Introduction: We aimed to assess the efficacy and safety of a standardized hyperbaric oxygen (HBO2) therapy protocol in patients with retinal artery occlusion (RAO). Methods: A retrospective study was conducted in our tertiary care center from July 2016 to September 2019. Patients experiencing central RAO and branch RAO for less than seven days were included. Once the diagnosis was made, patients were urgently referred to the HBO2 department to receive a first 90-minute HBO2 session at a pressure of 2.5 ATA. Patients underwent two daily sessions seven days a week for at least 15 days. If no reperfusion was seen on fluorescein angiography on Day 15, treatment was continued for an additional week with an assessment on Day 21. The primary endpoint was BCVA improvement defined as a decrease by 0.3 logMAR at one month. Results: Twenty-eight patients were included during the study period. Fifty-seven percent of patients were treated more than 12 hours after the onset of the first symptoms. The mean BCVA was 1.5 logMAR at the time of referral and improved to 0.9 logMAR after HBO2 (p=0.001). A multivariate analysis identified a high blood pressure (p=0.039) and a low initial BCVA (p=0.005) as poor prognostic factors. Conclusion: Performing HBO2 sessions twice daily at a pressure of 2.5 ATA appears to be an effective and safe treatment for RAO.