Gonioscopy: uses old and new. The inheritance of occludable angles.
The goniolens has become increasingly important in the practice of ophthalmology, For example, the treatment of angle closure and neovascular glaucoma is most effective in the earliest stages of the diseases, even prior to the onset of symptoms. Routine gonioscopy is essential if patients are to be provided optimum care. The critical nature of pressure gonioscopy is reviewed. The use of the goniolens to examine the corneal endothelium is described and recommended. Characterization of the configuration of the angle recess demands description of at least three aspects: (1) the angular approach to the recess, (2) the peripheral curvature of the iris, and (3) the point of insertion of the iris onto the ciliary body or endothelial surface. The nature of these three considerations is reviewed, as is their frequency in a normal population, in a group of ten people with definite 1 degree angle-closure glaucoma, and in 95 relatives of the subjects with angle-closure glaucoma. Marked anterior convexity of the peripheral iris appears to be highly correlated with the development of 1 degree angle closure. The three aspects of the angle configuration appear to be independently inherited. Gonioscopy of relatives of cases with 1 degree angle-closure glaucoma is highly recommended.