additional control signals can be generated for dynamically adjusting a set of parameters in the optical setup, such as light source intensity, duration, and timing. Furthermore, in various embodiments, said microcontroller can also be configured such that a frame synchronization signal received from the micro-display is used for generating additional control signals for dynamically adjusting parameters such as the varifocal lens focus, timing, rise time and settling time. Varifocal lens according to the present disclosure is configured to be electronically controllable, and is characterized by a focal length dynamically adjustable in response to control signals from the microcontroller, allowing for the creation of virtual images at depths adjustable from 0 diopters to infinity.

[0096] According to various embodiments in the present disclosure, a varifocal lens driver is comprised to provide control signals to the varifocal lens, enabling dynamic real-time focus adjustment to match the perceived depth of rendered images. These control signals which are generated by said varifocal lens driver can further be categorized as ones that control phase, ones that control amplitude, and ones that control shape. Microcontroller or a similar processing means can be set up such that it triggers / controls these signals from the varifocal lens driving means.

[0097] Several embodiments make use of a photodetector, which constitutes an optical setup based on the utilization of photodetectors (quantity of at least one). Said photodetector- based optical setup can provide information pertaining to the focal length of the varifocal lens, determining a focal length at a time, utilizing which a microcontroller or a processing means can generate a closed-loop, controlled drive signal to dynamically adjust the response time and waveform of said varifocal lens. Said optical setup may further be configured to comprise a PID controller, whereby the response time of the varifocal lens can be reducible to less than 50% of the time allocated for each frame of the microdisplay. In certain cases, said PID controller can be set up such that it reduces the response time of the varifocal lens to less than 3 milliseconds. This rapid response time allows the variable focus lens to settle at the desired focal distance, ensuring a sharp image is achieved. During the transition period, light sources are typically turned off to prevent image blurring.

[0098] In certain embodiments, the light source can be configuted such that it is activated after the varifocal lens focal length is set, and turned off before the end of the microdisplay frame duration. Further embodiments can utilize the light source parameters being controllable by a microcontroller / processor such that said light source can work synchronized with the varifocal lens and microdisplay, its intensity and color being controllable.

[0099] According to the present disclosure, the optical setup may comprise multiple wavelength light sources, which are properly aligned inside a light combiner such as fibers, dichroic mirrors and waveguides. The combined light may or may not be directed onto a diffuser surface. Certain embodiments can utilize an aperture element, which is placed after a diffuser surface, and can be moved freely together in the XYZ axis to achieve precise illumination and eye-box location. The diffuser surface can be rotated to provide temporal averaging to achieve spatially incoherent illumination for coherent light sources such as lasers. In fiber coupled light combiner with a diffusing surface case, the distance between the tip of the fiber and the diffuser can be adjusted electronically and / or mechanically in the longitudinal axis, which changes the spot size and therefore the effective source size on the diffuser. This provides an additional degree of freedom the change the exit pupil size. In certain embodiments, said processing means is configured to execute an image processing algorithm which is able to slice RGB images with a set of corresponding depth maps into multiplane images, facilitating the simulation of depth by quantizing depth information and segmenting the image into multiple plane. Said processing means can be further configured such that it is able to retrieve processed images from a queue, and render them to the display using efficient CPU and GPU-accelerated rendering, thereby enhancing the user experience in real-time applications through fast frame rates.

[0100] Certain embodiments of the present disclosure can be configured such that, for creating a white light source, RGB LEDs are coupled inside a multimode fiber optic member. A diffuser, acting as the light source, can be moved in the XY axis and rotated for achieving precise illumination. For intensity variation over the RGB LEDs, said processing means can be configured to control the intensity of individual LED units by pulse width modualtion.

[0101] In some embodiments, the varifocal lens diopter can be modified such that three-dimensional content depths as well as the location of contents in virtual image planes can be adjusted. Further modifications to the optical setup can be effectuate whereby the eye pupil is monitored for obtaining information pertaining to pupil gaze (i.e. pupil center variation) and accommodation information (i.e. pupil size) of the viewer's eye. For a bright pupil system, the optical setup of the system comprises an infrared LED which illuminates the eye, and a camera which captures the reflected infrared light bouncing back from the eye. Processing means can be further configuted to analyze this reflected light, based on which changes in pupil size can be tracked and eye movements / eye gaze movements can be monitored. In certain embodiments, vision simulator device / system can also simulate different intraocular lenses (IOLS), based on using an eye model including IOL in the exit pupil position. The depth and position of visual content can be manipulated and adjusted such that intraocular lens parameters are obtained. Subsequently, when generating visual content, said intraocular lens parameters can be rendered, creating a display that demonstrates various IOL functions for viewers.

