Abstract
Purpose :
It has been reported that retinal oxygen metabolism may be altered in exudative AMD (Geirsdottir 2014). The purpose of the study was to investigate the effect of bevacizumab on retinal vessel oxygen saturation in patients with exudative AMD.
Methods :
Oxygen saturation was measured in retinal arterioles and venules in 19 patients with exudative AMD before and seven days after intravitreal injection with 1.25 mg / 0.05 ml bevacizumab. A spectrophotometric oximeter, Oxymap T1 (Oxymap ehf, Iceland) was used for measurements.
Results :
Oxygen saturation in retinal venules was 52.3±8.1% before intravitreal injection of bevacizumab, and 49.1±8.7% one week after injection, p=0.0043. The arteriovenous difference in oxygen saturation was larger after intravitreal bevacizumab injection 42.3±7.3%, compared to before injection, 40.2±6.1% p=0.021. There was no statistically significant difference in vessel diameter before vs. after the drug delivery.
Conclusions :
The results indicate that retinal oxygen metabolism is affected by the anti-VEGF antibody bevacizumab, when injected intravitreally. Several possible mechanisms may explain this phenomenon. This could include more effective oxygen uptake by the tissue, possibly due to reduced edema, and perhaps recovery from a hypoxic state; or unknown effects of the drug on oxygen metabolism or vasculature.
Further research is needed to find whether oximetry can serve as a biomarker for the efficacy of anti-VEGF injections.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.