COVID-19 May Reduce Choroidal Vascularity Index in Early Postinfectious Phase

Choroidal vascularity index (CVI) and luminal area significantly decrease in mild and asymptomatic COVID-19 during the early postinfectious period, according to a study published in Journal Français d’Ophtalmologie. Choroidal thinning is also observed, but these values fail to achieve statistical significance, according to the report.

Researchers enrolled 137 patients in the investigation including individuals who recovered from COVID-19 (n=65; 60% women; mean age, 39.09 years) and age- and sex-matched control group participants (n=72; 60% women; mean age, 39.61 years). The study participants underwent ophthalmic examinations which included biomicroscopy and dilated fundus evaluation. The team obtained choroidal thickness measurements at the subfoveal level, 1000 μm nasal to the fovea, and 1000 μm temporal to the fovea in addition to total choroidal area, luminal area, stromal area, and CVI measurements.

Participants recovering from COVID-19 had a significantly reduced total choroidal area, CVI, and luminal area compared with control group participants (0.56 vs 0.67 mm²; 0.65 vs 0.69; 0.36 vs 0.46 mm², respectively, P <.001 for all). Choroidal thickness was thinner among participants recovering from COVID-19 in the subfoveal (P =.366), nasal (P =.465), and temporal (P =.836) quadrants compared with individuals in the control group, but these values did not attain statistical significance.  

“[I]n the asymptomatic or mildly non-hospitalized patients in our study, COVID-19 may affect the choroidal vascular structure with a decrease in the number of vessels or narrowing in the vessel lumen due to systemic and local inflammation, endotheliitis, and prothrombotic state,” according to the researchers. “In addition, a non-significant change in [stromal area] indicates that the choroidal stroma may be affected less than the choroidal vascular structure.” 

Study limitations include the inability to obtain choroidal measurements during the active state of the virus due to quarantine, a lack of simultaneous optical coherence tomography-angiography (OCT-A) imaging, and the use of manual calipers to obtain choroidal thickness measurements.