Effect of intravitreal ranibizumab on retinal oxygen saturation in diabetic macular edema - a pilot study

Abstract

Purpose: To determine the effect of intravitreal ranibizumab on the oxygen saturation in retinal vasculature of patients with diabetic macular edema (DME)

Methods: In 15 eyes of 15 consecutive patients with DME indicated to receive intravitreal injections of 0.5ml ranibizumab, we performed automatic retinal oximetry (Oxymap Inc., Reykjavik, Iceland) in the treated and the non-treated eye 15 minutes prior to and 15 minutes after intravitreal injection. The oxygen saturations in retinal arteries and veins was determined. Vessel segments of first or second degree were selected. The same segment was analysed before and after the injection. Oximetry data were compared by paired two-tailed t-test. The same examinations were performed in the untreated eye of the same patients.

Results: Intravitreal administration of ranibizumab did not alter the arterial hemoglobin saturation with oxygen (103.8 ± 9.7% prior to the injection and 104.9 ± 25.4% after the procedure, p = 0.853). The mean venous hemoglobin saturation with oxygen did not change significantly after intra-vitreal injection (63.7 ± 9.6% to 59.6 ± 7.9%, p = 0.168). In untreated eyes, arterial hemoglobin saturation with oxygen did not vary significantly (101.6 ± 5.2% prior to the injection of the other eye and 101.1 ± 5.4% after the procedure, p = 0.763). Consistently, the mean venous hemoglobin saturation with oxygen remained unchanged (67.7 ± 6.3% to 66.0 ± 8.1%, p = 0.262).

Conclusions: Oxygen saturation in retinal vessels of DME eyes is not altered significantly after intravitreal injection of ranibizumab.

Keywords: 635 oxygen • 688 retina • 561 injection