Hyperbaric Oxygen Therapy for Retinal Artery Occlusion

Central retinal artery occlusion (CRAO) is a stroke of the eye. The artery supplying the retina becomes blocked, cutting off oxygen to the tissue that makes sight possible. HBOT can keep retinal cells alive by delivering oxygen through an alternate path, buying time for the eye.

What Central Retinal Artery Occlusion Is

The central retinal artery is the primary blood supply to the retina. When it’s blocked, the result is sudden, painless vision loss in one eye. Patients often describe it as a curtain dropping across their vision.

Common causes include blood clots (emboli), atherosclerosis narrowing the artery, cardiac conditions, and hypercoagulable states that make clotting more likely.

The retina is unforgiving. It begins dying within 90-100 minutes of losing blood flow. And unlike many other conditions where the treatment window is days or weeks, CRAO is measured in hours.

If you experience sudden painless vision loss in one eye, call 911 or get to an emergency room immediately. Don’t wait to see if it improves.

Why HBOT Is the Treatment

When the retinal artery is blocked, the retina is starved of oxygen. The cells are still alive, but they won’t stay that way long.

HBOT supersaturates blood plasma with oxygen at 10-15 times normal concentration. At that level, oxygen dissolves directly into the plasma rather than relying on red blood cells to carry it. From the plasma, it can diffuse through the vitreous humor and adjacent tissue, reaching the retina through pathways that don’t depend on the blocked artery.

The goal isn’t to fix the blockage. It’s to keep retinal cells alive long enough for the blockage to clear, for other treatments to help, or for collateral circulation to develop.

In 2024, CMS added CRAO to Medicare’s NCD 20.29 coverage, recognizing the growing clinical evidence supporting HBOT as part of the CRAO treatment approach.

What the Research Shows

Hadanny et al. (2021) published findings on HBOT for acute CRAO, showing visual improvement in a portion of patients treated within the therapeutic window. The UHMS and ophthalmology societies increasingly include HBOT in the CRAO treatment pathway when a hyperbaric facility is available.

The treatment window matters enormously. Most benefit occurs within hours of symptom onset. After 24 hours, the chance of meaningful visual recovery drops sharply.

Who Treats CRAO with HBOT

CRAO treatment involves multiple specialists. An ophthalmologist manages the eye, an emergency medicine physician handles the acute presentation, and a hyperbaric medicine physician oversees the HBOT sessions.

Not every hospital has a hyperbaric chamber on site. Transfer to a facility with one may be necessary. That’s a reason to move fast. Call the nearest hyperbaric facility while simultaneously getting emergency eye care.

Find a hyperbaric provider near you at our provider directory. For information on what HBOT costs and how insurance works, see our cost guide and insurance guide.

For a full list of conditions treated with HBOT, visit the conditions hub.

Frequently Asked Questions

What other treatments are used for CRAO besides HBOT?

Other approaches your care team may consider include anterior chamber paracentesis (reducing eye pressure to dislodge a clot), intraocular pressure-lowering medications, and ocular massage. HBOT is typically used alongside these, not instead of them. Your ophthalmologist and emergency physician will determine the right combination.

Can HBOT restore vision lost to CRAO?

It depends on how quickly treatment begins and how much of the retina has been damaged. Some patients treated promptly see meaningful visual improvement. Others see partial recovery. Treatment started after 24 hours is much less likely to help. Ask your care team for a realistic assessment based on your specific situation.

Is CRAO different from a branch retinal artery occlusion?

Yes. A branch retinal artery occlusion (BRAO) affects only a part of the retina, causing partial vision loss. CRAO affects the entire central retinal artery and typically causes more complete vision loss. Both may be treated with HBOT, though CRAO is the more urgent situation.

References

Hadanny, A. et al. (2021). Hyperbaric oxygen therapy for acute central retinal artery occlusion: A prospective study. Clinical Ophthalmology. PMID: 33395388. https://pubmed.ncbi.nlm.nih.gov/33395388/

Medical Disclaimer: This page is for informational purposes only. It does not constitute medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before pursuing any medical treatment.