Color Confusion Research Articles

Postoperative recovery of visual function after macula-off rhegmatogenous retinal detachment.

PurposeTo determine which factors affect the recovery of visual function in macula off rhegmatogenous retinal detachment (RRD).MethodsIn a prospective study of forty-five patients with a primary macula-off RRD of 24 hours to 6 weeks duration, the height of the macular detachment was determined by ultrasonography. At 12 months postoperatively, best corrected visual acuity (BCVA), contrast acuity, and color confusion indexes (CCI) were obtained.ResultsMacular detachment was present for 2–32 (median 7) days before repair. A shorter duration of macular detachment was correlated with a better CCI saturé (p = 0.0026) and lower LogMAR BCVA (better Snellen visual acuity)(p = 0.012). Also, a smaller height of macular detachment was correlated with a lower LogMAR BCVA (p = 0.0034). A younger age and lower pre-operative LogMAR BCVA at presentation were both correlated with better postoperative contrast acuity in the total group (age: p = 1.7×10−4 and pre-operative LogMAR BCVA: p = 0.0034).ConclusionFunctional recovery after macula-off RRD is affected by the duration and the height of the macular detachment. Recovery of contrast acuity is also affected by age and BCVA at presentation.Meeting presentationARVO annual meeting 2013, May 7, Seattle, Washington, United States of America.Trial registration:trialregister.nl NTR839

0233 Long-term styrene exposure impairs colour vision in fibreglass reinforced plastics laminators

ObjectivesAlthough styrene has been reported to cause colour vision impairment, the results were still inconclusive. Whether the impairment was related to short-term or long-term exposure was not known. The study...

Comparison of Panel D-15 Tests in a Large Older Population

To determine the frequency and type of color vision defects in a large group of randomly selected older people using two versions of the D-15 and to examine the agreement between the two tests. The Adams desaturated D-15 test was administered under Illuminant C (MacBeth lamp, ∼ 100 lux) to a group of 865 individuals aged 58 to 102 years (mean, 75.2 ± 9.1 years). No exclusion criteria, other than the reported presence of a congenital color defect, were applied. Testing was binocular with habitual near correction. If any error was made on this test, the Farnsworth D-15 was administered under identical conditions. On both tests, a color confusion score of 30 or higher was considered failing, and for those failing the test, color defect type (blue-yellow, red-green, or nonselective) was determined using the method of Vingrys and King-Smith (1988). The majority (60.8%) of the people tested passed both tests. For the sample as a whole, the failure rates of the Adams desaturated D-15 and the Farnsworth D-15 were 36.2% and 20.76%, respectively. As expected, for both tests, failure rate increased markedly with age. Among those who failed both tests, 17.5% of the population, the proportion of specific agreement for red-green and blue-yellow defects was high, 88%. The vast majority of those failing either or both tests had blue-yellow defects, in agreement with previous studies. Blue-yellow defects were quite common among the aged, becoming increasingly prevalent with increasing age. More people failed the Adams desaturated D-15 than the Farnsworth D-15, but among those who failed, the proportion of blue-yellow defects was similar for the two tests, approximately 75%. The agreement between the two tests in identifying acquired red-green and blue-yellow errors was high.

Correlations between color perception and motor function impairment in children with spastic cerebral palsy

IntroductionThe aim of the present study was to evaluate color perception thresholds and relate them to the degree of motor impairment in children with spastic cerebral palsy (SCP).MethodsBinocular and monocular chromaticity discrimination thresholds were estimated for the protan, deutan, and tritan color confusion axes in 43 SCP children aged 6–15 years who were classified as tetraplegic (n = 12), diplegic (n = 16), and hemiplegic (n = 15) without ophthalmological complaints. Motor impairment was rated according to the Gross Motor Function Classification System (GMFCS) in five levels of severity.ResultsAnalysis of variance showed significantly reduced discrimination in tetraplegic children (p < 0.001) compared with the diplegic, hemiplegic, and control groups. We also found a positive correlation between chromaticity discrimination thresholds and GMFCS ratings in all of the groups.DiscussionChromaticity discrimination thresholds measured psychophysically were reduced for all three color confusion axis in tetraplegic children compared with normal children. Diplegic and hemiplegic children had similar results as normal children. The finding of a correlation between quantified motor impairment and color discrimination losses in SCP patients is a new observation that might help elucidate the causes of color perception loss in these patients. Visual information is essential for the rehabilitation of CP children. Knowledge of the degree of correlation between vision and motor impairment is valuable when planning a rehabilitation program.

