The muscles of the ocular system control the movement of the eyes and the eyelids. There are several disorders of the eye muscles that can cause the eyes to not move correctly or in unison or that can cause the eyelids to droop into the field of vision. Some of these conditions are congenital or develop during childhood, while others occur in adults. Glasses, eye drops and surgery are among the potential treatments for some of these conditions; these therapies may only have a limited amount of success in certain conditions, such as nystagmus.
Strabismus
In the disorder strabismus, the muscles of the eye do not work together properly, causing one eye to be lined up differently from the other eye. According to the Merck Manual, if the muscle misalignment is not corrected early enough in children, it can cause decreased vision in one eye. Treatments for strabismus include eyeglasses, eye medications and surgery.
Ocular Myasthenia
Myasthenia gravis is an autoimmune condition that leads to weakness in various muscles. According to the National Institute of Neurological Disorders and Stroke website, when the muscles involved are the muscles of the eye, the condition is called ocular myasthenia. In this eye muscle disorder, the patient may develop a droopy eyelid, also known as ptosis or double vision; the muscle problems tend to improve after a period of rest.
Graves' Eye Disease
In Graves' eye disease, the muscles and tissues around the eye become infiltrated by inflammatory cells; these tissues become swollen and cause muscle dysfunction and protrusion of the eyeball itself. This disease typically occurs in people with hyperthyroidism, but can also be seen in people who have normal thyroid glands, according to the Handbook of Ocular Disease Management.
Duane Syndrome
Duane syndrome is an eye muscle disorder that involves abnormal eye movements. Patients with Duane syndrome often have a difficult time turning one or both eyes outward or inward. This condition occurs when the nerves that direct the muscle movements do not develop properly during pregnancy, according to the American Association for Pediatric Ophthalmology and Strabismus. Surgery may be a treatment option for these patients.
Nystagmus
According to the American Association for Pediatric Ophthalmology and Strabismus, nystagmus is a muscle disorder that causes shaking movements of the eye. This condition can be congenital which means that it develops in an infant between 6 weeks and 3 months of age; nystagmus can also develop in older people because of poor vision in an eye. In congenital nystagmus, some patients may be treated with muscle surgery to stabilize the movement somewhat or to keep the child from turning his head into odd position to decrease the amount of movement in the eyes.
References
- Handbook of Ocular Disease Management:: Thyroid Ophthalmopathy (Graves' Disease)
- Merck Manual: Strabismus
- National Institute of Neurological Disorders and Stroke: Myasthenia Gravis Fact Sheet
- American Association for Pediatric Ophthalmology and Strabismus: Duane Syndrome
- American Association for Pediatric Ophthalmology and Strabismus: Nystagmus
