Color Vision Deficiency Research Articles

Effective Visualization of Radar Data for Users Impacted by Color Vision Deficiency

Abstract Color vision deficiency (CVD) is a decreased ability to discern between particular colors. Eight percent of genetic males and half a percent of genetic females have some form of CVD, with many in the radar community falling into this group. When presenting data on a two-dimensional plane, it is common to use colors to represent values via a colormap. Colormap choice in the radar community is influenced by the ability to highlight scientifically interesting features in data, institutional choices, and domain dominance of legacy colormaps. The problem with these current colormaps is that many do not project well for those with CVD (i.e., green next to red). In working with the CVD community to address this problem, multiple colormaps for moments such as equivalent reflectivity factor and Doppler velocity were created for users with forms of CVD such as deuteranomaly, protanomaly, protanopia, and deuteranopia using Python tools such as colorspacious and viscm. We show how these colormaps can improve interpretability for four cases: a mesoscale convective system, a pyrocumulonimbus storm, a wintertime midlatitude cyclone, and widespread storms with a large bird migration. These new radar equivalent reflectivity factor, Doppler velocity, and polarization colormaps are designed to highlight rain, frozen precipitation, nonmeteorological targets, and velocity-based items, are perceptually uniform, and are visually friendly for those with CVD.

Prevalence of congenital color vision deficiency (CCVD) among drivers in United Arab Emirates (UAE)

Purpose: This study was conducted to determine the prevalence of color vision deficiency (CVD) and create awareness about the burden of CVD among drivers. Methodology: This was a retrospective cross-sectional study of 3486 participants (men, n = 2789) who applied for/renewed their drivers’ licenses in Al Ain City, Abu Dhabi, United Arab Emirates (UAE). All drivers had their visual acuity (VA) and color vision measured using standard procedures and the data was analyzed using descriptive statistics. Results: The overall prevalence of CVD was 3.13% (95% CI: 2.59–3.75). No participants had visual impairment (best-corrected distance VA worse than 6/18) and no female driver had CVD. The prevalence of CVD among the male drivers was 3.91% (95% CI: 3.25–4.69), and more among the younger drivers (18–29 years). Conclusion: Although the prevalence of CVD was low, to ensure inclusivity and the safety of all road users in the UAE, it is recommended that traffic lights and road signs that mainly use connotative color coding be adapted to include denotative clues which can be interpreted by drivers with CVD. A prospective study in all approved eye testing centers for drivers should be conducted to obtain representative CVD data of drivers in the UAE.

The influence of color vision deficiency on vessel visibility during colorectal endoscopic submucosal dissection and the potential advantage of red dichromatic imaging to achieve color vision barrier-free.

Although color information is important in gastrointestinal endoscopy, there are limited studies on how endoscopic images are viewed by people with color vision deficiency. We aimed to investigate the differences in the visibility of blood vessels during endoscopic submucosal dissection (ESD) among people with different color vision characteristics and to examine the effect of red dichromatic imaging (RDI) on blood vessel visibility. Seventy-seven pairs of endoscopic images of white light imaging (WLI) and RDI of the same site were obtained during colorectal ESD. The original images were set as type C (WLI-C and RDI-C), a common color vision. These images were computationally converted to simulate images perceived by people with color vision deficiency protanope (Type P) or deutanope (Type D) and denoted as WLI-P and RDI-P or WLI-D and RDI-D. Blood vessels and background submucosa that needed to be identified during ESD were selected in each image, and the color differences between these two objects were measured using the color difference (ΔE 00) to assess the visibility of blood vessels. ΔE 00 between a blood vessel and the submucosa was greater under RDI (RDI-C/P/D: 24.05 ± 0.64/22.85 ± 0.66/22.61 ± 0.64) than under WLI (WLI-C/P/D: 22.26 ± 0.60/5.19 ± 0.30/8.62 ± 0.42), regardless of color vision characteristics. This improvement was more pronounced in Type P and Type D and approached Type C in RDI. Color vision characteristics affect the visibility of blood vessels during ESD, and RDI improves blood vessel visibility regardless of color vision characteristics.

Test time affects Farnsworth D15 outcomes in practiced, but not unpracticed, subjects with color vision deficiency.

