Comparison of the effects of intravitreal ranibizumab and aflibercept on retinal vessel diameters in patients with diabetic macular edema

Purpose: To evaluate and compare the effects of intravitreal ranibizumab and aflibercept treatment on retinal vessel diameters in patients with diabetic macular edema (DME). Methods: Thirty initial-treatment naive patients with DME who received three loading doses at monthly intervals of intravitreal ranibizumab or aflibercept were retrospectively reviewed. The diameters of the central retinal artery and vein sections at a distance of 1500 microns from the optical disc boundary were measured and evaluated at baseline and after the first, second, and third month of the treatment, using infrared images from optical coherence tomography (OCT) (Heidelberg Engineering, Heidelberg, Germany). Results: In the superotemporal artery (STA) measurements, the mean basal vessel diameter decreased from 110.00 +/- 17.25 mu m to 102.60 +/- 16.90 mu m (p = 0.001) in the third month of the treatment in the ranibizumab group. In the aflibercept group, measurements of the basal STA vessel diameter decreased from 110.20 +/- 21.25 mu m to 103.93 +/- 19.03 mu m (p = 0.001) at the third month. The mean basal inferotemporal artery (ITA) vessel diameter was significantly decreased at the third month in both ranibizumab (p = 0.001) and aflibercept groups (p = 0.005). In the superotemporal vein (STV) and inferotemporal vein (ITV) measurements, vessel diameters were found significantly decreased at the end of the third month compared with basal measurements in both the ranibizumab (p = 0.001; p = 0.001, respectively) and aflibercept (p = 0.001; p = 0.004, respectively) treatment groups. The retinal vessel measurements were not found to differ significantly between the two intravitreal treatment agents (p > 0.05). Conclusion: Both intravitreal ranibizumab and aflibercept agents cause a significant narrowing in the retinal vessel diameters in patients with DME after three loading doses at monthly intervals.