Diabetic retinopathy study. Preliminary results from 215 patients treated uniocularly with photocoagulation

Preliminary results of a controlled study on diabetic retinopathy are reported. Two hundred and fifteen patients with proliferative (PDR) and nonproliferative (NPDR) retinopathy were uniocularly treated by Xenon photocoagulation and followed for a minimum of 6 months--6 years. Intra- and epiretinal new vessel formations (RNF) decreased in treated but increased in untreated eyes at a high statistical significance. A transition of background retinopathy into the proliferative stage was significantly retarded after photocoagulation. An improvement of new vessel formations on the disc (DNF) was not evident after 3 years of follow-up. The progression of preretinal neovascularization (PRNF) was significantly reduced only for 1--2 years after treatment. The incidence of massive vitreous hemorrhages, however, which showed the highest quotient of contingency with PRNF was much lower in treated eyes also after 3 years. The difference was significant only in extensively photocoagulated eyes with more than 100 lesions on average. The effect of photocoagulation on diabetic maculopathy with preservation of a useful visual acuity was highly significant only in diabetics under 60 years of age, the effect increasing with time as the control eyes fared worse. By contrast, in patients over 60 years of age, the course of maculpathy was not influenced, and a linear decrease of visual acuity occurred in both treated and untreated eyes.