Congenital Colour Vision Deficiency Research Articles

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.

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.

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.

Development and validation of a new colour vision screener: A multi‐centre study

Aims/Purpose: The detection of acquired and congenital colour vision deficiency is of importance in the clinic for the early detection of ocular disease and determination of occupational suitability. Conventional methods of colour vision screening often fail to pass all normals and/or correctly identify those with acquired and congenital colour vision deficiency. The Colour Vision Screener (CVS) test [1] was developed to utilize an improved understanding of colour vision mechanisms to overcome the limitations present in conventional colour screening methods. This study aimed to use a robust multi‐centre methodology to fully validate the CVS test.Methods: Over 400 participants, including 124 normal trichromats, 166 deutans and 62 protans, were recruited from 10 international Colour Assessment and Diagnosis (CAD) testing centres. Each participant completed the CVS and the CAD test with calibrated visual displays. The red/green (RG) and yellow/blue (YB) CVS test sensitivity and specificity were established. The RG statistics were compared to the ‘gold standard’ reference for screening for RG congenital colour vision deficiency—the Ishihara pseudoisochromatic plate test.Results: The CVS test correctly identified ~99.1% of normal trichromats. All subjects with congenital RG loss and acquired loss on top of congenital RG deficiency were identified as having abnormal colour vision by the CVS. The Ishihara test, based upon 0 errors on the first 25 plates of the 38‐plate edition, correctly identifies ~80.6% of normal trichromats and 99.5% of subjects with congenital RG loss.Conclusions: Data collected across 10 international CAD centres demonstrate that the CVS can achieve a high sensitivity without sacrificing specificity. This multi‐centre study demonstrates that the CVS is quick, efficient, and easy to use and allows for the rapid and reliable screening of congenital and acquired colour vision deficiencies in large populations.Reference1. Barbur JL, Rodriguez‐Carmona M, Evans BEW. Colour vision assessment‐3. An efficient, two‐step, colour assessment protocol. Colour Research &amp; Application 2021; 46: 33–45. https://doi.org/10.1002/col.22599

Prevalence of Congenital Color Vision Deficiency in Southern Taiwan and Detection of Female Carriers by Visual Pigment Gene Analysis.

This study aimed to investigate the prevalence of color vision deficiencies (CVDs) and determine whether carriers could be detected by analyzing the visual pigment genes. Materials and Methods: The data of students who underwent routine CVD screening using the Ishihara color test in Kaohsiung, Southern Taiwan were analyzed. Furthermore, the DNA samples of 80 randomly selected females and four obligate carriers were analyzed. The most upstream genes, downstream genes, and the most downstream genes in the red/green pigment gene arrays were amplified separately using polymerase chain reaction (PCR), and exon 5 of each gene was analyzed. The prevalence of congenital red-green CVD in this study was 3.46% in males and 0.14% in females. The PCR analysis of the first gene, downstream gene, and last gene revealed normal patterns in 73 normal cases. Seven unusual patterns were detected in two proton carriers and five deutan carriers. Among the randomly selected females, 8.8% (7/80) were CVD carriers. The prevalence of CVD among male Taiwanese students in this study was 3.46%. Female carriers of congenital CVD can be identified by molecular analysis of the visual pigment genes. The proportion of CVD carriers among the randomly selected females was 8.8%, which was slightly higher than expected and further studies are warranted.

The impact of display saturation on visual search performance in congenital colour vision deficiency.

