Hyperbaric Oxygen Therapy in Acute Retinal Ischemia (CRAO and BRAO): A Narrative Review

Background

Acute retinal ischemia, including central retinal artery occlusion (CRAO) and branch retinal artery occlusion (BRAO), is associated with sudden and often profound visual loss, with no universally accepted effective treatment. Hyperbaric oxygen therapy (HBOT) has been proposed as a potential rescue therapy by enhancing retinal oxygenation through choroidal diffusion, particularly in the early stages of ischemia; however, its clinical role remains controversial.

Objective

To provide a narrative review of the current clinical evidence regarding the use of HBOT in acute retinal ischemia caused by CRAO and BRAO, with a focus on treatment timing, therapeutic protocols, and visual outcomes.

Methods

A narrative review of English-language studies published between January 2016 and December 2025 was conducted using PubMed. Studies evaluating HBOT in CRAO or BRAO were included. Data regarding treatment timing, protocols, and visual outcomes were synthesized descriptively.

Results

Twenty-three studies met the inclusion criteria, comprising predominantly case reports, small case series, and retrospective cohort studies, with a limited number of prospective investigations. Baseline visual acuity was typically poor, frequently exceeding 2.0 logMAR. HBOT protocols were heterogeneous but most commonly involved 100% oxygen at pressures between 2.0 and 2.8 ATA, with session durations of 90-120 minutes and intensified treatment during the first 24-72 hours. Across studies, clinically meaningful visual improvement (≥0.3 logMAR) was reported in a substantial proportion of patients, particularly when HBOT was initiated early. Patients with BRAO generally demonstrated more favorable visual recovery compared with those with CRAO. Several studies also reported visual improvement despite delayed initiation of HBOT beyond traditional therapeutic time windows.

Conclusions

HBOT has been associated with visual improvement in selected patients with retinal artery occlusion, particularly when treatment is initiated early. Visual outcomes are more favorable in branch retinal artery occlusion than in central retinal artery occlusion, and HBOT is generally well tolerated.

However, the available evidence remains limited and heterogeneous, highlighting the need for prospective, standardized studies.