Effect of intravitreal ranibizumab on the ocular circulation of the untreated fellow eye

Purpose To evaluate the effects of unilateral intravitreal ranibizumab (IVR) on the ocular circulation of the fellow eyes. Methods Fifteen eyes of 15 patients with macular edema (average age 69.6 ± 11.8 years) were studied. Eleven eyes had diabetic macular edema (DME) and four eyes had macular edema associated with a branch retinal vein occlusion. Each eye received 0.5 mg of IVR. The blood circulation on the optic nerve head of the treated and untreated eyes were determined by laser speckle flowgraphy (LSFG, Softcare Co., Ltd) before, 1 day, and 1 week after the IVR. The mean blur rate (MBR) and the relative changes of the MBRs determined as dMBR(%) = 100−(MBR before/MB after) × 100) were evaluated. The central macular thickness (CMT) and the rate of reduction in the thickness (dCMT = 100−(CMT before/CMT after) × 100) were also evaluated. Results The mean dMBR was significantly higher in the treated eyes than the untreated eyes at 1 day (−16.4 ± 17.0% vs 2.31 ± 19.3%) and at 1 week (−12.0 ± 14.6% vs 4.50 ± 25.9%) after the IVR ( P = 0.02, paired t tests). Conclusion These findings indicate that if ranibizumab enters the systemic circulation, the concentration is not high enough to affect the ocular circulation of the fellow eyes.