DUANE SYNDROME:

If you can't quite place Duane Syndrome among your personal cache of familiar (or even often-heard) medical conditions, you're most probably in company of a great number of Americans: while the birth defect itself is considered rare, so too is the likelihood many of us even know of the existence of such an affliction.

Affecting just one tenth of a percent of the general population, this congenital disorder that limits movement of the eye(s) was first described by A. Duane, more than a century ago. Duane Retraction Syndrome (DRS) is congenital in nature, meaning that its presence is extant from birth, and in simplest terms, is characterized by the inability to move the eye out wards from the "straight ahead" position - - - an act more than ninety-nine percent of us perform perhaps dozens of times daily without conscious thought. Classified as one of the known extraocular muscle fibrosis syndromes, medical conditions which involve the muscles that move our eyes, DRS is believed by researchers to occur as an abnormality from between the third and eighth weeks of gestation, a period critical in the formation of ocular muscles and the cranial nerves which control them. Ocular muscles are required to perform what on the surface seems a "given," the rotating of our eyes outward, but whether due to environmental factors or unknown genetic disorders, the connections among nerves which supply those muscles to the eyes during weeks three through eight fail to develop in the fetus who will be born with Duane Syndrome.

Decades of research have led medical scientists to believe that it is the absence of the cranial nerve VI, also known as the abducens nerve, which leads to DRS. The muscle this nerve is responsible for controlling is responsible itself for rotating the eye outward, and it is from this inability to pivot the eye toward the ear that the vast majority (seventy percent) of Duane Syndrome patients suffer. Thirty percent of those diagnosed have limited to zero ability in moving the eye(s) inward, toward the nose.