Retinal Vein Occlusions
The retina is the light sensing tissue at the back of the eye. It is nourished by tiny blood vessels that bring blood into (arteries) and out (veins) of the eye. A retinal vein occlusion means that a vein in the retina has become clogged. The blockage causes a painless decrease in central or peripheral vision, resulting in blurry or distorted vision.
There are two types of retinal vein occlusions, branch retinal vein occlusion and central retinal vein occlusion. Branch retinal vein occlusion involves a blockage of a smaller vein, which then dilates and leaks fluid and blood into the retina. In a central retinal vein occlusion, the main vein exiting the eye becomes blocked within the optic nerve, causing more extensive retinal bleeding and swelling.
Retinal vein occlusions are more common in older individuals as well as persons with hypertension, diabetes, or glaucoma.