Eye movement is controlled by three cranial nerves and several central gaze centers. Disorders of the nerves or gaze centers can lead to diplopia, or double vision. Disorders that affect the eye muscles or the neuromuscular junction can also cause diplopia. Double vision can be extremely disabling, as it can interfere with performing basic daily tasks. Intermittent diplopia can indicate the presence of a serious underlying disease.
Multiple Sclerosis
Multiple sclerosis is an autoimmune disease in which myelin, the protective coating surrounding nerve fibers, is destroyed. It's more common in women and usually starts in the third or forth decade of life. Symptoms can come and go, or progress without remission. According to the National Institutes of Neurological Disorders and Stroke, visual symptoms are often the first sign of the disease. Visual symptoms include intermittent double vision, blurry vision and sudden loss of vision in one eye.
Myasthenia Gravis
Myasthenia gravis is an autoimmune disease that affects the transmission of signals between nerves and muscles. Muscles become weak after activity, regaining their strength after adequate rest. According to the National Institute of Neurological Disorders and Stroke, weakness of the eye muscles, which can cause intermittent double vision, can be one of the first symptoms.
Ocular Neuromyotonia
Intermittent double vision is the hallmark of ocular neuromyotonia, or ONM, a rare disease in which the eye muscles can't relax properly. Double vision may occur spontaneously or after a patient looks towards one direction, upon which he may find himself unable to move his eyes to a different direction. ONM is often preceded by radiation to the areas surrounding the optic chiasm, where optic nerves from both sides of the brain meet and exchange fibers. According to a case report published in the "Annals of Neurology," carbamazepine--brand name Tegretol--may help alleviate the symptoms.
References
- Mayo Clinic: Multiple Sclerosis
- Merck Manuals: Diplopia, Approach to the Ophthalmologic Patient
- National Institute of Neurological Disorders and Stroke: Multiple Sclerosis
- National Institute of Neurological Disorders and Stroke: Myasthenia Gravis
- "Annals of Neurology"; Ocular neuromyotonia: clinical features, physiological mechanisms, and response to therapy; Frohman EM and Zee DS; May 1995
