Systems and methods for stereoscopic chromatic wavelength

Abstract

Systems and methods for stereoscopic chromatic system wavelength contrasting are provided. A system comprises two filters, for filtering different wavelengths in each eye to reduce metamerism caused by color-blindness without introducing new metamers. The system may be implemented as a pair of glasses which may also be corrective, as contact lenses which may also be corrective, as ocular implants or in a virtual- or augmented- reality system. Additionally, a surgical procedure is contemplated, wherein a semi-transparent hologram is implanted in the eye to filter the colors in the eye's visual field. A method for stereoscopic chromatic wavelength contrasting is described. Over time, the method may be used to reduce metamerism without introducing new metamers. The method may further be used to assess perception of color using the systems described herein.

Description

SYSTEMS AND METHODS FOR STEREOSCOPIC CHROMATIC WAVELENGTH CONTRASTINGTechnical Field

[0001] The embodiments disclosed herein relate to systems to correct colorblindness, and in particular to active and passive systems for stereoscopic chromatic wavelength contrasting.Introduction

[0002] Color vision results from photoreceptors (known as rod and cone receptors) in the eye sensing the wavelengths of incoming light differently. As a simplified explanation, the receptor cells are arrayed on the retina so that three types of cone (S, M and L) and one rod are present for each perceivable point in the visual field. In a normative human eye, each cone senses a different band of frequencies of incoming light, while the rods sense a broad range of frequencies.

[0003] FIG. 1A illustrates the relative, normalized wavelength-based sensitivity (absorbance) of the different cone and rod receptors in an eye with three functioning cone types and functioning rods. Incoming light with a given wavelength (on the horizontal axis) causes the cones and rods to generate a signal as per their individual sensitivities to the input wavelength. S type cones respond most strongly to short-wavelengths of visible light (blue hues) with peak absorbance at ~419 nm; M type cones respond most strongly to medium-wavelengths of visible light (green hues) with peak absorbance at ~531 nm; and L type cones respond most strongly to long-wavelengths of visible light (red hues) with peak absorbance at ~559 nm.

[0004] Referring to FIG. 1 B, each cone’s spectral sensitivity is a continuous function, and as the output from the cone corresponds to the intensity sensed, each cone’s output may correspond to at least two distinct incident frequencies / wavelengths 3, 4 when received at the brain as shown in FIG. 1 C. This results in a metamer indicated by line 5.

[0005] The brain combines the level sensed by each of the three cones and the rod, for every point in the visual field, to generate color and brightness information for thatpoint. For example, referring to FIG. 1 D, the brain may interpret the levels 14, 15 (two distinct points of reference) sensed from an L cone response 10 and an M cone response 11 to perceive a wavelength 12 as a red / green hue despite the presence of (normal) metamers indicated by lines 7, 8. As the sensitivity spectra of the S, M and L types of cones overlap significantly, the brain is able to correlate the three cone levels and one rod level, for many points across the visual field, to produce a coherent image.

[0006] Color-blindness (or color vision deficiency, “CVD”) is a decreased ability for a person to distinguish between certain colors, rather than true blindness. Color-blindness may be caused by the absence, malformation or non-functionality of one (or more) type of cone receptor.

[0007] When only two types of cone receptor are fully functioning, the brain is unable to disambiguate certain color / wavelength ranges. This condition is known as “dichromacy,” and “dichromats” are individuals with this condition. Dichromats are unable to disambiguate some colors which trichromats (individuals with trichromacy, or three different functioning cone types) are able to distinguish from one another. For example, a dichromat will perceive light with a wavelength which stimulates both cones equally as being white, and equivalent in color to light of two blended colors, where each color stimulates one cone receptor maximally. This means that only two colors are needed to generate light perceived as white by a dichromat. The functional third cone type of a trichromat provides additional information needed to distinguish this light from true white light; a dichromat, however, does not have this additional information.

[0008] In another form of color-blindness known as anomalous trichromatism, all three types of cone receptor are present, but the spectral sensitivity of one cone type is shifted to be nearly identical to the spectral sensitivity of a second cone type. For example, as shown in FIG. 1 E, the spectral sensitivity of L cones may be shifted to overlap with that of M cones such that the wavelength 12 stimulates both L and M cones similarly resulting in a metamer indicated by line 6. The output of both L and M cones 10, 11 when received at the brain cannot thus be distinguished so both long and medium wavelengths are perceived as the same color. This results in a smaller perceivable color spectrum andcauses a decreased ability for a person to distinguish between certain shades of red (protanomaly) and certain shades of green (deuteranomaly).

[0009] FIG. 2 illustrates how certain colors (red, R; orange, 0; yellow, Y; green, G; blue, B; indigo, I; and violet, V) may be perceived by a normal eye having functioning rods and 3 functioning cone types (FIG. 2A), and how they may be perceived by eyes with different kinds of color-blindness (FIGS. 2B-2C) having functioning rods, but only two functioning cone types. FIG. 2 is simplified for explanatory purposes and actual color perception may vary from individual to individual. The glyph in the upper-right corner of each of FIGS 2B-2D indicates which cone receptor (red or green light sensitive) is nonfunctional for each respective kind of color-blindness.

[0010] FIG. 2B depicts a severe form of red-green color blindness, deuteranopia, where green-sensitive cones are completely non-functional. Individuals with deuteranopia are unable to distinguish red-green hues and generally perceive “color” in what is deemed yellow hues (Y1-Y7) and blue hues (B1-B5) in normal vision. FIG. 20 depicts protanopia, a severe form of red-green color blindness where red-sensitive cones are absent. Individuals with deuteranopia are unable to distinguish red-green hues generally perceive “color” as what is deemed yellow hues (Y11-Y17) and blue hues (B6-B10) in normal vision. Other forms of color-blindness may cause an inability to disambiguate other color ranges. For example, Tritanopia, is a blue-yellow color-blindness resulting from reduced sensitivity in blue-sensitive S cones.

[0011] The inability of the eye to disambiguate two different spectral densities, or in other words, the tendency of the eye and brain to perceive two different incoming colors as the same color, is known as metamerism, and the two conflated colors are known as metamers. Color vision tests may be administered to determine the nature of colorblindness in an individual. One such test, used by many organizations, such as the US Navy, which require color vision for certain jobs, is the Ishihara color vision test.

