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Caroline Silvas Seto, Dora Fix, Ronaldo Sano; Color vision evaluation in albino patients by Cambrigde Colour Test and Ishihara Plates.. Invest. Ophthalmol. Vis. Sci. 2017;58(8):4300.
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© ARVO (1962-2015); The Authors (2016-present)
Color vision in albino patients is an issue that needs to be studied due to controversy among published studies, whose methods did not yet have computerized psychophysical tests with good sensitivity and specificity. We performed a cross-sectional study to evaluate the color vision of albino individuals using the Cambridge Colour Test (CCT) and Ishihara plates.
The study included 28 albino patients selected from the Pro-Albino project. Patients were referred to the Psychophysics and Visual Electrophysiology Laboratory (Psychology Institute of the University of São Paulo), where the tests were performed. The inclusion criterion was minimal visual acuity in both eyes 20/400. The exclusion criterion was ophthalmologic changes secondary to other diseases. The thresholds were used according to the age group, based on a control group. For statistical analysis of the results of the CCT, the color discrimination thresholds for each axis were compared between the albino patients and the control group using the Student's t-test.
The CCT showed three individuals presenting protanomaly, one tritanomaly and four diffuse changes, not specific. Nineteen individuals showed no change in color vision. Just one albinism subject in the sample showed abnormal color vision in the Ishihara plates. The sample tend to present higher thresholds of chromatic discrimination in the axes of confusion compared to the control group. However, there was no statistically significant difference for the discrimination thresholds in the protan (p = 0.146), deutan (p = 0.084) and tritan (p = 0.164) axes between groups.
Although studies have shown that foveal cones density in albino patients is lower, such alteration does not necessarily represent the presence of color vision impairment. In addition, the cases of protanomaly detected by the CCT were also not identified by the Ishihara planks, although such deficiency was detected by both tests. The presence of tritanomaly found in one individual was not detected in the Ishihara plates, as well as protanomaly cases, revealing the importance of performing the CCT in patients with albinism for their detection. Three individuals had protanomaly, constituting the most prevalent deficiency in this study. Although observed a small number of color vision deficiencies in the sample, the prevalence of these defects was higher than in the general population.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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