Medical Monday: Duane Syndrome

It's that time again: Medical Monday! I blog each Monday about a different condition Connor has and then post a link to it on the side bar as I go. This way people can get a better idea of what Connor deals with on a daily basis and his family and friends can understand what I'm saying when I call and spout ridiculously long medical terms.

DISCLAIMER: I would like to emphasize for those people who stumble upon this blog that I'm not a doctor, and I have no medical experience other than the approximately 900 doctor's appointments I've been to in the past two years. I just know about these things in relation to how they apply to Connor and not anyone else's child, so if you want accurate info on this sort of thing, please please please ask your doctor or go to the medical library instead of looking it up on the Internet. The library is your friend.

So today's topic is Duane Syndrome. What is going on in this picture? Other than total frosting decimation, I mean. You may notice that what we call Connor's "wonky eye" (very technical term there) or "wonkavision" (because we aren't Roald Dahl fans in this house at all) is clearly visible. What most people think when seeing this picture is that Connor is looking straight at the camera and one of his eyes is turning in. Actually what's happening is the opposite-- he's looking up and away from the camera, and it's the eye that's looking straight ahead that's the problem. Connor has Duane Syndrome.

There are six muscles responsible for the movement of the eyes. Two of them control the horizontal movement-- one for inward movement, and one for outward. Each eye muscle receives its instructions from one of three cranial nerves. In Duane Syndrome (DS), cranial nerve VI, also known as the abducens nerve, is either missing or malfunctioning. This nerve sends the instructions for the outer movement of the eye.

There are three main types of Duane Syndrome. Connor has Type I DS, which means that he can move his eyes inward, but not outward. When Connor wants to look at something to his right, for example, his left eye will turn inward as it should. His right eye will get to about mid-line and then won't go any farther. In order to keep his depth perception and look at something with both eyes, he has to turn his head. This means that he's unable to track something unless it is fairly slow, because he has to turn his head to keep it in both eyes in line. (Try doing this sometime-- look straight in front of you and turn your head to watch something instead of your eyes. It's exhausting.) It also causes problems because people automatically align themselves with the eye that's straight ahead and think he's paying attention, when in fact the dog or mime in a box or whatever it is he's actually trying to look at is off to one side. About 80% of people with DS have it in only one eye. Connor is one of the "lucky" 20% that has it in both. In his case, his left eye has a little more movement than his right.

There's not much they can do for DS. Surgery isn't going to help when it's a problem with the nerve and not with the muscle-- usually the only reason surgery would be involved with DS is to correct a head tilt caused by someone trying to keep their eyes aligned. You can't really "retrain" the problem either by using a patch, for the same reason. Connor actually compensates pretty well.

Here's some good links involving Duane Syndrome:

National Human Genome Research Institute

Orphanet: Duane Syndrome

American Association for Pediatric Opthamology and Strabismus

~Jess