Clinical Indications for Hyperbaric Oxygen Therapy

Hyperbaric consultation should be considered as early as possible when CRAO is confirmed or strongly suspected.

Particular consideration should be given when:

• Sudden painless monocular vision loss occurred recently
• CRAO has been confirmed by ophthalmologic examination
• Retinal tissue may remain viable
• An appropriate hyperbaric facility can be accessed promptly

Current evidence suggests that earlier treatment is associated with better visual outcomes, with the greatest benefit generally observed when HBOT begins within the first several hours after symptom onset.

Treatment within 24 hours may still be considered, but the likelihood of meaningful visual recovery decreases as retinal ischemia continues.

HBOT as Part of Emergency Stroke Care

CRAO should not be managed solely as an ophthalmologic disorder.

The American Heart Association recognizes CRAO as a form of acute ischemic stroke requiring urgent evaluation for vascular and embolic disease.

Evaluation may include:

• Emergency ophthalmologic assessment
• Neurologic evaluation
• Carotid vascular imaging
• Cardiac evaluation
• Electrocardiography
• Assessment for atrial fibrillation
• Stroke risk-factor assessment
• Evaluation for giant cell arteritis when clinically appropriate

HBOT should be coordinated with this evaluation and should not delay treatment of an identified underlying vascular or inflammatory condition.

Clinical Evidence and Guidelines

Central Retinal Artery Occlusion is recognized by UHMS as an accepted indication for HBOT.

The clinical evidence consists primarily of observational studies, retrospective cohorts, systematic reviews, and physiologic research rather than large randomized controlled trials.

Recent studies consistently suggest that treatment timing is one of the most important factors influencing outcome.

A 2026 systematic review and meta-analysis found that HBOT was associated with improved visual outcomes overall, with studies initiating treatment within 12 hours demonstrating the most consistent improvement.

A separate 2026 cohort of 101 eyes found substantially greater visual recovery when HBOT began within 12 hours, with benefit decreasing as treatment was delayed beyond 24 hours.

These findings support rapid recognition and referral while also highlighting the need for additional prospective clinical trials.

Medicare Coverage

Central Retinal Artery Occlusion is not specifically included among the nationally covered HBOT indications under Medicare National Coverage Determination 20.29.

This is an important distinction because CRAO is recognized as an HBOT indication by UHMS, but Medicare coverage criteria are separate from clinical guidelines.

Commercial payer policies may vary and should be reviewed individually.

When to Refer

Consider immediate hyperbaric medicine consultation when a patient develops:

• Sudden painless monocular vision loss
• Confirmed or strongly suspected CRAO
• Severe acute visual loss consistent with retinal ischemia
• Recent symptom onset with potentially viable retinal tissue

CRAO should be treated as a time-sensitive retinal ischemic stroke. Hyperbaric consultation should occur in parallel with urgent ophthalmologic and stroke evaluation.

The earlier HBOT can be initiated in an appropriate patient, the greater the potential opportunity to preserve retinal function.