Just as a stroke can occur suddenly and without warning, symptoms of a retinal vein occlusion or ‘eye stroke’ usually occur quite suddenly. A sudden loss of vision, or sudden blurring of vision, is often the first sign that many people are aware of. The severity of symptoms differs from person to person. It depends on whether the blockage is central or a branch vein.
Branch retinal vein occlusion (BRVO)
A branch retinal vein occlusion (BRVO) refers to a blockage of the smaller retinal veins. This usually results in blurred vision or a missing area of vision. Many people with a BRVO find that their vision gradually improves again over time, as the eye naturally heals itself.
Central retinal vein occlusion (CRVO)
A blockage to the central or main retinal vein is more serious. Usually, it involves a more severe loss of vision. Total loss of central vision is not unusual, and recovery is less likely than with a BRVO.
In most cases of retinal vein occlusions, vision problems are caused by fluid leaking from blocked blood vessels into the vitreous ‘gel’ inside the eye.
However, a secondary problem is the growth of new and abnormal blood vessels. These grow into the vitreous cavity rather than into the damaged retina and often bleed, blocking off vision. This is known as a vitreous haemorrhage.
CRVO, in particular, can also lead to glaucoma in some people.