[A prospective study on necessary and sufficient retinal photocoagulation for diabetic retinopathy]

The present studies were performed to determine whether slight photocoagulation was better than heavy photocoagulation for the early stage of progressive proliferative diabetic retinopathy (PDR). The authors selected 17 patients who had bilateral PDR of equal severity (BI or BII stage according to Fukuda's classification). In every case, we randomly performed heavy photocoagulation (laser burns were 1142 +/- 179) to one eye and slight photocoagulation (405 +/- 166) to the other eye. More than 6 months after the last photocoagulation, the effects of these treatments were compared in both eyes by fundus pictures, visual acuity and posterior vitreous fluorophotometric values. The results of judgement by fundus pictures and by vitreous fluorophotometric values were in perfect agreement. Eight cases (47%) in whom eyes received slight photocoagulation showed result better than the other eye. Two cases (12%) which received heavy photocoagulation were better than the other eye. Seven cases (41%) showed the same level of severity. No significant differences were found between slight and heavy photocoagulation.