Postoperative quality of life in macula‐off rhegmatogenous retinal detachment patients and its relation to visual function

AbstractPurpose To assess which aspects of postoperative visual function (visual acuity, contrast acuity, or color confusion) are correlated with visual function‐related quality of life measurements after successful surgery for macula‐off rhegmatogenous retinal detachment (RRD).Methods In patients with a primary macula‐off RRD, best correct visual acuity (BCVA), color confusion indices (CCI saturé and desaturé), and contrast acuity were measured at 12 months postoperatively in both the RRD eye and the fellow control eye, and the 25‐item National Eye Institute Visual Function Questionnaire (VFQ‐25) was filled out.Results Forty‐five patients with a primary unilateral macula‐off RRD were included. There was a significant difference between operated and fellow control eyes with regard to LogMAR BCVA (P &lt; 0.0001), Log contrast acuity (P &lt; 0.0001), saturé CCI (P = 0.018), and desaturé CCI (P = 0.018). Correlations were observed between the composite VFQ‐25 score and postoperative LogMAR BCVA (R = ‐0.53, P &lt; 0.0005) and Log contrast acuity (R = 0.47, P = 0.001). In addition, correlations were found between postoperative LogMAR BCVA and Log contrast acuity and the following subscales: driving, near acuity, role difficulties, and general vision. Also, a correlation between the subscale mental health and LogMAR BCVA was found. No correlations were found between any VFQ‐25 scales and the CCIs.Conclusion Postoperative BCVA, contrast acuity and color confusion in operated macula‐off RRD eyes were significantly worse compared to their fellow control eyes. Several vision‐related quality of life parameters were highly correlated with postoperative BCVA and contrast acuity.

Blue–yellow colour vision impairment and cognitive deficits in occasional and dependent stimulant users

Specific blue-yellow colour vision impairment has been reported in dependent cocaine users and it was postulated that drug-induced changes in retinal dopamine neurotransmission are responsible. However, it is unclear whether these changes are confined to chronic cocaine users, whether they are specific for dopaminergic stimulants such as cocaine and amphetamine and whether they are related to cognitive functions such as working memory, encoding and consolidation. In 47 occasional and 29 dependent cocaine users, 23 MDMA (commonly known as 'ecstasy') users and 47 stimulant-naive controls, colour vision discrimination was measured with the Lanthony Desaturated Panel D-15 Test and memory performance with the Auditory Verbal Learning Test. Both occasional and dependent cocaine users showed higher colour confusion indices than controls. Users of the serotonergic stimulant MDMA (26%), occasional (30%) and dependent cocaine users (34%) exhibited more frequent blue-yellow colour vision disorders compared to controls (9%). Inferior performance of MDMA users was caused by a subgroup with high amphetamine co-use (55%), while MDMA use alone was not associated with decreased blue-yellow discrimination (0%). Cognitive performance was worse in cocaine users with colour vision disorder compared to users and controls with intact colour vision and both colour vision impairment and cognitive deficits were related to cocaine use. Occasional cocaine and amphetamine use might induce blue-yellow colour vision impairment, whereas the serotonergic stimulant MDMA does not impair colour vision. The association between colour vision impairment and cognitive deficits in cocaine users may reflect that retinal and cerebral dopamine alterations are linked to a certain degree.

Ophthalmic findings in acute mercury poisoning in adults

The aim of this study is to report ophthalmic findings of acute mercury poisoning in 48 adults referred to emergency department. Full ophthalmologic examination including the best corrected visual acuity, external eye examination, reaction to light, a slit-lamp examination, funduscopy, intraocular pressure measurements, and visual field (VF) and color vision (CV) tests were performed at the presentation and repeated after 6 months. The parametric values of VF test, the mean deviation (MD), and pattern standard deviation (PSD) were recorded in order to compare patients and the 30 healthy controls. The mean parameter of color confusion index in patients was found to be statistically different than controls (p < 0.01). The MD and PSD in patients were different from controls statistically significant (p < 0.01 and p < 0.01, respectively). There was no correlation between the ocular findings and the urine and blood mercury levels. Methyl mercury, held in the school laboratory for experimental purpose, may be a source of poisoning. In this case series, we showed that acute exposure to mercury had hazardous effect on the visual system, especially CV and VF. We propose that emphasizing the public education on the potential hazards of mercury is crucial for preventive community health.