[0012] Using traditional filtering techniques, it is not possible to overall reduce metamerism. Some commercially available color-blindness glasses filter out certain ranges of the visible spectrum, to improve contrast between spectral regions which may be metamers for certain color-blind individuals. However, this filtering itself creates newmetameric regions of the spectrum, thereby simply replacing one metameric with another as shown in FIG. 1 F. An color-blindness metamer indicated by line 2 may be corrected / compensated by shifting of the spectral sensitivity of a cone type e.g., L cones, such that an original output 13a changes to a shifted output 13b but it comes at the expense of creating a new metamer indicated by line 9. The resulting change in vision typically does not change the wearer’s ability to pass a color vision test like the Ishihara test. Furthermore, if the corrected metamers are in different lighting conditions (e.g., one color is in a brighter light or shade or is emitting light) that will counteract the contrast “enhancement” as the brain lacks the needed context from wavelengths that are blocked.

[0013] Another filtering technique relies on breaking binocular redundancy in human vision. So-called binocular rivalry - the tendency of the brain to interpret differing images from the two eyes by alternating or otherwise causing an overlap of the two images - can create a perceived phenomenon which may be interpreted as a new color or pattern.

[0014] Accordingly, there is a need for new active and passive filtering techniques leveraging binocular rivalry which could reduce metamerism caused by color-blindness, without introducing new metamers.Summary

[0015] Disclosed is a system with two filtering lenses for reducing metamerism caused by color-blindness. The system may be implemented as a pair of glasses which may also be corrective, as contact lenses which may also be corrective, as ocular implants which may also be corrective, or in a virtual- or augmented-reality system as described herein. Additionally, a surgical procedure is described, wherein a semitransparent hologram is implanted in the eye to filter the colors in the eye’s visual field.

[0016] According to some embodiments, there is a system for stereoscopic chromatic wavelength contrasting. The system comprises a first filter for blocking a first range of wavelengths from a first eye and a second filter for blocking a second range of wavelengths from a second eye, wherein the second range of wavelengths is different tothe first range of wavelengths. The first and second range of wavelengths are selected according to a non-functional cone type in the first eye and the second eye.

[0017] According to various embodiments, the filters are narrow band filters selected from the group of: absorption filters, interference filters; Lyot filters; refractive filters; diffractive filters; and acousto-optic filters.

[0018] According to various embodiments, the filters are selected from the group of: notch filters, high-pass filters, low-pass filters, short-pass filters.

[0019] According to an embodiment, there is an augmented realty (AR) system for stereoscopic chromatic wavelength contrasting. The AR system comprises at least one camera for capturing a field of view, a left eye display and a right eye display. A processing unit is configured to receive the field of view from the camera as a left eye field of view and a right eye field of view; detect a first range of wavelengths in the left eye field of view and output a first filtered image to the left eye display wherein transmission of the first range of wavelengths to the left eye display is at least reduced; detect a second range of wavelengths in the right eye field of view and output a second filtered image to the right eye display wherein transmission of the second range of wavelengths to the right eye display is at least reduced.

[0020] Other aspects and features will become apparent, to those ordinarily skilled in the art, upon review of the following description of some exemplary embodiments.Brief Description of the Drawings

[0021] The drawings included herewith are for illustrating various examples of articles, methods, and apparatuses of the present specification. In the drawings:

[0022] FIG. 1A is a diagram illustrating relative sensitivity (absorbance) of the different cone and rod receptors in the eye;

[0023] FIG. 1 B is a representation of a cone’s spectral sensitivity;

[0024] FIG. 1 C is a representation a single cone’s output;

[0025] FIG. 1 D is a representation of M and L cones’ output in normal vision;

[0026] FIG. 1 E is a representation of M and L cones’ output in color-blindness;

[0027] FIG. 1 F is a representation of M and L cones’ output using traditional colorblindness glasses;

[0028] FIG. 1 G is a representation of M and L cones’ output using the systems and methods described herein, according to an embodiment;

[0029] FIG. 1 H is a representation of a color test graphic deciphered using the systems and methods described herein, according to an embodiment;

[0030] FIG. 2A is a diagram illustrating how certain colors are perceived in a normal eye;

[0031] FIG. 2B is a diagram illustrating how certain colors are perceived in an eye with deuteranopia;

[0032] FIG. 2C is a diagram illustrating how certain colors are perceived in an eye with protanopia;

[0033] FIG. 3A is a diagram illustrating how certain colors are perceived in a normal eye;

[0034] FIG. 3B is a diagram illustrating how certain colors are perceived in an eye with deuteranopia when treated with the systems and methods disclosed herein, according to an embodiment;

[0035] FIG. 3C is a diagram illustrating how certain colors are perceived in an eye with protanopia when treated with the systems and methods disclosed herein, according to an embodiment;

[0036] FIG. 4 is a key for interpretation of FIGS 5-7;

[0037] FIG. 5A is a diagram illustrating (normal) base color vision;

[0038] FIG. 5B is a diagram illustrating how traditional color-blindness glasses filter the incoming spectrum, and the modified response curve for each rod and cone receptor based on that filtering;

[0039] FIG. 6 is a diagram illustrating how a monocular system for stereoscopic chromatic wavelength contrasting filters light in one eye, and how this is perceived by a user with one cone type not functional, according to an embodiment;

[0040] FIG. 7 is a diagram illustrating how a system for stereoscopic chromatic wavelength contrasting filters light differently in each eye to create binocular rivalry in a individual with one non-functional cone type, according to an embodiment;

[0041] FIGS. 8A and 8B are diagrams of surgically implanted holograms for stereoscopic chromatic wavelength contrasting, according to several embodiments;

[0042] FIGS. 9A-9D are diagrams of various filter arrangements for stereoscopic chromatic wavelength contrasting, according to various embodiments;

[0043] FIG. 10 is a block diagram of an augmented reality system for stereoscopic chromatic wavelength contrasting, according to an embodiment; and

[0044] FIGS. 11A-11 D are flow charts of methods for stereoscopic chromatic wavelength contrasting, according to various embodiments.Detailed Description

[0045] Various apparatuses or processes will be described below to provide an example of each claimed embodiment. No embodiment described below limits any claimed embodiment and any claimed embodiment may cover processes or apparatuses that differ from those described below. The claimed embodiments are not limited to apparatuses or processes having all of the features of any one apparatus or process described below or to features common to multiple or all of the apparatuses described below.

[0046] A description of an embodiment with several components in communication with each other does not imply that all such components are required. On the contrary a variety of optional components are described to illustrate the wide variety of possible embodiments of the present invention.

[0047] Further, although process steps, method steps, tasks, algorithms or the like may be described (in the disclosure and I or in the claims) in a sequential order, such processes, methods and algorithms may be configured to work in alternate orders. In other words, any sequence or order of steps that may be described does not necessarily indicate a requirement that the steps be performed in that order. Unless a specific order of steps or actions is required for proper implementation of the systems and methodsdescribed herein, the steps described herein may be performed in any order that is practical and / or may be interchanged or modified without departing from the scope of the claims. Further, some steps may be performed simultaneously.

