Long-term effectiveness of modified grid laser photocoagulation for diffuse diabetic macular edema.

Fifty eyes of 42 patients with background diabetic retinopathy and diffuse macular edema were included in a prospective, randomized, clinical study to determine the long-term visual results of modified grid laser photocoagulation compared with the natural course of the disease. At the end of the three annual follow-up visits there were more eyes with improved visual acuity in the treatment group and more eyes with worse visual acuity in the control group. However, statistical analysis of the data showed that only at the end of the first and the second year was there a significant statistical difference between the two groups. At the end of the third year no statistically significant difference was found. These results suggest that modified grid laser photocoagulation is not an effective procedure for the long-term management of diffuse diabetic macular edema compared with the natural course of the disease.