Abstract
BACKGROUND: COVID-19, caused by SARS-CoV-2, may lead to long-term retinal changes. Visual symptoms and retinal alterations have been reported in Long COVID; however, the available evidence remains limited. Swept-source OCT (SS-OCT) and OCT angiography (SS-OCTA) enable non-invasive evaluation of retinal structure and microvasculature. This study aimed to assess retinal alterations before and one year after COVID-19 using SS-OCT and SS-OCTA in a longitudinal design. METHODS: This prospective longitudinal study was conducted at West China Hospital, Sichuan University. All enrolled participants underwent SS-OCT and SS-OCTA before infection, and at 1 month, and 1 year after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Retinal structural and microvascular alterations were quantified using the Early Treatment Diabetic Retinopathy Study (ETDRS) grid, including the thickness of peripheral retinal nerve fiber layer (pRNFL), ganglion cell inner plexiform layer (GCIPL), inner nuclear layer (INL) and outer retina, and the vessel density (VD) of superficial vascular plexus (SVP), intermediate capillary plexus (ICP) and deep capillary plexus (DCP). The foveal avascular zone (FAZ) area was measured in the inner retinal layer. RESULTS: A total of 44 eyes from 22 participants were analyzed (mean age: 30.59 ± 9.36 years; 17 females and 5 males). Significant reduction in thickness of pRNFL, GCIPL, and outer retina, increased thickness of INL, decreased VD of SVP, and increased VD of ICP and DCP were observed in participants one month after COVID-19 infection (All P < 0.05), which remained persistently altered one year after COVID-19 infection (All P < 0.05). CONCLUSIONS: These findings indicate long-term retinal dysfunction following COVID-19 infection, highlighting the importance of ongoing ophthalmic monitoring. Non-invasive SS-OCT and SS-OCTA could offer valuable tools for detecting and managing retinal alterations associated with long COVID in the post-pandemic era.