Amblyopia defined

Amblyopia is also known as lazy eye. It is a condition, usually found in children, in which one or both eyes do not develop properly. An easy way to explain this is that the "eye-brain" connection does not communicate properly; therefore, the child does not know what clear vision is...or what 20/20 vision is. The eye anatomy itself is normal, but the neural pathway to the brain is not normal, causing decreased vision.

Prevalence of amblyopia

Amblyopia is one of the most common treatable forms of vision impairment in children. Its prevalence is as high as 3-5% in some studies. It is most common in infants and young children and it is imperative that this condition is caught early.  The chance of successful vision restoration goes down dramatically after age 8, therefore the earlier this condition is caught the better chance of successful treatment.

Causes of amblyopia

The causes of amblyopia are varied. A very common condition that can cause amblyopia is strabismus, a misalignment of the eyes. This occurs when one eye has an abnormal turning in or out, causing the brain to stop using the misaligned eye. Other causes may come from a high prescription such as nearsightedness, farsightedness, or astigmatism. In the case of these conditions, the eye’s vision is out of focus and so the brain turns off that image. Eye disease processes can also cause amblyopia. One of these conditions is known as a cataract. A cataract is a condition of the lens of the eye developing an opacity so that light cannot pass through. Abnormal retinal conditions and hereditary factors can also cause amblyopia.

Treatment of amblyopia

In order to increase the chances for success, this condition must be detected early. The recommended ages for early eye examination are 6 months old, then 2-3 years of age, and then school age.

Patching, or occlusion therapy

One of the most common treatments for amblyopia is patching, also known as occluding, the better or stronger eye.  This forces the brain to use the weaker eye.  An adhesive eyepatch on the skin or a slip-on patch over glasses can be incorporated for occlusion therapy. A blurring contact lens or dilating eye drop can also be used to occlude the good eye.

Surgery

Cataract, eye muscle, or retinal surgery can be incorporated to help treat the underlying cause of amblyopia in some cases.

Vision therapy

Vision therapy has been proven to be successful in the treatment of amblyopia. Vision therapy, or VT, incorporates a series of vision training procedures that helps improve eye movement control, visual acuity, depth perception, and eye coordination. Vision therapy can be done in an office or home setting.

Signs and symptoms of Amblyopia

The most common way amblyopia is diagnosed is a detection of a decreased red reflex in the child's eye.  A diagnostic instrument used by the optometrist, ophthalmologist, or pediatrician, can pick up a bright reflection in the normal eye and a dim reflection in the amblyopic eye. Upon further examination, the eye is dilated to see if a refractive error of myopia, astigmatism, or hyperopia is the cause.

Another sign of amblyopia is an eye that turns in or out. A symptom that may be indicative for amblyopia is if the child prefers the vision out of one eye.  This can sometimes be detected when occluding the better eye--the child may become fussy and upset because she cannot see out of the lazy eye.

 Citations:
1. Amblyopia informational patient brochure. APOS.org. January 2013