Evaluation of Retinal and Optic Nerve Parameters in Recovered COVID-19 Patients: Potential Neurodegenerative Impact on the Ganglion Cell Layer

<b>Background/Objectives:</b> This study aimed to analyze optic nerve parameters, retinal nerve fiber layer thickness (RNFLT), ganglion cell layer thickness (GCLT), and subfoveal choroidal thickness (ChT) in patients who have recovered from coronavirus disease 2019 (COVID-19). <b>Methods:</b> This comparative study included 78 recovered COVID-19 patients (16 men, 62 women) and 56 age- and sex-matched healthy controls (18 men, 38 women). COVID-19 was confirmed in all patients, either through the detection of viral RNA in nasopharyngeal swabs via reverse transcriptase polymerase chain reaction or by serological testing for SARS-CoV-2 antibodies. Spectral-domain optical coherence tomography (SD-OCT) was used to assess optic nerve parameters, RNFLT, GCLT, and ChT. <b>Results:</b> The mean age was 35.0 ± 8.3 years in the COVID-19 group and 31.5 ± 8.3 years in the control group, with no statistically significant differences in age or sex distribution between groups (<i>p</i> = 0.41 and <i>p</i> = 0.16, respectively). Optic nerve parameters and RNFLT (overall and across the four peripapillary quadrants) did not differ significantly between the COVID-19 and control groups. However, the mean ganglion cell-inner plexiform layer (GC-IPL) thickness was significantly reduced in all quadrants in the COVID-19 group compared to the controls. No significant difference was observed in mean subfoveal ChT between groups. <b>Conclusions:</b> A significant reduction in ganglion GCLT was observed in recovered COVID-19 patients compared to healthy controls, suggesting a potential neurodegenerative effect of the disease on the optic nerve.