Imposing a time limit on the Farnsworth D15 test may prevent patients from compromising the test. This study aimed to investigate the effect of test time on the Farnsworth D15 color vision test in unpracticed and practiced subjects and determine an optimal test time. Twenty-one subjects (mean/standard deviation age, 33.1/9.3 years) with a range of congenital color vision deficiency participated in the study. Pseudoisochromatic plate screening, Farnsworth D15, and anomaloscope testing were performed for classification purposes. At each of 2 visits, 10 trials of the Farnsworth D15 were performed with a range in test times from 30 seconds to 10 minutes. Between visits, subjects practiced the test. Major crossovers were used as the outcome measure. A repeated-measures analysis of variance compared the scores across trials. Post hoc Dunnett's testing analyzed the pairwise data. Although no significant difference in the mean number of major crossovers was found across the 10 trials for the first visit ( F (9, 180) = 1.30, p=0.24), a significant difference was found for the second visit ( F (9, 180) = 4.77, p<0.001). The range of mean number of major crossovers for the second visit was 1.71 to 5.1, with the 30-second trial resulting in the largest number of major crossovers and the longest trial resulting in the smallest number of major crossovers. Analysis showed that a 2-minute time limit resulted in a Farnsworth D15 outcome that would be expected based on the anomaloscope for a majority of subjects. In this study, test time was found to affect performance in practiced subjects but not in unpracticed subjects. Based on this study, we recommend enforcing a time limit of 2 minutes to discourage those who try to pass the Farnsworth D15 through practice. Additional measures, such as recording patient behavior, can also be taken.

Accessibility of United States ophthalmology hospital webpages to people with visual disabilities

PurposeEnhancing the accessibility of ophthalmology webpages can help individuals with vision access needs obtain essential appointment information, educational resources, and available ophthalmic services. This study evaluated the accessibility of these webpages for patients with visual impairment and color vision deficiencies. DesignRetrospective cross-sectional study. MethodsIn February 2024, the Web Content Accessibility Guidelines 2.0 (WCAG 2.0) were used to assess the accessibility of the web homepages of the top-ranked ophthalmology institutes in the United States using three evaluation tools: AChecker, ARC Toolkit, and WAVE. The webpages of the 38 top-ranked hospitals for ophthalmology in the 2023 US News & World Report were evaluated. ResultsAll assessed ophthalmology hospital and institute webpages had accessibility issues. The issues identified by each tool significantly impeded webpage navigation, with the mean number of issues as follows: AChecker (13.08, SD = 14.51), ARC Toolkit (16.21, SD = 17.68), and WAVE (6.47, SD = 7.14). The mean number of color contrast issues per website was 10.18 (SD = 15.84), present in 87 % (33/38) of the websites assessed. Most issues made information and interface components difficult to perceive (297/497, 59.76 %), and websites difficult to navigate or operate (145/497, 29.18 %). Common issues affecting people who are blind or have low vision and rely on screen readers included the absence of alternative text for images, hyperlinks without destination information, and missing instructions for user data input (e.g., search bars). ConclusionsOphthalmology webpages should be revised to comply with WCAG guidelines to improve accessibility for people with vision access needs. Addressing these issues can reduce information inequities for patients with visual disabilities and enhance their understanding of clinical processes, treatment, care plans, and available services such as transportation and online support groups.

A Comprehensive Cross-sectional Analysis of Prevalence of Congenital Color Vision Deficiency among Patients

A Comprehensive Cross-sectional Analysis of Prevalence of Congenital Color Vision Deficiency among Patients

Impact of Prolonged Screening and COVID-19 Infection on Acquired Colour Vision Deficiencies Assessed by the Farnsworth–Munsell 100 Hue Test

Over the past decade, global screening time has increased, a trend intensified by the COVID-19 pandemic, leading to the integration of screens into daily life. Studies have documented the adverse effects of prolonged screening on ocular health and binocular vision, such as dry eye syndrome, blurry vision, headaches, myopia, and visual fatigue. However, it remains unclear if prolonged screening affects the development of colour vision defects. Objectives: This study aimed to determine the relationship between (a) prolonged screening and acquired colour vision deficiencies and (b) COVID-19 infection and acquired colour vision deficiencies. Methods: A population of 50 individuals with normal trichromatic vision, aged 20 to 30 years, with an average daily screening time of 516.7 min, was evaluated. Participants were initially screened using the Ishihara 32-plate Test to exclude those with congenital colour vision deficiencies. The Farnsworth–Munsell 100 Hue Test (FM100H) and Square Root Total Error Score (√TES) were used to evaluate acquired colour vision deficiencies under standardized conditions. The dataset underwent dual analysis: (1) detailed statistical scrutiny and (2) comparison of √TES values with historical data from 1982, 1991, 2001, and 2002. Results: The global group had a √TES (Mean ± SD) of 5.40 ± 1.58, the COVID-19 subgroup 5.46 ± 1.62, and the non-COVID-19 subgroup 5.32 ± 1.51. No significant differences were found between the √TES values from this population and those reported in previous studies. Statistical analysis showed no significant correlation between gender and COVID-19 infection with √TES values. Conclusions: Neither screening time nor COVID-19 infection appears to significantly impact the occurrence of permanently acquired colour vision deficiencies in individuals aged 20 to 30 years.

