Retinal Vein Occlusion
Retinal vein occlusion is a condition that occurs when the natural venous drainage system of the retina gets blocked. There are two type of retinal vein occlusion: branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO).
The normal circulation of blood vessels to the retina involves arteries that bring oxygen and nutrients and veins that drain the deoxygenated blood away. When the vein gets blocked in a retinal vein occlusion, the pressure builds in the vessel and the small blood vessels leading up to that point of blockage burst and get damaged. This leads to bleeding within the retina in this area, swelling (since the vessels become leaky), and lack of proper blood supply. CRVO is caused by blockage in the main vein that drains the retinal vasculature, whereas a BRVO is caused by a blockage in a smaller vein that drains a portion of the retinal vasculature.
CRVO has two main types: ischemic CRVO and non-ischemic CRVO. In the ischemic form, major compromise in the blood supply to large parts of the retina has occurred. This form has a worse prognosis and could lead to loss of vision or even loss of the eye if not adequately treated.
The lack of blood supply, bleeding and swelling in the retina (see picture) can lead to blurry vision when it affects the macula. In addition, if the eye’s supply of oxygen is severely compromised, the eye can react by developing new abnormal blood vessels called neovascularization. This can lead to a potentially painful form of glaucoma called neovascular glaucoma, which could lead to too much pressure on the optic nerve and permanent vision loss. Less commonly, vein occlusion can also lead to vision loss when it causes scar tissue to build in the eye and/or causes retinal detachment.
How Is Retinal Vein Occlusion Diagnosed?
Retinal vein occlusion is diagnosed by doing a complete and dilated eye exam by your ophthalmologist. In addition, retina specialists perform a number of other tests including optical coherence tomography, photos and fluorescein angiogram to confirm the diagnosis and evaluate the extent of possible damage.
What Are the Risk Factors for Getting a Vein Occlusion?
Generally, retinal vein occlusion affects those that are 50 years or older. Risk factors are similar for CRVO and BRVO and include:
- High blood pressure
If a retinal vein occlusion happens in someone younger than age 50 or in both eyes, your doctor may order additional tests to rule out other inflammatory or hypercoagulable diseases that may cause this.
What Can Be Done to Prevent a Retinal Vein Occlusion?
About 10% of the time, a retinal vein occlusion can occur in the other eye. Thus, it is important to get checked by your primary care doctor and adequately treat those health issues that can increase your risk of vein occlusion.
What Is the Treatment of Retinal Vein Occlusion?
Treatment for retinal vein occlusion depends on the extent of damage. If there is macular edema causing blurry vision, there are several options:
Intravitreal injections of anti-vascular endothelial growth factor (anti-VEGF) medicines:
This treatment involves delivering medicine directly into the inside of the eye to chemically bind some of the signals that causes leaking into the eye. Read more ›
Intravitreal injections of steroids:
These medicines are delivered into the eye in a similar manner as anti-VEGF treatment. Some formulations of these medicines can last in the eye for months. Read more ›
Focal and grid laser treatment:
This laser surgery can directly treat the areas of leaks and stimulate the cells to pump out fluid from the area.
If neovascularization occurs, then scatter laser treatment is indicated to help shut off the signal for these new blood vessels to form. If neovascular glaucoma develops then additional treatments or even surgery may be needed with the help of a glaucoma subspecialist.
Sometimes the abnormal blood vessels may bleed into the eye, causing vitreous hemorrhage. Pars plana vitrectomy surgery may be indicated in cases of vitreous hemorrhage, macular scarring or retinal detachment associated with retinal vein occlusion.
If it is determined that the patient has a clotting disorder that led to vein occlusion, the patient may also need to take a blood thinner as part of their treatment, as directed by their primary care physician.
For More Information
- AAO: What Is Central Retinal Vein Occlusion (CRVO)?
- AAO: What Is Branch Retinal Vein Occlusion (BRVO)?