Most eye problems are associated with disorders that occur within the confines of the eye. However, there are many vision problems that instead are related to the nervous system. Neuro-ophthalmology is a sub specialty of neurology and ophthalmology and requires specialized training and expertise in problems of the eye, brain, nerves and muscles.
A neuro-ophthalmologist, like Dr. R. Aouchiche, diagnoses and treats diseases of the visual pathways, such as optic nerve diseases, optic neuritis which is often seen in the context of multiple sclerosis or ischemic optic neuropathy, a circulation disturbance found in a disease of the elderly called temporal arteritis. These conditions represent ophthalmic emergencies and require prompt treatment to prevent total loss of sight.
Neuro-ophthalmologists also diagnose and treat conditions involving the ocular motor system which commonly cause diplopia (double vision) and encompass various disorders including thyroid disease, a muscle condition called myasthenia gravis and multiple circulatory conditions such as diabetes mellitus and hypertension.
Often seemingly unrelated neurologic disorders such as multiple sclerosis, brain tumors and strokes can affect the eyes.
To learn more about specific neuro-ophthalmologic diseases, click here (www.nanosweb.org)
Double vision – diplopia
Over the past several years, West Coast Eye Care has treated an increased number of patients for diplopia, commonly called double vision. Double vision can occur at any age and usually occurs as a consequence of the eyes being misaligned. It is not a normal state and can be a sign of serious eye or neurological disease. Each eye has six different muscles responsible for moving it which means the brain must control twelve muscles simultaneously through a pathway of nerve connections that course throughout the central nervous system.
What causes double vision?
Eye muscle control is complex and vulnerable to many disease conditions. Three different cranial nerves supply the eye muscles of each eye and any condition affecting them such as strokes, injuries or brain tumors can cause double vision. Diabetes frequently causes diplopia when the diabetic process is responsible for a small stroke to one of the cranial nerves. Thyroid disease and myasthenia gravis can affect the eye muscles also causing double vision.
Children can also experience double vision usually after an injury or infection such as a viral illness. Interestingly, children born with crossed eyes do not have diplopia. Their brain “turns off” or suppresses the information from a misaligned eye so that double vision does not occur. Adults do not have this protective mechanism and cannot suppress the double image.
Symptoms of double vision
A person with double vision sees two separate images – sometimes very close like a ghost image and some so far apart that the second image may be ignored. Images may be horizontally or vertically separated or both. Covering one eye usually eliminates diplopia. The condition and severity of the double vision may vary based on where the person is looking. For instance, images may appear closer together when looking to the right and further apart when looking to the left. Adopting a particular head position may make the images single again.
Treatment of double vision
Under certain circumstances, the underlying cause can improve spontaneously and double vision can regress without treatment. If not, diplopia may be treated by applying special optical devices called prisms to the patient’s glasses. This is usually done through a comprehensive eye muscle evaluation performed by an orthoptist or eye muscle technician. If diplopia persists after medical or orthoptic treatment, muscle surgery may be needed. Eye muscle surgery adjusts the muscles to straighten the eyes which will eliminate double vision.