Lazy Eye

Lazy Eye and Lazy Eye Surgery

What is a Lazy Eye?

Lazy eye or Amblyopia, is a condition that starts in early childhood, where the vision does not develop properly. It usually affects only one eye but can develop in both. The condition happens when there is an insufficient connection between the eye/s and the brain.

Approximately 1 in 50 children develop a lazy eye. If detected and treated early, long-term reduced vision problems can be avoided.

How do I recognise a lazy eye?

Lazy eyes frequently do not present with any symptoms and younger children are often either unaware of the problem, or unable to explain it. Older children may complain that they cannot see as well with one eye and struggle with reading, drawing or writing.

If your child is too young to explain their vision, try covering each eye with your hand. The child might be happy with the bad eye being covered but will be unhappy with the good eye being covered. If this happens, it could be a sign that they can see out of one eye better than the other.

When should I seek medical advice for a lazy eye?

A lazy eye is often diagnosed during routine eye tests and before the parents realise there is a problem.

All newborn babies have an eye test in the first few days after birth, and again at 2-3 months old. Conditions such as cataracts can be detected this early, but a problem such as squint or long sight may not be apparent until the child is older.

Lazy eye is difficult to treat after the age of 6, so it’s recommended that children have their vision tested after turning 4. This should be organised by your local council.

Of course, if you have any concerns you should visit your GP or optician for further advice and referral to an eye specialist if necessary.

What causes a lazy eye?

There are 3 main types of amblyopia (lazy eye):

  1. Strabismic Amblyopia

This is the most common cause and stems from a misaligned eye, or squint. To avoid double vision, the brain ignores the signals from the misaligned eye.

  • Refractive Amblyopia

Even with perfect eye alignment, there can be unequal refractive errors in the eyes. An example of this can be significant short or long sightedness or astigmatism in one eye, which the other eye does not suffer from. The brain will begin to ignore the eye with the issue and therefore causes it to become lazy.

  • Deprivation Amblyopia

This is caused by an obstruction to light entering the eye, usually caused by a congenital cataract. It is important to treat this quickly to allow normal visual development to continue.

Like a camera, the eyes work through the process of light passing through the lens to the retina, the light-sensitive tissue at the back of the eye. The retina then translates the image into nerve signals that go to the brain. The brain combines these signals into an image.

Lazy eye happens when these brain connections don’t work properly. These connections build up during a child’s first 8 years and need a clear image from the eye in order to develop correctly. Without this, the brain doesn’t have strong pathways for vision information in the future.

How is a lazy eye treated?

The earlier a lazy eye is treated, the higher the chance of success. If treatment begins before a child is 6, it has a high rate of success. If treatment does not begin until after a child is 8, it’s rare to be successful.

The two main treatments of lazy eye are treating any underlying eye problems and/or helping the affected eye to be used, in order that the vision develops correctly.

Correcting vision problems

Short- and long-sightedness and astigmatism can all be corrected with glasses or contact lenses. Glasses can also be used to straighten a squint, which can fix the lazy eye.

Children will often need a great deal of encouragement to wear their glasses, particularly as they may say that they see better without them. This is because they have become used to a particular way of focusing and are not used to the glasses doing this for them.

Cataracts require removal surgery to improve vision in the affected eye/s. Cataract surgery for children is a relatively simple procedure and further details are on our children’s eye problems page.

Patching Treatment

This treatment can be very effective and involves putting a patch over the good eye, forcing the lazy eye to work. Depending on how old the child is, how they manage with a patch and how serious the amblyopia problem is will determine how long the patch is required for. Patches work best on children that are younger than 6 years old and needs to be worn for a few hours a day for several months. This can be a time-consuming and difficult process for a child, because initially you are making their eyesight worse by covering the ‘good’ eye. If a child struggles with wearing a patch, there is the option of treatment with eyedrops.


Atropine eyedrops can be just as effective as a patch and are often preferred as a treatment if a child doesn’t like wearing a patch. The eyedrops work to dilate the pupil in the good eye, which blurs the vision. This will encourage use of the lazy eye. There are occasional side effects, but these are rare:

  • Eye irritation
  • Reddening of the skin
  • Headaches

Lazy Eye Surgery

On occasion, eye muscle surgery is required to correct a squint by strengthening or weakening certain muscles in order to stop the eye misaligning. Eye muscle exercises have also been successful in some cases and prevent the requirement for surgery. These exercises include pencil push-ups and computer vision therapy.

Whatever the solution, the earlier you can treat a lazy eye, the higher the chance of success. If you have any concerns please get in touch or speak to your doctor or optician.