Difficulties with vision
Problems with the eyes are common in MS caused by damage either to the nerve that carries the visual signal from the eye to the brain (optic nerve) or to those controling the movement of the eye. Damage to the optic nerve is called optic neuritis and causes temporary loss or disturbance in vision, sometimes accompanied by pain behind the eye. Typically, normal vision is restored within a few weeks and it is rare for MS to cause total blindness. However, these symptoms often continue to recur, usually in one of eye at a time. Long term damage to the optic nerve can cause blurring of vision, which cannot be corrected with glasses, and/or loss of colour vision. Sometimes the person experiences a dark, blank area in the middle of their vision called a 'central scotoma' that also cannot be corrected with glasses.
Double vision, caused by weakening or lack of co-ordination of the eye muscles, also occurs. Patching one eye when driving or reading will stop the double image but a permanent patch will reduce the brain's ability to adapt to the problem and produce a single image on its own. Glasses with special prisms that minimise double vision are available in some cases.
One or both eyes may also suffer a rhythmic jerkiness called nystagmus that in most cases does not lead to apparent symptoms.
Treatment
A mild visual loss that you can cope with may well disappear on its own after a while. However, your doctor can offer a short course of steroids infused into the blood in order to try to reduce the severity and duration of the attack.
Reference
Averbuch-Heller L. Acquired Nystagmus. Current Treatment Options in Neurology 1999; 1(1):63-73.
