Effect of pars plana vitrectomy for proliferative diabetic vitreoretinopathy on preexisting diabetic maculopathy

Vitrectomy is the treatment of choice for proliferative diabetic vitreoretinopathy with tractions and persistent vitreous hemorrhage. Since vitrectomy has recently been discussed as a possible therapy for diabetic maculopathy as well, we were especially interested in studying the change in diabetic maculopathy following surgery. For that purpose a grading system developed at our clinic was used.

In a retrospective study we evaluated fundus photographs and fluorescein angiograms of 33 eyes of 30 patients who had undergone vitrectomy for proliferative diabetic vitreoretinopathy at our clinic between 1990 and 1997. In all eyes diabetic maculopathy was present at the time of surgery. The grading was performed using preoperative images and images taken a median of 18 months postoperatively.

Best corrected visual acuity increased by 3.7 lines on average. Intraretinal dot and spot hemorrhages, hard exudates, microaneurysms on fundus photos, and leakage and cysts on fluorescein angiograms decreased after surgery. The extent of the foveolar avascular zone and the extent of the perifoveolar ischemic area worsened, however.

Vitrectomy seems to help diabetic eyes not only by removal of membranes, tractions, and vitreous hemorrhage; it seems to have a positive influence on the course of diabetic maculopathy as well. We suspect that the removal of the posterior vitreous membrane is one of the crucial factors in interrupting the disease process. From these results the indication for vitrectomy in diabetic patients may have to be reconsidered and extended to include diabetic maculopathy prior to the development of ischemia.