Effects of Idebenone on Color Vision in Patients With Leber Hereditary Optic Neuropathy

Background:The authors investigated the correlation of protan and tritan color vision with disease characteristics in Leber hereditary optic neuropathy (LHON). The authors also characterized the therapeutic potential of idebenone in protecting patients from developing dyschromatopsia in LHON.Methods:Color contrast data of 39 LHON patients participating in a randomized, double-blind placebo-controlled intervention study were evaluated. Patients reported disease onset <5 years before enrolment and were genetically confirmed. Protan and tritan color contrast sensitivity was measured using a computer graphics method in patients receiving idebenone (Catena; 900 mg/d; N = 28) or placebo (N = 11) for 6 months.Results:Mean age of patients was 28.1 years, 87.2% were men, 76.9% carried the m11778G>A mutation, and mean duration since onset was 2 years. Assessing protan and tritan color vision at baseline revealed a high degree of color confusion even in young patients (<25 years) and with a short history of disease (<1 year). Treatment with idebenone improved tritan color vision compared with placebo (P = 0.008 at week 24); a similar trend was seen for protan. The effect of idebenone was most prominent in patients with discordant visual acuity (interocular difference of logMAR >0.2). In this subgroup, the treatment effect at week 24 was 20.4% (P = 0.005) in favor of idebenone for the tritan color domain and 13.5% (P = 0.067) for the protan domain.Conclusion:This study confirms that protan and tritan color confusion is an early symptom in LHON. Treatment with idebenone can protect from loss of color vision, particularly in patients who are at imminent risk of further vision loss.

Ophthalmic Findings of Acute Mercury Poisoning in Primary School Students

Purpose: To report ophthalmic findings in acute mercury poisoning in the primary school students. Methods: Seventy two children exposed to mercury vapor and 42 healthy controls were enrolled in the study. Full ophthalmologic examination including best corrected visual acuity, external eye examination, a slit-lamp examination, funduscopy, intraocular pressure measurements, Visual Field (VF), Visual Evoked Potential (VEP) and Color Vision (CV) tests were performed at the presentation and after six months. The parametric values of VF, Mean Deviation (MD) and Pattern Standard Deviation (PSD) were compared between groups. Results: The visual acuity less than two lines in ETDRS chart in 7(9.7%) patients, color vision impairment in 6(8.3%) patients were determined with ophthalmic examination. There were a significant difference in the color confusion index of patients, (p<0.05). The mean parametric VF values of MD and PSD were found statistically, significant difference (p<0.001, p<0,001 respectively), The latency values of VEP were 7% of 20 patients over 100 ms. There were no correlation between ophthalmic findings and mercury levels in urine and blood. Conclusion: While visual acuity minimally affected, advanced visual functions were significantly impaired in a way independent of mercury level. The goal of this paper is to draw attention to the importance of public education on potentially hazardous effects of mercury in terms of preventive community health. In particular, both primary school teachers and students should be trained concerning poisonous gases such as mercury.

Mercury exposure and color vision loss of some Koreans in a fishery area

This study was conducted to evaluate the relationship between exposure to mercury and color vision loss in populations located within fishery areas in South Korea. From a total of 511 subjects, 401 were assessed for acquired color vision loss. Subjects determined to have congenital loss or subjects with visual acuity less than 0.6 were excluded from the study. Mercury concentrations were analyzed in blood, urine, and hair samples. The Ishihara test was used to assess congenital color vision loss, and the Lanthony test was used for acquired color vision loss. Acquired color vision loss was present in 56 (14%) of the subjects and 345 (86%) subjects were normal. The geometric means of mercury concentration were 3.78 μg/L in blood, 0.64 μg/g creatinine in urine, and 1.16 μg/g in hair. Although mercury was identified in relatively low concentrations, mercury concentrations in subjects with acquired color vision loss were higher than that of normal subjects. The frequency of color vision loss in subjects with higher mercury concentrations was increased compared to subjects with lower mercury concentrations. The color confusion index increased with increasing mercury levels. This study suggests that exposure to low levels of mercury affects color vision loss as an early marker of neurotoxic damage in humans.

