Lazy eye

Amblyopia – Lazy Eye

Amblyopia is the technical term for a lazy eye.  This is a condition where one or both eyes doesn’t reach the normal level of vision and is then a so called lazy eye.

Amblyopia normally begins in early infancy or childhood particularly where one eye has a much higher prescription than the other.  It most commonly affects one eye but sometimes both eyes can be affected.  The brain is able to learn how to see better up until about 8 years of age.  That is why it is so important to correct this problem early.

If amblyopia is detected early then it can usually be treated successfully by making sure your child has the correct prescription glasses or contact lenses.  We also prescribe intensive eye exercises to improve the vision and cortical development of that eye.

If not detected or treated early enough a lazy eye can permanently reduce vision even to the extent that you can’t drive a car or you may even be legally blind.

How can I tell if my child has amblyopia?

Often when a child only has one lazy eye it may be almost impossible for a parent to tell.  These are often picked up in vision screenings at school or at your child’s first eye examination.  A quick test at home is to cover each eye in turn and find out if your child can still see your face or things you are holding.  If they don’t like having one particular eye covered it may be because that eye is blurry and they don’t partiuclarly like using it.  If this is the case you should bring them in for a check up.

A common cause of amblyopia is a turned eye (strabismus) and if you notice this at all you should bring your child into see us for an examination.

If you notice that your baby or child has a crossed eye or is blinking a lot or has problems focussing on you then it is a good time for an eye examination.

What are the common causes of amblyopia and how are they treated?

Turned eye (Strabismus)

The most common cause is strabismus or a turned eye.  Because both eyes are not aligned correctly the brain switches one off to avoid double vision (where you see two of everything).  This means the vision never really develops properly in the misaligned eye leading to a lazy eye.

Sometimes strabismus can be caused by high levels of long sightedness that can then be corrected with glasses or contact lenses.  Thankfully we can measure this in our practice even on small children.


If one eye has a much greater refractive error (short/long sightedness or astigmatism) than the other the brain will use the eye that is easier to see with and ignore the other.  This means the brain never really develops properly to use the “bad” eye and it results in the eye becoming lazy.

This is treated by correcting the refractive error and perhaps through patching the good eye to make the lazy eye do more work.  Often we need to use intensive visual exercises to improve the lazy eye.


Sometime a baby can be born with cataracts (congenital catarats) that block the light from reaching the back of the eye.  If this is the case the brain cannot see properly so doesn’t learn to focus with the eye leading to a lazy eye.  This needs to be treated urgently by an eye doctor (ophthalmologist) to remove the cataract.  Then an optometrist will prescribe glasses or contact lenses to correct any refractive error.  Sometimes we will need to patch the good eye to force the brain to use the lazy eye and to improve.

If I am an adult or have an older child with amblyopia what can be done?

It used to be thought that there was little success in treating a child over 8 years of age or an adult with long standing amblyopia.

Recent research suggests that intensive visual therapy can be used along with the right prescription glasses or contact lenses to improve vision.

If you would like to learn what is possible please make an appointment to see us.

Early detection and treatment is essential

If amblyopia can be detected early there is a much greater chance of doing something about it.  We recommend your child have their first eye examination at about 6 months of age and again at age 3 to ensure that any small problems are picked up before they become bigger ones.

To learn about the environment your child needs to see as clearly as possible, otherwise they will fall behind.  A lazy eye will not improve on its own and can lead to a permanent reduction in vision.