Colour-related search tasks are common in many professional fields. The study investigated whether increasing chromatic saturation can enhance the visual performance of individuals with colour vision deficiency (CVD) in colour-related search tasks. 10 normal trichromats (5M, 5F; Mean (SD) age: 23.1 (3.3) years) and 15 individuals with CVD [8 deutans and 7 protans identified by HRR plates] (14M, 1F; aged 28.6 (8.7) years) participated in this study. Four naturalistic sceneries of everyday tasks/ birds, animals and flowers of 15 different colour combinations (1 pair of colours in each combination. e.g., 'brown/black' or 'red/green') were presented in 'low' saturation, 'original' (unaltered images) and 'high' saturation condition using the Psychopy program on a colour-calibrated monitor. On each trial, the subject was asked to identify a specific-coloured target. Overall, the visual search performance index (expressed as product of accuracy and a reciprocal of reaction time (%correct*s-1) of the normal trichromats [Mean (SD):77.76% correct*s-1 (16.32)] was significantly higher than CVD [45.71% correct*s-1 (18.95)] in the "original" test images (p = 0.001), but in individuals with CVD, there was no significant difference between 'original' [45.71% correct*s-1 (18.95)] and 'high' saturation condition ([47.43% correct*s-1 (20.07)]; p > 0.05). However, colour-wise, increased saturation showed improvements (≥ 10%) in protans mainly for 'red' combinations with other colours such as white (i.e., 'red/white'), purple, orange, grey, green, brown and black. The study suggests that increasing the saturation of certain colour combinations can potentially aid in the visual search performance of individuals with CVD. This knowledge will help in better counselling and management of the patients.

CON_PCA method to solve the human monochromacy color blindness

Color blindness is an inherited genetic ocular disorder. Acquired or congenital color blindness can become a major cause of problems in everyday life tasks. Contributing to solving the trouble of color blindness is important. Because the problem of color blindness leads to the non-discrimination of data seen by the infected person. Data visualization can contribute to solving the hassle of color blindness. This paper proposed a new technique using data visualization ideas that may contribute to easy data recognition. Our focus has been on monochromacy color blindness. The results are based on the famous Ishihara data sets measuring color blindness. The efficiency of the results was mathematically proven using equations and images via a website to simulate color blindness.

Colour perception deficits after posterior stroke: Not so rare after all?

Cerebral achromatopsia is an acquired colour perception impairment caused by brain injury, and is generally considered to be rare. Both hemispheres are thought to contribute to colour perception, but most published cases have had bilateral or right hemisphere lesions. In contrast to congenital colour blindness that affects the discrimination between specific hues, cerebral achromatopsia is often described as affecting perception across all colours. Most studies of cerebral achromatopsia have been single cases or case series of patients with colour perception deficits. Here, we explore colour perception deficits in an unbiased sample of patients with stroke affecting the posterior cerebral artery (N=63) from the Back of the Brain project. Patients were selected based on lesion location only, and not on the presence of a given symptom. All patients were tested with the Farnsworth D-15 Dichotomous Colour Blindness Test and performance compared to matched controls (N=45) using single case statistics. In patients with abnormal performance, the patterns of colour difficulties were qualitatively analysed. 22% of the patients showed significant problems with colour discrimination (44% of patients with bilateral lesions, 28% with left hemisphere lesions and 5% with right hemisphere lesions). Lesion analyses identified two regions in ventral occipital temporal areas in the left hemisphere as particularly strongly related to impaired performance in colour perception, but also indicated that bilateral lesions are more strongly associated with impaired performance that unilateral lesions. While some patients only had mild deficits, colour perception impairments were in many cases severe. Many patients had selective deficits only affecting the perception of some hues. The results suggest that colour perception difficulties following PCA stroke are common, and that they vary in severity and expression. In addition, the results point towards bilateral processing of colour perception with a left hemispheric domination, contradicting previous reports.

Effects of eye dominance on shade matching and color perception among the dentist population.

The purpose of this study was to evaluate the influence of eye dominance on color perception, and shade matching. A total of 104 participants were selected for the study. There were 3 groups: Group I: 3rd and 4th year dental students and interns (n = 40); Group II: postgraduates (n = 34); Group III: senior residents and faculty members (≥ 6 years of clinical experience) (n = 30). All participants were evaluated for congenital color blindness with Ishihara plates, their dominant eye with Mile's test, and their color perception with the Farnsworth-Munsell 100 hue test. The shade guide test was used for shade matching with a second corresponding set of Vitapan classical shade guides. The results of Mile's test revealed that 60.6% were right-eye dominant and 39.4% were left-eye dominant. There was a statistically significant difference among all participants between the dominant eye and the non-dominant eye in shade matching. The dominant eye has a positive effect on shade matching and the ability to match shades becomes better with an increase in clinical experience.

