Retinal oximetry does not predict 12-month visual outcome after anti-VEGF treatment for central retinal vein occlusion: A multicentre study
Abstract
Purpose: Central retinal vein occlusion (CRVO) entails retinal hypoxia that often causes visual impairment. It has been shown that oxygen saturation in larger retinal vessels correlates with the visual acuity at the time of diagnosis of CRVO but has no predictive value for the visual outcome in patients treated with anti-VEGF medication after 3 months.
However, assessing the predictive value of retinal oxygen saturation after 12 months is essential because this is when the main restitution after CRVO occurs. Methods: Retinal oximetry was performed in 117 patients referred with CRVO to three European centres.
The correlation between oxygen saturation and visual acuity at baseline and the predictive value of oxygen saturation in larger retinal vessels for the 12-month visual outcome after treatment with anti-VEGF medication were studied. Results: In the affected eye, the oxygen saturation was significantly higher in the arterioles, significantly lower in the venules, and the arterio-venous (A-V) significantly higher than in the unaffected eye (p < 0.001 for all comparisons).
Correlations between best-corrected visual acuity (BCVA) and oxygen saturations were moderate and negative for arterioles (p < 0.001), positive for venules (p = 0.03) and negative for the A-V difference (p = 0.001). Best-corrected visual acuity (BCVA), but not oxygen saturation or the other explanatory variables at baseline, contributed significantly to predicting BCVA after 12 months.
Conclusion: Retinal vessel oxygen saturation is affected in CRVO, and saturation correlates with BCVA. However, retinal oximetry cannot replace measures of visual function as a predictor of visual outcome after 12 months of anti-VEGF treatment for CRVO.