Ranibizumab treatment improves diabetic macular oedema without influencing retinal oximetry parameters

Abstract

Purpose: To evaluate the effect of ranibizumab on retinal oximetry in eyes with diabetic macular oedema (DME).

Methods: In this prospective interventional study, 30 eyes (30 patients) with DME were treated with three-monthly intravitreal ranibizumab injections, followed by pro re nata administration for 12 months. Retinal oximetry was performed using an Oxymap T1.

Results: The mean number of injections was 6.6 ± 2.5. No adverse event was observed throughout the study period. Ranibizumab treatments for 12 months improved the macular oedema (p = 0.002) and achieved a recovery of visual acuity (VA; p = 0.011). However, oxygen saturation levels in the major retinal blood vessels, either the arteries or the veins, remained unchanged during the observational period. Arterial oxygen saturation was 100.3 ± 9.4% before treatment and 100.9 ± 10.7% (p = 0.698) at 6 months. Venous oxygen saturation was 56.4 ± 8.9% before treatment and 55.6 ± 8.6% (p = 0.529) at 6 months. In addition, there were no significant changes in diameters of the major retinal arteries and veins. Greater improvement of VA at 12 months was correlated with a smaller number of ranibizumab injections (r = 0.459, p = 0.011). The number of ranibizumab injections during these 12 months correlated with an increased baseline central retinal thickness (r = 0.385, p = 0.035).

Conclusion: Ranibizumab treatments for DME improved the macular oedema and achieved VA recovery, but no changes were noted in the retinal oxygen saturation.

Keywords: diabetic macular oedema; oxygen consumption; ranibizumab; retinal oximetry; retinal vessels.