What is Duane Syndrome?
Duane syndrome, also called Duane retraction syndrome (DRS), is a group of eye muscle disorders that cause abnormal eye movements. People with Duane syndrome have difficulty rotating one or both eyes outward (abduction) or inward (adduction).
How do normal eye movements occur?
Six muscles, which control the movement of the eye, are attached to the outside wall of the eye. In each eye, there are two muscles that move the eye horizontally. The lateral rectus muscle pulls the eye out towards the ear and the medial rectus muscle pulls the eye in towards the nose. There are four other muscles, which move the eye up or down and at an angle. Each eye muscle receives the command for movement from the cranial nerves that exit the brain.
Are there different types of Duane Syndrome?
Duane syndrome is often characterized by whether the primary abnormality is a reduced ability to turn the affected eye(s) outward (type I), inward (type II), or both (type III). Type I is the most common form of Duane syndrome.
What is the cause of Duane Syndrome?
In Duane syndrome, the sixth cranial nerve that controls the lateral rectus muscle (the muscle that rotates the eye out towards the ear) does not develop properly. Why the nerve does not develop is not yet understood. Thus, the problem is not primarily with the eye muscle itself, but with the nerve that transmits the electrical impulses to the muscle. There is also irregular innervation of a branch from the third cranial nerve, which controls the medial rectus muscle (the muscle that rotates the eye toward the nose). This is why abnormalities may be found in both left gaze and right gaze.
Who gets Duane Syndrome?
Duane syndrome affects girls more often than boys. In addition the left eye is more likely than the right eye to be affected. The reason for this is not known. Around 20 % of Duane syndrome patients have both eyes affected. No particular race or ethnic group is more likely to be affected.
What are other characteristics of Duane Syndrome?
- Strabismus- the eyes may be misaligned and point in different directions at all times
- Head position- patients often maintain a head posture or head turn to keep the eyes straight
- Amblyopia- reduced vision in the affected eye
- Eyelid narrowing- the affected eye may appear smaller than the other eye
- Upshoot or downshoot- with certain eye movements, the eye may occasionally deviate upward or downward.
Is Duane Syndrome congenital (present from birth)?
Duane retraction syndrome is present from birth, even if it is not recognized during infancy. An abnormal head posture and strabismus are often visible in old photographs taken in early childhood.
Is Duane Syndrome hereditary?
In 90% of cases, the patient has no family history of Duane syndrome. Ten percent of patients will have an affected family member and these tend to be cases where both eyes are involved. There is currently no test that can determine whether a patient has a hereditary form.
Do Duane Syndrome patients have other eye problems?
The problem with the 6th cranial nerve is usually an isolated condition and the child is usually otherwise completely normal. Occasionally, Duane syndrome may be found in association with other eye problems, including disorders of other cranial nerves, nystagmus ( an involuntary back-and-forth movement of the eyeball), cataract, optic nerve abnormalities, microphthalmos (abnormally small eye), and crocodile tears.
Do Duane Syndrome patients have non-ocular medical problems?
The problem with the cranial nerve is usually an isolated condition and the child is otherwise completely normal. However, some patients with Duane syndrome have other problems, such as hearing impairment, Goldenhar Syndrome, spinal and vertebral abnormalities. There is also an increased frequency of Duane syndrome in patients with thalidomide Embropathy.
When is Duane Syndrome treated?
Treatment for Duane syndrome is indicated for one of three reasons:
- To eliminate strabismus and prevent amblyopia (or lazy eye)
- To eliminate a cosmetically significant head position
- To eliminate a cosmetically significant upshot or downshoot
The goal of treatment is to restore normal eye alignment in the straight-head position, eliminate an abnormal head posture and to prevent amblyopia. In most cases, eye muscle surgery is required. Because the function of the affected nerve and muscle cannot be restored, the other eye muscles are adjusted to compensate and allow for better eye alignment.
For the great majority of patients, Duane syndrome is not cosmetically noticeable nor does it require any treatment. With careful follow-up, the long-term prognosis for good vision is usually excellent.
The content of this Web site is for informational purposes only. If you suspect that you or your child has an ocular problem, please consult your pediatrician, family practitioner, or ophthalmologist to decide if a referral to a pediatric ophthalmologist is required.