What is retinal vascular occlusion?

Retinal vascular occlusion affects the eye, specifically the retina. The retina is the light-sensitive layer of tissue that lines the back of your eye. It’s covered with special cells called rods and cones that convert light into neural signals and send these signals on to the brain so you can see. The retina is vital for vision.

The vascular system includes blood vessels called arteries and veins, which transport blood throughout your body, including your eyes. Your retina requires a constant supply of blood to make sure your cells get enough nutrients and oxygen. Blood also removes the waste your retina produces. However, it’s possible for one of the vessels carrying blood to or from the retina to become blocked or to have a blood clot. This is called an occlusion.

The occlusion can cause blood or other fluids to build up and prevent the retina from properly filtering light. When light is blocked or fluids are present, a sudden loss of vision can occur. The severity of vision loss may depend on where the blockage or clot occurred.

Retinal vascular occlusion is a potentially serious condition, especially if hardening of the arteries, or atherosclerosis, already exists. It most often occurs in middle-aged and older people.

There are two types of retinal vascular occlusion. The type depends on which blood vessel is affected:

Retinal artery occlusion

Retinal artery occlusion is a blockage of one of the retinal arteries, which are blood vessels that carry oxygenated blood from the heart to your retina. A blockage in the main artery of your retina is called a central retinal artery occlusion. A branch retinal artery occlusion happens when the blockage occurs further along in the smaller branches of your artery.

Retinal vein occlusion

Retinal vein occlusion is blockage of one of your retinal veins, which are blood vessels that carry deoxygenated blood back to your heart. Retinal vein occlusion is also divided into two types:

  • Central retinal vein occlusion (CRVO) is a blockage in the main vein of your retina, which is called the central retinal vein.
  • Branch retinal vein occlusion (BRVO) occurs when the blockage is in a smaller branch of veins throughout the retina.

Blockages in your main vein or artery are often more serious than blockages in your branch veins or arteries.

The specific cause of vascular blockage or blood clots in the retina is unknown. It may occur when the veins of the eye are too narrow. However, other factors that affect blood flow can put you at a higher risk of having retinal vascular occlusion. These risk factors include:

  • atherosclerosis, or hardening of the arteries
  • blood clots, which often travel from elsewhere in the body to the eye
  • a blockage or narrowing in the carotid arteries of the neck
  • heart problems, including irregular rhythm or valve issues
  • diabetes
  • high blood pressure
  • high cholesterol
  • being overweight
  • intravenous (IV) drug use
  • being over the age of 60
  • glaucoma, which is a condition that damages your optic nerve
  • smoking
  • rare blood disorders
  • macular edema, which is fluid buildup, swelling, and thickening of the central part of the retina
  • inflammatory disorders such as giant cell arteritis

The primary symptom of retinal vascular occlusion is a sudden change in vision. This could include blurry vision, or a partial or complete loss of vision.

The vision symptoms usually only occur in one eye. Physical pain is not a symptom of retinal vascular occlusion.

The changes in eyesight could be short term or permanent, depending on how quickly you seek treatment and if you have other health conditions. You should make an appointment with your ophthalmologist, or eye doctor, right away if you experience any changes in your vision. Definitely go to the emergency room immediately if you suddenly lose your vision in one eye.

The condition can occasionally lead to complications and more serious symptoms. Vision may be severely and permanently affected if any of the following complications occur:

Macular edema is a swelling in the macula, or the central part of your retina, due to a buildup of blood.

Neovascularization is an abnormal growth of blood vessels caused by poor blood flow and a lack of oxygen to your retina.

Neovascular glaucoma involves fluid buildup and high pressure in your eye. This is a serious complication. It’s associated with severe vision loss and possibly loss of the eye.

Retinal detachment is rare. It’s a separation of your retina from your eye tissue.

Your ophthalmologist will perform a comprehensive exam to diagnose retinal vascular occlusion. They’ll check your vision, pressure within your eyes, and the physical appearance of your eyes. Your doctor will assess your eye function and the look of the pupil. They may also measure your blood pressure and suggest a blood test to check for blood clotting conditions.

The following eye tests may also be done:

  • Optical coherence tomography (OCT) can be used to take a high definition image of your retina.
  • An instrument called an ophthalmoscope can be used to examine your retina.
  • In fluorescein angiography, a dye is injected into a certain vein in your arm. This vein is the one that travels to the blood vessels of the retina. Your doctor can use this to see what happens to the dye once it’s in your eye.

Your doctor may suggest other heart tests if they suspect blood clots are coming from somewhere else in your body. These tests may include an echocardiogram, electrocardiogram, and a heart monitor to check your heart’s rhythm. These tests will assess your heart and vascular system.

The best way to prevent retinal vascular occlusion is to identify and treat the risk factors. Since retinal vascular occlusion stems from vascular issues, it’s important to make lifestyle and dietary changes to protect your blood vessels and keep your heart healthy. These changes include:

  • exercising
  • losing weight or maintaining a healthy weight
  • eating a healthy diet low in saturated fat
  • not smoking or quitting smoking
  • controlling diabetes by keeping your blood sugar at a healthy level
  • taking aspirin or other blood thinners after consulting with your doctor first

Routine checkups with your doctor can help you learn whether or not you have any of the risk factors of retinal vascular occlusion. For example, if your doctor discovers you have high blood pressure or diabetes, you can start preventive treatment right away.

There’s no medication available that’s specific for retinal artery occlusions. Most people with this condition will have permanent changes to their vision.

To treat retinal vascular occlusion, your doctor may recommend medication such as blood thinners or injections into the eye.

Medications used to treat retinal vein occlusion include:

  • antivascular endothelial growth factor (anti-VEGF) drugs such as aflibercept (Eylea) and ranibizumab (Lucentis), which are injected into the eye
  • corticosteroid drugs that are injected into your eye to control the swelling

In some cases, laser therapy can be used to break down the blockage in the blood vessels and to keep more damage from occurring.

It’s possible to develop a blockage in your other eye. Your doctor will develop a prevention plan for you if they’re concerned that your other eye is at risk.

The outlook depends on the severity of your condition. Many people will recover and regain most of their vision capabilities, but not all. It’s possible that your vision will not return. Since retinal vascular occlusion typically only affects one eye, your brain may adjust to the change in vision after a few months. Once the eye adjusts, the loss of vision may become less of a problem for you.

If you have other eye conditions or complications from retinal vascular occlusion, such as complete vision loss or glaucoma, you may not fully recover your vision. You’ll need to work with your doctor to ensure that your eye conditions are managed properly.

The treatment of risk factors like diabetes and atherosclerosis dramatically reduces your risk of the occlusion recurring or causing further damage. In rare cases, a blood clot that continues to move throughout your bloodstream could cause a stroke.