Amblyopia (AKA 'Lazy Eye')

Amblyopia is a common childhood vision condition that you have likely heard of but just didn't know it. Amblyopia is a bit of a tongue twister (and we are not even selling seashells on the seashore) which is why many people know it as 'lazy eye'. Well before you start judging the work ethic of your eyes, let us talk about amblyopia – a common childhood vision condition that prevents kids from seeing 20/20 if left untreated.
 

Amblyopia is the leading cause of vision loss in children. Amblyopia can result from any condition that prevents one of the eyes from seeing clearly. In some cases one eye does not see as well as the other – meaning the lesser seeing eye develops amblyopia. In other cases, both eyes are incapable of seeing clearly so both eyes develop amblyopia. What causes amblyopia? Conditions such as misalignment of the eyes (strabismus), esotropia, exotropia, a cataract, or when one eye is more nearsighted, more farsighted or has more astigmatism than the other eye.

When someone has amblyopia there may not be an obvious problem with the eye. This is because vision loss occurs along nerve pathways between the brain and the eye. Due to this lack of stimulation, the brain learns to favor one eye typically due to poor vision in the other eye. From this stand point amblyopia can really be viewed as a binocular (two eyed) vision condition that manifests in one eye.

Individuals with amblyopia have decreased depth perception, and have difficulty seeing 3-D images. Parents often times say that their child is clumsy, has a tendency to stumble or bump into objects. In addition to blurry vision, difficulties with accommodation (eye focusing), binocularity (eye teaming), contrast sensitivity and suppression (ignoring the signal from one eye) can result. Interestingly, amblyopia (an eye condition) can negatively impact one's language abilities – due to impaired sight-sound correlations in early life.

There are several types of amblyopia:

• Strabismic amblyopia

• Deprivation amblyopia

• Refractive amblyopia

The types of amblyopia have different causes:

• Strabismic amblyopia develops when the eyes are not straight. One eye may turn in, out, up, or down. As a result, the brain begins to ignore or turn-off that eye. When this happens vision in that eye declines.

• Deprivation amblyopia develops when there is a cataract or similar condition that deprives the eye of visual stimulation or experiences.

• Refractive amblyopia develops when there is a large, or unequal, amount of refractive error (glasses prescription) between the two eyes. The brain learns to see through the eye that has a lesser need for glasses and learns to ignore the other eye.

It is not easy to readily recognize amblyopia, especially deprivation or refractive amblyopia. Unless the child has an eye-turn it is difficult for parents to know something is wrong.

How common is amblyopia?

Amblyopia is the most common cause of vision impairment or vision loss among children. Amblyopia affects approximately 2 to 3 out of every 100 children, making amblyopia more common than most people think. If you suspect that your child has amblyopia, schedule an appointment with a binocular vision specialist. Accurate diagnosis, early intervention and proper treatment can change a child's life.

How is amblyopia detected?

Amblyopia is detected by finding the difference in visual acuity between the two eyes. Poor vision in one eye does not always mean a child has amblyopia. An eye doctor trained in pediatrics is the best choice for detecting amblyopia. The eye doctor will dilate your child's eyes to determine if any other eye diseases may be affecting your child's vision.

Early diagnosis and treatment is important, and increases the chance for complete recovery. Both the American Optometric Association and the American Academy of Ophthalmogy recommend children (who are not considered high risk) have their first eye examination as an infant, again at 3 years of age, and yearly once school-aged. Children who are considered high risk, or who have certain medical conditions may require more frequent visits to the eye doctor. An individual does not “out grow” amblyopia, nor does amblyopia go away on its own. If amblyopia is not diagnosed for several years or until the individual is an adult, treatment takes longer and in some cases may be less effective. A Residency-Trained Pediatric Optometrist or pediatric opthalmologist are best suited for diagnosing and treating amblyopia.

What is the treatment for amblyopia?

Treatment for amblyopia can include a combination of prescription lenses, prisms, patching and vision therapy. If strabismus is the cause of amblyopia and treatment with glasses, patches or drops, or vision therapy do not fully correct the alignment of the eyes, surgery might be an option.
 

• Prescription glasses are used to provide clearer vision so the brain receives clearer, focused images which will teach the brain to “pay attention to” or “switch on” the weaker eye. This allows the brain to begin using the eyes together and normal vision to develop.

• Patching, or atropine drops, is used to make the amblyopic eye (the weaker eye) work to recognize images. When vision in the stronger eye is blocked by a patch, or blurred by the use of atropine drops, it forces the brain to recognize images seen by the weaker eye.

• Vision therapy teaches the two eyes to work together as a team, which addresses the binocular nature of the condition.

• Strabismus surgery may be an option if strabismus is the cause of amblyopia and treatment with glasses, patches or drops, or vision therapy do not fully correct the alignment of the eyes. Cataract surgery will be the first step in treatment if amblyopia is caused by a cataract.

One of the major misconceptions with amblyopia is that you can only treat it up to a certain age. Some people will say 8-years-old, others may say 13-years-old. This is a very outdated way of thinking about amblyopia. Current research (and our clinical experience) has shown that amblyopia can be treated at any age. We have adults actively treating their amblyopia and seeing 20/20 for the first time in their life.

The best way to find out if amblyopia is present is to have a comprehensive eye examination with a Residency-Trained Pediatric Optometrist or Pediatric Ophthalmologist. Do not wait for your child to fail a school screening – be proactive with your child's eye care.

Vision problems, such as amblyopia, can have far reaching impacts beyond 20/20 vision.