Evaluation of contrast sensitivity in patients with congenital red-green color vision deficiency.

To evaluate mesopic and photopic contrast sensitivity in patients with congenital red-green color vision deficiency regarding with and without glare conditions and to compare these findings with age- and gender-matched healthy controls with normal color vision. Patients with congenital red-green color vision deficiency and age- and gender-matched healthy controls were included in this cross-sectional comparative study. Contrast sensitivity measurements were taken from all subjects in 4 different conditions; binocular mesopic-without glare, mesopic-with glare, photopic-without glare, photopic-with glare, and the results were compared. Twenty one patients with color vision deficiency (13 deuteranopic, 8 protanopic) and 22 age- and gender-matched healthy controls were included in the study. The mean age was 35.2 ± 13.5years in the protan group, 30.6 ± 7.7years in the deutan group, 32.0 ± 8.8years in the control group, and there was no significant difference in age between the groups (P > 0.05). The mean mesopic and photopic contrast sensitivity values of the groups at all spatial frequencies (1.5, 3, 6, 12, 18cpd) were not statistically significant when evaluated by the multifactor repeated measures test of ANOVA to evaluate the effect of light conditions (with and without glare) (P > .05). Mesopic and photopic contrast sensitivity values of patients with congenital red-green color vision deficiency were similar to healthy controls regarding with and without glare conditions.

Visual evoked potentials in patients with congenital color vision deficiency.

Congenital color vision deficiency (CCVD) is an eye disease characterized by abnormalities in the cone cells in the photoreceptor layer. Visual evoked potentials (VEPs) are electrophysiological tests that physiologically examine the optic nerve, other visual pathways, and the visual cortex. The aim of this research was to determine whether there are VEP abnormalities in CCVD patients. Patients with CCVD and healthy individuals were included in this prospective case-control study. Participants with eye disease or neurodegenerative disease were excluded from the study. Pattern reversal VEP (PVEP), flash VEP (FVEP), and optical coherence tomography were performed on all participants. Twenty healthy individuals (15 male) and 21 patients with CCVD (18 male) were included in the study. The mean ages of healthy individuals and patients with CCVD were 29.8 ± 9.6 and 31.1 ± 10.9years (p = 0.804). Retinal nerve fiber layer thickness and central macular thickness values did not differ between the two groups. In PVEP, Right P100, Left N75, P100, N135 values were delayed in CCVD patients compared to healthy individuals (p = 0.001, p = 0.032, p = 0.003, p = 0.032). At least one PVEP and FVEP abnormality was present in nine (42.9%) and six (28.6%) of the patients, respectively. PVEP or FVEP abnormalities were found in 13 (61.9%) of the patients. This study indicated that there may be PVEP and FVEP abnormalities in patients with CCVD.

Assessing the Impact of Simulated Color Vision Deficiency on Ophthalmologists' Ability to Differentiate between Choroidal Melanoma and Choroidal Nevus.

