Traffic Accident and Color Vision

Daily experience shows that colour of a very distant object cannot be accurately determined. It is assumed that visual acuity (VA) loss is one of the factors at play in this case. The effects of reduced VA as a result of refractive error or optical defocus on colour vision have not been examined. Such study willdictate the need or otherwise for optical correction before assessment of colour vision. The purpose of this study therefore, was to investigate the effects of optical defocus on colour vision in individuals with normal colour vision. Twenty nine young adult subjects (11 male and 18 females) were included in this study. Their ages ranged from 11 to 29 years with a mean of 22.1 ± 3.4 years. All subjects had VA of 6/6 or better and normal colour vision. The colour vision was evaluated with the Farnsworth panel D-15 (desaturated). Each subject was optically defocused to VA of 6/24, 6/60 and 1/60(6/360) at 6 meters respectively and colour vision was assessed at each reduced VA. At VA of 6/24, colour vision was not affected in all subjects. When the VA was reduced to 6/60, however, 15 (51%) of the subjects failed the colour vision test. When the VA was further reduced to 1/60 by optical defocus, 24 (83%) of the subjects failed the colour vision test. It was concluded that optical defocus and reduced VA can adversely affect colour vision test findings. While VA reduction to 6/24 may not affect the colour vision results, VA of 6/60 can. It is therefore, recommended that in clinical colour vision testing and colour vision screening, VA should first be assessed andcompensated, especially if uncorrected VA is 6/24 or worse.

PurposeNormal color vision depends on normal long wavelength (L), middle wavelength (M), and short wavelength sensitive (S) cones. Hereditary “red-green” color vision deficiency (CVD) is due to a shift in peak sensitivity or lack of L or M cones. Hereditary S cone CVD is rare but can be acquired as an early sign of disease. Current tests detect CVD but few diagnose type or severity, critical for linking performance to real-world demands. The anomaloscope and newer subjective tests quantify CVD but are not applicable to infants or cognitively impaired patients. Our purpose was to develop an objective test of CVD with sensitivity and specificity comparable to current tests.MethodsA calibrated visual-evoked potential (VEP) display and Food and Drug Administration-approved system was used to record L, M, and S cone-specific pattern-onset VEPs from 18 color vision normals (CVNs) and 13 hereditary CVDs. VEP amplitudes and latencies were compared between groups to establish VEP sensitivity and specificity.ResultsCone VEPs show 100% sensitivity for diagnosis of CVD and 94% specificity for confirming CVN. L cone (protan) CVDs showed a significant increase in L cone latency (53.1 msec, P < 0.003) and decreased amplitude (10.8 uV, P < 0.0000005) but normal M and S cone VEPs (P > 0.31). M cone (deutan) CVDs showed a significant increase in M cone latency (31.0 msec, P < 0.000004) and decreased amplitude (8.4 uV, P < 0.006) but normal L and S cone VEPs (P > 0.29).ConclusionsCone-specific VEPs offer a rapid, objective test to diagnose hereditary CVD and show potential for detecting acquired CVD in various diseases.Translational RelevanceThis paper describes the efficacy of cone-specific color VEPs for quantification of normal and abnormal color vision. The rapid, objective nature of this approach makes it suitable for detecting color sensitivity loss in infants and the cognitively impaired.

Background: The Farnsworth D15 test is designed to categorise colour vision deficiency as severe or moderate. The level of difficulty of the test was set so that those who passed it should be able to recognise surface colour codes, such as those used for electrical wiring. The test is widely used to provide advice to patients with abnormal colour vision and is often used for occupational selection when reliable recognition of surface colour codes is required. However, there has been only one previous study of the correlation between performance at the D15 test and the naming of surface colour codes and there has been no study of whether a person who passes the D15 can reliably name surface colours. Methods: One hundred and two people aged 11 to 65 years with abnormal colour vision were recruited from consecutively presenting optometric patients and were asked to name the colours of fabric, paint and cotton thread samples. There were 10 colours in each class of material and the samples were presented in a large (five to 10 degree angular subtense) and small size (2.5 deg and a single thread). The errors made were compared to those made by an age‐matched control group of equal size with normal colour vision. Results: The correlations between the Farnsworth D15 colour confusion index and colour naming errors were 0.62 for the large stimuli and 0.73 for the small stimuli. Its sensitivity and specificity identifymg those who made more errors than the worst performing colour normal person were 0.80 and 0.69 (large stimuli) and 0.75 and 0.71 (small stimuli). A Nagel anomaloscope range of less than 35 scale units provides essentially the same sensitivity and specificity. Conclusions: About 40 per cent of those with abnormal colour vision can name the main colours correctly under good visibility conditions. The D15 test is an imperfect predictor of those who can name surface colour codes correctly but it does provide useful information for general counselling. It is not suitable as a single test for occupational selection because it will pass 20 per cent who cannot name surface colours correctly and fail 30 per cent who can. In occupations in which recognition of surface colour codes is of critical importance, it may be best not to select people with abnormal colour vision because of the lack of a colour vision test that is a perfect predictor of the ability to recognise surface colours.

