Blindness in Mongolism (down's Syndrome).

IN a previous communication (Cullen and Butler, 1963), the ocular abnormalities encountered in a survey of 143 mongoloids at the Rosewood State Hospital in Maryland were enumerated, and particular attention was drawn to the occurrence of keratoconus in over 5 per cent. of these patients. The purpose of this paper is to elaborate the incidence and causes of blindness in this same group. In the earlier paper no mention was made of the fact that several blind mongoloids were discovered among those examined, and, as the cause of blindness was in all but one instance associated with cataract or keratoconus, they were classified under these aetiological headings. Earlier surveys of the ocular abnormalities in mongoloids by Ormond (1912), Lowe (1949), Skeller and Oster (1951), and Woillez and Dansaut (1960) do not list any patient as being blind. More recently Eissler and Longenecker (1962) reviewed the ocular findings in 396 mongoloids and, though they made no attempt to compile uncommon ocular conditions, they did not state whether any of this very large number of patients were blind. When one considers that serious ocular conditions occur so commonly in mongoloids, and that the eyes of such patients might be expected to respond unfavourably to trauma or to surgical insult, it is surprising that no reference has hitherto been made to the not unexpected occurrence of blindness, particularly if they survive for more than 30 years. The diagnosis of blindness was, in our experience, often difficult to establish with certainty, owing to the low mental state of these patients. The presence or absence of light perception was usually not possible to assess by questioning and, in many cases, the pupil reactions could not be relied upon either. In this survey blindness was only accepted when it was quite obvious, as in the case of the phthisical eyes which form the largest group in the series. Indeed, many more of the patients examined would be classified as blind for registration purposes, and others would be graded as partially sighted. Of the 143 patients examined, seven were blind in both eyes and three others had one blind eye, giving a total of seventeen blind eyes in ten patients. The ages ranged from 14 to 54 years and seven patients were over thirty years old. It must be remembered that mongoloids now often survive beyond their thirties, and that they are then physically older than their years, so that, in