[0048] When a single device or article is described herein, it will be readily apparent that more than one device I article (whether or not they cooperate) may be used in place of a single device I article. Similarly, where more than one device or article is described herein (whether or not they cooperate), it will be readily apparent that a single device I article may be used in place of the more than one device or article.

[0049] As used herein, a “processing unit” refers to a component or system that is designed to execute instructions / algorithms, process data, perform computations, and / or control other components within a system, as the case may be. Further, the processing unit may include specific hardware (e.g., a computer processor) and / or software components for performing the above-mentioned tasks. The processing unit may be integrated with other components of a system, such as memory, I / O interfaces, or network interfaces. A processing unit may also include, for example, field programmable gate arrays (FPGAs) or application specific integrated circuits (ASICs) to rapidly perform processing operations.

[0050] A “processor” as used herein refers to a computer processor, such as a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general- purpose processor can be a microprocessor, but in the alternative, the processor can be a controller, or microcontroller, combinations of the same, or the like. A processor can also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. Although described herein primarily with respect to digital technology, a processor may also include primarily analog components. For example, any of the signal processing algorithms described herein may be implemented in analog circuitry. In some embodiments, a processor can be a graphics processing unit (GPU). The parallel processing capabilities of GPUs canreduce the amount of time for training and using neural networks (and other machine learning models) compared to central processing units (CPUs). In some embodiments, a processor can be an ASIC including dedicated machine learning circuitry custom built for one or both of model training and model inference.

[0051] The term “computer-readable medium” refers to any available medium that can be accessed by a computer or processor. By way of example, and not limitation, such a medium may comprise RAM, ROM, EEPROM, flash memory, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer. The wavelength filtering described herein may be stored as one or more instructions on a processor-readable or computer- readable medium.

[0052] As used herein, the term “code” may refer to software, instructions, code or data that is / are executable by a computing device or processor.

[0053] The phrase “based on” as used herein shall mean both “based only on” and “based at least on” unless expressly specified otherwise.

[0054] The term “determining” encompasses a wide variety of actions and, therefore, “determining” can include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or another data structure), ascertaining and the like. Also, “determining” can include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory) and the like. Also, “determining” can include resolving, selecting, choosing, establishing and the like.

[0055] The terms “filter” and “block,” including variations thereof, are used interchangeably herein to refer to the exclusion of certain wavelengths of light by physical (e.g., narrow-band filters) or electronic (e.g., processor implemented) means.

[0056] The term “passive” as used herein refers to systems or apparatuses containing optical filters configured to filter a predetermined wavelength or wavelengths. Examples of “passive” apparatus include glasses, contact lenses and implantable lenses.

[0057] The term “active” as used herein refers to systems or apparatuses containing tunable filters and / or electronic circuits for modulated filtering of one or more wavelengths. Examples of “active” apparatuses include virtual- or augmented-reality systems.

[0058] The term “about,” or a tilde (~) when preceding a value herein, refers to the usual error range for the respective value readily known to the skilled person in this technical field.

[0059] In commercially available “color blindness glasses,” filtering lenses are fitted to glasses to attempt to remove certain wavelengths from the wearer’s perception across both eyes blocking the same range of wavelengths in each eye where the red and green cones mostly overlap. This can have the effect of rebalancing the colors in the visual field to resolve certain metamers, but at the cost of creating new metamers. 3D glasses work most commonly by blocking all but a narrow range of colors that they separate their intended images onto. Fundamentally, these types of filtering reduces the total amount of visual information, and less information cannot resolve ambiguities caused by missing information - such “solutions” can only shift the problem from one set of spectrum segments to another.

[0060] In contrast, the systems and methods disclosed herein use the principle of binocular rivalry and stereoscopic chromatic wavelength contrasting to at least improve red-green color-blindness without introducing new metamers in some embodiments. The systems herein block specific narrow wavelength ranges to let everything but those wavelengths through to provide contrasting sets of information to each eye. The contrast between the left and right eye images, known as binocular rivalry, creates a perception which may be considered analogous to color vision.

[0061] For the most common color-blindness, red-green color-blindness, this would be achieved by blocking specific wavelengths corresponding to green for one eye and red for the other eye. Filtering of these wavelengths may shift some green-receptive photoreceptors to more red sensitivity over time. Similarly, the sensitivity of some red- receptive photoreceptors may be shifted to green sensitivity over time. This effect is illustrated in FIG. 1 G.

[0062] It should be noted that the “shifting” of spectral sensitivity provided by the systems and methods described herein and illustrated in FIG. 1 G does not alter the structure or properties of a cone receptor itself; rather, what is altered is the way the brain cognitively processes and interprets the output of the “shifted” cone by binocular rivalry. With acclimatization and training, over time the brain may interpret the levels 17, 19 sensed from a shifted L cone response 16 and a shifted M cone response 18 to perceive the wavelength 12 as a red hue that is distinguishable from a green hue (or vice versa). By isolating the problematic wavelengths that cause red / green metamer pair confusions, and not affecting unnecessary wavelengths to create new metamers in other regions of the visible spectrum, unnecessary and unwanted distortion to vision is reduced.

[0063] Notably and more generally, this approach allows for perception of a wider color spectrum using only two functional cone types, compensating for the absence, or reduced functioning of a third. By using the remaining / shifted cone / rods, two sets of data (one from each eye) are created. Then with internal processing of binocular vision in the brain the data can come together and provide the missing points of reference for (near) trichromatic vision. This means even if lighting conditions or context changes as long as both eyes are effected similarly, the user is provided enough information to differentiate red, orange, yellow and green from each other and in time process wavelengths in a way similar to a trichromat. Accordingly, while the systems and methods herein are described in respect of red-green color-blindness, it will be apparent to those skilled in the art that the same may be adapted for use in other forms of color-blindness, for example, yellowblue color-blindness (tritanopia).

[0064] As an example, using the systems and methods herein, the Ishihara color vision test graphic in FIG.1 H may be deciphered by a color-blind individual - information from one eye (e.g., the left eye) may be perceived as a first “color” and information from the other eye (e.g., the right eye) may be perceived as a second “color” by the brain to resolve the numerals from the background.

