[Treatment of diabetic cystoid macular edema by argon laser photocoagulation]

Diabetic maculopathy remains the main cause of poor visual acuity in diabetic retinopathy either proliferative or non proliferative. Although photocoagulation in the macular area is known to be effective in treatment of exudates, results in treatment of cystoid macular edema (CME) are still questionable. 36 eyes with diabetic CME and non ischaemic capillary bed were treated with argon laser photocoagulation in the macular area. Two groups of patients were studied. Group I consisted of 16 eyes with CME and with circinate exudates in the paramacular area. Mild argon burns (50-200) were applied on the microvascular abnormalities and on the pigment epithelium in the center of the circinate exudates. The macula (1500 of diameter) was not treated in this group. As expected, results on the exudates rings were good. CME disappeared in 43% of the cases, and regressed in 23% of the cases. Nevertheless 3 years after treatment the mean visual acuity was found to be slightly worse than before the treatment. Group II consisted of 20 eyes with CME, exudates were absent or scattered. Mild argon burns were applied on the area of macular cysts avoiding only the foveal avascular zone (500 of diameter). Exudates when present disappeared in all cases. CME disappeared in 80% of the cases and regressed in 15% of the cases. Three years after treatment mean visual acuity remained identical. Extensive review of the literature concerning the treatment of diabetic maculopathy shows a wide range of techniques and evaluation procedures. We propose the following method of treatment: when exudate rings are present with CME, treatment should be aimed first towards focal microvascular abnormalities avoiding the macular area. When exudates are absent or in cases of unchanged CME after extramacular photocoagulation, treatment should be aimed towards the microcystic area avoiding the foveal avascular zone, if visual acuity is less than 0,5.