Most people know that high blood pressure and other heart diseases pose risks to your overall health. But many do not know that that high blood pressure can affect vision by damaging the arteries in the eye.
A retinal artery occlusion (RAO) is a blockage in one or more of the arteries of your retina. The blockage is caused by a clot or occlusion in an artery, or a build-up of cholesterol in an artery. This is similar to a stroke.
There are two types of RAOs:
- Branch retinal artery occlusion (BRAO) blocks the small arteries in your retina.
- Central retinal artery occlusion (CRAO) is a blockage in the central artery in your retina. This is a form of a stroke in the eye and must be evaluated and treated immediately, just like a stroke
What are symptoms of a retinal artery occlusion (RAO)?
The most common symptom of a retinal artery occlusion (RAO) is sudden, painless vision loss. It can affect all of one eye, in the case of a central retinal artery occlusion (CRAO), or it can affect part of one eye, in the case of branch retinal artery occlusion (BRAO). Other symptoms include:
If you have any of these symptoms, get medical help right away to help prevent vision loss.
Who is at risk for a retinal artery occlusion (RAO)?
Men are more likely to have an RAO than women. The disease is most commonly found in people in their 60's. Having certain diseases increases your risk of RAO. These include:
How is a retinal artery occlusion (RAO) diagnosed?
If you experience sudden vision loss, you should contact your ophthalmologist immediately. He or she will conduct a thorough examination to determine if you have had a retinal artery occlusion (RAO). Your ophthalmologist will dilate your eyes with dilating eye drops. This will allow him or her to examine the retina for signs of damage.
Other tests your ophthalmologist may do are:
Since RAOs involve other aspects of your general health, your ophthalmologist will likely communicate with your primary care provider.
People who have RAOs are at a greater risk for having a stroke (when blood flow to the brain is cut off), so your ophthalmologist or regular doctor may order:
- an ultrasound of your carotid arteries (the main blood vessels in your neck that send blood to your eyes and brain). An ultrasound is a medical test that uses soundwaves to create images of the organs and tissues inside your body.
- an echocardiogram (ultrasound of the heart)
Both of these tests help look for blockage in the retinal artery. This is best done in an emergency room, much like a stroke evaluation. In most cases of CRAO, referral to a stroke center for evaluation is recommended because the risk of stroke is very high during the first 1 to 4 weeks.
Several treatments for retinal artery occlusion (RAO) may be tried but none have ever been proven to help consistently. These treatments must be given within a few hours after symptoms begin to be helpful. Treatments include:
- Breathing in (inhaling) a carbon dioxide-oxygen mixture. This treatment causes the arteries of the retina to widen (dilate)
- Removing some liquid from the eye to allow the clot to move away from the retina
- A clot-busting drug
Some patients regain vision after an RAO, although vision is often not as good as it was before. In some cases, vision loss can be permanent.