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Results for “Color Vision Defects”

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PubMed2002

Cross-sectional study of the ophthalmological effects of carbon disulfide in Chinese viscose workers.

This article presents cross-sectional investigation results of ophthalmological effects for the occupational exposure to carbon disulfide of workers at a large viscose fibre factory in the middle part of China. The total of 271 exposed subjects (191 males, 80 females) and 133 workers (93 males, 40 females) not exposed to any toxic agent in the working environment underwent ophthalmological examination. The self-administered questionnaire collected data on the medical history and ophthalmological complaints during the past three months. The ophthalmologic examination included routine examination for retinal capillary anomalies and and color vision with the FM 100-Hue test method. Nearly all subjects did not use respirators, smocks or aprons, gloves or other personal protective devices during work time. The average personal CS2 exposure level in the present study was 13.7-20.05 mg/m3. The FM 100-Hue test results showed that the total error scores of the exposed group, whether male or female, were higher than that of the control, the discrimination of the green and blue zones was also impaired significantly. A fundus examination showed no retinal capillary anomalies or other serious ophthalmological symptoms that may be related to effects of CS2. In conclusion, color vision was disturbed in workers exposed to CS2, at levels below the present threshold value. Reduced color discrimination may be attributed to long-term carbon disulfide exposure and suggests that health surveillance of workers exposed to carbon disulfide should include the FM 100-Hue Test as a sensitive and easy method.

Adult↗
PubMedDate not supplied

Dose-related color vision impairment in toluene-exposed workers.

Occupational exposure to various neurotoxic chemicals can impair color vision. We evaluated this possibility in toluene-exposed workers. Thirty-three rubber workers and 16 referents were studied. We estimated toluene exposure by measuring urinary excretion of the unmodified form of the solvent (i.e., TolU). Color vision was tested with the Lanthony D-15 desaturated panel, and the outcomes were expressed quantitatively with the Color Confusion Index and the Total Confusion Index. Toluene-exposed workers had a subclinical reduction in color vision, compared with referents. We related this effect to solvent cumulative exposure--estimated as the product of urinary excretion of unmodified toluene by previous toluene exposure duration. This approach supports the hypothesis that impairment progresses as exposure continues. In the examined group of workers, toluene exposure was within the occupational limit proposed by the American Conference of Governmental Industrial Hygienists. The observed loss in color vision raises doubts on the real protection afforded by this limit--at least for effects of the solvent on the eyes. Finally, the Total Confusion Index was a more sensitive index than the Color Confusion Index in the evaluation of toluene-related color-vision impairment, suggesting that this index should be adopted in future studies of the effects of chemicals on color perception.

Adult↗
PubMedDate not supplied

Two-year evolution of perchloroethylene-induced color-vision loss.

Progression of perchloroethylene-induced color-vision impairment was studied in 33 dry-cleaner workers at 12 establishments in Modena, Italy. In an initial survey, we evaluated exposure with personal passive samplers, and we assessed color vision with the Lanthony D-15 desaturated panel. Two years later, workers were reexamined. In 19 workers (subgroup A), exposure to perchloroethylene had increased (median of 1.7 ppm versus 4.3 ppm, respectively), whereas in the remaining 14 workers (subgroup B) exposure was reduced (2.9 ppm versus 0.7 ppm, respectively). Color vision worsened in subgroup A, but no vision changes were apparent in subgroup B. The results indicated that an increase in exposure during a 2-y period, even if slight, can cause color vision to deteriorate. A similar slight reduction in exposure did not lead to color-vision improvement; perhaps this lack of improvement resulted from (a) an insufficient reduction in exposure, (b) an insufficient reduction in duration of exposure, or (c) irreversible perchloroethylene-induced color-vision loss.

Adult↗
PubMed2001

Hypnotic color blindness and performance on the Stroop test.