[0065] Referring to FIG. 3, shown therein are diagrams illustrating how certain colors (red, R; orange, O; yellow, Y; green, G; blue, B; indigo, I; and violet, V) may be perceived by a normal eye (FIG. 3A), and how they may be perceived by eyes withdifferent kinds of color-blindness (FIGS. 3B-3C) using the systems and methods described herein. FIG. 3 is simplified for explanatory purposes and actual color perception may vary from individual to individual. Comparing FIGS. 2B and 3B, the systems disclosed herein provide improved color perception in Deuteranopia such that certain orange hues (O1-O4) and green hues (G1-G3) may be perceived. Similarly, comparing FIGS. 2C and 3C, color perception in Protanopia may be improved such that certain orange hues (Os-Os) and green hues (G4-G6) may be perceived.

[0066] According to various embodiments, the systems described herein implement physical or electronic filtering means to provide variations of images with selected wavelengths of light filtered for the brain to interpret. This can be done most simply with one filtered image provided to the right eye and a different filtered image provided to the left eye, but this can also be done by providing a patterned image to both eyes. In some embodiments the different images are generated by computer- implemented means e.g., by a VR headset similar to how a sense of stereoscopic images may be created by providing slightly different angles and fields of view. Alternatively, or in combination, selective removal of wavelengths of light in specific ranges may be performed.

[0067] According to various embodiments, precise optical filters drastically reduce, if not substantially eliminate, light of certain wavelengths from reaching the eye. According to various embodiments, a passive optical filter is precisely fitted to the wavelengths to be blocked, as determined by the deficiency in color sensing in the eyes. Preferably, the filter blocks 80%-99% of total light of the relevant wavelengths. Preferably, the optical filter should operate on as wide an incident angle of light as possible.

[0068] According to various embodiments, the image presented to each eye is filtered with narrow-band filters which are different from one eye to the other (i.e. , the right eye image may be filtered to block certain wavelengths and the left eye image may be filtered to block certain other wavelengths different from those blocked for the right eye). The ranges of wavelengths which are filtered are chosen depending on the nature of the wearer’s color-blindness.

[0069] The use of very narrow-band filters is critical to allowing the remainder of the visible spectrum to remain unaffected. This reduces color distortion throughout the spectrum, and allows objects, graphics, artwork and other items to be viewed largely as naturally as possible. This is a significant benefit, as object recognition and art appreciation are improved when colors remain as they are without glasses. When embodied as lenses on glasses, or as contact lenses, the use of narrow-band filters also may allow the lenses to appear clear or almost clear. This provides a further benefit, as significantly colored glasses or contact lenses may be obtrusive or distracting to others interacting with the wearer.

[0070] Referring to FIG. 4, shown therein is a key for interpreting FIGS. 5-7. A visible light spectrum 100 is shown at the top of each Figure. Each Figure includes a representation of the outer eye surface 110 and a representation of a filter 102, with the blacked out sections 104 indicating which parts of the visible light spectrum 100 are absorbed / blocked by the filter 102. According to various embodiments, the filter 102 may be positioned in front of the eye (in the case of glasses or contact lenses), or behind the outer eye surface (in the case of an implant). Each Figure includes a representation of an L cone receptor 122, an M cone receptor 124, and an S cone receptor 126 (non-functional cone receptors are shown as blacked out) and rod receptor 128.

[0071] The bottom of each Figure is a graph 130 of the resulting normalized response curves 132, 134, 136, for the respective L, M and S cones 122, 124, 126 and the response curve 138 for the rods 128 after being filtered. The x-axis of the graph 130 corresponds to the wavelengths of the spectrum 100.

[0072] Referring to FIG. 5A, shown therein is a diagram illustrating (normal) base color vision in both eyes with functional rods 228 and three types of functional cones 222, 224, 226.

[0073] FIG. 5B illustrates the effect of traditional color-blindness glasses which filter the same wavelengths of light from both eyes. As noted above (FIG. 1 F), the result is rebalancing the colors in the visual field to resolve certain metamers, but at the cost of creating new metamers. In addition, there is a loss of visual information (from both eyes)in the trough regions 240, 211. In some cases, as seen with the trough 240, the blocked wavelengths may correspond to the peak sensitivity of one or more cone type.

[0074] Referring to FIG. 6, shown therein is a diagram illustrating the effect of a monocular system 300 for stereoscopic chromatic wavelength contrasting, according to an embodiment. The system 300 is implemented with an individual who has nonfunctioning M cones 324 and thus an inability to perceive red and green hues (e.g., as seen in deuteranopia, FIG. 2B). The system 300 includes a filter 302 to block certain “green” wavelengths (e.g., in the range of 500-550 nm) from one eye (Eye A). The other eye (Eye B) is unfiltered to provide contextual visual information to the individual which may be useful for improving color perception without creating new metamers and which may be blocked in traditional color-blind glasses. The filter 302 may be implemented as a monocle, a contact lens or an ocular implant.

[0075] The system 300 may (in particular, when used in conjunction with the methods described herein), over time, cause a shifting in the spectral sensitivity of the functional L cones 322 and / or S cones 326 in Eye A to create binocular rivalry between Eye A and Eye B and improve perception of color. In other embodiments, the system 300 may be adapted to block other wavelengths of light to in one eye to improve perception of color where another cone type is absent or not functioning.

[0076] Referring to FIG. 7, shown therein is a diagram illustrating a system 700 for stereoscopic chromatic wavelength contrasting, according to an embodiment. The system 700 filters light differently in each eye to create binocular rivalry in an individual with one non-functional cone type (L cones in this case). The system 700 includes a first lens having a notch filter 702 to exclude certain wavelengths of light (e.g., in the range of 500-565 nm) in a first eye (Eye A) and a second lens having a notch filter 704 (or low band pass filter) to block different wavelengths of light (e.g., in the range from 590 nm to at least 750 nm) in a second eye (Eye B). The lenses 702, 704 are implemented as ocular implants. In other embodiments, the lenses 702, 704 may be implanted as glasses or contact lens.

[0077] Over time, the system 700 may (in particular, when used in conjunction with the methods described herein), over time, cause a shift in spectral sensitivity of functionalM cones 724a, 724b in Eye A and Eye B. For example, blocking of “green” wavelengths in Eye A may shift the spectral sensitivity of M cones 724a toward “red” wavelengths; blocking of “red” wavelengths in Eye B may shift the spectral sensitivity of M cones 724B toward “green” wavelengths. The net result is a binocular rivalry between Eye A and Eye B and may improve perception of color. Notably, the blocked wavelength ranges (in either eye) do no coincide with the peak spectral sensitivity of any functioning cones 722, 726 or rods 728 which may enhance the spectral shifts, and improved perception of both red and green hues over time.

