X.L.NG1, A. SHRIVASTA2, S.W.T. ZHOU3, J.M.LEE1, H. CHUN1, R.MAITRA2, S.NATARAJAN4, R.AGRAWAL1
Tan Tock Seng Hospital1, Radical Health, New Delhi, India2, Khoo Teck Puat Hospital3, Aditya Jyot Eye Hospital, Mumbai, India4
To evaluate the impact of COVID-19 infection on retinal microvascular structure and its effect on the global and focal retinal arteriole-to-venule ratio (AVR) across retina.
In a comparative cross-sectional case-control study, fundus photos were obtained in COVID-19 infected patients and healthy controls. Retinal arteriole-to-venule ratio was measured over 16 points across the retina using retinal vascularity index (RVI) – a novel semi-automated computerized parameter based on retinal vasculature. A linear mixed model was generated using age and gender as covariates in both the groups.
51 COVID-19 positive patients and 65 healthy controls were enrolled in the study. Overall, the mean RVI of all 16 points across the retina was 0.32 ± 0.02 in COVID-19 patients and 0.34 ± 0.02 in control subjects (P=0.438). Out of the 16 points being measured, 4 points had statistically significant greater value in COVID patients as compared to those in normal controls.
An influence of COVID infection on retinal vascular alterations was not ascertained in our study based on RVI results. However, localised greater RVI values were found in some of the points in COVID positive patients , which indicates a likely more focal change of the vasculature. This prompts further development of different architectural retinal vascular parameters to consolidate the use of retinal vascular indices in evaluating various types of retinal microangiopathy.