Background: Color vision deficiency (CVD) is an often-overlooked issue within the medical community, and its consequences remain insufficiently explored. We aim to evaluate how CVD affects diagnostic accuracy and distinguish between malignant choroidal melanoma and benign choroidal nevus among ophthalmologists. Methods: In this cross-sectional study, we engaged ophthalmologists through a web-based survey distributed via the professional ophthalmology society's social media channels. The survey encompassed a series of three fundus images representing normal fundus, choroidal nevus, and choroidal melanoma. Each image underwent simulation for the three primary types of CVD-protanopia, deuteranopia, and tritanopia-alongside a non-simulated version. Results: The study included 41 participants, averaging 40 years of age (±9.2), comprising 28 (68%) men and 13 (32%) women. Significantly lower rates of identifying orange pigments were observed in simulated protanopia images compared to non-simulated ones (p = 0.038). In simulated deutranopia images, the recognition of melanotic lesions was notably reduced compared to non-simulated images (p = 0.048). No such limitation was observed for tritanopia. However, participants retained their ability to identify subretinal fluid and estimate tumor thickness in simulated and non-simulated images. Concerning simulated images of choroidal nevi, participants misdiagnosed nevi as choroidal melanoma in 37% of cases in simulated protanopia nevi images and 41% in simulated deutranopia nevi images. This resulted in unnecessary referrals of benign lesions as malignant, emphasizing the potential for mistaken diagnoses. Nevertheless, almost all simulated images of malignant melanoma were correctly referred for specialized oncological treatment. Conclusions: The simulated CVD conditions of protanopia and deuteranopia affected the accuracy of identifying the melanotic nature of the choroidal tumor and the presence of orange pigments. This limitation led to challenges in correctly diagnosing choroidal melanoma and choroidal nevus, resulting in extra referrals for nevus cases. However, participants were safe and could still determine the possible risk of eyes with choroidal melanoma, so most referred melanoma cases to specialized oncologists as needed.

Fast image recoloring for red–green anomalous trichromacy with contrast enhancement and naturalness preservation

Color vision deficiency (CVD) is an eye disease caused by genetics that reduces the ability to distinguish colors, affecting approximately 200 million people worldwide. In response, image recoloring approaches have been proposed in existing studies for CVD compensation, and a state-of-the-art recoloring algorithm has even been adapted to offer personalized CVD compensation; however, it is built on a color space that is lacking perceptual uniformity, and its low computation efficiency hinders its usage in daily life by individuals with CVD. In this paper, we propose a fast and personalized degree-adaptive image-recoloring algorithm for CVD compensation that considers naturalness preservation and contrast enhancement. Moreover, we transferred the simulated color gamut of the varying degrees of CVD in RGB color space to CIE L*a*b* color space, which offers perceptual uniformity. To verify the effectiveness of our method, we conducted quantitative and subject evaluation experiments, demonstrating that our method achieved the best scores for contrast enhancement and naturalness preservation.

Spectrally-Selective and High-Resolution Visualization Detection of UVR Based on Efficient Photo-Oxidation

Ultraviolet radiation (UVR) is like a double-edged sword, which has dual significance to human life and health. Current UV sensors struggle to accurately discriminate and quantify UVA, B, and C simultaneously. Additionally, common colorimetric sensors have low visualization resolution. Herein, we constructed a ratiometric fluorescent UVR sensing strategy with spectrally-selective, accuracy, significant color change, and adjustable sensitivity based on the photo-induced fluorescence quenching properties of carbon dots (CDs) and the photosensitization of protoporphyrin IX (PPIX). For daily UVR monitoring, a portable fluorescence reader is developed, which can simultaneously detect dose and intensity. Unlike conventional radiometers, it can sensitively and rapidly discriminate and quantify UVA, B, and C in complex light sources at a lower cost (< 100 $). To ensure the safety of UVR use, wearable fluorescent film sensors (< 0.5 $/piece) we developed for real-time visual monitoring of the cumulative dose of UVA/B during UV phototherapy. Considering individuals with color vision deficiency, we propose a strategy to transform “color analysis” into “count analysis” through creative design, making quantification easier. CDs-PPIX composite offers great potential for UVR detection in our daily lives due to its excellent performance.

Enhancing statistical chart accessibility for people with low vision: insights from a user test