[0078] As compared to traditional color-blind glasses (FIG. 5B), the system 700 differentially filters a narrow band of wavelengths from each eye, as opposed to blocking the same wavelengths from both eyes. In the system 700, wavelengths that are blocked from one eye are received by the other eye. This visual information may provide additional context to the individual which may improve color perception without creating new metamers.

[0079] As compared to a monocular system 300, the system 700 may provide for faster and / or increased shifting of spectral sensitivity of cones 724a, 724b with more precise wavelength isolation and with less distortion to vision. This may enable the perception of a wider range of hues of a color than with only using the monocular system 300.

[0080] In an embodiment, the filters 702, 704 comprise an optical density filter overlapped with a narrow band filter covering the blocked wavelengths while leaving “yellow” wavelengths unblocked to further enhance contrast between the blocked wavelengths and the rest of the visible spectrum in each eye. When the brain / pupils adjust to the overall brightness (perceived as a neutral level), this has the effect of making the blocked wavelength ranges to be darker than the neutral level, while making the unblocked range that is contrasted appear brighter than the neutral level. This in effect causes Eye A to see green hues as dimmer, while red and yellow hues appear even brighter than the neutral level. Eye B sees red hues dimmer, while yellow and green hues appear brighter than the neutral level. This may further enhance the binocular rivalry and provide for faster or enhanced color perception without creating new metamers.

[0081] In various embodiments, the following ranges of wavelengths may be filtered to reduce metamers caused by color-blindness according to the affected cone type:• Blue (S cone) compensation: 400 nm or 419 nm to 450 nm;• Green (M cone) compensation: 500 nm to 550 nm;• Red (L cone) compensation: 550 nm to at least 630 nm.

[0082] In an embodiment, the following ranges of wavelengths generalized to be a range of hues considered to be yellow in normal vision may be filtered for addressing red- green color-blindness:• In one eye, blocking wavelengths 590 nm and higher;• In the other eye, blocking wavelengths 520-565 nm; and• The wavelength ranges 565-590 nm, and 0-520 nm, remain unfiltered in both eyes.

[0083] In an embodiment, the following ranges of wavelengths may be filtered for addressing red-green color-blindness:• In one eye blocking 500 nm - 570 nm while not impeding wavelengths outside this range; and• In the other eye blocking 590 nm and higher in the visual spectrum while not impeding wavelengths below 590 nm.To achieve the selective blocking of wavelengths, a notch filter with peak OD 6 may be employed to block the 500-570 nm range. The notch filter may, for example, cover a 495- 575 nm wavelength range to ensure a minimum OD of 5 is achieved at 500 nm and 570 nm. A low pass / short pass filter with peak OD 6 may be employed to block wavelengths of 590 nm and higher. The low pass / short pass filter may, for example, start at 585 nm to ensure a minimum OD of 5 is achieved by 590 nm. .

[0084] The principle of binocular rivalry between eyes may also be applied to groups / clusters of cone receptors within an eye. For example, according to some embodiments, a patterned image filter may be applied to both eyes as described below.

[0085] Referring to FIG. 8, shown therein is a diagram of a semi-transparent filtering hologram 802 surgically implanted into the eye 804, according to an embodiment. The hologram 802 is generally positioned between the iris 808 and the rod and cone receptors on the retina 806. The hologram 802 generates a color-filtered image 810 on the retina 806 preferably without introducing other distortions or changes in the visual field.

[0086] In some embodiments, the color filtering from the hologram implant 802 would be similar or identical to the filtering discussed elsewhere in this disclosure. For example, a first hologram 802 implanted into a first eye 804 is configured to block a first range of wavelengths from the retina 806 in the first eye and a second hologram 802 implanted into a second eye is configured to block a second range of wavelengths from the retina in the second eye.

[0087] Referring to FIG. 8B, in some embodiments, a hologram implant 812 is configured with a filtering pattern to block certain wavelengths from certain groups / clusters of rods / cones on the retina 816. For example, the hologram 812 may block red wavelengths in some regions 822 and block green wavelengths in other regions 824. In some embodiments, no wavelengths may be blocked in some other regions 826. The result is a patterned color-filtered image is generated on the retina 816. The filtering pattern and the spacing of the regions 822, 824, 826 may mimic the spacing and clustering of different cone types on the retina 816 and / or account for physical constrains of light at those scales. In various embodiments, various hologram implants 812 may be provided to produce different color-filtered images on the retina 816 e.g., a striped pattern, a checkerboard pattern, etc.).

[0088] Over time, this patterned blocking of certain wavelengths may cause a shift in the spectral sensitivity of certain cone receptors 828, 829 in the regions 822, 824 to be more green or red-sensitive, respectively, to create a “binocular rivalry” effect between receptors or groups of receptors within an eye. This in turn may result in an improvement in color perception over time and may be particularly useful to improve color perception in color-blind individuals having only one eye. This patterned filtering technique may also be used in both eyes if filtering holograms are implanted in both eyes.

[0089] Referring to FIGS. 9A-9D, according to various embodiments, narrow-band filters 902, 904, 906, 908 may be positioned differently relative to the outer eye surface 910 and rod and cone receptors 920.

[0090] As shown in FIGS. 9A and 9B, the filter 902, 906 may be positioned external to the eye, i.e. in front of the outer eye surface 910. As shown in FIG. 9A, the filter 902 may be implemented on a lens in a pair of glasses, which lens may also be corrective for visual distortion. In the embodiment shown in FIG. 9B, the filter 906 is implemented on a contact lens which may also be corrective for visual distortion.

[0091] In some embodiments, as shown in FIGS. 90 and 9D, the filter 904, 908 is internal to the eye i.e., behind the outer eye surface 910. In such embodiments, the filter is implemented on a intraocular implant which may also be corrective for visual distortion (FIG. 9D) or implemented as a semi-transparent filtering hologram (FIG. 9C).

[0092] In an embodiment, the amount of light absorbed / blocked by the filter 902, 904, 906, 907 at any wavelength should be as close as possible to the expected absorption spectrum (i.e., as expected in a normal eye) of the non-functional cone type in the eye.

[0093] In an embodiment, the amount of light absorbed / blocked by the filter 902, 904, 906, 907 at any wavelength should be maximal wherever the non-functional cone type has significant absorption, and zero outside of this range.

[0094] In an embodiment, the amount of light blocked by the filter 902, 904, 906, 907 at any wavelength should be at least 10%, or a minimum threshold for the brain to cause binocular rivalry. The minimum threshold may vary from individual to individual.

