Duanes Syndrome - Type of squint
A : Child has a head turn where the face is slightly turned to her left
B : When the child looks right there is a slight narrowing of her left eye
C: When the child looks straight the left eye appears slightly inwards or Esotropia
D : When she looks to her left the left eye looks bigger and the left eye is not able to move beyond midline
How do normal eye movements occur?
The 6 muscles that control the movement of the eye are attached to the outside of the wall of the eye. In each eye, there are 2 muscles that move the eye horizontally. The lateral rectus muscle pulls the eye out and the medial rectus muscle pulls the eye in toward the nose. Four other muscles move the eye up or down and at an angle. Each eye muscle receives the command for movement from cranial nerves that exit the brain.
What is Duanes Syndrome ?
Duane syndrome, also called Duane retraction syndrome (DRS), is a congenital and non-progressive type of strabismus. It is characterized by difficulty rotating one or both eyes outward or inward. There may also be changes of eyelid position on attempted movement of the eyes.
Duane syndrome is due to miswiring of the eye muscles. This causes some eye muscles to contract when they should not and other eye muscles not to contract when they should. This probably occurs around the sixth week of pregnancy and is due to poor development of tiny parts of the brainstem that control the eye muscles. In Duane’s the problem is not primarily with the eye muscle itself but with the nerve that transmits the electrical impulses to the muscle.
Duane syndrome is often characterized by whether the primary abnormality is a reduced ability to turn the affected eye(s) outward (eso duane’s), inward (exo duane’s), or both (type III).
What are the characteristics of Duane Syndrome?
- Strabismus-the eyes may be misaligned and point in different directions some or all of the time.
- Refractive Errors
- Head position-patients often maintain a head posture or head turn to keep the eyes straight. Infact when we see children with Duanes syndrome and are following these children we instruct the parents to look out for the head posture. If the head posture suddenly dissapears its not a good sign because then it means that the child may not be using both eyes and the child may thus deveop Amblyopia.
- Amblyopia (reduced vision in the affected eye) – occurs in 10% of patients.
- 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
Treatment in duanes is usually done one or more of the following reasons
- For headposture
- For a squint
- For improving cosmetic appearance of the face ( the eyelid narrowing )
The treatment involves operating on the eye muscles and changing their position so that the squint and head posture reduces. Depending on the type of duanes syndrome your surgeon will decide which muscles to operate upon.
Frequently Asked Questions
Surgery for Duanes Syndrome usually yields good results. Our main aim of surgery is to reduce the head posture and usually patients do well.
These days with newer types of surgeries like transpositions we are even able to improve the eye movements so that the patients look almost normal after surgery.
The surgeon plans the surgery in such a way, so that he gives the best cosmetic correction. So yes, if the upshoot or downshoot of the squinting eye was a blemish then that would be considered while planning the surgery and post surgery the squinting would not be visible or significantly reduced.