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 transports 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 have a blood clot. This is called an
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 elderly people.
What are the Different Types of Retinal Vascular Occlusion?
There are two types of retinal vascular occlusions. The type
depends on which type of 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
- 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.
Causes of Retinal Vascular Occlusion
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
- 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
- rare blood disorders
- macular edema, which is fluid buildup, swelling,
and thickening of the central part of the retina
Symptoms of Retinal Vascular Occlusion
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 optometrist, or eye
doctor, right away if you experience any changes in your vision.
Complications of Retinal Vascular Occlusion
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.
Diagnosing Retinal Vascular Occlusion
Your optometrist will perform a comprehensive exam to help
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.
Preventing Retinal Vascular Occlusion
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:
- 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.
Treating Retinal Vascular Occlusion
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 your other
eye is at risk.
Outlook for People with Retinal Vascular Occlusion
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
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.
Retinal vascular occlusion is a potentially serious
condition. A blood clot that continues to move throughout your blood stream
could cause a stroke.