[0095] According to various embodiments, different types of filters, based on different physical principles may be used in the disclosed systems and method. Each of these filter types are contemplated and suitable for use: absorption filters, interference filters; Lyot filters; refractive and diffractive filters; and acousto-optic filters.

[0096] According to various embodiments, filters described herein may be implemented as lenses with photo chromatic coating to ensure the response of rod cells in particular are not over saturated in various lighting conditions.

[0097] According to various embodiments the transmission or absorption / filtering profiles of filters used in the systems described herein, (e.g., bandpass filters, notch filters, or high-pass I low-pass I short pass filters, or the like) are “sharp” e.g., capable of going from an optical density (OD) of zero (total transmission) to an OD of 6 (substantially total absorption) within 5-10 nanometers of filtering range.

[0098] According to various embodiments, a filter may comprise two overlapping short and long pass filters to overall reduce visible light reaching the eye while blocking the relevant wavelengths. According to various embodiments, a filter may comprise a short pass filter and a neutral density filter to overall reduce visible light reaching the eye while blocking the relevant wavelengths. In some embodiments, the systems described herein may include a first filter comprising overlapping short and long pass filters to block a first range of wavelengths from a first eye and a second filter comprising a short pass filter and a neutral density filter to block a second range of wavelengths from a second eye. Such embodiments may provide for an enhanced binocular rivalry in some lighting conditions.

[0099] According to various embodiments, active mechanisms such as tunable filters could be used for modulated filtering of one eye or both eyes. In these embodiments, the range of wavelengths filtered for each eye may be adjusted and / or the intensity of light passing through the filters may be modulated e.g., using neutral density filters or photochromatic lens coatings. Tunable filters may also be switched on or off for alternated filtering of one eye, or the other eye, or both eyes. This may result in the individual experiencing a “flickering” effect to provide additional visual data (additional points of reference) to the aid in color perception. For example, in a simple implementation, each eye has a range of wavelengths blocked, then unblocked in a particular pattern which may result in the individual experiencing a flickering pattern on a particular colored object which may be perceived as a color. Modulated fi Itering / f lickering may also be implemented using an AR system described herein.

[0100] Referring to FIG. 10, shown therein is a diagram of an augmented reality (AR) system 600 for color-blindness, according to an embodiment. The AR system 600 is configured to capture a visual field and reproduce it for a wearer, but with certain colorwavelengths blocked as per the required filtering, differently for each eye. This implementation has the benefit of being able to create very precise digital wavelength filtering and color modification without regard for the design or manufacture of optical filtering materials.

[0101] The AR system 600 includes a processing unit 610, memory 620, non- transitory mass storage 630, one or more camera(s) 640, a network interface 650, and an AR display 660, all of which are communicatively coupled via bi-directional bus 670. According to certain embodiments, any or all of the depicted elements may be utilized, or only a subset of the elements. Further, the system 600 may contain multiple instances of certain elements, such as multiple processors or memories, or transceivers. Also, elements of the system 600 may be directly coupled to other elements without the bidirectional bus 670. Additionally, or alternatively to a processor and memory, other electronics, such as integrated circuits, may be employed for performing the required wavelength filtering operations.

[0102] The memory 620 may include any type of non-transitory memory such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), read-only memory (ROM), any combination of such, or the like. The mass storage element 630 may include any type of non-transitory storage device, such as a solid state drive, hard disk drive, a magnetic disk drive, an optical disk drive, USB drive, or any computer program product configured to store data and machine executable program code. According to various embodiments, the memory 620 or mass storage 630 may have recorded thereon code, algorithms or instructions executable by the processing unit 610 for performing any of the aforementioned wavelength filtering operations explicitly or implicitly described herein.

[0103] The one or more camera(s) 640 may be stereo vision cameras 640 configured to capture respective fields of view corresponding to the right eye and the left eye of a wearer. The processing unit 610 may be configured to receive the input from each respective camera 640 and apply a digital wavelength filtering technique (e.g., a filtering algorithm) to each respective field of view to create a binocular rivalry. For example, the processing unit 610 may filter a first range of wavelengths in the right fieldof view and filter a second range of wavelengths in the left field of view, where the first range of wavelength is different to the second range of wavelengths.

[0104] The AR display 660 may be head-wearable display including a separate left eye display and a right eye display. The AR display 600 may be semi-transparent allowing the wearer to view images on the display and look through the display to view the surrounding environment. The processing unit 610 may be configured to output differently filtered images to the right eye display and the left eye display, respectively to create a binocular rivalry effect. For example, the processing unit 610 may output a first image (or series of images) that omits or reduces transmission of a first range of wavelengths in the left display and output a second image (or series of images) that omits or reduces transmission of a second range of wavelengths in the right display.

[0105] In some embodiments, the processing unit 610 may be configured to project extra color onto, or darken, certain colored objects in each of the left eye and right eye displays to enhance the binocular rivalry effect and improve contrast. For example, the processing unit 610 may be configured to project extra green light onto green objects in the left eye display and project extra red light onto red objects in the right eye display. In some embodiments, the processing unit 610 may be configured to simultaneously project extra color on certain objects and darken other objects in each of the left eye display and the eye display, respectively.

[0106] In another embodiment (not shown), a laser stimulation system is contemplated. Lasers of particular wavelengths may be configured to stimulate individual cones or groups / clusters of cones on the retina to provide a perception of the “greenest” green and “reddest” red to stimulate those respective receptors. Continued stimulation of these receptors may, over time, cause a spectral shift in sensitivity of those receptors and create a binocular rivalry effect to improve color perception as described herein.

[0107] The stereoscopic chromatic wavelength contrasting systems described herein may require a period of acclimatization. Methods for use of a stereoscopic chromatic wavelength contrasting system are described below.

[0108] Referring to FIG. 11 A, shown therein is a flow chart of a method 20 for stereoscopic chromatic wavelength contrasting, according to an embodiment. Themethod 20 may be used to improve perception of color in an individual with colorblindness. The method 20 may be used to assess / evaluate perception of color in an individual with color-blindness. The method 20 may be used in conjunction with the systems described herein. The method 20 is described in relation to red-green colorblindness, but may be adapted for use with other kinds of color-blindness as would be appreciated by those skilled in the art.

[0109] The method 20 includes 3 phases 21 , 22, 23. The objectives of the first phase 21 are to build comfort and passive base functionality. The objective of the second phase 22 is to reinforce what the individual is experiencing with the appropriate wavelength ranges. The objective of the third phase 23 is to develop an association and understanding for digital “color illusion” and how that equates to what the individual will actually experience.

