What is Central Retinal Vein Occlusion (CRVO)?
Arteries carry blood from the heart to various parts of the body and veins return it. The venous circulation in the retina is like a tree with numerous branches, all of which drain into one major vein, the central retinal vein. When the central retinal vein is blocked, the retinal circulation of blood is halted or reduced, producing a back up of blood and fluid into the retinal tissue. An excessive accumulation of fluid is referred to as macular edema, which further decreases visual acuity can cause blurry or distorted vision.
CRVO is more common in patients with high blood pressure, arteriosclerosis, glaucoma, and diabetes. Rarely an underlying clotting disorder may be identified, though in some cases no clear cause is found. Your retina specialist will determine the appropriate systemic medical evaluation while taking your age and medical history into consideration.
What can be done to improve vision?
The only known way to improve vision is to treat the associated macular edema. Treatment options proven to be effective in reducing macula edema and improving vision to some degree include medicines injected into the eye such as vascular endothelial growth factor (VEGF) inhibitors (Lucentis – FDA approved, Eylea – FDA approved, Avastin – used off-label) or steroids (triamcinolone – used off-label, Ozurdex – FDA approved). Laser, surgery, eye drops, and glasses do not help to improve vision.
With time, a minority of patients may experience a spontaneous improvement in vision. However, in most cases the vision remains the same or worsens without treatment. The ultimate visual outcome cannot be accurately predicted, but in general, the more severe the occlusion and associated macular edema, the less likely that vision will improve spontaneously. Your retina specialist will review the risks, benefits, and alternatives of the various treatment options with you in further detail and make tailored recommendations based on the unique findings of your eye.
Why are follow-up visits necessary?
Patients need to be seen at regular intervals because in about one-third of all cases, a severe form of glaucoma called neovascular glaucoma develops and eye pressure can rise to very high, dangerous levels, which can cause irreversible damage to the optic nerve. If it looks like this is about to occur, a laser treatment and/or an injection of a VEGF inhibitor into the eye are necessary. Although these treatments can help prevent or control the glaucoma, they do not improve vision. In general, a patient should come back sooner than scheduled if there is ever a marked decrease in vision or eye pain.