Lazy eye

A lazy eye (amblyopia) is when the vision in 1 eye does not develop properly. Rarely, both eyes can be affected.

Check if you have a lazy eye

A lazy eye does not always cause symptoms and is often first diagnosed during an eye test.

The main symptoms include:

Many children do not notice anything wrong with their vision.

You can check a younger child's eyes by covering each eye with your hand, 1 at a time. They may complain if you cover their good eye.

Older children may say they're not able to see as well with 1 eye and may have problems with reading, writing and drawing.

Non-urgent advice: Go to an opticians if:

  • you're worried about your or your child's vision
  • you have not had an eye test for 2 years

What happens during an eye test

To check if you or your child have a lazy eye, an eye test specialist called an optometrist will usually do an eye test.

You'll be asked to look at lights or read letters while different lenses are placed in front of your eyes.

To check the health of your eyes, you or your child may be given eye drops so the optometrist can see the back of your eye more clearly.

If you or your child needs glasses, you'll be given a prescription. You can take this to any optician.

Find out more about eye tests for children


NHS eye tests

NHS eye tests are free for some people, including:

  • children aged under 18, or under 19 and in full-time education
  • people who have diabetes or glaucoma
  • people on some benefits, including Universal Credit

Find out more about free NHS eye tests

Treatments for a lazy eye

How lazy eye is treated depends on what's causing it.

Treatment for a lazy eye aims to improve vision in the weaker eye.

This may include:

Treatment should ideally start before the age of 7, when vision is still developing.

If lazy eye is caused by cataracts or a drooping eyelid, you may need surgery.

You may also need to have surgery if you have a squint. This will straighten the eyes and allow them to work together better, but does not improve your vision.

Help with the cost of glasses and contact lenses

Some people are entitled to a voucher to help towards the cost of glasses or contact lenses, including:

  • children aged under 18, or under 19 and in full-time education
  • if you're on some benefits, including Universal Credit

If you do not have a voucher, you'll have to pay for glasses or contact lenses.

Find out more about NHS optical vouchers

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Page last reviewed: 4 January 2023
Next review due: 4 January 2026