Determination of congenital color blindness in phase ii students of başkent university medical faculty

Determination of congenital color blindness in phase ii students of başkent university medical faculty

The prevalence of colour blindness among the males of the Bhoksha tribe in Dehradun, India

Colour Blindness is an X-linked recessive disorder which predominantly appears in males. Colour blindness is the inability or decreased ability to perceive colour differences by the human eye under normal lighting conditions. The purpose of the present study was to find out the prevalence of congenital Red-Green colour blindness among the people of the Bhoksha tribe in Dehradun district, Uttarakhand. The study was conducted with a total number of 204 individuals aged from 5 years to 85 years (mean ± SD is 22.71 ± 13.15) among the randomly selected male population. Colour blindness was examined using a standard Ishihara Chart under proper light. Among the total sample of 204 males in the community, 3 males are found to be colour blind which means that 98.53% were found to be normal, and the frequency of colour blindness was 1.47%. These three cases represented protanopia, deuteranopia and achromatopsia. Colour blindness appeared among the Pundir, Chauhan and Kakkad clans of the Bhoksha tribe in three villages. In conclusion, 1.47% were found to be colourblind in this study among the Bhoksha tribe of Dehradun, which is very high as compared with the prevalence in other tribal populations in India, although they were unaware of it. The present study supports Post and Pickford’s (1962, 1963) hypothesis of relaxation of selection.

Aids for color vision deficiency: introduction to the feature issue.

Approximately 8% of Caucasian males and 0.5% of females have congenital red-green color vision deficiencies (CVD), and a number of eye diseases are accompanied by acquired CVD. This feature issue includes ten contributions regarding existing and proposed algorithms and devices intended to help CVD subjects compensate for their color deficiencies. It also addresses limitations in the effectiveness of CVD aids for subjects with different types and degrees of color vision deficiency.

A large population study reveals a novel association between congenital color vision deficiency and environmental factors

The molecular genetics underlying color-vision deficiencies (CVD) has been established and widely studied. The aim of this study is to assess the associations between the prevalence of CVD and both genetics (place of origin) and environment (place of birth).

Coloured filters can simulate colour deficiency in normal vision but cannot compensate for congenital colour vision deficiency

Red-green colour vision deficiency (CVD) affects ~ 4% of Caucasians. Notch filters exist to simulate CVD when worn by colour vision normal (CVN) observers (simulation tools), or to improve colour discrimination when worn by CVD observers (compensation tools). The current study assesses effects of simulation (Variantor) and compensation (EnChroma) filters on performance in a variety of tasks. Experiments were conducted on 20 CVN and 16 CVD participants under no-filter and filter conditions (5 CVN used Variantor; 15 CVN and 16 CVD used EnChroma). Participants were tested on Ishihara and Farnsworth-Munsell 100 hue tests, CVA-UMinho colour discrimination and colour naming tasks and a board-game colour-sorting task. Repeated-measures ANOVAs found Variantor filters to significantly worsen CVN performance, mimicking protanopia. Mixed-model and repeated-measures ANOVAs demonstrate that EnChroma filters do not significantly enhance performance in CVD observers. Key EnChroma results were replicated in 8 CVD children (Ishihara test) and a sub-sample of 6 CVD adults (CVA-UMinho colour discrimination and colour naming tasks) for a smaller stimulus size. Pattern similarity exists across hue for discrimination thresholds and naming errors. Variantor filters are effective at mimicking congenital colour vision defects in CVN observers for all tasks, however EnChroma filters do not significantly compensate for CVD in any.

Chromatic discrimination in fixed saturation levels from trichromats and subjects with congenital color vision deficiency

