Short and long-term impact of intravitreal anti-VEGF therapy interruption in retinal vein occlusion during the COVID-19 pandemic: functional outcomes and AI-based fluid analysis of macular edema.

Background: The aim of the study is to investigate the short- and long-term effects of delayed intravitreal anti-VEGF injections (IVI) for macular edema (ME) in retinal vein occlusion (RVO) patients during the first wave of the COVID-19 pandemic.

Methods: This is a retrospective observational study analyzing a cohort of patients followed at the medical retina department of the Jules Gonin Eye Hospital. During the COVID-19 lockdown, treatment for patients with ME secondary to RVO was deferred due to emergency federal dispositions. The impact on best corrected visual acuity (BCVA) and on OCT changes (i.e. central subfield thickness (CST), intraretinal fluid (IRF), and subretinal fluid (SRF)) were assessed at several time points before and after the lockdown over a 2-year period. The OCT parameters were assessed by the mean of an artificial intelligence (AI) software (Discovery, RetinAI).

Results: A total of 64 patients were included in the study. BCVA significantly decreased following a mean treatment delay of 10 weeks. However, BCVA returned to baseline levels after 6 months, with no significant differences observed after 2-years of follow-up. OCT analysis revealed an increase in CST, IRF and SRF following the treatment delay, which decreased and return to pre-lockdown values after 3 months. No significant differences in OCT parameters were observed at the two-year follow-up.

Conclusion: The results of our study suggest that delaying IVI for RVO patients during the COVID-19 lockdown resulted in a temporary decline in BCVA and a recurrence of ME. However, these effects were not sustained long term, as both BCVA and ME control returned to baseline levels by 6 months, with no significant changes observed at the two-year follow-up.