Photocoagulation treatment in diabetic retinopathy: a two-year pre- and five-year post-treatment study.

A randomized controlled study covering a two-year pre-treatment and a five-year post-treatment period was performed in 42 patients with diabetic retinopathy given photocoagulation treatment in one eye. Patients with progressive diabetic retinopathy of equal intensity in both eyes were selected from a single diabetes department. The course of diabetic retinopathy was assessed by ophthalmoscopy and composite fundus photographs as well as fluorescence angiography. In the first two-year post-treatment period non-proliferative retinopathy improved in the coagulated eyes and also, albeit to a lower degree, in the control eyes. In the next three years the treated eyes showed further improvement or stabilization, whereas the control eyes showed either stabilization or deterioration of the retinopathy. The most favourable results were obtained in proliferative diabetic retinopathy, which regressed in the majority of the eyes, the other eyes remaining stable or progressing only very slightly, in contrast with the control eyes, in the great majority of which proliferative diabetic retinopathy developed or progressed.