Vascular endothelial growth factor is a critical stimulus for diabetic macular edema

center dot PURPOSE: The role of vascular endothelial growth factor (VEGF) in diabetic macular edema (DME) was tested with ranibizumab, a specific antagonist of VEGF. center dot DESIGN: A nonrandomized clinical trial. center dot METHODS: Ten patients with chronic DME received intraocular injections of 0.5 mg of ranibizumab at baseline and at one, two, four, and six months. The primary outcome was change in foveal thickness between baseline and seven months, and the secondary outcome measures were changes from baseline in visual acuity and macular volume. center dot RESULTS: Mean values at baseline were 503 mu m for foveal thickness, 9.22 mm 3 for macular volume, and 28.1 letters (20/80) read on an Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity chart. At seven months (one month after the fifth injection), the mean foveal thickness was 257 mu m, which was a reduction of 246 mu m (85% of the excess foveal thickness present at baseline; P =.005 by Wilcoxon signed,rank test for likelihood that this change is due to ranibizumab rather than chance). The macular volume was 7.47 mm(3), which was a reduction of 1.75 mm(3) (77% of the excess macular volume at baseline; P =.009). Mean visual acuity was 40.4 letters (20/40), which was an improvement of 12.3 letters (P =.005). The injections were well-tolerated with no ocular or systemic adverse events. center dot CONCLUSION: Intraocular injections of ranibizumab significantly reduced foveal thickness and improved vi. sual acuity in 10 patients with DME, which demons strated that VEGF is an important therapeutic target for DME. A randomized, controlled, double-masked trial is needed. to test whether intraocular injections of ranibizumab provide long,term benefit to patients with DME.