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Optometrist checking a child's eye

Lazy Eye - Amblyopia

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What is Amblyopia?

Amblyopia ('lazy eye') happens when the vision in one eye doesn't develop properly in early childhood. You may not be able to notice it easily in your child, but if it isn't treated it will become a permanent visual problem.

What Causes Amblyopia?

Babies are able to see when they are born, but they have to learn how to use their eyes. They have to learn how to focus, and then how to use both eyes together. Our vision continues to develop until we are about 9 to 12 years old. After that, our eyesight is complete and can't be easily changed.

However, sometimes the vision in one eye doesn't develop properly. This may be caused by misaligned eyes (called strabismus) or because one eye is out of focus compared with the other. When this happens, the brain 'shuts off' the eye that is out of focus, and the child depends only on the better eye to see.

An eye disease such as a cataract or anything else that stops a clear image from being focused inside the eye can cause amblyopia in children. They may also inherit conditions from their parents that lead to amblyopia.

How Is Amblyopia Diagnosed?

You may not be able to tell that your child has amblyopia. Many children with the condition look completely normal and see well with their good eye. If your child has an eye that turns in, out, or up, or if he or she closes one eye (especially in bright sunlight), these are warning signs.

Some family doctors and pediatricians screen eyesight. There might also be vision screening as part of a preschool checkup in your community. If there is any doubt about your child's vision, they will refer you to an eye doctor for more tests.

How Is Amblyopia Treated?

A child's vision is fully developed by age 9, so amblyopia must be treated early in life, preferably before age 6. It is hard to reverse amblyopia after that age. If it is treated early enough, amblyopia can usually be reversed.

The Doctor's Role

Amblyopia is best treated by an ophthalmologist, often with the help of an orthoptist. Treatment may involve glasses to correct blurred vision or help straighten the eyes, and patching or blurring the vision of the good eye to force the lazy eye to work. Surgery can be necessary as well, to mechanically realign the eyes. Exercises or other types of visual training are not effective in treating amblyopia.

The Parents' Role

If amblyopia isn't treated, it will lead to a lifetime of poor vision in one eye. This puts your child at higher risk of vision loss if the seeing eye is injured. As well, an eye with poor vision can become misaligned (strabismus), which can affect your child's 3-D vision, making certain activities difficult and even limiting some job opportunities.
Parents play a vital role in making sure their child does not have this disability. First, it is important to recognize any signs of a problem. For example, it is not true that all babies are cross-eyed. If your child is 6 months old and is still cross-eyed, you should see a doctor as soon as possible. Second, you should never wait for your child to 'just grow out of' an eye problem. If you think something is wrong with your child's eyesight, have it checked.
You will need to work with the doctors and others (such as teachers) to ensure your child wears the glasses or patch as prescribed. You play a key role in making sure your child has a lifetime of good eyesight. The earlier the treatment is started, the sooner it is likely to be successful.

© Copyright by the Canadian Ophthalmological Society