[Effects of photocoagulation on diabetic macular edema]

Retrospective analysis of clinical cases observed for three years with respect to the appearance of the fundus and visual acuity was conducted to evaluate the effect of photocoagulation therapy on macular edema in relation to whither diabetic retinopathy was accompanied by, focal or cystoid, macular edema. In addition to glycemic control, focal and direct treatment of responsible lesions was found effective for focal macular edema in simple diabetic retinopathy. Concerning all types of retinopathy, the prognosis of focal macular edema was significantly favorable to that of cystoid macular edema. Blood sugar control also influenced the prognosis of focal edema. The changes of retinopathy were closely associated with the prognosis of focal macular edema in preproliferative and proliferative retinopathy. Disseminated photocoagulation and panretinal photocoagulation showed no difference as to the results of indirect treatment of focal macular edema in preproliferative retinopathy. Macular alterations other than macular edema occurred in a higher proportion of cases of proliferative retinopathy than in simple or preproliferative retinopathy. This accounted for low visual recovery in the former group in comparison to simple retinopathy. It was concluded that the direct treatment of the involved lesions is effective for focal macular edema in simple retinopathy and that extensive photocoagulation in preproliferative and proliferative retinopathy indirectly has a favorable influence on focal edema by means of amelioration of retinopathy.