Color vision tests use estimative of threshold color discrimination or number of correct responses to evaluate performance in chromatic discrimination tasks. Both approaches have advantages and disadvantages. In the present investigation, we compared the number of errors during color discrimination task in normal trichromats and participants with color vision deficiency (CVD) using pseudoisochromatic stimuli at fixed saturation levels. We recruited 28 normal trichromats and eight participants with CVD. Cambridge Color Test was used to categorize their color vision phenotype, and those with a phenotype suggestive of color vision deficiency had their L- and M-opsin genes genotyped. Pseudoisochromatic stimuli were shown with target chromaticity in 20 vectors radiating from the background chromaticity and saturation of 0.06, 0.04, 0.03, 0.02, 0.01, and 0.005 u’v' units. Each stimulus condition appeared in four trials. The number of errors for each stimulus condition was considered an indicator of the participant's performance. At high chromatic saturation, there were fewer errors from both phenotypes. The errors of the normal trichromats had no systematic variation for high saturated stimuli, but below 0.02 u’v' units, there was a discrete prevalence of tritan errors. For participants with CVD, the errors happened mainly in red-green chromatic vectors. A three-way ANOVA showed that all factors (color vision phenotype, stimulus saturation, and chromatic vector) had statistically significant effects on the number of errors and that stimulus saturation was the most important main effect. ROC analysis indicated that the performance of the fixed saturation levels to identify CVD was better between 0.02 and 0.06 u’v’ units reaching 100%, while saturation of 0.01 and 0.005 u’v’ units decreased the accuracy of the screening of the test. We concluded that the color discrimination task using high saturated stimuli separated normal trichromats and participants with red-green color vision deficiencies with high performance, which can be considered a promising method for new color vision tests based in frequency of errors.

Congenital Colour Vision Deficiency among Patients Attending Outpatient Department of Ophthalmology in a Tertiary Care Centre: A Descriptive Cross-sectional Study.

Congenital colour vision deficiency may affect a person's day-to-day activity and may also affect the choice of occupation a person chooses. This study aims to find the prevalence of congenital colour vision defects in patients presenting in outpatient department of Ophthalmology in a tertiary care centre. A descriptive cross-sectional study was conducted in a tertiary care centre after receiving ethical clearance from the Institutional Review Board of Kathmandu Medical College and Teaching Hospital (Reference number: 1006202102). The study was conducted for a 3 months period from 2021 July to 2021 September. Research participants were selected by the convenience sampling technique. A detailed ophthalmological examination was performed and colour vision was tested using Ishihara pseudoisochromatic colour vision chart. Only congenital colour vision defects were included in the study. Statistical Package for the Social Sciences version 20.0 was used for data analysis. Point estimate at 95% confidence interval was calculated along with frequency and proportion for binary data. The overall prevalence of congenital colour vision deficiency was 14 (5.24%) (2.54-7.86 at 95% Confidence Interval). The prevalence of congenital colour vision defects in females was 1 (0.74%) and in males was 13 (9.77%). The mean age of the participants with congenital colour vision deficits was 27.42±7.90 years. The prevalence of congenital colour vision deficiency was similar to the prevalence in other studies done in a similar setting. Awareness should be raised about this condition and people need to be screened at an early age to prevent disappointments in career choices later in life. colour vision defect; Nepal; prevalence.

Prevalence of Congenital Colour Vision Deficiency in Belagavi, Karnataka, India: A Hospital-based Cross-sectional Study

Introduction: Colour vision deficiency is a common ocular disorder, but it often goes unnoticed due to lack of awareness and screening programmes. If detected early in life, it can help people choose suitable career paths and genetic counselling can help reduce the birth of colour-blind children and future disappointments in life. Aim: To determine the prevalence of congenital Colour Vision Deficiency (CVD) among the general population in Belagavi at a tertiary level hospital and to spread awareness regarding CVD. Materials and Methods: This was a hospital-based crosssectional study, conducted at Jawaharlal Nehru Medical College, Belagavi, Karnataka, India (tertiary care hospital), from February 2022 to July 2022. The study population constituted 3131 people who visited the Ophthalmology Outpatient Department for routine eye examinations. A detailed ophthalmological examination was done, and colour vision was tested using Ishihara’s (38 plate) pseudoisochromatic test. Data was analysed using statistical software version 4.2.1 and Microsoft excel. Results: The mean age of the study population was 40.74±15.86 years. The overall prevalence of congenital CVD was 150 (4.79%). The prevalence of congenital colour vision defects was 13 (0.9%) in females, and 137 (8.12%) in males (p-value &lt;0.001). Deuteranomaly was the most common type of congenital CVD, found among 88 (58.67%), followed by protanopia among 28 (18.67%), followed by protanomaly and deuteranopia, each accounting for 17 (11.33%). Conclusion: The prevalence of CVD among people belonging to the Belagavi district was remarkable. The p