AbstractA remote user test was performed with two versions (one accessible and one non-accessible) of three types of web-based charts (horizontal bar chart, vertical stacked bar chart, and line chart). The objectives of the test were: (a) to validate a set of heuristic indicators for the evaluation of the accessibility of statistical charts presented in a previous work (Fariñas Falcón et al. in Mediocentro Electrónica 21(1):65–68, 2017); (b) to identify new barriers and preferences for users with low vision in the access and use of this content not previously contemplated. 12 users were tested, with a variety of conditions associated with low vision: low visual acuity (6 users), reduced central vision (2 users), reduced peripheral vision (2 users), blurry vision (1 user), sensitivity to light (3 users), Nystagmus (2 users) and color vision deficiency (CVD) (4 users). From a quantitative standpoint, accessible versions of charts were more efficient, effective, and satisfactory. From a qualitative point of view, results verify the relevance of heuristics H2, Legend; H3, Axes; H6, Data source (as data table); H10, Safe colors; H11, Contrast; H12, Legibility; H13, Image quality; H14, Resize; H16, Focus visible; H17, Independent navigation; related to the proposed tasks. As new observations, tooltips were highly valued by all users, but their implementation must be improved to avoid covering up significant parts of the charts when displayed. The data table has also been frequently used by all users, especially in the non-accessible versions, allowing them to carry out tasks more efficiently. The position and size of the legend can be a significant barrier if it is too small or appears in an unusual position. Finally, despite the limitations related to color perception, some users prefer color graphics to black and white, so, to target all profiles, it is necessary to redundantly encode categories with colors and patterns as well.

COMPREHENSIVE COLOR VISION ENHANCEMENT FOR COLOR VISION DEFICIENCY: A TENSORFLOW AND KERAS BASED APPROACH

Individuals with color vision deficiency (CVD) often encounter challenges in navigating and interacting with their environment due to limitations in perceiving colors accurately. This deficiency can impede various daily tasks and activities, leading to dependency on others for assistance with color-related tasks and potentially limiting independence and inclusivity. Addressing these challenges, our research focuses on the development of a machine learning-based color transformation system. Leveraging TensorFlow and Keras frameworks, the system employs advanced machine learning techniques to identify and transform colors within images, ultimately enhancing visibility for individuals with CVD. The primary objective is to empower individuals with CVD by providing a real-world tool that improves color visibility in images and enables self-assessment of their condition. This solution aims to enhance navigation, reduce dependency on others for color-related tasks, and foster inclusivity through technological innovation. Additionally, our research emphasizes the accuracy and reliability of the machine learning models through rigorous testing and validation procedures, ensuring effectiveness across various scenarios and image types. An intuitive and user-friendly graphical user interface (GUI) is prioritized to cater to individuals with diverse technical abilities. Beyond its immediate impact, the research seeks to raise awareness and promote understanding of color vision deficiency within the broader community, ultimately contributing to a more equitable and accessible society for all.

Outcome of pediatric cataract surgery including color vision, stereopsis, and cognition in a tertiary eye care center in India.

Pediatric cataract is an important cause of avoidable childhood blindness in India. Although there are studies on clinical features and visual acuity outcomes of pediatric cataract surgery, there are no studies that look into aspects of color vision, stereopsis, and cognitive functions in children with cataracts. Studying these parameters pre- and postsurgery will help us assess the overall components of visual function that are critical for the child's development. With this in mind, we aimed to study the clinical features, outcome of treatment, color vision, stereopsis, and cognitive functions in children with cataracts. Design: Hospital-based prospective descriptive study. Data of 68 children (0 < 18 years) were collected, on the clinical features, visual acuity, color vision, stereopsis, and social and intelligence quotient before and after surgery. Data analysis was performed using Graph Pad Prism software version 9.4.0 (673). Ninety eyes of 68 children (36-bilateral/32-unilateral) were operated. A total of 46 children were available at 6 months' follow-up (28 bilateral cataracts (46 eyes) and 18 unilateral cataracts). Nineteen (67.8%) of the bilateral, had a best corrected visual acuity of 6/6-6/18 in the better eye and nine (50%) of the unilateral had a visual acuity of 6/18-6/6 in the operated eye. Preoperatively, 61.5% of the children had a stereopsis of 100-600 arc-secs. Post-operatively, 84.4% of the children had a stereopsis in the range <50-600 arc-secs. All children had color vision deficiency. Preoperatively, 62% of the children had strong and moderate deficiency, whereas postoperatively, 66.6% had mild deficiency. We found negative correlation (r = -0.503) between social quotient and percentage of visual impairment indicating that when visual impairment increases social quotient decreases. The mean IQ preoperatively was 94.36 ± 2.98 and postoperatively 101.38 ± 2.77, with 95% confidence interval P value was statistically significant (P = 0.0001). This shows better and faster performance postoperatively. Majority of the children had improved visual acuity after surgery. This outcome can be extrapolated to the overall improvement in stereopsis, color vision, and higher cognitive functions.