A suggestion for hypnotic color blindness was investigated by administering a reverse Stroop color-naming task. Prior to the suggestion for color blindness, participants learned associations between color names and shapes. Following the color blindness suggestion, participants were required to name the shapes when they appeared in colors that were either congruent or incongruent with the learned associations. The 18 high hypnotizable participants who passed the suggestion were slower to name (a) shapes in which the color name was incongruent with the color in which it was printed, (b) "unseen" rather than "seen" shapes, and (c) color-incongruent shapes that were printed in the color in which they were "color-blind." These patterns are discussed in terms of potential cognitive and social mechanisms that may mediate responses to hypnotic color blindness.

Color Vision Defects↗
PubMed2005

Projected color slides as a method for mass screening test for color vision deficiency (a preliminary study).

This article compared the efficiency of the mass screening test with projected color slides in detecting color-blindness with the authentic classic method of Ishihara. The study was conducted in a randomly selected lecture room with 104 students aged between 19-25 years (median 21). Using Ishihara projected slides, performed mass screening test. Re-testing was done individually with printed Ishihara plates. Six male and one female with color-blindness were detected. The frequency of color-blindness was 13.6% among males, with a total incidence of 6.7%. The results of two testing methods were compared statistically. Sensitivities and specificities of both tests were 100%. Using projected slides of Ishihara plates instead of the authentic method is an effective and timesaving method for detecting color-blindness. This method can be suggested as a mass-screening test and might be beneficial in detecting color-blindness in large populations such as students, soldiers, and so on.

Adult↗
PubMed1984

Measurements of the Pulfrich effect over days of exposure.

Mean depth settings and subjective reports appear to confirm previous subjective reports from users of the X-Chrom prescription lens that Pulfrich Effect depth distortions decrease with continued exposure to light intensity disparity. Depth setting variability across Days of exposure indicates a rapid increase in depth judgment errors which persists without decrement across Days. This increased variability, the apparent depth decrements, and color discrimination improvements shed light on the visual processing underlying the Pulfrich Effect and reveal a potentially dangerous illusion.

Adult↗
PubMedDate not supplied

Cone-mediated multifocal electroretinogram in early age-related maculopathy and its relationships with subjective macular function tests.

PURPOSE: To investigate the multifocal electroretinogram (mfERG) and subjective function in early age-related maculopathy (ARM). METHODS: Seventeen subjects with early ARM with visual acuity (VA) of 6/12 or better and 20 age-matched control subjects were examined. We assessed mfERGs, high and low contrast distance VA, near VA, low luminance VA, contrast sensitivity, saturated and desaturated Panel D-15 and visual fields (mean sensitivity). The mfERG responses were analysed by comparing central-overall (method 1) and superior-inferior (method 2) ratios. RESULTS: The mfERG did not discriminate between the groups whereas colour vision (tritan deficiency), contrast sensitivity, and high contrast and low contrast VA showed significantly reduced responses for the early ARM group compared with the control group (p < or = 0.01). The mfERG first-order kernel responses correlated significantly with the desaturated D-15 in both methods (r = -0.5, p < or = 0.05). Fundus grading was not correlated with the mfERG measures. CONCLUSIONS: Although the mfERG correlated significantly with the desaturated D-15 in early ARM, suggesting it operates at a sensitive level, it failed to discriminate between the control and ARM groups. In our sample, the subjective function measures were more sensitive than the mfERG measures.

Aged↗
PubMed1975

Colour-blindness and sensitivity to PTC in Hadza.

211 Hadza (Tanzania) males, including members of both western and eastern groups, were tested for red-green colour blindness with the Ishihara non-numeral plates. Three closely related individuals were considered to be protanopes. It is possible that they received the gene from an Isanzu ancestor. 118 individuals (both sexes) were tested for taste-deficiency to PTC using a single solution and a sorting test. 22% of the males and 27% of the females were considered to be non-tasters. Since this appeared to be a high figure for an African population a sample of 53 eastern Hadza males was later tested using solutions 1, 3, 5, 7, 9, 11, 13. A conservative interpretation of the threshold distribution gave an estimate of 43% non-tasters. Corrections were applied for the inclusion of close relatives in the samples. The results are discussed in relation to other African data.

