It’s a rare syndrome present from birth. In this disorder, some of the child’s eye muscles contract when they shouldn’t. Others fail to contract when they should.
The result, according to the National Human Genome Research Institute, is that the baby is unable to move the eye outward toward the ear (known as abduction) or has a limited ability to move it toward the nose (adduction). Most children are diagnosed by the time they’re 10. About 60 percent of the patients are girls. Around 80 percent of patients are affected by Duane Syndrome (DS) in just one eye.
The syndrome was named after New York ophthalmologist Alexander Duane. Although he didn’t discover the condition, he worked extensively with children and reported in detail on the condition in 1905. Duane’s Syndrome is also known by other names. Among them are Duane’s Retraction (DR) Syndrome, Eye Retraction Syndrome and Retraction Syndrome. Some ophthalmologists refer to it as congenital retraction syndrome or Stilling-
While about 70 percent of DS patients suffer from no other disorders, the remainder often have malformations of the skeleton, ears, eyes, kidneys and nervous system. They also sometimes present with upper-limb malformation and hearing loss as well as abnormalities of the heart.
Symptoms of Duane Syndrome vary according to its three types. For patient with Type 1 DS, the affected eye has limited ability to move toward the ear. However, the ability to pull toward the nose remains normal or close to it. Nearly 80 percent of cases are this type.
When a child suffers from Type 2 DS, the affected eye has trouble moving toward the nose but is able to move toward the ear fairly normally. Around seven percent of cases fall into this category.
Type 3 accounts for approximately 15 percent of all DS cases. The eye has difficult moving in either direction. Various subgroups within each of the three types are classified according to where the eyes are positioned when the child looks straight.
The cause of Duane Syndrome remains a mystery. Clearly, the medial and lateral rectus muscles – those that move the eye – somehow misfire. Patients lack the sixth cranial nerve, which is involved in eye movement. Many researchers believe the condition is the result of some type of disturbance during the development of the embryo. Whether it’s caused by genetic or environmental issues has never been solved. However, since cranial nerves and ocular muscles develop between the weeks three and eight of a pregnancy, this is probably when the problem arises.
Geneticists have identified both dominant and recessive forms of DS. In the case of a dominant gene, only one gene from one parent can cause the child to have a condition. Recessive genes, however, must copy from both parents for the condition to be present. The precise chromosomal location for DS is unknown.
According to the Optometrists Network, children with DS should not undergo surgery unless they show a cosmetic problem while looking straight ahead. Instead, the site recommends that their eye practitioner fit them with special glasses with a prism to eliminate the need to turn their heads. Vision therapy is sometimes also an effective treatment for secondary problems of Duane Syndrome.