Definition and Causes
Central retinal artery occlusion (CRAO) is a blockage in one of the small arteries that supply blood to the retina of the
eye. The retina is the back wall of the eye that senses light and transmits images to the brain. People with CRAO experience
sudden blindness, blurring, or partial loss of vision. The vascular event is usually brief and painless, but retinal damage
and impaired vision may be permanent.
Artery blockages, or occlusions, are caused by clots or fat deposits circulating with the blood. Hardening of the arteries
(arterio- or atherosclerosis) and other cardiovascular diseases greatly increase the risk. CRAO may also be an early warning
sign of stroke, heart attack, or other life-threatening medical emergencies.
As a vascular event, CRAO differs from retinitis pigmentosa, macular degeneration, macular edema, and other progressive
diseases of the retina.
Hyperbaric Oxygen Approval Status
Arterial Insufficiencies: Central Retinal Artery Occlusion
page in the Undersea and Hyperbaric Medical Society resource library to learn more about CRAO, the rationale for hyperbaric
oxygen therapy, and clinical outcomes and success factors.
Treatment with Hyperbaric Oxygen Therapy
Hyperbaric oxygen therapy (HBOT) is one of the few treatments proven effective for central retinal artery occlusion. Physicians
may also use intravenous (IV) and topical medications or carbogen therapy, a combination of carbon dioxide and oxygen gas, to
reduce pressure and increase blood circulation in the eye. CRAO is a vascular event requiring speedy attention. Proper treatment
in the first 24 hours is critical.
The retina consumes oxygen at a rate faster than any other organ in the body. It is highly sensitive to ischemia, or lack
of blood supply. In the treatment of CRAO hyperbaric oxygen therapy has succeeded where others in the last 100 years have
But quick access to an emergency-ready chamber is a must. Or as
puts it, “Hyperbaric oxygen therapy (HBOT) may be beneficial if begun within 2-12 hours of symptom onset. Institute
treatment with other interventions first, as transport to a chamber may usurp precious time.” Central retinal artery
occlusion offers yet another good reason, then, for the healthcare community to demand 24/7 access to hyperbaric
HyperbaricLink recommends the following websites for anyone seeking authoritative information, patient advocacy, and community
support for central retinal artery occlusion, eye disease, and vision loss.
A service of the US National Library of Medicine and the National Institutes of Health, MedlinePlus offers plenty of helpful
links from its easy-to-read article on retinal artery occlusion.
The “Voice of the Nation’s Blind,” with more than 50,000 members, the NFB is a leading source of information about vision loss
and a strong force in advocacy, education, research, technology, and programs to improve blind people’s lives.
A volunteer eye health and safety organization dedicated to fighting blindness and saving sight, Prevent Blindness America
provides vision screening, education, advocacy, and research support.
The central retinal artery entry in Wikipedia provides some basic information about CRAO, with a few nice photographs and
medical illustrations of the eye.
Start with the following resources to explore current research activities and the peer-reviewed medical literature on
hyperbaric oxygen therapy for central retinal artery occlusion (CRAO).
ClinicalTrials.gov keeps the official list of human clinical trials currently enrolling, in progress, and recently completed.
One may reasonably question the size and legitimacy of any study not listed here.
Search ClinicalTrials.gov for current studies of retina + hyperbaric oxygen therapy
A specialized Google search engine, Google Scholar indexes scholarly articles, patents, and legal opinions and journals.
Google Scholar may generate excessive search results, but entries provide easy access to full-text journal articles.
Search Google Scholar for "retina" + "hyperbaric oxygen"
HBOEvidence uses computerized tools to appraise the key randomized controlled trials (RCTs) in the hyperbaric medical
literature. One may reasonably question the overall strength of HBOT evidence for any disease or condition not covered here.
Read the HBOEvidence appraisals for treatment of
with hyperbaric oxygen therapy.
A service of WebMD, Medscape offers specialists, primary care physicians, and other health professionals robust and integrated
medical information and educational tools.
Read the Medscape article
Central Retinal Artery Occlusion
US National Library of Medicine
National Institutes of Health
PubMed keeps the official list of scientific papers published in reputable peer-reviewed medical journals. One may reasonably question the importance and
legitimacy of any study not listed here.
Search PubMed.gov for journal articles relating to hyperbaric oxygen therapy and the retina
- Arterial insufficiencies
- Blood clot
- Carbogen therapy
- Eye disease
- Heart attack
- Macular degeneration
- Macular edema
- Retinitis pigmentosa
- Vascular event
- Vision loss
The Mind's Eye (unabridged audiobook)
by Oliver Sacks
(Random House Audio, 2010).