Fellow eye effect of unilateral intravitreal bevacizumab injection in eyes with diabetic macular edema

Aims Anti-vascular endothelial growth factor compounds are routinely used for the treatment of diabetic macular edema (DME). We aim to evaluate for the existence and magnitude of treatment effect on fellow un-injected eyes. Methods A consecutive group of patients with bilateral DME who received unilateral bevacizumab injections was retrospectively evaluated. Data collected included demographics, ophthalmic and systemic findings, and optical coherence tomography (OCT) measurements of macular thickness. Results Thirty-five patients were evaluated. Mean follow-up was 245 days (range: 30-800), and the mean number of bevacizumab injections was 3.6 (range: 1-11). At end of follow-up, the mean (SD) OCT central subfield thickness reduced by 72 +/- 112 micron in the injected eye (from 469 +/- 139 to 397 +/- 120 micron; P = 0.001), while in the non-injected eye it reduced by 49 +/- 75 micron (from 380 +/- 130 to 331 +/- 106 micron; P<0.001). Sixteen injected eyes (45.7%) showed central subfield thickness reduction of >= 50 micron while 10 (28.6%) non-injected eyes showed such thickness reduction. Improved VA following treatment was detected in 14 (40%) injected eyes and in 15 (43%) non-injected eyes. Conclusions Unilateral bevacizumab injections in patients with bilateral DME are often associated with bilateral response. Summary Statement Anti-vascular endothelial growth factor compounds are routinely used for the treatment of diabetic macular edema (DME). In this retrospective study, we show that unilateral bevacizumab injections often result in reduction of the macular thickness in the fellow un-injected eye.