[0110] Referring to FIG. 11 B, shown therein is a flow chart of the first phase 11 . In the first phase 11 , using passive glasses, the individual will be presented with various (physical I true wavelength color) tokens to sort under controlled conditions (e.g., in a training setting with the same ambient lighting conditions, using the same pool of color tokens).

[0111] At 210, wavelengths to be filtered are determined based on the individual’s color-blindness. For example, for red-green color-blindness wavelengths corresponding to red light are filtered from a first eye and wavelengths corresponding to green light are filtered from a second eye.

[0112] At 211 , passive filtering glasses to block the first and second range of wavelengths are obtained. To create a binocular rivalry, the glasses include a first filter for filtering a first range of wavelengths from a first eye (e.g., the right eye) of the individual and a second filter for filtering a second range of wavelengths from a second eye (e.g., the left eye) of the individual. The first and second filters may be selected from a plurality of pre-set filters for blocking particular ranges of wavelengths. The first and second filters may be installed into glasses frames to obtain the passive filtering glasses. Alternatively, the passive filtering glasses may be selected from a plurality of pre-determined passive filtering glasses for blocking particular ranges of wavelengths.

[0113] At 212, physical “true wavelength color” tokens are selected. True wavelength color refers to the fact that the color of a given token corresponds to a narrow range of the visible spectrum as perceived by an individual with normal vision. For example, a “red” token may correspond to wavelengths between 655-660 nm. The color of the tokens are selected according to the metamer(s) experienced by the individual and wavelengths of be filtered in each eye. The tokens are selected to be as close as possible in color to the extreme opposite ends of the filtered wavelength spectrum under consideration (e.g., for red-green color-blindness, tokens colors of near green and near red wavelengths). The relative proportion of “red” and “green” tokens should not be consistent or equal, so as to minimize predictions over observations.

[0114] In various embodiments, one or more of steps 210, 211 , 212 may be performed concurrently or may be combined or may not be performed.

[0115] At 213, the glasses are provided to the individual. The individual is not informed what eye is being filtered with respect to what range of wavelengths / color (wavelengths near red or green).

[0116] At 214, the individual is instructed to sort the tokens, how they wish, e.g., based on in which eye the token appears darker or lighter. The individual is not to know when sorting the tokens, if they are sorting the tokens into "red” or “green" piles - only that the goal is to sort the tokens into 2 piles based on appearance such that all tokens in a pile match from the perspective of the individual. This may provide for the individual to naturally associate token colors with visual distinctions. The sorting is timed, with the objective being to sort as many tokens as possible within a time limit. This should help develop a rote sense of which eye is experiencing the darkened colors, and to track accuracy and confidence.

[0117] At 215, as the individual gains proficiency at sorting the tokens, a wider range of token colors within the range of filtered wavelengths may be added to the pool of tokens, up until the transition bands of the first and second filters ranges are reached. Over time, tokens with colors from outside the filtered wavelength ranges can be added with instructions to set those tokens aside in a third pile - however, this should not bedone until later rounds of training when the individual becomes proficient in sorting the tokens into 2 piles.

[0118] Referring to FIG. 11 C, shown therein is a flow chart of the second phase 22. In the second phase 22, the filters for the right and left eye remain constant and the individual will now be notified and reinforced with that information. The sorting from phase 1 is repeated with the new knowledge and feedback, with the ranges of possible token colors increasing overtime as in phase 1 . Once the same skill level as measured in phase 1 is reached, the training may proceed further.

[0119] At 221 , glasses with filters to block the first and second range of wavelengths are provided to the individual. The filters and glasses may be the same as those used in step 213. The individual is informed of which eye is filtered with respect to what range of wavelengths / color.

[0120] At 222, the individual is instructed to sort the tokens, as they wish, e.g., based on in which eye the token appears darker or lighter. The sorting is timed, with the objective being to sort as many tokens as possible within a time limit. This should reinforce the rote sense of which eye is experiencing the darkened / lightened colors, and to track accuracy and confidence.

[0121] At 223, as the individual gains proficiency at sorting the tokens, a wider range of token colors within the range of filtered wavelengths may be added to the pool of tokens, up until the transition bands of the first and second filters are reached. Over time, tokens with colors from outside these ranges can be added with instructions to set those tokens aside in a third pile.

[0122] At 224, the individual is instructed to arrange the tokens in a line from lightest to darkest based on a reference gradient covering the range of wavelengths. Prediction over observation is not a problem in this test. The task is timed, with the objective being to arrange as many tokens as possible in a line within a time limit.

[0123] At 225, the speed / time of total task completion is evaluated. After the individual is shown to be proficient in the test, testing then moves on to free-form association of colors.

[0124] At 226, with the same tokens, the individual is asked to arrange them in a line again, but is no longer provided a reference gradient. The task is timed, with the objective being to arrange as many tokens as possible in a line within a time limit.

[0125] At 227, the result is compared to the reference gradient for accuracy and shown to the individual to help reinforce understanding. If necessary, training may return to earlier steps (e.g., step 222 or 224) or earlier phases (e.g., the first phase 21 ) until proficiency is shown.

[0126] Referring to FIG. 11 D, shown therein is a flow chart of the third phase 23. In the third phase 23, the known tokens (true wavelength colors) are presented with their digital “counterparts.” The training and testing in this phase involves placing these with each other as a direct matching game; this training is similar to phase 2 but first with only digital, and then a mix of some digital tokens and some physical tokens to be arranged. It is vital that “digital colors” are not experienced until properly integrated as part of the third phase 23. Eventually the wearer will be proficient at recognizing these two sensations of “color” as equivalent.

[0127] It should be noted that: the RGB (red-green-blue) illusion colors (i.e., as produced by combining colored pixels on a display screen) rely on the external limit stimulation being confused as being the same as the overlap of two complete separate cones; however, a color like magenta isn't based on an inherent confusion and overlap of two cones as it's two cones’ outer ranges stimulated at the same time. This is the "illusion" used instead for the original overlap color “illusion”.

[0128] At 231 , glasses with filters to block the first and second range of wavelengths are provided to the individual. The filters and glasses may be the same as those used in steps 213 and 221. The individual is informed of which eye is filtered with respect to what color.

[0129] At 232, the individual is instructed to match digital tokens with other digital tokens e.g., according to how dark / light the digital tokens appear. The digital tokens are displayed to the individual on a display e.g., a monitor. The task is timed, with the objective being to match as many tokens as possible within a time limit.

[0130] At 233, the speed / time of total task completion is evaluated. After the individual is shown to be proficient in the matching digital tokens, testing then moves on.

