Ophthalmology

Amblyopia (Lazy Eye)

Penn pediatric ophthalmologists at Children's Hospital of Philadelphia combine the expertise of ophthalmology, neurology and pediatric ophthalmology to treat a variety of eye-related conditions. To refer a child for treatment, call (215) 590-2791 for an appointment in Pediatric Ophthalmology.

What is Amblyopia?

Amblyopia is an early childhood condition in which one or (rarely) both eyes do not develop the normal capacity to see.

It is one of the most common causes of irreversible visual impairment, affecting up to 2% of the population.

The impairment can be mild to moderate, ranging from a relatively good 20/30 to a legally blind 20/200.

Because amblyopia affects the visual center of the brain which develops within the first 5-6 years of life, it must be treated in early childhood. After the age of 5 or 6 the condition becomes permanent.

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Causes of Amblyopia

There are four basic causes of amblyopia:

Refractive Error: The eye may be very nearsighted, farsighted or have a lot of astigmatism. In these cases of refractive amblyopia, the images are so blurry that the brain never sees a normally focused image coming from the affected eye.

Eye Disease: Another disease, such as a cataract, obstructs light that normally enters the eye causing obstructive amblyopia. Or, in the case of a disease like optic nerve hypoplasia that damages the eye and vision, the damage is compounded by amblyopia.

Strabismus: The eyes may be crossed, otherwise known as strabismus. This situation may lead to strabismic amblyopia.

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Treatment for Amblyopia

Amblyopia is very treatable if caught early. The treatment for amblyopia depends upon the cause:

Refractive amblyopia from astigmatism, farsightedness, or nearsightedness can be treated by glasses and patching.

Obstructive amblyopia (such as from a cataract) can only be treated if the obstruction is first cleared (e.g., cataract removal). Then, any refractive error must be treated and patching performed to force the eye to be used.

Patching treats strabismic amblyopia as well as amblyopia from other diseases, such as optic nerve or retinal dysfunction.

Patching

Patching involves placing a patch over the strong eye to force the weaker eye to be used. The use of a patch should be carefully prescribed and monitored by an ophthalmologist.

There are several potential complications with using a patch.
The most common problem is that patching does not improve vision in the amblyopic eye. In some cases, patching can result in a reversal of the amblyopia - the previously good eye becomes impaired while the treated eye improves. Lastly, some children may develop strabismus after patching. In general, however, treating the amblyopia is still the more important consideration.

Eye Drops

In some cases eye drops can be used in place of a patch to blur the "good" eye.

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Early Detection of Amblyopia

Amblyopia must be detected early. No newborn should leave the hospital until the primary physician has performed a direct ophthalmoscopy and checked for a good red reflex. Parents should have their children evaluated if they suspect visual impairment, observe crossing of the eyes, notice a white pupil, or have a family history of amblyopia and/or strabismus.

Verbal children should have annual screening vision exams in a physician's office or at school. Abnormal vision in either eye warrants further evaluation by an ophthalmologist.

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Visual loss from Amblyopia

Visual loss from amblyopia cannot be treated in older children or adults. Individuals with significant visual loss in the affected eye should wear impact resistant glasses at all times, and protective eyeglasses during high-risk activities.

Individuals with good eyesight in one eye are not handicapped. However, they do need to protect their good eye from secondary injury. Some studies have suggested that amblyopic individuals tend to have a higher risk for secondary injury to their good eye.

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