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Results for “Color Vision Defects”

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PubMed1983

Limited improvement of color deficient vision with colored filters.

For over a hundred years, colored filters have helped people with less than normal color vision, to discriminate colors. Filtered light does not restore missing or abnormal pigments within the defective eye. Contrast and discrimination provided by a suitable colored filter can help discrimination of a given set of colors, but may prevent seeing other sets of colors. The use and limitations of color filters are described as aids for color deficient vision.

Color Vision Defects↗
PubMed1981

A study of some genetic markers among Ramgarhias, an artisan caste of Punjab.

156 males and 63 females belonging to the Ramgarhia community, an endogamous group of Punjab, were taken for the study of genetical markers like taste ability to PTC, mid digital hair and colourblindness, whereas 75 (50 males and 25 females) were tested for serum proteins. 71.70% males and 73.85% females were found to be tasters. The mid digital hair was absent in 67.34% of females and 64.74% of males. No female was found to be colourblind, however, 4.48% males were found having defective colourvision. The phenotypic frequencies of Hp 2--2, Hp 2--1 and Hp 1--1 were found to be 64.00%, 32.00% and 4.00%, respectively. No variant of transferrins and albumin was found.

Blood Proteins↗
PubMed2002

The validity of the University of Waterloo Colored Dot Test for Color Vision Testing in adults and preschool children.

PURPOSE: Most color vision tests require a high level of cognitive ability and as such are problematic for preschool children and multiply challenged individuals. Our goal was to design a color vision test for these groups and evaluate the clinical utility for preschool children. METHODS: The University of Waterloo Colored Dot Test (UWCDot) for Color Vision Testing requires the subject to distinguish a colored disc from seven gray discs. The target disc was a Munsell color along the deutan, protan, or tritan confusion line with gray. The first phase estimated the sensitivity and specificity of the test for adults. Thirty-one adults with normal color vision and 21 adults with congenital red-green defects participated. In the second phase, the utility of the UWCDot test for screening preschool children was determined. Subjects were 281 males and 269 females aged 2.5 to 5 years with normal vision. Their color vision was also assessed with the Standard Pseudoisochromatic Plates, Part 1 (SPP1). RESULTS: The sensitivity and specificity of UWCDot for adults approached the values for the desaturated D-15 when subjective responses were scored. Monitoring fixational eye movements produced sensitivity and specificity values that were similar to the anomaloscope. After adjusting the scoring criterion for the preschool children by using the females as a control, 2.9% of the males were identified as red-green deficient, 1.8% were blue-yellow deficient, and 3.2% had an unclassified deficiency. By definition, 1% of the females failed the test. Counting fixational eye movements was not a useful scoring method in the preschool children. Comparisons with SPP1 indicated that the UWCDot uncovers approximately 35% of the individuals with definite red-green color vision defects. CONCLUSIONS: Our results indicate that the UWCDot is capable of detecting approximately 35% of the preschool children who have a congenital red-green color vision defect. These individuals are likely to have a more severe deficiency.

Adult↗
PubMed1980

[Incidence of color blindess in East African Negroes].

1008 Bantu and 295 Nilotes of Kenya were tested with regard to protanopia-deuteranopia by means of the ISHIHARA-Plate No. 11 (16 plates edition). Four (0.55%) of the male Bantu and two (1.03%) of the male Nilotes showed a partial or total red-green-blindness. With the females of these samples no case of defective colour vision was observed.

Black People↗
PubMed1990

Gene frequency and type of colour blindness in Ethiopians.

All 954 boys and 1064 girls attending two schools in north-western Ethiopia were tested in February 1988 for colour blindness using the Ishihara plates. A total of 40 colour blinds (4.2%) were found among males and 2 (0.2%) among females. There were 31 (3.2%) deutans and 9 (0.9%) protans among males. Both female colour blinds were deutans. This study confirms a previous observation on the gene frequency of colour blindness in this population. For the first time it also provides information on the frequency of this polymorphism in female Ethiopians, as well as types of red-green defects.

Adolescent↗
PubMed2003

The Tehran Eye Study: research design and eye examination protocol.

BACKGROUND: Visual impairment has a profound impact on society. The majority of visually impaired people live in developing countries, and since most disorders leading to visual impairment are preventable or curable, their control is a priority in these countries. Considering the complicated epidemiology of visual impairment and the wide variety of factors involved, region specific intervention strategies are required for every community. Therefore, providing appropriate data is one of the first steps in these communities, as it is in Iran. The objectives of this study are to describe the prevalence and causes of visual impairment in the population of Tehran city; the prevalence of refractive errors, lens opacity, ocular hypertension, and color blindness in this population, and also the familial aggregation of refractive errors, lens opacity, ocular hypertension, and color blindness within the study sample. METHODS DESIGN: Through a population-based, cross-sectional study, a total of 5300 Tehran citizens will be selected from 160 clusters using a stratified cluster random sampling strategy. The eligible people will be enumerated through a door-to-door household survey in the selected clusters and will be invited. All participants will be transferred to a clinic for measurements of uncorrected, best corrected and presenting visual acuity; manifest, subjective and cycloplegic refraction; color vision test; Goldmann applanation tonometry; examination of the external eye, anterior segment, media, and fundus; and an interview about demographic characteristics and history of eye diseases, eye trauma, diabetes mellitus, high blood pressure, and ophthalmologic cares. The study design and eye examination protocol are described. CONCLUSION: We expect that findings from the TES will show the status of visual problems and their causes in the community. This study can highlight the people who should be targeted by visual impairment prevention programs.

Blindness↗
PubMed1981

Xenon arc and argon laser photocoagulation in the treatment of diabetic disc neovascularization. Part 2. Effect on colour vision.

Patients with long-standing diabetes develop acquired colour vision defects in parallel with retinal vascular changes. This may take the form of an overall loss of hue discrimination or a specific tritan (blue) defect. A battery of colour vision tests can be used to monitor the different features of diabetic retinopathy and to assess the effects of treatment. Diabetic disc new vessels form when approximately a quarter of the retina is ischaemic. The colour vision defect in these patients is usually severe and is frequently tritanopic. The effect of both argon laser and xenon arc panretinal photocoagulation is to increase the severity of the colour defect. All the eyes examined were tritanopic after treatment and did not recover during the 12-month follow-up period. The severity of this acquired colour vision defect can result in practical difficulties for the patient.

Adult↗