[0131] At 234, the individual is instructed to match a mix of physical and digital tokens i.e. , to match a digital token to a physical token or vice-versa. The task is timed, with the objective being to match as many tokens as possible within a time limit.

[0132] At 235, the speed / time of total task completion is evaluated. If necessary, training may return to earlier steps (e.g., step 232) or earlier phases (e.g., second phase 22) until proficiency is shown.

[0133] After the third phase 23, regular training with corrections and color association continues, and the individual’s perception will improve as the foundation established is reinforced.

[0134] The systems and methods described herein may be particularly effective when used with color-blind children. Color-blind adults may already have developed cognitive compensating mechanisms to account for the inability to perceive certain colors and thus may be more resistive to the systems and methods herein. Children may have less developed (or non-existent) compensating mechanisms to account for colorblindness. Thus, the systems and methods herein may be more effective at causing spectral shifts of cones receptors (and the related cognitive associations to particular colors) in children as compared to adults.

[0135] While the above description provides examples of one or more apparatus, methods, or systems, it will be appreciated that other apparatus, methods, or systems may be within the scope of the claims as interpreted by one of skill in the art. The invention should therefore not be limited by the above-described embodiments, methods, and examples, but by all embodiments and methods within the scope and spirit of the invention. Thus, the present disclosure is not intended to be limited to the implementations shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

Claims:1 . A system for stereoscopic chromatic wavelength contrasting comprising: a first filter for blocking a first range of wavelengths from a first eye; and a second filter for blocking a second range of wavelengths from a second eye wherein the second range of wavelengths is different to the first range of wavelengths.

2. The system of claim 1 , wherein the first filter and the second filter are selected from the group of: absorption filters, interference filters; Lyot filters; refractive filters; diffractive filters; and acousto-optic filters.

3. The system of claim 1 , wherein the first filter and the second filter are selected from the group of: notch filters, high-pass filters, low-pass filters, short-pass filters.

4. The system of claim 1 , wherein the first filter and the second filter block at least 80% of light in the first range of wavelengths and the second range of wavelengths, respectively.

5. The system of claim 1 , wherein the first filter and the second filter are selected to block the first range of wavelengths and the second range of wavelengths, respectively, according to a non-functional cone type in the first eye and the second eye.

6. The system of claim 5, wherein the first range of wavelengths and the second range of wavelengths are selected according to an expected absorption spectrum of non-functional cone type.

7. The system of claim 1 , wherein the first range of wavelengths is 500-565 nm and the second range of wavelengths is 590 n to at least 750 nm.

8. The system of claim 1 , wherein the first filter and the second filter are implemented as one of: a pair of glasses; contact lenses; and ocular implants.

9. The system of claim 8, wherein the pair of glasses, the contact lenses and the ocular implants are corrective for visual distortion.

10. An augmented reality system for stereoscopic chromatic wavelength contrasting comprising: at least one camera for capturing a field of view; a left eye display and a right eye display; and a processing unit configured to: receive the field of view from the camera as a left eye field of view and a right eye field of view; implement a digital wavelength filtering technique to filter a first range of wavelengths from the left eye field of view to output a first filtered image to the left eye display; implement the digital wavelength filtering technique to filter a second range of wavelengths from the right eye field of view to output a second filtered image to the right eye display, wherein the second range of wavelengths is different to the first range of wavelengths.

11. An augmented reality system for stereoscopic chromatic wavelength contrasting comprising: at least one camera for capturing a field of view;a left eye display and a right eye display; and a processing unit configured to: receive the field of view from the camera as a left eye field of view and a right eye field of view; detect a first range of wavelengths in the left eye field of view and output a first filtered image to the left eye display wherein transmission of the first range of wavelengths to the left eye display is at least reduced; detect a second range of wavelengths in the right eye field of view and output a second filtered image to the right eye display wherein transmission of the second range of wavelengths to the right eye display is at least reduced, wherein the second range of wavelengths is different to the first range of wavelengths.

12. A method for stereoscopic chromatic wavelength contrasting:(A) providing passive filtering glasses to an individual without informing the individual of a range of filtered wavelengths filtered by the glasses;(B) instructing the individual to sort physical tokens based on to which eye a physical token appears darker, each physical token being a true wavelength color within the range of filtered wavelengths;(C) timing sorting in step (B) with the objective of sorting as many of the physical tokens as possible within a time limit; and(D)widening a range of colors of the physical tokens; and(E) repeating steps (B)-(D) one or more times.

13. The method of claim X, wherein widening the range of colors of the physical tokens comprises increasing the range of colors within the range of filtered wavelengths.

14. The method of claim X, wherein widening the range of colors of the physical tokens comprises increasing the range of colors beyond the range of filtered wavelengths.

15. The method of claim X, further comprising determining the range of filtered wavelengths based on the individual’s color-blindness.

16. The method of claim X, further comprising obtaining the passive filter glasses, the passive filtering glasses comprising a first lens for blocking a first range of wavelengths from a first eye and a second lens for blocking a second range of wavelengths from a second eye.

17. The method of claim X, further comprising selecting the physical tokens, wherein a color of each token is selected to be as close as possible to opposite ends of the range of filtered wavelengths.

18. The method of claim X, further comprising:(F) informing the individual of the range of filtered wavelengths filtered by the glasses; and(G)repeating steps (B)-(D) one or more times.

19. The method of claim Y, further comprising:(H) instructing the individual to arrange the physical tokens in a line from lightest to darkest based on a reference gradient covering the range of filtered wavelengths;(I) timing step (H) with the objective of arranging as many of the physical tokens as possible within a time limit; and(J) repeating steps (H)-(l) one or more times;20. The method of claim Y, further comprising:(K) instructing the individual to arrange the physical tokens in a line from lightest to darkest based without aid of the reference gradient;(L) timing step (K) with the objective of arranging as many of the physical tokens as possible within a time limit;(M) comparing a result of arrangement to the reference gradient; and(N) repeating steps (K)-(M) one or more times.21 . The method of claim Z, further comprising:(O)informing the individual of the range of filtered wavelengths filtered by the glasses;(P) instructing the individual to match a first digital token with a second digital token based on how dark the digital tokens appear, each digital token being a true wavelength color within the range of filtered wavelengths;(Q) timing step (P) with the objective of matching as many of the digital tokens as possible within a time limit; and(R) Repeating steps (P)-(Q) one or more times.

22. The method of claim ZZ, further comprising:(S) instructing the individual to match a digital token with a physical token based on how dark the tokens appear;(T) timing step (S) with the objective of matching as many of the digital tokens to the physical tokens as possible within a time limit; and(U) Repeating steps (S)-(T) one or more times.

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