Subtle Shades of Impairment: Childhood Tetrachloroethylene Exposure May Cause Subclinical Deficits in Adult Vision

People come into regular contact with tetrachloroethylene (also known as perchloroethylene, or PCE) through dry-cleaned clothes, and the chemical has become a frequent contaminant in surface and groundwater, often due to improper disposal. PCE has been associated with neurologic and visual impairment in exposed adults. Now investigators have detected visual impairment in adults whose exposure to PCE-contaminated drinking water had occurred years earlier—from gestation through age 5 years [EHP 120(9):1327–1332; Getz et al.]. Some 660 miles of improperly cured vinyl-lined drinking water pipes installed between 1968 and 1980 leached PCE into the water delivered to residences at different parts of the Cape Cod region of Massachusetts. Previous studies of this cohort—exposed and unexposed adults born to Cape Cod parents from 1969 through 1983—have detected evidence that PCE exposure may contribute to other neurologic impairments, including post-traumatic stress disorder, bipolar disorder, and diminished performance on tests of memory, learning, and visuospatial functioning. In this study, the investigators tested the visual acuity (sharpness of vision), contrast sensitivity (ability to distinguish gradations of light and dark), and color discrimination (ability to correctly identify colors) in 25 exposed and 40 unexposed members of the cohort. The researchers used an algorithm to estimate PCE exposure based on each individual’s residence during gestation and early childhood, since the presence and degree of PCE contamination in drinking water varied by locale. Tests of color discrimination revealed that high PCE exposure was significantly associated with color confusion, with all major errors occurring in blue–yellow discrimination. Only the highest PCE exposure level was associated with impaired contrast sensitivity, but these results were not statistically significant. Visual acuity did not appear to be affected; most study participants had 20:20 vision, and no differences were observed between exposure groups. The measured vision impairments are subclinical, meaning they would not have directly noticeable effects on an individual’s vision. Previous studies have only assessed relationships between PCE exposure and vision in either childhood or adulthood. The results of this retrospective study must be confirmed, given its small sample size, but the findings suggest that childhood PCE exposure may cause long-term visual impairment. Further study of this or other exposed populations is necessary to understand the long-term effects of early-life exposure to PCE.

Color confusion ellipses from absolute judgments

The axis of maximum variability in settings of unique white lies near the blue/yellow diagonal in the MacLeod-Boynton chromaticity diagram (Beer and MacLeod, VSS 2005). This axis coincides with the locus of natural daylight illuminants. A possible reason for this oblique orientation is color constancy. An observer may be willing to accept as white any chromaticity that could plausibly be interpreted as a white reflectance spectrum under a natural illuminant, and natural illuminants vary mainly along this blue/yellow direction. Here we extend this work to points in chromaticity space other than unique white. Observers were asked to memorize the color of a particular stimulus, presented in a dark surround, at the beginning of an experimental session. Observers fixated a single-pixel central fixation dot, and the stimulus was presented parafoveally, rotating through twelve positions around the fixation dot in order to avoid adaptation of one particular retinal location. Observers were then required to set matches to this remembered chromaticity for the rest of the session. The matching stimulus also rotated around a centrally presented fixation dot, and observers adjusted its chromaticity within an isoluminant plane using a tracker ball. Each observer set 35 matches to each remembered color. The distributions of matches show a blue/yellow diagonal elongation. This elongation is not attributable to nonuniformity of the chromaticity diagram, since it is more pronounced in absolute color judgments than in side-by-side-discrimination. A possible explanation for our results is color constancy: observers remember an "object" with a particular reflectance spectrum, and accept as color matches to this object the chromaticities which that reflectance spectrum yields under a range of plausible natural illuminants. Meeting abstract presented at VSS 2012

Prenatal and Early Childhood Exposure to Tetrachloroethylene and Adult Vision

Background: Tetrachloroethylene (PCE; or perchloroethylene) has been implicated in visual impairments among adults with occupational and environmental exposures as well as children born to women with occupational exposure during pregnancy.Objectives: Using a population-based retrospective cohort study, we examined the association between prenatal and early childhood exposure to PCE-contaminated drinking water on Cape Cod, Massachusetts, and deficits in adult color vision and contrast sensitivity.Methods: We estimated the amount of PCE that was delivered to the family residence from participants’ gestation through 5 years of age. We administered to this now adult study population vision tests to assess acuity, contrast sensitivity, and color discrimination.Results: Participants exposed to higher PCE levels exhibited lower contrast sensitivity at intermediate and high spatial frequencies compared with unexposed participants, although the differences were generally not statistically significant. Exposed participants also exhibited poorer color discrimination than unexposed participants. The difference in mean color confusion indices (CCI) was statistically significant for the Farnsworth test but not Lanthony’s D-15d test [Farnsworth CCI mean difference = 0.05, 95% confidence interval (CI): 0.003, 0.10; Lanthony CCI mean difference = 0.07, 95% CI: –0.02, 0.15].Conclusions: Prenatal and early childhood exposure to PCE-contaminated drinking water may be associated with long-term subclinical visual dysfunction in adulthood, particularly with respect to color discrimination. Further investigation of this association in similarly exposed populations is necessary.

