The Chronic Primary Glaucomas

One of the outstanding problems in ophthalmology to-day is the elucidation of etiological factors in the primary glaucomas, i.e., those not directly resulting from obvious pathological or anatomical defects of the eye. Our knowledge of the mechanisms productive of intraocular hypertension in such cases has been greatly augmented in recent years by the publications of Duke-Elder, Seidel, Magitot, Meesmann, Thiel and others. That increased tension may be due to a disturbance of the physico-chemical equilibrium between the uveal capillary blood on the one hand and the intraocular fluid (largely contained in the vitreous body) on the other, may seem a satisfactory hypothesis in certain types of cases. In others an increase in volume of the intraocular vascular bed may offer a very good reason for hypertension and the displacement of the vitreous body. The action of abnormal intraocular chemical bodies on the physical condition of the vitreous gel may result in an increased volume of the posterior segment, and the safety valve mechanism of the filtration angle which at first copes with this vitreous swelling may be thrown out of action by the encroachment on the anterior chamber. This conception too seems to adapt itself to clinical appearances which are all too familiar to ophthalmologists in India. In the case of glaucoma simplex in relatively young subjects, with an anterior chamber of normal