Amblyopia or a lazy eye is a disorder that causes the eye to fail to achieve its normal visual acuity. This condition begins in infancy or early childhood and typically affects only one eye, though there are cases where both eyes are affected by amblyopia. Approximately 2-3 percent of the United States population suffers from some degree of this condition.
If amblyopia is diagnosed early in life it can often be prevented from causing permanent damage to the child's vision. If a lazy eye is left untreated it can cause the affected eye to become permanently disabled, leading to legal blindness.
Symptoms of Amblyopia
Amblyopia often first appears during infant vision development which can make it difficult to determine the presence of symptoms. Children with this condition often experience strabismus, have crossed eyes or a noticeable misalignment of the eyes. Your child may become fussy or cry when you cover one of their eyes. This may be more prominent if you cover one eye as opposed to the other, implying that your child has one "good" eye and one that has vision that is blurred.
Causes of Amblyopia
There are generally three types of amblyopia, the causes for which differ from each other.
- Strabismic Amblyopia. Strabimus is one of the most common causes of a lazy eye. If your eyes are misaligned your brain will ignore the signals from the eye that is misaligned to prevent double vision. This will cause the eye that is being ignored to become lazy from disuse.
- Refractive Amblyopia. In this case, the eye experiences refractive errors that cause a significant amount of farsightedness, nearsightedness or astigmatism in one eye that is not present in the other. To make up for this error, the brain will rely on the eye that has stronger vision and ignore the eye that is reporting errors. This will cause the eye to become lazy because it is not being used.
- Deprivation Amblyopia. If something is obstructing the light moving into a child's eye it can cause that eye to become lazy. Cogenital cataracts are a common cause of this disorder.
Detection for Amblyopia
Early detection increases the treatment options that are available to those with amblyopia. Your child should have an eye exam at 6 months, at age 3 and when they start school to ensure that their vision is developing properly. Amblyopia will not be corrected without treatment and the longer the condition is left without treatment, the higher the risk is for permanent damage to the eyes.
A refractive error that is causing amblyopia may also cause behaviors that could be mistaken for other developmental disorders. Your child may earn low scores on IQ tests, have trouble reaching for objects or crawling. Your doctor may note symptoms in your child that are similar to autism. An eye examination can help to determine if a vision problem is what is causing your child's behavior or if another condition will need to be addressed.
Treatments for Amblyopia
The type of treatment necessary to restore function to the lazy eye will vary based on what is causing the amblyopia.
Strabismic amblyopia is often corrected with surgery that will straighten the eyes. The eye with good vision will then be covered with a patch while the patient undergoes vision therapy to teach the eyes to work together.
Refractive amblyopia can often be corrected with specialized glasses or contact lenses that will allow the damaged eye to see at the same rate as the "good" eye. This will encourage the brain to note the signals from the eye it was ignoring previously.
Those that have amblyopia may need to wear a patch for several hours a day or for a few weeks or months to fully adjust their vision. Atropine eye drops may also be used in place of an eye patch. These drops will be placed in the good eye to blur the vision, forcing the brain to take signals from the damaged eyes. This is ideal for active children because you will not need to monitor them to ensure they are wearing the patch like they should. Talk to your doctor about using atropine drops because long-term use of this medication can cause paralysis of the ciliary muscle that allows the eye to focus.
Older children suffering from amblyopia may find that computer programs can be used to improve the contrast sensitivity or visual acuity of eyes affected by this condition. In studies of these programs, 70.5 percent of patients saw an improved ability to read 2 additional lines on an eye examination chart after completing the program.