What is Amblyopia?

The medical name for lazy eye is ‘amblyopia’ (am-blee-OH-pee-uh). It starts from reduced vision, generally in only one eye. 

The condition is the leading cause of decreased vision among children. It generally develops from birth up to age seven years.

Amblyopia develops from a miscommunication between the eyes and the brain. If one eye is stronger than the other, the brain slowly begins to prefer it and ‘tunes out’ the weaker eye. Over time, the brain relies so much on the stronger eye that vision in the weaker one gets worse.

Early detection is vital

Amblyopia does not go away on its own.

If amblyopia is left untreated, it can have long term consequences for a child’s vision, and lead to permanent vision problems. 

The key to helping your child’s vision and preventing long-term problems with amblyopia is early diagnosis and treatment by your eye doctor (optometrist). 

The earlier the diagnosis, the better the chance of a complete recovery.

What causes amblyopia?

If vision in one eye is worse than in the other, the two ‘views’ provided by the eyes can not be combined into one clear image by the brain. Instead, the brain responds by dulling or ignoring the image sent by one of the eyes (usually the weaker one).  

Over time, the brain gets used to working with the strong eye, and it ‘turns off’ the other one. Unfortunately, the eye ignored by the brain will not develop normal vision.

There are three different causes to lazy eye amblyopia, but fundamentally, the condition stems from one eye being stronger than the other.

Strabismic amblyopia 

Strabismic is the most common cause of lazy eye amblyopia.

Strabismus is the condition of misalignment, when both eyes don’t look in the same place at the same time. When this happens, the brain begins to ignore the visual input from the misaligned eye.

Refractive amblyopia 

Refractive amblyopia is when the eyes are aligned, but one eye has significant far-sightedness or near-sightedness. 

The brain then chooses to go with the information coming in from the less-affected eye and tunes out the impaired one.

Deprivation amblyopia 

Deprivation amblyopia is the most severe form of lazy eye. 

It happens when there is a cloudy area in the lens (cataract) that prohibits clear vision in that eye. Urgent treatment is required to prevent vision loss.

Symptoms of amblyopia

Often, children with amblyopia have no obvious symptoms and the condition goes undetected until they have their first comprehensive eye exam.   

Noticeable symptoms include…

  • One eye is fully or partially shut
  • The child’s head is always turned or tilted to one side
  • The child bumps into things frequently

Is lazy eye the same as crossed eyes?

Contrary to popular opinion, lazy eye and crossed eyes are not the same thing. 

The medical term for crossed eyes is ‘strabismus,’ which is a problem with eye-alignment. That is: both eyes do not look at the same place at the same time.

Lazy eye, on the other hand, is a lack of development of clear vision (acuity) in one of the eyes.

Frequently, crossed eyes cause your eye to become lazy. Often, to avoid double vision caused by crossed eyes, the brain ignores the input from one of the eyes. This leads to laziness in the eye. Although they appear similar they are two distinctly different conditions.

Crossed eyes (‘strabismus’) is a condition of misaligned eyes. When the eyes point in two different directions. Lazy eye (‘amblyopia’) is when visual input from one eye is ignored by the brain. 

Lazy eye treatment

Early treatment of amblyopia lazy eye is crucial. Amblyopia treatment is as follows:


If a vision problem is causing amblyopia, your optometrist will be able to treat it first. They may recommend glasses or contacts (for children who are near-sighted or far-sighted) or surgery (for kids with cataracts).

Eye Patches

The next step is to retrain the brain and force it to use the weaker eye. The more the brain uses it, the stronger it gets. Training involves putting an eye patch over the good eye so that the lazy eye has to work. Eye patching is an effective idea. Since the brain is only getting information from the eye that doesn’t have the eye patch on, it can’t ignore it. The eye patch is worn a few hours each day by the child.

Eye drops

Another option is putting special eye drops in called atropine eye drops, which are less conspicuous than patches. Atropine works on the same principle as patching, but is less conspicuous. Atropine eye drops temporarily blur out the stronger eye and force the brain to take signals from the ‘lazy eye.’ The drops will cause blurry vision for a short while in the good eye, resulting in the lazy eye having to work harder and as a result, will get stronger.

Effective treatment of lazy eye is highly successful when it is started early – the sooner your child starts having a regular eye exam in order to commence treatment, the better.

Eyecare Plus encourages all parents to schedule routine eye exams for their young children before they start school.

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