Fluorescein angiographic features, natural course and treatment of radiation retinopathy.

Fifteen patients who developed retinopathy following radiotherapy for cephalic tumours were studied by fluorescein angiography. Nine patients with unilateral or bilateral retinopathy had serial angiograms at six monthly or yearly intervals. Angiography revealed a wide range of retinal microvascular changes which were graded 1-4 according to the extent and degree of capillary malformation, incompetence and closure. All patients showed slow progression of retinopathy with remodelling of the affected microvasculature and increased capillary fallout and leakage to dye. The earliest retinopathic changes were capillary dilatation and closure and microaneurysm formation. Telangiectatic-like vessels were a feature of the established retinopathy and probably represented collateral channels which bordered sites of capillary occlusion. Two patients with progressive macular oedema and declining vision responded favourably to focal laser photocoagulation which returned a measure of competence to some residual dilated capillaries.