Amblyopia (lazy eye)

What it is

In early childhood, the brain learns to see using signals from both eyes. If one eye sends a blurry or misaligned image, the brain starts to ignore it. Vision in that eye then fails to develop fully, even though the eye itself may look healthy. This is amblyopia, often called lazy eye. It is a common cause of vision loss in one eye in children.

Causes

• Strabismus: the eyes point in different directions
• Refractive differences: one eye is much more nearsighted, farsighted or astigmatic than the other
• Deprivation: something blocks light into one eye, such as a childhood cataract or a droopy eyelid

Signs

Amblyopia often has no obvious signs, because children see well with the stronger eye. Watch for an eye that wanders, squinting or shutting one eye, head tilting, bumping into things on one side, or poor depth perception. A child may get upset when the stronger eye is covered.

How it is diagnosed

A comprehensive eye exam checks vision in each eye separately, alignment and focusing, often with dilating drops. Vision screening at school or the doctor’s office can miss it, so children need full eye exams.

Treatment

Treatment makes the brain use the weaker eye:

• Glasses to correct any focusing difference
• Patching the stronger eye for part of each day
• Atropine eye drops that blur the stronger eye
• Treating the cause, such as surgery for strabismus or a cataract

Treatment can take months, and it works best when started early. Follow-up visits make sure the gains last.

Questions people ask

Is it too late to treat amblyopia in older children?

Treatment works best in young children, but research supported by the National Eye Institute shows it can also help many older children and teens. Talk to an eye doctor at any age.

Is lazy eye the same as a turned eye?

Not exactly. Amblyopia means weak vision in one eye. A turned eye is strabismus, which is one possible cause of amblyopia.

Sources

1. National Eye Institute, Amblyopia (lazy eye)