|SSM Cardinal Glennon Children's Medical Center|
Amblyopia is a problem in the way the brain interprets visual images from one or both eyes. This makes it harder for kids to do things like read a blackboard from a distance or catch a ball. As a result, many kids with amblyopia report having trouble with schoolwork or participating in gym class.
Amblyopia can go undetected for months or even years because parents chalk up poor grades or athletic ability to a child not being academically or athletically gifted. But sometimes the solution is as easy as visiting the eye doctor.
Treatment for amblyopia can correct the way the brain processes visual images and, ultimately, strengthen vision. The earlier treatment starts, the better. Waiting or not getting a proper diagnosis for a child could lead to irreversible vision loss later.
From birth until about 6 years of age, vital connections are formed between a child's eyes and brain. Anything that blocks or blurs vision in one or both eyes may then inhibit or block the development of these connections. This can cause the brain to not fully recognize the images seen by one or both eyes.
When this happens, the brain begins to ignore or suppress the images seen by the otherwise healthy eye, and the eye becomes weaker, losing vision strength (acuity). This eye is then referred to as "amblyopic."
One of the most common causes of amblyopia is strabismus, or wandering of one or both eyes either inward (called esotropia), outward (called exotropia), up (hypertropia), or down (hypotropia).
When eyes are misaligned, the straight or straighter eye may become dominant. The vision strength (acuity) of the straight eye stays normal because the eye and its connection to the brain are working normally. The misaligned or weaker eye, though, does not focus properly and the brain suppresses or ignores its signal, eventually leading to amblyopia.
Not all kids with amblyopia will have crossed or wandering eyes — in fact many have eyes that are perfectly straight. If so, amblyopia is usually the result of an anatomical or structural problem that interferes with or blocks vision, such as a droopy eyelid or a cataract.
Another cause of amblyopia is severe far-sightedness (hyperopia), near-sightedness (myopia), or astigmatism (a form of blurry vision). These vision problems ("refractive errors") cause vision to be blurry, and it's these blurry images that are sent to the brain. Over time, the brain begins to ignore or suppress these unclear images, resulting in amblyopia in one or both eyes.
Another cause could be having different vision strengths in each eye — a condition known as anisometropia. When one eye sees more clearly than the other, the brain can ignore or suppress the vision of the blurry eye.
Genetics play a role, too. Amblyopia tends to run in families. It's also more common in children born prematurely or those affected by developmental delays.
Signs & Symptoms
Most children with amblyopia won't complain of vision problems. Over time, they become accustomed to having good vision in one eye and poor vision in the other.
It's usually a parent or teacher who notices that a child is struggling with a vision problem — whether it's noticing crossed eyes, frequent squinting, or tilting the head to see better. Some kids will demonstrate poor depth perception (stereopsis) and difficulty seeing in 3D.
Treatment for amblyopia involves forcing the brain to pay attention to the images of the amblyopic or weaker eye so that vision in that eye gets stronger. This is done through glasses, eye patches, eye drops, surgery, or a combination of these:
Eye Exams Essential for Toddlers & Preschoolers
Kids reach visual maturity by about 8 years old; after that, vision problems can be harder to treat. The earlier amblyopia is diagnosed and treated, the better the chances to restore vision and avoid permanent vision loss.
Sometimes there are no apparent signs of a vision problem, so it's important for kids to undergo yearly vision screenings. These exams should begin in the toddler and preschool years so that problems are caught before a child reaches visual maturity.
Most vision screening exams are done at the pediatrician's office or at school by the school nurse. If problems are found, your child will be referred to a pediatric ophthalmologist for further evaluation and treatment.
If your child is due for a vision screening, call your doctor to schedule one.
Reviewed by: Jonathan H. Salvin, MD