Can hyperbaric oxygen therapy revolutionise the management of central retinal artery occlusion? A systematic review and meta-analysis of its efficacy and safety

Introduction Central retinal artery occlusion (CRAO) is a vision-threatening ophthalmic emergency with limited proven treatment options. Hyperbaric oxygen therapy (HBOT) may improve inner retinal oxygenation through choroidal diffusion, but its efficacy remains uncertain. Methods We conducted a Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-compliant systematic review and meta-analysis. Six databases were searched from inception to 3 February 2026. Comparative and non-comparative studies of HBOT for CRAO were included. The primary outcome was comparative best-corrected visual acuity (BCVA) using logarithm of the minimum angle of resolution (logMAR)-derived continuous data. Secondary outcomes included line gain, retinal revascularisation, adverse events and study-defined categorical visual improvement. Clinically non-equivalent categorical outcomes were narratively synthesised rather than pooled. Results Twenty-two observational studies were included. Comparative meta-analysis showed better final BCVA in HBOT-treated patients than controls at <6 months (mean difference 0.350 logMAR; 95% confidence interval (CI) 0.125 to 0.574; p=0.002; I-squared (I²)=0.0%) and ≥6 months (mean difference 0.419 logMAR; 95% CI 0.219 to 0.620; p<0.0001; I²=0.0%). Categorical visual improvement was variably defined as ≥0.3 logMAR gain, Snellen-line gain, any documented improvement or unspecified change, precluding pooling. Barotrauma was the most frequent adverse event (8.3%; 95% CI 3.6% to 17.7%). Conclusion HBOT was associated with better final BCVA in non-randomised CRAO comparisons, but certainty was very low. HBOT should remain an investigational, time-sensitive adjunct pending randomised trials. PROSPERO registration number CRD420251129566.