[0102] A varifocal lens driver designed to adjust the diopter of the varifocal lens by modifying the lens's current is utilized in certain embodiments. For enhanced precision in controlling the varifocal lens's diopter, an IR LED and a photodetector are comprised, as depicted according to Figure 2. These components may be aligned either on-axis or off-axis. The rays emitted by the IR LED, after traversing the varifocal lens and additional, fixed lenses in some embodiments, are directed towards a photodetector using a hot mirror. By channeling feedback from the photodetector back to the tunable-lens driver, which integrates a microcontroller, the system achieves finer control over the varifocal lens's diopter.

[0103] According to certain embodiments, the device utilizes another IR LED in conjunction with a camera, positioned on-axis relative to the viewer's eye. This setup enables the monitoring of eye gaze (pupil center), as a pupilometer (crystal lens cloudy area) and the accommodation of the eye's crystal lens (pupil size). Feedback from the camera to the lens driver allows for the adjustment of the content's position across different depth planes. This means the image position over the spatial light modulator (SLM) within each targeted depth pixel can be finely controlled. Moreover, it facilitates the modification of any depth plane's focus or the relocation of contents closer to or further from the viewer's eye. Consequently, the integration of this hardware and the associated algorithms enables the device to serve as an ophthalmic tool for assessing the viewer's eye gaze (pupil center) and crystal lens accommodation capabilities. All of these data (pupillometry, gaze, accommodation) can be used for study and diagnosing neurology and neuro-ophthalmology conditions.

[0104] Said device, according to certain embodiments, is configured such that it adjusts for vision issues and dysphotopsias such as astigmatism and corneal distortions, with the aid of computer generated holography algorithms, or in certain cases with the aid multiple varifocal lens members in the optical setup.

[0105] The device proposed according to the teaching of the present disclosure is near-eye ophthalmic simulation device which is usable before cataract and / or refractive lens exchange operations. On several embodiments, it comprises a a light source (102), microdisplay (101), and optical elements capable of forming an exit pupil (103), at an exit pupil plane (105) wherein, the said exit pupil (103) is configured to create a projected pattern on the retina (112) of the viewer, the projected pattern being configuted to appear at a virtual image plane (109) when the viewer's pupil (106) substantially coincides with the exit pupil plane (105) for carrying visual information. In several embodiments of interest, the device further comprises a variable focus lens (108) in the optical path of the device at a substantially coincident location with an optical conjugate plane (111) of the exit pupil plane (105), and said variable focus lens (108) is configured to control a virtual image distance (110) of the virtual image plane (109), and; said variable focus lens (108) is placed at a substantially coincident position with the optical conjugate of the said light source (102).

[0106] According to an embodiment of the present invention, the focal distance of the variable focus lens (108) is changeable such that the virtual image distance (110) can be modified without substantially changing the location of the exit pupil plane (105). According to an embodiment of the present invention, the size and position of exit pupil (103) can be controlled with a variable aperture (104) coupled with said light source (102).

[0107] According to an embodiment of the present invention, said light source (102) is a LASER, LED, tip of a fiber or a spot formed by a light source on a diffuser (125) surface.

[0108] According to an embodiment of the present invention, the microdisplay (101) is arranged to show an amplitude pattern.

[0109] According to an embodiment of the present invention, the microdisplay

[0110] (101) is arranged to provide phase modulation and display a phase pattern, in the form of a computer-generated hologram.

[0111] According to an embodiment of the present invention, the light source

[0112] (102) or variable aperture (104), variable focus lens (109) and exit pupil plane (105) are arranged to be optical conjugates.

[0113] According to an embodiment of the present invention, microdisplay (101), retina (112) and virtual image plane (109) are arranged to be optical conjugates.

[0114] According to an embodiment of the present invention, said device comprises a photodetector (113) and a control unit (114).

[0115] According to an embodiment of the present invention, control unit (114) is configured generate a closed-loop controlled drive signal to dynamically adjust the response time (118) and waveform (119) of said variable focus lens (108) based on a signal acquired from said photodetector (113). According to an embodiment of the present invention, said control unit (114) is further configured to acquire a frame synchronization signal (115) from the microdisplay (101), a signal from the photodetector (113), and to generate control signals (116).

[0116] According to an embodiment of the present invention, said control unit (114) is further configured to dynamically adjust the focal length of the variable focal lens (108) with control signals using a lens driver (117), whereby virtual image distance (110) can be moved between a near and a far focus planes of the user's eye, ranging from 20 centimeters to optical infinity.

[0117] According to an embodiment of the present invention, said control unit (114) is further configured to generate dynamically adjust light source intensity, color, duration, waveform and timing.

