Ocular dimensions in the heredity of angle-closure glaucoma.

It has long been recognized that heredity plays a part in the aetiology of glaucoma. Fran §ois and Heintz-de Bree (I966) postulated a dominant heredity in open-angle glaucoma. They noted a 98 per cent. penetrance for a dominant gene in some families, but admitted that in other families the penetrance for a dominant gene was very low. Armaly (i 967a), on the other hand, suggested a polygenic inheritance in open-angle glaucoma. A similar controversy exists in diabetes mellitus, where Vallance-Owen (i967) suggests dominance, and Falconer (i965) a multifactorial aetiology. The pattern of angle-closure glaucoma among affected families also shows a variable prevalence. There have been a few reports of a high prevalence with transmission through two or more generations suggesting an autosomal dominant pattern, e. and Lowe (i964). Autosomal recessive inheritance has been reported by Waardenburg (I 949) and Biro (I95i). However, in many families, only one affected member is found. If a dominant heredity is to be postulated in angle-closure as in open-angle glaucoma, a very variable and generally low penetrance of the gene must be assumed to explain the very variable prevalence of the condition in different families. Lowe (1970b) suggested a polygenic aetiology in angle-closure glaucoma. Angle-closure glaucoma occurs most frequently, but not exclusively, in eyes which are ocular dimensions found in hypermetropia which play such an important part in the aetiology of angle-closure glaucoma. Hence hypermetropia is associated with a shallow anterior chamber