Retinal vein occlusion is the obstruction or blockage of the retinal veins. The blockage, also known as occlusion, can occur because of a blood clot or fluid build-up in the tiny veins of the retina. It impacts the retina’s effectiveness in filtering light, and as a consequence, the patient’s sight.
The degree of vision impairment depends on the location of the occlusion. If the blockage occurs in the central or main vein it is known as central retinal vein occlusion (CRVO). This type of blockage is more serious and involves severe loss of vision. It may cause total loss of central vision. CRVO may also lead to glaucoma.
If the occlusion is located in the smaller retinal veins it is called branch retinal vein occlusion (BRVO). It may cause a missing area of vision or blurred vision. Often in BRVO, the eye naturally heals itself and vision improves again over time.
In most cases of RVO, vision problems occur because of fluid leaking from the blocked retinal blood veins inside the eye. A secondary cause of vision loss is the growth of new and abnormal retinal blood vessels. These blood vessels grow into the cavity inside the eye, and often, bleed and block off vision. This is referred to as vitreous hemorrhage.
Retinal vein occlusion is one of the most significant causes of blindness from retinal disorders worldwide. It is only second to diabetic retinopathy.
Also Known As
- Eye stroke
- Central retinal vein occlusion (CRVO)
- Branch retinal vein occlusion (BRVO)
Causes and Risk Factors
Often, retinal vein occlusions occur because of hardening arteries which cause blood clots. It is more like an eye stroke. Occlusions are more common in patients with damaged or narrow blood vessels. And, people with chronic disorders that cause blockages.
RVO risk factors include:
- Blood disorders affecting clotting
- High blood pressure or hypertension
- High cholesterol
- Age - people over 60
- Eye conditions such as macular edema, glaucoma, or vitreous hemorrhage
Signs & Symptoms
The primary sign or symptom of RVO is the sudden, painless, blurring or loss of vision. It can affect all or part of one eye.
Other symptoms may include:
- Dark spots or strings, floaters in the eye
- Pain in the eye, in severe cases
Retinal vein occlusion is diagnosed with a complete eye exam. The eye professional checks the patient’s vision and measures the intraocular pressure. The professional also examines the vessels and surfaces of the eye.
Other tests may include:
- Optical coherence tomography
- Fluorescein angiography
- Retinal photography
- Blood tests
Treatment seeks to maintain the stability of vision and focuses on the issues arising from the blockage.
There is no way to open or reverse the occlusion. Treatment prevents another occlusion from occurring in the same or the other eye.
The eye doctor may prescribe anti-VEGF therapy or steroid implant. Some patients are given blood thinners such as aspirin.
The doctor may use focal laser treatment where there is macular edema. Laser therapy also helps to stop the development of the blood vessels that can cause glaucoma.
A vitrectomy removes fluid and tissue from the inside of the eye.
RVO patients should watch their blood sugar, blood pressure, and cholesterol levels.
The long term outlook depends on the severity of the condition. Many patients recover and regain most of their vision.
Potential retinal vein occlusion complications include:
- Macular edema
- retinal ischemia
- Neo-vascular complications such as retinal traction, vitreous hemorrhage and glaucoma.
Patients should go for regular checkups to keep taps on the condition.
Retinal vein occlusion is a sign of general vascular disease. As such, measures that prevent other blood vessel disorders may decrease the risk of RVO.
Preventive measures include:
- Regular exercise
- A low-fat diet
- Lowering blood pressure
- Proper diabetes management
- Reducing HDL cholesterol
- Maintaining a healthy weight
- Not smoking
- Avoid excess alcohol
It is essential to note that getting regular eye exams helps to detect and diagnose any eye disorders early on.