[0118] According to an embodiment of the present invention, said lens driver (117) comprises a PID controller (120) whereby the response time (118) of the variable focus lens (108) is reduced to less than half of each frame of the microdisplay (101), preferably below 3 milliseconds.

[0119] According to an embodiment of the present invention, said control unit (114) is configured to activate and deactivate the the light source (102) between setting of the lens focal length and the end of microdisplay (101) frame duration.

[0120] According to an embodiment of the present invention, said control unit (114) is configured to synchronize the light source (102) with the variable focus lens (108) and microdisplay (101), and dynamically control intensity and color of said light source (102). According to an embodiment of the present invention, said device comprises light sources (102) in multiple wavelengths, such as red, green, blue and white; and said device is configured to combine said light source outputs using a light combiner (121) such as fibers (122), dichroic mirrors (123) and waveguides (124).

[0121] According to an embodiment of the present invention, said device further comprises a variable aperture (104) situated after a diffuser (125) surface, said aperture freely movable in-plane to control the exit pupil (103) location within the exit pupil plane (105).

[0122] According to an embodiment of the present invention, the diffuser (125) surface is configured to be freely rotatable such that spatially incoherent illumination can be achieved when a coherent light source (102) is used.

[0123] According to an embodiment of the present invention, visual information carried through the optical path is configured to comprise at least a visual test; selectable from a group including visual acuity, side effects such as halo (126) and glare (127), contrast, defocus curves, or depth perception.

[0124] According to an embodiment of the present invention, said visual information carried corresponds to at least a multiplicity of a single perspective image (128) said perspective image being at different depths.

[0125] According to an embodiment of the present invention, said perspective images comprised by said multiplicity of image (128) are achieved by temporal multiplexing (129).

[0126] According to an embodiment of the present invention, said device is configured such that different perspective images (128) create different images on the retina (112) and appear at different focus distances. According to an embodiment of the present invention, said device is configured to align the exit pupil (103) with the relatively clear areas of the cataractous lens, which are determined using cataract densitometry (130) or pupil tracking unit (131) or other measurement means.

[0127] According to an embodiment of the present invention, said device is configured such that the size of said exit pupil (103) can be controlled with a variable aperture that can be placed either at the light source or at the variable focus lens plane and the size of the exit pupil is smaller than 2.0 millimeters, preferably 1.2 millimeters.

[0128] According to an embodiment of the present invention, said device is configured such that said at least one exit pupil (103) is displayed in a time-sequential manner.

[0129] According to an embodiment of the present invention, said ophthalmic simulation device is a binocular device configured to display stereoscopic image pairs to simulate three-dimensional vision.

[0130] According to an embodiment of the present invention, said light source is a point light source such as an LED with a small emission emission area that is less than 1 millimeter.

