Unilateral proliferative diabetic retinopathy. II. Clinical course.

One hundred thirty-six patients with proliferative diabetic retinopathy (PDR) in one eye and nonproliferative diabetic retinopathy (NPDR) in the fellow eye on initial examination were followed up for at least three months. Eight percent of the eyes with NPDR were eliminated from further consideration by treatment within the first three months. Proliferative diabetic retinopathy developed in 58% of the remaining eyes with NPDR, usually within two years of the initial examination. Proliferative diabetic retinopathy developed in a significantly greater percentage of diabetics who were younger than 40 years than in diabetics older than 60 years. Poor visual prognosis among eyes that initially had NPDR was associated with advanced angiopathy or exudation on initial examination and also may have been associated with the subsequent development of PDR. Neither the development of PDR nor the final visual acuity in these eyes could be correlated with vascular disease outside the eye, the degree of PDR in the fellow eye, or the presence of higher intraocular pressure in the eye with NPDR on initial examination. Forty-one percent of the eyes with unilateral PDR were eliminated from consideration by prompt treatment. Most remaining eyes with PDR also showed progressive fundus pathologic conditions.