[The sub-classification of pre-proliferative diabetic retinopathy]

The authors divided 155 eyes (106 cases) affected by pre-proliferative diabetic retinopathy into three sub-groups according to the severity of retinopathy and followed them for one year. The criteria for and numbers of eyes in each group were as follows; 1) mild type with soft exudate and without apparent non-perfused areas on fluorescein angiography (39 eyes). 2) moderate type with soft exudate and demonstrable non-perfused areas (103 eyes). 3) severe type with soft exudates, non-perfused 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 eyes in the mild type underwent photocoagulation unless they advanced to a more severe type. Nine eyes of the mild type 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 sub-groups were analyzed after one year of follow up. The proportion developing proliferative retinopathy was 0% in mild type, 17% in moderate type and 46% in severe type. Based on the above results, we conclude that the sub-classification we propose in this paper can be applied in managing patients with pre-proliferative diabetic retinopathy.