Time-Dependent Efficacy of Hyperbaric Oxygen Therapy in Central Retinal Artery Occlusion.

INTRODUCTION

To determine the effect of the timing of hyperbaric oxygen (HBO₂) treatment on functional and structural outcomes in central retinal artery occlusion (CRAO).

METHODS

This single‑center retrospective cohort study analyzed 101 eyes with CRAO treated with HBO₂. Eyes were stratified by symptom‑to‑treatment interval: ≤12 hours (Group 1), 12-24 hours (Group 2), 24-36 hours (Group 3), and >36 hours (Group 4). Best‑corrected visual acuity (BCVA-logMAR), central macular thickness (CMT), and inner retinal hyperreflective band thickness (IRHBT) were recorded at presentation, week 1, and month 6.

RESULTS

Presentation BCVA was 2.16 ± 1.04, improving to 1.77 ± 1.02 at month 6 (p = 0.03). The mean BCVA gain was greatest in Group 1: -0.85 ± 0.96, and declined markedly with delayed treatment initiation (Group 2: -0.48 ± 1.38; Group 3: -0.10 ± 1.50; Group 4: -0.08 ± 1.77). In Group 1, the mean BCVA improved significantly from 2.04 ± 0.78 logMAR at presentation to 1.19 ± 0.56 logMAR at the 6-month follow-up (p = 0.02). Early treatment was also associated with more pronounced reductions in CMT and IRHBT, whereas anatomical changes were negligible when therapy was initiated beyond 24 hours. Baseline CMT and IRHBT showed modest but significant correlations with final BCVA (r = 0.37, p = 0.03 , and r=0.34, p=0.04, respectively).

DISCUSSION: HBO₂ provides a significant, time-sensitive benefit for CRAO; initiating treatment within 12-24 hours maximizes recovery and retinal remodeling, validating HBO₂ as a critical adjunct and necessitating rapid triage in ophthalmic emergencies.