Association Between Retinal Nerve Fiber Layer Thickness and Abnormalities of Vision in People With Human Immunodeficiency Virus Infection

To investigate relationships between contrast sensitivity (CS), color vision, and retinal nerve fiber layer (RNFL) among people with human immunodeficiency virus (HIV) infection; to evaluate the effect of time since diagnosis of HIV infection on RNFL thickness. Noninterventional cross-sectional study. We evaluated 102 eyes of 57 HIV-infected individuals without ocular opportunistic infections. Peripapillary RNFL thickness was determined with spectral-domain optical coherence tomography in 4 quadrants. CS was measured with the Pelli-Robson technique (expressed as logCS); color vision was measured with the Lanthony desaturated 15-hue technique (expressed as color confusion index [C-index], with higher scores indicating worse color vision). Correlations between values were assessed using Spearman correlation coefficients. Median RNFL thickness (average of 4 quadrants) was 102.9 μm (range, 75.0-134.7 μm). Median logCS was 1.90 (range, 1.25-1.95). Median C-index was 1.58 (range, 0.96-4.07). Temporal RNFL thickness was correlated with logCS (r=0.295, P=.003) and C-index (r=-0.338, P=.0005). Time since diagnosis of HIV infection was shorter for those with thick average RNFL than for those with thin average RNFL (P=.18). Both worse CS and worse color vision are correlated with thinning of the temporal RNFL, with possible threshold effects. Increased prevalences of abnormal CS and abnormal color vision in this population are therefore likely attributable to neuroretinal compromise. This pattern of structural and functional losses may reflect preferential damage to small-caliber axons in the maculopapillary bundle, possibly associated with mitochondrial dysfunction, providing a potential disease mechanism for HIV-associated "neuroretinal disorder."

The FPGA Implementation of Color Gamut Conversion in Laser Display

Because of the laser's larger colour gamut, the images played by the laser display will be more vivid and more colourful, but the most standard signals are coding by the formats which have small gamut, so sometimes the images displayed by the laser may have the phenomenon of colour deviation and colour confusion. The paper proposes a system to solve the problem, and implement the system on FPGA platform.

Derivation of Color Confusion Lines for Pseudo-Dichromat Observers from Color Discrimination Thresholds

The objective is to develop a method of defining color confusion lines in the display RGB color space through color discrimination tasks. In the experiment, reference and test square patches were presented side by side on a CRT display. The subject's task is to set the test color where the color difference from the reference is just noticeable to him/her. In a single trial, the test color was only adjustable along one of 26 directions around the reference. Thus 26 colors with just noticeable difference (JND) were obtained and made up a tube-like or an ellipsoidal shape around each reference. With color-anomalous subjects, the major axes of these shapes should be parallel to color confusion lines that have a common orientation vector corresponding to one of the cone excitation axes L, M, or S. In our method, the orientation vector was determined by minimizing the sum of the squares of the distances from JND colors to each confusion line. To assess the performance the method, the orientation vectors obtained by pseudo-dichromats (color normal observers with a dichromat simulator) were compared to those theoretically calculated from the color vision model used in the simulator.

Elucidating the effect of yellow illumination on color confusion in the semiconductor-related manufacturing industry

This study investigates how yellow lighting and white lighting affect color confusion in contrast with how sunlight does by using the Farnsworth–Munsell 100 Hue Test System (FM100). Forty college students with normal color vision are enrolled in this study. The experimental setup involves ceiling lighting at a 90° angle on the FM100 with an illuminance of 550 lx, in which the subjects view the FM100 at a 45° angle. All color chips of the FM100 that are fully discriminable under sunlight are arranged in a color circle (FM100 color circle) with equal hue steps resembling those of a 100 Munsell hue circle. Under colored lighting, however, colors may be undistinguishable, resulting in the misplacement of some of the color chips. Color confusion is then determined by counting the number of times a color chip is misplaced, which is called an error score. All error scores are plotted on the FM100 color circle, which is called the color error sheet, to reveal the range and severity of color confusion due to the colored lighting. Experimental results indicate that, although yellow lighting significantly introduces color confusion, white lighting does not. Additionally, yellow lighting does not cause serious impairment in distinguishing between the yellow (its own color) and blue colors (complementary of yellow), but causes significant impairment in distinguishing between the green and red colors. On the error scoring sheet, both the two nonconfusion series and the two confusion series are complementary and orthogonal. This observation allows us to postulate that, although colored lighting does not cause significant impairment in distinguishing between its own complementary colors, it does between its orthogonal colors. © 2010 Wiley Periodicals, Inc.