Optic neuritis is an inflammatory condition affecting the optic nerve. It presents with sudden diminution of vision, also affecting colour vision, contrast sensitivity and stereoacuity. Steroids are given in optic neuritis to reduce inflammation of optic nerve. The aim of this study was to compare the visual functions in patients with optic neuritis before and after treatment with steroid therapy. This prospective study was conducted from November 2021 to October 2022 in the Department of Ophthalmology of a tertiary-level hospital. Thirty-seven eyes affected by optic neuritis of were included in the study. All the patients were given IV methylprednisolone for 3 consecutive days followed by oral prednisolone for 11 days in tapering doses. Visual functions such as visual acuity, colour vision, contrast sensitivity and stereoacuity at presentation and after treatment were compared. Among 37 eyes, 24 (64.86%) had best corrected visual acuity <1/60-perception of light at presentation, improving after six weeks with 21 (56.76%) achieving visual acuity 6/6-6/18. At presentation, only 1 (2.71%) had normal colour vision while at six weeks, 9 (24.32%) had normal colour vision. Contrast sensitivity could not be assessed in 29 (78.37%) cases at presentation due to poor vision, which reduced to 12 (32.43%) at six weeks. None had good stereoacuity at presentation; however, 6 (16.22%) had good stereoacuity after six weeks. The study showed that steroid therapy improved visual functions in patients with optic neuritis.

Numerical Confusion Errors in Ishihara Testing: Findings From a Population-based Study

Normal human color vision is usually thought to be based on only three spectrally different cone types. However, two facts suggest the possibility that some color-normal males could have more than three cone pigment types: (1) Most people with normal color vision have more than two photopigment genes on each X-chromosome and (2) there appear to be genetically specified variations in spectral positions of the normal middle-wavelength-sensitive (MWS) and long-wavelength-sensitive (LWS) pigments. For example, a male might have one gene encoding an LWS pigment and two genes encoding slightly different MWS pigments. If all three different X-encoded genes were expressed in different cones, then this person would have four spectrally different cone types. How firm is the assumption that more than two of the X-encoded pigment genes can be expressed? Both analysis of the statistics of photopigment gene number among different color vision phenotypes and analysis of the arrangement of pigment genes on the X-chromosome yield insight into this aspect of photopigment gene expression. These analyses suggest that individuals with multiple pigment genes on the X-chromosome may express more than two of those genes.

Aims: To investigate whether there is an association between congenital colour vision defects (CVD) and occupational choice and employment history, in order to inform the debate about the value of...

The X-linked red- and green-pigment genes are arranged in a head-to-tail tandem array. The colour-vision defect of deuteranomaly (in 5% of males of European descent) is associated with a 5'-green-red-3' visual-pigment hybrid gene, which may also exist in males with normal colour vision. To explain why males with a normal red, a normal green and a green-red hybrid gene may have either normal or deutan colour vision, we hypothesized that only the first two genes are expressed and deuteranomaly results only if the green-red hybrid gene occupies the second position and is expressed preferentially over normal green-pigment genes occupying more distal positions. We used long-range PCR amplification and studied 10 deutan males (8 deuteranomalous and 2 deuteranopic) with 3 visual pigment genes (red, green and green-red hybrid) to investigate whether position of the hybrid gene in the array determined gene expression. The green-red hybrid gene was always at the second position (and the first position was always occupied by the red gene). Conversely, in two men with red, green and green-red hybrid genes and normal colour vision, the hybrid gene occupied the third position. When pigment gene mRNA expression was assessed in post-mortem retinae of three men with the red, green and green-red genotype, the green-red hybrid gene was expressed only when located in the second position. We conclude that the green-red hybrid gene will only cause deutan defects when it occupies the second position of the pigment gene array.

