Purpose: To compare eyes that underwent surgery with untreated fellow eyes to assess the efficacy of vitrectomy for diabetic macular edema.
Methods: In a nonrandomized clinical trial, seven adult patients with mean age of 53 years (range 42 to 64) and the same degree and duration of diabetic macular edema in both eyes were followed up for more than 5 months after unilateral vitrectomy. The treated eye was selected at random, but if visual disparity between the both eyes was more than 3 lines, we operated on the worse side. We compared the preoperative and postoperative foveal thicknesses (the distance between the inner retinal surface and retinal pigment epithelium) and the best-corrected visual acuity by a certified examiner with those of the untreated fellow eye.
Results: In the seven eyes that underwent surgery, the foveal thickness decreased by an average of 622 to 269 microm (P =.027, Wilcoxon signed-rank test). In the fellow eyes, the average decrease in foveal thickness was from 617 to 546 microm (P =.176, Wilcoxon signed-rank test). The best-corrected postoperative visual acuity in the eyes that underwent surgery improved more than 2 lines in four eyes (57%) and remained the same in three eyes (43%). In the fellow eyes, it improved more than 2 lines in one eye (14%), remained the same in three eyes (43%), and decreased more than 2 lines in three eyes (43%).
Conclusion: In eyes with diabetic macular edema that underwent surgery, the foveal thickness significantly decreased after vitrectomy. Vitrectomy may be effective for treating diabetic macular edema.