[The influence of hard exudates on the results of vitrectomy for macular edema due to diabetic retinopathy].

Purpose: To demonstrate surgical results of diabetic macular edema from the distribution of hard exudates.

Methods: We reviewed 485 eyes of 325 patients followed up more than 1 year who underwent vitreous surgery for diabetic macular edema. Four groups were identified from the distribution of hard exudates in the macular region: no hard exudate type, 179 eyes; hard exudate type, 211 eyes; macular deposit type, 73 eyes; and waxy type, 22 eyes. We evaluated the preoperative characteristics, the period required for absorption of macular edema, visual outcome, and postoperative complications among the four types.

Results: In the waxy type, the macular edema was absorbed more slowly than no hard exudate type and hard exudate type(p < 0.05) more patients had proteinurea and were treated by grid photocoagulation before surgery than the other types, and the rate of occurrence of rubeotic glaucoma and attrition by death was higher than in the other types. Visual acuity was significantly improved in all types postoperatively(p < 0.05). Preoperative and postoperative visual acuity were as follows: no hard exudate type, 0.28, 0.48; hard exudate type, 0.21, 0.33; macular deposit type, 0.10, 0.17; and waxy type, 0.04, 0.11.

Conclusion: The distribution of hard exudates was directly related to surgical results for diabetic macular edema. The waxy type had poor prognosis.