Background: Colour vision assessment correlates with damage of the visual pathway and might be informative of overall brain damage in multiple sclerosis (MS). Objective: The objective of this paper is to investigate the association between impaired colour vision and disease severity. Methods: We performed neurological and ophthalmic examinations, as well as magnetic resonance imaging (MRI) and optical coherence tomography (OCT) analyses, on 108 MS patients, both at baseline and after a follow-up of one year. Colour vision was evaluated by Hardy, Rand and Rittler plates. Dyschromatopsia was defined if colour vision was impaired in either eye, except for participants with optic neuritis (ON), for whom only the unaffected eye was considered. We used general linear models adjusted for sex, age, disease duration and MS treatment for comparing presence of dyschromatopsia and disease severity. Results: Impaired colour vision in non-ON eyes was detected in 21 out of 108 patients at baseline. At baseline, patients with dyschromatopsia had lower Multiple Sclerosis Functional Composite (MSFC) scores and Brief Repeatable Battery-Neuropsychology executive function scores than those participants with normal colour vision. In addition, these patients had thinner retinal nerve fiber layer (RNFL), and smaller macular volume, normalized brain volume and normalized gray matter volume (NGMV) at baseline. Moreover, participants with incident dyschromatopsia after one-year follow-up had a greater disability measured by the Expanded Disability Status Scale and MSFC-20 and a greater decrease in NGMV than participants with normal colour vision. Conclusions: Colour vision impairment is associated with greater MS severity.

This paper describes a novel test of colour vision using a standard personal computer, which is simple and reliable to perform. Twenty healthy individuals with normal colour vision and 10 healthy individuals with a red/green colour defect were tested binocularly at 13 selected points in the CIE (Commission International d'Eclairage, 1931) chromaticity triangle, representing the gamut of a computer monitor, where the x, y coordinates of the primary colour phosphors were known. The mean results from individuals with normal colour vision were compared to those with defective colour vision. Of the 13 points tested, five demonstrated consistently high sensitivity in detecting colour defects. The test may provide a convenient method for classifying colour vision abnormalities.

In living color

Purpose:To investigate the quality of life (QoL) in a sample of color vision deficit (CVD) patients in India and how color vision deficiency affects them psychologically, economically, and in productivity related to their work and occupation.Methods:A descriptive and case–control study design using a questionnaire was conducted on N = 120 participants, of whom 60 were patients of CVD (52 male and eight female) who visited two eye facilities in Hyderabad between 2020 and 2021 and 60 were age-matched normal color vision participants who served as controls. We validated English–Telugu adapted version of CVD-QoL, developed by Barry et al. in 2017 (CB-QoL). The CVD-QoL consists of 27 Likert-scale items with factors (lifestyle, emotions, and work). Color vision was assessed using the Ishihara and Cambridge Mollen color vision tests. A six-point Likert scale was used, with lower scores indicating poor QoL (from 1 = severe issue to 6 = no problem).Results:The CVD-QoL questionnaire’s reliability and internal consistency were measured, including Cronbach’s α (α =0.70–0.90). There was no significance between the group in age (t = −1.2, P = 0.67) whereas the Ishihara colour vision test, scores showed a significant difference (t = 4.50, P < 0.001). The QoL scores showed a significant difference towards lifestyle, emotions and work (P = 0.001). The CVD group had a poorer QoL score than the normal color vision group odds ratio [OR] =0.31, 95% confidence interval [CI], (P = 0.002, CI = 0.14–0.65, Z = 3.0) . In this analysis, a low CI indicated that the OR was more precise.Conclusion:Color vision deficiency affects Indians’ QoL, according to this study. The mean scores of lifestyle, emotions, and work were lower than the UK sample.Since CVD is underreported and possibly affects developing countries more, advocacy for a new health care plan on CVD is essential. Increasing public understanding and awareness could also help diagnosing the CVD population.

