VISION EVALUATION IN PEOPLE WITH DOWNS-SYNDROME

We tested the colour vision of 72 people with Down's syndrome using th e Ishihara test and an anomaloscope. We found that 13 of the subjects, 6 males and 7 females, had defective colour vision according to Pickf ord's classification. In monocular vision 10 eyes were protan (five si mple, three extreme and two deviant), one eye was simple deuteranomalo us and the remaining eyes were normal: in binocular vision four of the subjects were protan (two simple and two deviant), two subjects were deutan (one simple and one deviant) and the rest were normal. Many of our subjects had lens opacities, strabismus, nystagmus, hypermetropia, high myopia and astigmatism, confirming literature reports. The contr ast sensitivity function measured with the VCTS test showed a consider able loss of low-frequency sensitivity in our subjects compared to a n ormal population, which was more marked in the more severely impaired subjects.