A child with amblyopia actually possesses a lazy brain, rather than a lazy eye, because for some reason, the brain shuts off power to one eye and uses a single eye to see while the other remains unfocused. Although the most common cause of amblyopia is strabismus, a child can suffer from a lazy eye because of nearsightedness or farsightedness without showing any outward signs. Untreated amblyopia results in permanent vision loss! So how can parents know if their child is seeing clearly if both eyes seem to move in sync and there's no indication of trouble?
"They can't. And neither can a pediatrician," says Dr. Cooper. "Every child should have one eye exam with drops. If we could get every child seen at nine months, we could probably eliminate amblyopia."
Once a child is diagnosed with amblyopia, the treatment options are similar to those for strabismus: patching or eye drops to force the patient to use the blurry eye more often, vision therapy to train the eyes to work as a team, and possibly surgery to align the eyes if strabismus is the cause of the amblyopia. According to Dr. Cooper, "The earlier you begin treatment, the greater the rate of success. At nine months of age, the chances are extremely high of developing normal vision. However, the success rate decreases with each year and levels out at age six. A younger child can be treated with short-term patching and the right glasses, while an older child needs patching, glasses, and vision therapy."
Surgery, it should be noted, doesn't actually cure amblyopia. It's a cosmetic cure that corrects the strabismus, which causes amblyopia. So a child can come out of strabismus surgery with perfectly aligned eyes that still don't function together. "People think that if their child has an eye turn and has surgery to correct it, their child has good vision, but it's not so and the child can develop poor vision the rest of their life," warns Dr. Cooper. "The brain controls the eyes. If you align the eyes, but don't fix the brain process, they don't stay aligned and drift back. So kids with inward eye turns are best treated with glasses, surgery, and vision therapy." In fact, children who have alignment surgery, but forgo vision therapy to teach the eyes to work together, frequently require multiple surgeries because the untrained eyes regress back to their old positions. Dr. Cooper estimates that it happens about 60 percent of the time.
Patching, glasses, and vision therapy exercises are the only ways to actually train the brain to use both eyes in tandem, and those options require a certain amount of dedication from Mom and Dad to make sure they're done properly. Young children often balk at wearing an eye patch because it feels weird and hurts to remove. (Imagine having to remove a giant bandage stuck over your eye every day for months.) Older children are embarrassed to wear the patch because of teasing at school. Blurring eye drops help alleviate some of the problems associated with the patch, but young children may fight getting eye drops more than wearing the patch!
Similarly, wearing eyeglasses is hard for anyone to get used to, especially children who don't understand the benefits. Glasses may be forgotten, removed when the child is out of their parent's supervision, broken, or lost. Even kids who faithfully wear their glasses are subject to ridicule from classmates.
Vision therapy exercises can be fun and painless, but they require time and travel to the doctor's office. Although some vision therapy can be performed at home, most doctors require patients to come in for regular office visits because the exercises often require the use of special prisms and lenses. Parents must be disciplined enough to make each office visit, plus make time to sit down with their child for home-based therapy each day.
For more information about strabismus and amblyopia, visit the Strabismus website.