The present study examined effects of role-play experience on reading the mind of people with different perception. It is normally difficult but very important in daily life to understand people with different characteristics, including those with restricted color vision. We explored the mechanisms of reading the mind of people with different perception. Forty university students were introduced to a communication task in which the use of mindreading was essential. During each trial, participants viewed a shelf, presented on a laptop computer, which contained several familiar objects, and they were instructed to touch an object on the shelf following an instruction issued by a partner who stood at the opposite side of the shelf. There were two partners: one was a monkey with normal color vision and the other was a dog with restricted color vision. The monkey could see all the objects in the same colors as the participants, whereas the dog saw some objects in different colors (e.g., he saw as yellow objects that the participants saw as red). Participants were required to respond according to the partner's instruction. In the restricted color vision condition, the dog saw the colors of objects differently; thus, participants had to work out his intentions (i.e., mind read), according to his different perspective. In the normal color vision condition, all objects were in the same colors as those seen by the monkey. Before the test phase, the role-play group had a role-play experience in which participants assumed the role of people with restricted color vision. No-role-play participants made significantly more errors in the restricted color vision condition than in the normal color vision condition, whereas among role-play participants, there was no difference between conditions. These results suggest that role-play experience facilitates reading the mind of people with perceptual experiences different from our own.

PurposeTo assess color vision and its association with retinal structure in persons with congenital aniridia.MethodsWe included 36 persons with congenital aniridia (10–66 years), and 52 healthy, normal trichromatic controls (10–74 years) in the study. Color vision was assessed with Hardy-Rand-Rittler (HRR) pseudo-isochromatic plates (4th ed., 2002); Cambridge Color Test and a low-vision version of the Color Assessment and Diagnosis test (CAD-LV). Cone-opsin genes were analyzed to confirm normal versus congenital color vision deficiencies. Visual acuity and ocular media opacities were assessed. The central 30° of both eyes were imaged with the Heidelberg Spectralis OCT2 to grade the severity of foveal hypoplasia (FH, normal to complete: 0–4).ResultsFive participants with aniridia had cone opsin genes conferring deutan color vision deficiency and were excluded from further analysis. Of the 31 with aniridia and normal opsin genes, 11 made two or more red-green (RG) errors on HRR, four of whom also made yellow-blue (YB) errors; one made YB errors only. A total of 19 participants had higher CAD-LV RG thresholds, of which eight also had higher CAD-LV YB thresholds, than normal controls. In aniridia, the thresholds were higher along the RG than the YB axis, and those with a complete FH had significantly higher RG thresholds than those with mild FH (P = 0.038). Additional increase in YB threshold was associated with secondary ocular pathology.ConclusionsArrested foveal formation and associated alterations in retinal processing are likely to be the primary reason for impaired red-green color vision in aniridia.

We have used antibodies specific to either the red/green-or blue-sensitive cones in order to compare their ratio and distributions to that of the rods in the retinae of 3 primate species that differ in their capacity for color vision. We have found that the monoclonal antibody CSA-1 (Johnson and Hageman, 1988) and the polyclonal antibody 4942A, specific to the red- and green-cone opsin (Lerea et al., 1989), applied to retinal whole-mounts labeled approximately 90% of all cones in the diurnal Old-World rhesus monkey (Macaca mulatta) and all of the cones in the nocturnal New-World owl monkey (Aotus trivirgatus) and nocturnal prosimian bushbaby (Galago garnetti). The polyclonal antibody 108B, specific to the blue-cone opsin (Lerea et al., 1989), labeled about 10% of the cones across the entire surface of the rhesus monkey retina, but failed to label any cones in the retina of the 2 nocturnal species. Only the retina of the rhesus monkey possessed an all-cone foveola in which the density of cone inner segments was 17-fold greater than that in the fovea of the owl monkey or bushbaby retina. Surprisingly, the density of cones per unit area outside of the fovea was comparable in all 3 species. Rod density in the dorsal retina was elevated in all animals examined, but was 2-3 times greater in the nocturnal species than in the rhesus monkey retina. Application of the photoreceptor-class-specific antibodies may provide further insights into the evolution and development of wavelength sensitivity in the retina, as well as enhance our understanding of normal and abnormal color vision in humans.