Retinal vein occlusion
Retinal vein occlusions are the second most common cause of blood vessel-related vision loss (the first is diabetic retinopathy). The condition occurs most often in men and women over the age of 50, particularly those in their 60s and 70s. Risk factors include high blood pressure, high cholesterol, diabetes, smoking, glaucoma, and, rarely, blood clotting and inflammatory conditions.
Treatment depends on the severity of the blockage and the location of the blocked vein. If the largest vein leaving the eye is affected, the condition is known as a central retinal vein occlusion, or CRVO; otherwise, it is called a branch retinal vein occlusion, or BRVO. BRVOs often occur with no pain or noticeable loss of vision. It is important to have routine eye exams to detect any developing problems early. You can keep tabs on your vision between appointments by closing one eye at a time.
Retinal vein occlusions are detected during a retinal exam. A fluorescein angiogram may be performed to confirm the diagnosis and/or aid in treatment planning. Indications that an occlusion is present include bleeding in the eye, macular swelling or ischemia (loss of blood supply), and neovascularization – abnormal growth of new blood vessels. The initial bleeding can prevent the ophthalmologist from seeing any other symptoms for three to six months or longer. The patient is monitored during this time until the blood clears.
There are now treatments available for treatment of complications of Vein occlusions. Anti-VEGF agents such as Avastin, Lucentis or Eylea can be injected in the eye to treat macular edema or neovascularization. Laser photocoagulation treatment can also be used for complications of vein occlusion like neovascularization. Emphasis is also placed on risk management, treatment of symptoms and prevention of further vision.
Macular swelling may also be treated with lasers or steroids. Surgery may be recommended if scar tissue forms on the retina. Neovascularization typically appears six months to a year after the occlusion. It can cause bleeding, retinal detachment and reduced vision in its advanced stages, so laser photocoagulation treatment is recommended to slow or stop vessel growth. If bleeding continues, a vitrectomy may be performed to remove the blood and abnormal vessels and some of the vitreous gel. Vitrectomy can also relieve tension from a retinal detachment. Selected BRVO patient may undergo a vitrectomy followed by an arteriovenous sheathotomy, a new procedure in which the blocked vein is surgically separated from the artery compressing it.
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