Impairment of color vision in aircraft maintenance workers

The purpose of the study was to examine possible persisting effects to color vision in a group from the Royal Australian Air Force who had exposure to formulations containing neurotoxins during F-111 fuel tank maintenance, relative to two contemporaneous comparison groups. Color vision was tested in 512 exposed personnel, 458 technical-trade comparisons, and 330 non-technical comparisons using the Ishihara test plates and the Lanthony D-15 Desaturated Color disk arrangement test. Participants were excluded if they failed the Ishihara test as this indicates congenital color blindness. From the Lanthony results, the type of color deficient vision (CDV) was diagnosed, and additionally, the Bowman's color confusion index (CCI) was calculated. Regression models were used to examine whether there was an association between color vision deficiencies and F-111 fuel tank maintenance, adjusting for possible confounders. The CCI ranged from 1 to 2.8 (median 1.2, quartiles 1.1, 1.4) in the 2,600 eyes tested. Forty five percent of all participants had blue-yellow CDV in at least one eye. Deficiencies of this nature are caused by environmental exposures. Logistic regression demonstrated statistically significant differences in CCI category in the exposed group versus technical group (odds ratio 1.7: 95% CI 1.3-2.0) and a blue-yellow confusion in the exposed group versus technical group (odds ratio 1.4: 95% CI 1.1-1.7). No differences were observed between the exposed group and the non-technical group. The results indicate reduced color discrimination among the exposed subjects compared to one of two control groups. The findings may be due to previous exposure to solvents among the air force personnel.

Colour change in cyanosis and the confusions of congenital colour vision deficient observers

Visual recognition of cyanosis is an important clinical activity. While pulse oximetry is almost universal in the hospital environment, there are circumstances where it is not available or may be unreliable. Cyanosis recognition is affected by lighting colour. In addition, there is, mainly anecdotal, evidence that people with greater colour vision deficiencies (CVDs) have particular difficulty and there is no effective lighting strategy to assist in the observation. The change of blood colour with oxygenation has been shown to lie close to the direction of colour confusions made by congenital red-green dichromats. The important sites of observation are lips, nail beds and palm creases. 10 subjects who were known to be chronically hypoxaemic were recruited from the chronic respiratory program. Their blood oxygen saturation (SpO(2)) varied from 84% to 96% pre-exercise, and 61-84% post-exercise. Ten normal subjects were recruited whose SpO(2) was 99% or 100%. The spectral radiances of lips, nail beds and palm creases were measured using a telespectroradiometer and compared with the spectral radiances of a white tile of known spectral reflectances measured in the same location. This is a non-contact method of measurement, avoiding the blanching caused by pressure of contact methods. The spectral reflectances were calculated, and the chromaticities calculated for a Planckian radiator T = 4000K. Measurements on lips yielded the most consistent results. The colour changes pre- and post-exercise and compared with normal colour lie generally along a deutan confusion line. These results show the direction of the colour change and confirm the, previously anecdotal, difficulties in detecting cyanosis by observers with CVDs.

Occupational exposure to different levels of mixed organic solvents and colour vision impairment

Mixed organic solvents have a broad range of applications in industry. Occupational exposure to organic solvents has been shown to be associated with colour vision impairment. The study was designed to determine the impact of chronic occupational exposure to organic solvent mixtures on colour vision of car industry painters. 408 workers of assembly location and 2 different paint locations of a car manufacturing company were included in the study. The workers were studied in three groups. The first group consisted of those working in the assembly location with no exposure to organic solvents. The second and third groups included those working in the new and old paint locations, exposed to organic solvents at lower and higher levels than the permissible level, respectively. The Lanthony D-15 desaturated (LD-15) test was used for screening acquired colour vision impairment. The frequency of acquired colour vision impairment was 44.28% for workers of the old paint location, 29.31% for workers of the new paint location, and 3.90% for workers of the assembly location, indicating a significant difference ( p < 0.001). The results of logistic regression indicated there was a significant relationship between colour confusion index (CCI) and exposure to organic solvents ( p < 0.001) for the old and new paint locations. We suggest that chronic occupational exposure to organic solvents at higher and even lower levels than the permitted levels may lead to acquired colour vision impairment. It is recommended that LD-15 test would be implicated in the early diagnosis of nervous system disorders in workers exposed chronically to organic solvents.