Amblyopia

Overview

Amblyopia is reduced vision in one eye caused by visual system dysfunction. In case of amblyopia one of the two eyes is almost not used in the vision process. Thus, the eyes register different images and the brain fails to bring them together.

Amblyopia generally develops in childhood. Early diagnosis and treatment can help prevent long-term problems with your child’s vision

Symptoms

The following symptoms and signs can point to amblyopia:

• One of the two eyes wanders inward or outward
• Eyes do not work together
• Squinting or shutting an eye

Sometimes lazy eye is not evident without an eye exam.

When to see a doctor

You should immediately see a doctor if you notice your child’s eye wandering at any time after the first few weeks of life. It is important to keep in mind that amblyopia often affect people whose relatives suffered from strabismus, congenital cataract and other eye diseases.

Causes

Amblyopia has three main causes:

• Strabismus
• Anisometropia
• Obstruction of the visual axis

Strabismus can cause amblyopia because misalignment of the eyes results in different retinal images being sent to the visual cortex. When this misalignment occurs, a child’s brain can pay attention to only one eye at a time, and the input from the other eye is suppressed.

Anisometropia (inequality of refraction in the two eyes due to astigmatism, myopia, or hyperopia) can also cause amblyopia because it results in different focus of the retinal images, with the image from the eye with the greater refractive error being less well focused.

Obstruction of the visual axis at some point between the surface of the eye and the retina (for example, by a congenital cataract) interferes with or completely prevents formation of a retinal image in the affected eye. This obstruction can cause amblyopia.

Treatment

• Eyeglasses or contact lenses
• Cataract removal
• Atropine drops
• Treatment of strabismus if present

Treatment of amblyopia should start with the elimination its causes. Any underlying causes must be treated (for example, eyeglasses or contact lenses to correct refractive error, cataract removal, treatment of strabismus). Use of the amblyopic eye is then encouraged by patching the better eye or by administering atropine drops into the better eye to provide a visual advantage to the amblyopic eye.