Central Retinal Vein Occlusion
The retina is fed by a system of blood vessels (arteries and veins) like a tree, with the trunk in the optic nerve and branches extending to the farthest edges of the retina. A central retinal vein occlusion (CRVO) is blockage of the large vein in the trunk thereby reducing blood flow to the entire retina. Since the retina is like film in a camera, a patient experiences central retinal vein occlusion as painless vision loss. Vision may be affected to varying degrees, and patients who present with relatively good vision tend to maintain good vision long-term.
Central retinal vein occlusion occurs most often in patients with high blood pressure, diabetes, carotid artery disease, or high intraocular pressure (glaucoma). In some cases, no clear cause is found for CRVO, and in some cases CRVO is caused by rare conditions such as blood disorders or medications that cause spontaneous clotting. Your doctor will determine the appropriate medical workup depending on your age and medical history.
Blood flow in the retina may be damaged permanently to some degree. Swelling may occur in the central part of the retina (macular edema). In some cases, the eye may grow abnormal blood vessels. Abnormal blood vessels in the front of the eye may cause elevated eye pressure, or neovascular glaucoma. Imaging tests may be helpful in identifying these complications of CRVO. Optical coherence tomography (OCT) is a non-invasive scan of the retina which measures and locates swelling in the retina. Fluorescein angiography (FA) evaluates blood flow in the retina with a series of photographs taken after intravenous injection of a dye (fluorescein).
Treatment of CRVO depends on the findings on examination and diagnostic imaging. If swelling is present in the macula (macular edema), your retinal surgeon may recommend injection of one or more medicines into the eye. If the eye is growing abnormal blood vessels (neovascularization), your surgeon may recommend laser treatment. In some cases, micro-incisional sutureless vitrectomy surgery is recommended to remove blood from the eye or to treat macular edema that has not responded to any other treatments. In all cases, treatment of underlying medical conditions such as high blood pressure or diabetes is critical to preventing another retinal vein occlusion in the future.
Treatments for macular edema associated with central retinal vein occlusion include laser, intravitreal injection (injection of medicine into the eye), or surgery. Medications which can be injected into the eye in these cases include bevacizumab (Avastin, which is used off-label for this condition), ranibizumab (Lucentis, which is FDA approved for this condition), aflibercept (Eylea, which is FDA approved for this condition), and dexamethasone (Ozurdex steroid implant, which is FDA approved for this condition).