Amblyopia is a condition in which vision in one eye is decreased because of a problem in the way the eye and the brain work together. One eye is preferred over the other. It almost always appears early in childhood. Amblyopia is commonly referred to as lazy eye.
The problem with the affected eye can be any one of a number of things. These include:
- Decreased vision in the eye due to nearsightedness or farsightedness
- The eyes not working together because of eye muscle weakness, which is called strabismus. The bad eye can turn in or out.
- Other more serious eye conditions such as cataracts.
The key in amblyopia treatments is to get the “lazy eye” to work. In the past, this was almost always done by patching the good eye and forcing the bad eye to do all the seeing. It was believed that this needed to be done in early childhood, seven years of age at the latest, or the bad eye would never regain vision. Some eye care professionals also believed patching needed to be done most of the time. This was a problem for young school-age children who often removed the patch.
While strabismus can be seen by parents, because one of the child’s eyes is turning in or out, other causes of amblyopia may not be visible.
The challenges in treating amblyopia are:
- To discover it early.
- To treat it early.
- To make the treatment acceptable to children and parents.
- To find a way to treat older individuals who were not treated earlier.
Amblyopia Treatments have been scientifically compared for effectiveness. There are two main treatments currently in use. One is patching, for much less time than in the past. The other is using eye drops to blur vision in the good eye, which has a similar effect, making the bad eye work.
Before using eye patch or drops, glasses must be prescribed to correct vision, if necessary.
A large study compared regimens of patching and eye drops for different amounts of amblyopia and learned what seems to work best. For a moderate amount of amblyopia, patching for 2 hours a day is effective. This can be done at home. For more severe amblyopia, patching for 6 hours a day may be needed, along with one more hour of using the eye for close-up work.
Using a drug called atropine eye drops in the good eye blurs vision temporarily. This can work as well as patching.
It is also now known that amblyopia treatments can work on much older children and adolescents.
Amblyopia can reoccur after treatment. It is recommended that patching be decreased gradually, rather than just stopped. Using atropine drops after patching may prevent reoccurrence. Patching can be used again if the condition comes back in children. Research is being done to determine what can be done to treat reoccurrences later in life.
If a child has strabismus with weak eye muscles, the condition must be corrected surgically after the amblyopia is corrected.
Researchers have discovered unexpected things about amblyopia that may affect treatment in the future. Using a special type of MRI machine, they can get an idea about what may be wrong in the way the brain is handling the information from the eyes. Amblyopia may come on at the time a child is beginning to have depth perception.
They have also found a rare genetic cause of amblyopia, an inherited type of strabismus. Study of the abnormal genes in these cases may yield important information.
Research continues to try and find the best timing of patching and atropine drop therapy, how to prevent reoccurrences and how to treat older people. More answers are expected soon.