Adolescent↗
PubMed1977

Red-green colour blindness in the Isle of Man and Cumbria.

The frequencies of red-green colour-blind males in the indigenous population of two regions of Britain, the Isle of Man (5.6 per cent) and Cumbria (5.0 per cent), do not readily fit into the pattern of a SW-NE gradient in the frequency of the colour-blind gene in Britain suggested by earlier studies. Frequencies of red-green colour-blind females are also given for these two populations.

Adolescent↗
PubMed1978

The incidence of colour-blindness among the tribal populations of Andhra Pradesh.

Among 126 Valmiki, 128 Bagatha, 129 Konda Dora and 73 Samanta tribals of Andhra Pradesh, the incidence of red-green colour-blindness in the males ranges from zero to 2.27 per cent. Samanta males exhibit no colour-blindness. In the females, only Konda Doras exhibit a frequency of 2.44 per cent of the trait. Comparison of the present data with the other available tribal and non-tribal data of Andhra Pradesh shows that our results fall well in the range for other data. Post's (1962) hypothesis of relaxation of selection against colour-blindness is also supported by our Andhra Pradesh data.

Adolescent↗
PubMed2006

Optic neuritis secondary to Angiostrongylus cantonensis infection.

PURPOSE: To describe a case of optic neuritis secondary to Angiostrongylus cantonensis infection. METHOD: Case report of a patient with eosinophilic meningitis secondary to A. cantonensis infection. The patient developed a sudden decrease in visual acuity with a visual field defect and color vision loss in his left eye. Both visual evoked potential and clinical manifestations suggested the diagnosis of optic neuritis (os). RESULT: After two weeks of larvicidal drugs and steroid treatment, the patient's visual acuity and color vision had dramatically improved. CONCLUSION: Optic neuritis may occur in patients with A. cantonensis meningitis. Treatment with a combination of steroid and larvicidal agents may be beneficial to these patients.

Adult↗
PubMed2005

Congenital color blindness in young Turkish men.

We investigated a healthy population of men from different regions of Turkey for the presence of congenital red-green color blindness. Using Ishihara pseudoisochromatic plates, 941 healthy men from the Turkish army were tested for congenital red-green color blindness. The prevalence of red-green color blindness was 7.33 +/- 0.98% (5.10% protans and 2.23% deutans). These ratios were higher than other reported samples from Mediterranean Europe. Higher percentages of color blindness were found in regions with a lower education level and more consanguineous marriages.

Adult↗
PubMed2005

Abnormal distribution of red/green cone opsins in a patient with an autosomal dominant cone dystrophy.

PURPOSE: To define the distribution of the red/green and blue opsins in cones from donor eyes from an affected member of a clinically well-characterized family with an autosomal dominant form of cone dystrophy. METHODS: Tissue was fixed and processed for immunohistochemistry. Cryosections were studied by indirect immunofluorescence, using well-characterized antibodies to cone cytoplasm, rhodopsin, and cone opsins. The cone-associated matrix was also labeled with the lectin PNA. The affected donor eyes were compared to a postmortem matched normal eye. RESULTS: Electroretinogram (ERG) testing three years prior to the affected member's death showed normal rod function, while the cone b-wave amplitude was reduced 40% below the lower limit of normal. Fundus exam showed only isolated drusen within the macula. Either a normal-appearing or only nonspecific macular findings were noted in the other affected family members who were examined. Immunofluorescence studies showed that blue cone opsin was restricted to the outer segments of blue cones in the affected retina. Red/green opsins were distributed along the entire plasma membrane of these cone types, from the tip of the outer segment to the synaptic base. Cone-associated matrix displayed a heterogeneous distribution. These patterns were observed both in the macula and in the periphery of the affected retina. Cone pedicles appeared larger than normal. In contrast, rhodopsin staining appeared normal. CONCLUSIONS: The immunocytochemical data obtained suggest that the clinical manifestation of this dystrophy is associated with an abnormal distribution of cone red/green opsins. Additionally, changes in the cone pedicles could have contributed to the abnormal cone ERG in this patient.

Aged↗