This is one of several hereditary, nonprogressive forms of strabismus (abnormal alignment of the eyes) in which the eye movements are restricted. Although the name implies a disease of the muscles that move the eye, the primary disorder is one of maldevelopment of the nerves that supply those muscles.
Eyeball movements are severely restricted and they seem to be fixed in their position. In CFEOM1, the eyes are deviated down and move little if at all. The eyelids may droop (ptosis) severely and can cover part of the pupil. Patients often raise their chin and tilt their heads far back to look ahead. To look around, they have to move their heads. Since blinking is abnormal, the corneas (windshield of the eye) can dry out and this may lead to serious complications. Often one eye becomes lazy (amblyopia) and does not see well. Refractive errors such as astigmatism are common.
There are no consistent systemic abnormalities in the rest of the body.
Althought rare, this type of eye movement problem occurs worldwide and is passed from one generation to the next in a vertical pattern consistent with an autosomal dominant pattern. Only one mutation is necessary to cause the disorder and thus an affected parent has a 50% chance of passing it to each of his/her children.
The diagnosis is made by an ophthalmologist based on clinical examination of the eyes. Surgery can correct the deviation of the eyes although it is not possible to restore full movement. Surgery can also correct some of the droopy eyelids. It is important to monitor individuals with this problem to ensure that the cornea receives the proper protective lubrication. The lazy eye should be treated appropriately as well to maintain good vision and, of course, the proper glasses or contacts should be worn for the best vision.