What is Amblyopia?
In most children, the brain processes images coming in from the eyes without any problems. However, in some children the brain can't interpret the messages from one or both of the eyes — which is one way to define amblyopia. Also known as "lazy eye," amblyopia basically means that the brain and the eye aren't connecting like they should be. Kids suffering from this disorder have a hard time catching a ball or reading what their teacher is writing on the board. This is why kids who have amblyopia often struggle in school or taking part in sports. Many times, amblyopia goes without diagnosis because parents think that their children's struggles have to do with a lack of talent in the classroom or on the ball field.
What are the Types of Amblyopia?
Between birth and the age of six, the brain and eyes build important connections between them. If something blurs or conceals vision in one or both eyes, those connections may not develop like they should. This can keep the brain from recognizing the images that the eyes send them later on. Over time, when the brain starts ignoring the images coming from the affected eye(s), that eye begins to weaken — and it becomes "amblyopic."
Some amblyopic children have eyes that have crossed or wander. If the eye moves inward, that's called esotropia. Exotropia happens when the eye turns outward. If it moves up, that is hypertropia. An eye moving down has hypotropia. In some cases, you can't tell by looking at a child's eyes that they have amblyopia, because they look straight ahead. In those cases, the amblyopia happens as a result of a structural or anatomical issue, such as a cataract or an eyelid that droops. Other causes can include severe near-sightedness (myopia) or far-sightedness (hyperopia), or a blurry type of vision known as astigmatism. When the brain receives blurry images as a result of these conditions, it learns to ignore them — leading to amblyopia.
Not all patients will have symptoms consistent with severe amblyopia. Sometimes, they are more subtle, such as a tilt of the head when watching TV or reading a book. Many times, a child will start to decrease in their school performance or athletics. If you think your child is not using both eyes or you are seeing subtle clues, it's best to have their eyes checked by an optometrist.
How is Amblyopia Treated?
The general idea behind the treatment of amblyopia is to get the brain to recognize the images coming from the affected eye(s) so that that eye strengthens over time. The options include glasses, eye drops, eye patches and surgery — or a combination.
Doctors prescribe glasses when one eye sees more clearly than the other or if there are severe errors in refraction. Glasses help clarify the images that go to the brain, training it to recognize them and "turn the eye on." This teaches the brain to use both eyes, moving toward normal vision.
Many kids with amblyopia end up wearing an eye patch over the stronger eye for up to six hours a day for as long as several years. One type of patch attaches like a band-aid, while the other fits over a lens on a pair of eyeglasses. Kids are often resistant to eye patches at first, but they generally adjust quickly. If they simply refuse to wear the patch, then atropine eye drops are an alternative. Like the patch, atropine drops go in the stronger eye, temporarily blurring it, forcing the brain to rely on the images coming from the weaker eye.
In rare cases, such as strabismus or the failure of any other remedies to work, surgery on the eye muscle is a possible option. If a drooping eyelid or cataract has caused the problem, surgery is an option as well. The procedure adjusts the muscle(s) that make the eyes wander. It is fairly invasive, but it is also considered effective and safe. Most patients don't have to stay overnight.