Subclassification of preproliferative diabetic retinopathy.

One hundred and fifty-five eyes (106 cases) affected by preproliferative diabetic retinopathy were divided into three subgroups according to the severity of retinopathy and were followed for one year. The criteria for and numbers of eyes in each group were as follows: 1) mild type with soft exudates and without apparent nonperfused areas on fluorescein angiography (39 eyes), 2) moderate type with soft exudates and demonstrable nonperfused areas (103 eyes), 3) severe type with soft exudates, nonperfused areas and venous beading (13 eyes). The proportion undergoing photocoagulation was 23% in the mild type, 81% in the moderate type and 100% in the severe type. None of the mild type eyes underwent photocoagulation unless they advanced to a more severe type. Nine of the mild type eyes which progressed to moderate type during the follow-up period underwent focal photocoagulation. Panretinal photocoagulation was performed in 29% of moderate type eyes and 77% of severe type eyes. The courses of these three subgroups were analyzed after one year of follow-up. The proportion developing proliferative retinopathy was 0% in the mild type, 18% in the moderate type and 46% in the severe type. Based on the above results, it was concluded that the subclassification we proposed in this paper can be applied to the management of patients with preproliferative diabetic retinopathy.