Not many people know that double vision or diplopia is not a disease, but can be the symptom of a disease. Joseph J. Allen, O.D., FAAO and creator of the YouTube channel Doctor Eye Health, looks at the causes of double vision.
One common cause is strabismus, or the eyes naturally turning in or out. Cross-eyes are the best well known form of strabismus. This can get worse when a person is tired. Strabismus can be treated with glasses or contacts, vision therapy and, in extreme cases, surgery.
A second common cause of double vision is thyroid eye disease. This is a problem of the autoimmune system. The body’s own cells attack the back of the eyes, causing the muscles around the eyes to swell. This can make people look bug-eyed. Thyroid eye disease can usually be treated with oral medication, but sometimes surgery is necessary.
Another common cause of double vision is myasthenia gravis. This is another problem of the autoimmune system. Neurotransmitters are important for communication between nerves and muscles. This condition interferes with that communication. Myasthenia gravis can progress so that people can’t swallow or breathe. It’s treated with medication, physical therapy and sometimes surgery.
Another disease that causes double vision is muscular dystrophy. Unfortunately, there is no cure, although there are treatments to help make life with the disease more manageable.