Retinal Vein Occlusion

Types

There are two types of retinal vein occlusion:

• Central retinal vein occlusion: There is one central retinal vein in each eye. It is the main vein that all the smaller branch retinal veins merge into. The occlusion of the central retinal vein often leads to severe visual loss due to the extensive areas involved.
• Branch retinal vein occlusion: A branch vein is occluded, resulting in a localized damage to the retina. Severity of visual loss depends on the location of the occluded branch. If the branch occluded is near the center of the vision, visual loss can be significant.

Causes

The most common cause of the vein occlusion is arteriosclerosis, a hardening of the crossing artery due to plaque build-up, resulting in the narrowing of the vein and eventual blockage. This process is similar to the pathologic process underling the stroke and heart attack. Retinal vein occlusion is more common in certain people who have hypertension, glaucoma, diabetes, older age, and blood disorders.

Symptoms

Sudden onset of blurred vision in one eye is the most common presenting symptoms. This occurs when the central part of the retina, called the macula, develops swelling due to the leakage of fluid from the occluded vein. Pain is usually absent unless high eye pressure develops inside the eye due to the growth of abnormal blood vessels in the iris in response to the chronic poor blood flow. This condition, called neovascular glaucoma, has a poor prognosis and usually require surgery. Sometimes bleeding into the vitreous cavity of the eye can occur if the abnormal blood vessels grow on the surface of the retina. This can cause a sudden appearance of moving black spots in the vision.

Diagnostic tests
Complete eye examination with dilation of the pupil is needed to diagnose retinal vein occlusion. Special tests such as a fluorescein angiogram and the OCT help diagnose and plan treatment strategy.

Treatment

1. Intraocular injection of anti-angiogenic drugs such as steroids and Avastin, Lucentis, Vabysmo, Eylea and Eylea HD are mainline treatments to resolve macular edema due to vein occlusion.

2. Laser is used to prevent growth of abnormal blood vessels. It is also sometimes used, to reduce macular edema in conjunction with anti-angiogenic drugs.

3. Pars Plana Vetrectomy is sometimes used in case of severe bleeding into the vitreous cavity.

4. Evaluation by your primary care physician is advised to treat any contributing systemic diseases such as hypertension and hyperlipidemia.