Amblyopia

What is Amblyopia?

The leading cause of vision loss amongst children, amblyopia is the term for decreased vision due to abnormal development of vision in infancy or childhood. Amblyopia can occur in one or both eyes and may not be something obvious that can be seen by others.

Amblyopia occurs because nerve pathways between the brain and the eye are not properly stimulated. The brain learns to see only blurry images with the amblyopic eye. As a result, the brain may favor the stronger eye. Thus, another word for amblyopia is often lazy eye.

What kinds of amblyopia are there?

There are several different types and causes of amblyopia: strabismic amblyopia, deprivation amblyopia, and refractive amblyopia. The end result of all forms of amblyopia is reduced vision in the affected eye(s).

What is strabismic amblyopia?

Strabismic amblyopia develops when the eyes are not straight; one eye may turn in, out, up, or down. When this happens, the brain begins to ignore, or “turns off” the eye that is not straight. Subsequently, vision in that eye can be even more impaired or completely lost. It is actually preferable for a child to have an eye cross or drift that switches between both eyes equally, rather than a constant eye cross or drift of one eye.

What is deprivation amblyopia?

Deprivation amblyopia develops when blocks the vision of one eye (such as a cataract or droopy eyelid). If not treated very early, these children never learn to see well and can have very poor vision. This can occur in one or both eyes.

What is refractive amblyopia?

Refractive amblyopia occurs when there is a significant amount of hyperopia, myopia, or astigmatism in one or both eyes. Since this is how the child has seen their whole life, they do not recognize that their vision is blurry. This can occur in just one eye, or even in both eyes. The only treatment for this is wearing glasses full-time.

Since it took months or years for the child’s brain to learn to see poorly, we expect it to take at least a few weeks or months for the glasses to start slowly improving the vision. Sometimes if the glasses are not helping quickly enough we may need to use an eye patch or drops to speed the process along. Once the vision is normal, this does not mean the child no longer needs glasses; often, if we abruptly stop utilizing glasses, the vision will slip again.

When should amblyopia be treated?

Early treatment is always best. If necessary, children with refractive errors (nearsightedness, farsightedness, or astigmatism) can wear glasses or contact lenses when they are as young as one week old. Children with cataracts or other amblyogenic conditions are usually treated promptly in order to minimize the development of amblyopia. If the vision is not good enough in one or both eyes it can impact the child’s ability to get a driver’s license or limit certain career choices as an adult.

How old is TOO old for amblyopia treatment?

The older a child is, the more difficult amblyopia is to treat. However, in some cases we have treated amblyopia and improved the vision (though not usually to 20/20) in teenagers or even adults.

How is amblyopia treated?

One of the most important treatments for amblyopia is correcting the refractive error with consistent use of glasses and/or contact lenses. We often start with glasses and add additional treatments if the glasses alone are not helping.  If a child has an eye cross or drift, surgery may be needed, but in most cases we try to improve the vision first before correcting the eye cross or drift. When this alone does not work we often use eye patches, eye drops, or even computer programs to improve the vision. If a child has a cataract or a droopy eyelid this may also need to be corrected.

What are appropriate goals of amblyopia treatment?

In all cases, the goal is the best possible vision in each eye. While not every child can be improved to 20/20, most can obtain a substantial improvement in vision. The earlier the treatment for amblyopia, the more successful the treatment tends to be.

Can surgery be performed to treat amblyopia?

No. Surgery can be done to straighten a crossed or drifting eye, remove a cataract, or fix a droopy eyelid, but there is no surgery to correct the vision in an amblyopic eye.

What happens if amblyopia treatment does not work?

In some cases, treatment for amblyopia may not succeed in substantially improving vision. It is hard to decide to stop treatment, but sometimes it is best for both the child and the family. Children who have amblyopia in one eye and good vision only in their other eye can wear safety glasses and sports goggles to protect the normal eye from injury. As long as the good eye stays healthy, these children function normally in most aspects of society.

 

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