Ocular microvascular changes in COVID-19: role of hypoxia, D-dimer, IL-6 and systemic treatment

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been associated with endothelial dysfunction, which may also compromise the microcirculation within ocular tissues. This prospective study evaluated associations between radial peripapillary capillary (RPC) vessel density (VD) and systemic treatment, age, hypoxia, D-dimer, and interleukin-6 (IL-6) levels in patients recovering from coronavirus disease 2019 (COVID-19) related pneumonia.

Sixty-three individuals who were admitted to the hospital due to COVID-19 bilateral pneumonia underwent ophthalmic examination two months post-discharge. RPC VD was measured using optical coherence tomography angiography. Associations with age, arterial hypertension, and systemic treatment (dexamethasone, remdesivir, and oxygen therapy), oxygen saturation, D-dimer, and IL-6 levels were evaluated. The control group comprised 43 control participants with no history of COVID-19 who attended routine ophthalmic examinations.

No ophthalmic abnormalities were detected. RPC VD did not differ significantly with hypertension or systemic treatment with dexamethasone and remdesivir. However, patients receiving oxygen therapy had higher RPC VD. A borderline inverse correlation was observed between inferior RPC VD and age. There were no correlations between RPC VD and oxygen saturation. Significant inverse correlations were found between nasal RPC and mean RPC with D-dimer levels and between inferior RPC VD and IL-6 levels. No significant differences in RPC parameters were observed when comparing the COVID-19 group with controls.

Hypertension or systemic treatment had no significant effect on RCP VD. However, VD in specific RPC areas correlated inversely with D-dimer and IL-6 levels, highlighting the need for monitoring peripapillary microvasculature for potential long-term ocular effects of COVID-19.