Vitrectomy for persistent diffuse diabetic macular edema.

PURPOSE

To evaluate the potential benefit of vitrectomy in eyes with persistent diffuse macular edema.

DESIGN

Prospective randomized comparative clinical trial.

METHODS

Eyes with diffuse diabetic macular edema for 6 to 18 months, an attached posterior hyaloid, and grid laser photocoagulation performed at least 4 months before were included. Patients were randomized either to a vitrectomy group or to a control group.

MAIN OUTCOME MEASURES

Evaluations of Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity, reading vision, and retinal thickness were carried out at baseline and 1, 3, and 6 months after enrollment.

RESULTS

Fifty-six eyes (100%) were enrolled in this study. Twenty-five eyes (44.6%) were randomized into Gr I (vitrectomy group) and 31 eyes (55.4%) into Gr II (controls). Both groups were comparable in mean age (62.7 years and 63.9 years) and distribution of gender (one third male, two thirds female). ETDRS visual acuity showed a statistical significance in favor of Gr I at all time points (P = .035 to .005 Fisher's exact test). With Jaeger charts a significance for Gr I was found only at the 6-month examination (P = .01). With optical coherence tomography, the different behavior of retinal thickness changes in both groups during follow-up was statistically significant; P values were <.0001 for month 1, 3, and 6, preferring Gr I.

CONCLUSIONS

We provide evidence that vitrectomy with internal limiting membrane peeling is superior to observation alone in eyes with persistent diffuse diabetic macular edema for 6 to 18 months. Longer follow-up periods and larger series might be needed to confirm these results and gain additional information.