The Impact of Colour Vision Defect on Consumer’s Fruits Selection Process while Purchasing from Retail Fruit Shops in Bangladesh

Color Vision Defect affects about one in twelve males and two hundred women worldwide, according to research. CVD has a big impact in almost every marketing and branding circumstance, especially when product color is the key. This study began with a Red-Green CVD test of 522 Dhaka residents. Since few research have measured color blindness in Bangladesh, this study can be used as one of the Bangladesh color vision deficiency baseline results. The important factor of this study is whether this result is comparable to Bangladesh’s earlier result and whether Bangladesh has a lower/higher CVD prevalence than other nations. The most common CVD is Red-Green Colour Vision Defect. Green fruits turn yellow and red when maturing and CVD patients have trouble distinguishing neighboring colours like Red, Green, Brown, etc. After examining baskets of green and ripe yellow, red, and partly reddish fruits, this study evaluated the findings. This study found out that people with color vision defects had trouble choosing fruits from baskets. Furthermore, the study tested hypotheses to determine severity of Red-Green CVD and found out it to be less than expected probably due to coping mechanism, experience etc. in Red-Green CVD subjects.

Evaluation of the Efficacy of Enchroma Filters for Correcting Color Vision Impairment

Objective: This study examined the effectiveness of Enchroma Cx-14 filters on individuals with Red-Green color vision deficiency (CVD). Methods: ColorDx and the Farnsworth-Munsell (FM) 100-Hue test were used to assess subjective reactions to Enchroma. The ColorDx and FM, 100 Hue test error scores were computed and contrasted using Placebo (untinted glasses) and Enchroma CX-14, red, and green filters. Results: The findings demonstrated that while enchroma filters improved the mistake score in only two patients, they had no discernible impact on any CVD subject's performance. In one protan participant and all deutan individuals, colour discrimination was greatly enhanced by the red filter. Green filters and Enchroma did not raise mean error scores. Conclusion: Enchroma filters had limited effectiveness in improving color perception for individuals with Red-Green CVD.

Improving webtoon accessibility for color vision deficiency in South Korea using deep learning

Improving webtoon accessibility for color vision deficiency in South Korea using deep learning

The construction of genetics teaching resources related to colour blindness and their application in genetics teaching.

Red-green colour blindness is a classic example for the teaching of X-linked recessive inheritance in genetics course. However, there are lots of types of color vision deficiencies besides red-green colour blindness. Different color vision deficiencies caused by different genes may have different modes of inheritance. In recent years, many research achievements on colour blindness have been made. These achievements could be used as teaching resources in genetics course. Here, we summarize the construction of genetics teaching resources related to colour blindness and their application in genetics teaching in several chapters such as introduction, cellular and molecular basis of genetics, sex-linked inheritance, chromosomal aberration, gene mutation and advances in genetics. Teacher could use the resources in class or after class with different teaching methods such as questioning teaching method and task method. It may expand students' academic horizons and inspire students' interest in genetics besides grasping basic genetic knowledge.

Empirical tests of the effectiveness of EnChroma multi-notch filters for enhancing color vision in deuteranomaly

Manufacturers of notch filter-based aids for color vision claim that their products can enhance color perception for people with anomalous trichromacy, a form of color vision deficiency (CVD). Anecdotal reports imply that people with CVD can have radically enhanced color vision when using the filters. However, existing empirical research largely focussed on the effect of notch filters on performance on diagnostic tests for CVD has not found that they have any substantial effect. Informed by a model of anomalous trichromatic color vision, we selected stimuli predicted to reveal the effects of EnChroma filters. Using these stimuli, we tested the ability of EnChroma filters to enhance color vision for 10 deuteranomalous trichromats in three experiments: 1. asymmetric color matching between test and control filter conditions, 2. color discrimination measured using four alternative forced-choice, and 3. color appearance measured using dissimilarity ratings to reconstruct subjective color spaces using multidimensional scaling. To investigate potential effects of long-term adaptation or perceptual learning, participants completed all three experiments at two time points, on first exposure to the filters, and after a week of regular use. We found a significant effect of the filters on color matches in the direction predicted by the model at both time points, implying that the filters can enhance the anomalous trichromatic color gamut. However, we found minimal effect of the filters on color discrimination at threshold. We found a significant effect of the filters in enhancing the appearance of colors along the red-green axis at the first time point, and a trend in the same direction at the second time point. Our results provide the first quantitative experimental evidence that notch filters can enhance color perception for anomalous trichromats.