Claims

CLAIMS1) A near-eye ophthalmic simulation device usable before cataract and / or refractive lens exchange operations, comprising a a light source (102), microdisplay (101), and optical elements capable of forming an exit pupil (103), at an exit pupil plane (105) wherein, the said exit pupil (103) is configured to create a projected pattern on the retina (112) of the viewer, the projected pattern being configuted to appear at a virtual image plane (109) when the viewer's pupil (106) substantially coincides with the exit pupil plane (105), characterized in that the device further comprises a variable focus lens (108) in the optical path of the device at a substantially coincident location with an optical conjugate plane (111) of the exit pupil plane (105), said variable focus lens (108) is configured to control a virtual image distance (110) of the virtual image plane (109), and; said variable focus lens (108) is placed at a substantially coincident position with the optical conjugate of the said light source (102).2) A near-eye ophthalmic simulation device according to Claim 1, wherein the focal distance of the variable focus lens (108) is changeable such that the virtual image distance (110) can be modified without substantially changing the location of the exit pupil plane (105).3) A near-eye ophthalmic simulation device according to Claims 1 and 2, wherein the size and position of exit pupil (103) can be controlled with a variable aperture (104) coupled with said light source (102).4) A near-eye ophthalmic simulation device according to any preceding Claim, wherein said light source (102) is a LASER, LED, tip of a fiber or a spot formed by a light source on a diffuser (125) surface.5) A near-eye ophthalmic simulation device according to any preceding Claim, wherein the microdisplay (101) is arranged to show an amplitude pattern.6) A near-eye ophthalmic simulation device according to any preceding Claim, wherein the microdisplay (101) is arranged to provide phase modulation and display a phase pattern, in the form of a computergenerated hologram.7) A near-eye ophthalmic simulation device according to any preceding Claim, wherein the light source (102) or variable aperture (104), variable focus lens (109) and exit pupil plane (105) are arranged to be optical conjugates.8) A near-eye ophthalmic simulation device according to any preceding Claim, wherein microdisplay (101), retina (112) and virtual image plane (109) are arranged to be optical conjugates.9) A near-eye ophthalmic simulation device according to any preceding Claim, wherein said device comprises a photodetector (113) and a control unit (114).10) A near-eye ophthalmic simulation device according to any preceding Claim, wherein control unit (114) is configured generate a closed-loop controlled drive signal to dynamically adjust the response time (118) and waveform (119) of said variable focus lens (108) based on a signal acquired from said photodetector (113).11) A near-eye ophthalmic simulation device according to any preceding Claim, wherein said control unit (114) is further configured to acquire aframe synchronization signal (115) from the microdisplay (101), a signal from the photodetector (113), and to generate control signals (116).12) A near-eye ophthalmic simulation device according to any preceding Claim, wherein said control unit (114) is further configured to dynamically adjust the focal length of the variable focal lens (108) with control signals using a lens driver (117), whereby virtual image distance (110) can be moved between a near and a far focus planes of the user's eye, ranging from 20 centimeters to optical infinity.13) A near-eye ophthalmic simulation device according to any preceding Claim, wherein said control unit (114) is further configured to generate dynamically adjust light source intensity, color, duration, waveform and timing.14) A near-eye ophthalmic simulation device according to any preceding Claim, wherein said lens driver (117) comprises a PID controller (120) whereby the response time (118) of the variable focus lens (108) is reduced to less than half of each frame of the microdisplay (101), preferably below 3 milliseconds.15) A near-eye ophthalmic simulation device according to any preceding Claim, wherein said control unit (114) is configured to activate and deactivate the the light source (102) between setting of the lens focal length and the end of microdisplay (101) frame duration.16) A near-eye ophthalmic simulation device according to any preceding Claim, wherein said control unit (114) is configured to synchronize the light source (102) with the variable focus lens (108) and microdisplay (101), and dynamically control intensity and color of said light source (102).17) A near-eye ophthalmic sqimulation device according to any preceding Claim, wherein said device comprises light sources (102) in multiple wavelengths, such as red, green, blue and white; and said device is configured to combine said light source outputs using a light combiner (121) such as fibers (122), dichroic mirrors (123) and waveguides (124).18) A near-eye ophthalmic sqimulation device according to any preceding Claim, wherein said device further comprises a variable aperture(104) situated after a diffuser (125) surface, said aperture freely movable in-plane to control the exit pupil (103) location within the exit pupil plane(105).19) A near-eye ophthalmic sqimulation device according to any preceding Claim, wherein the diffuser (125) surface is configured to be freely rotatable such that spatially incoherent illumination can be achieved when a coherent light source (102) is used.20) A near-eye ophthalmic simulation device as set forth in any preceding Claim, wherein visual information carried through the optical path is configured to comprise at least a visual test; selectable from a group including visual acuity, side effects such as halo (126) and glare (127), contrast, defocus curves, or depth perception.21) A near-eye ophthalmic simulation device as set forth in any preceding Claim, wherein said visual information carried corresponds to at least a multiplicity of a single perspective image (128) said perspective image being at different depths.22) A near-eye ophthalmic simulation device as set forth in any preceding Claim, wherein said perspective images comprised by said multiplicity of image (128) are achieved by temporal multiplexing (129).23) A near-eye ophthalmic simulation device as set forth in any preceding Claim, wherein said device is configured such that different perspective images (128) create different images on the retina (112) and appear at different focus distances.24) A near-eye ophthalmic simulation device as set forth in any preceding Claim, wherein said device is configured to align the exit pupil (103) with the relatively clear areas of the cataractous lens, which are determined using cataract densitometry (130) or pupil tracking unit (131) or other measurement means.25) A near-eye ophthalmic simulation device as set forth in any preceding Claim, wherein said device is configured such that the size of said exit pupil (103) can be controlled with a variable aperture that can be placed either at the light source or at the variable focus lens plane and the size of the exit pupil is smaller than 2.0 mm, preferably 1.2 mm.26) A near-eye ophthalmic simulation device as set forth in any preceding Claim, wherein said device is configured such that said at least one exit pupil (103) is displayed in a time-sequential manner.27) A near-eye ophthalmic simulation device as set forth in any preceding Claim, wherein said ophthalmic simulation device is a binocular device configured to display stereoscopic image pairs to simulate three- dimensional vision.28) A near-eye ophthalmic simulation device as set forth in any preceding Claim, wherein said light source is a point light source such as an LED with a small emission emission area that is less than 1mm.

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