by EBSCO Medical Review Board
(Lazy Eye)


Amblyopia is a reduction of vision in one eye that cannot be fixed with glasses. It is also called lazy eye.

There are five types:

  • Anisometropic amblyopia—Vision in one eye differs from the other
  • Strabismic amblyopia—One eye is not aligned with the other
  • Stimulus deprivation amblyopia—Vision is blocked due to something in the eye, such as a cataract
  • Ametropic amblyopia—Poor vision in both eyes
  • Meridional amblyopia—Both eyes have an abnormal or irregular curve

Early treatment can help a person see better. It can also keep the vision problems from getting worse.

Strabismic Amblyopia
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Amblyopia can happen when one eye does not see as well as the other. Sometimes the brain starts to use the eye that sees better to do the work of both eyes. That can make the eye that is not working well even weaker. It not always clear why one eye has better vision than the other.

Eye problems that can cause this are:

  • Eyes that are not aligned
  • Vision problems that are not treated
  • Having a large difference in sight between both eyes
  • Vision problems at birth, such as a cataract or droopy eyelid

Risk Factors

This problem is often noticed during childhood. Things that may raise the risk of this problem are:

  • Being born very early or being a small baby at birth
  • One or both eyes turn outward or inward
  • Having family members who had it or other eye problems as kids
  • Having developmental disabilities


Some people may not have symptoms. Others may have:

  • Blurry vision
  • Problems telling how near or far an object is
  • Squinting
  • Shutting one eye when looking at things
  • Head tilting
  • Eyes that cross


The doctor will ask about symptoms and health history. An eye exam will be done. Vision in each eye will be tested. This is often enough to make the diagnosis.


The goal of treatment is to correct vision. Any underlying eye problems will first need to be treated, such as removing a cataract. Improving vision can be done by forcing the brain to use the weaker eye so that it gets stronger. The doctor may do this with:

  • A patch worn over the stronger eye
  • Glasses that have one lens blurred
  • Eye drops to make the stronger eye blurry

Wearing the glasses or patches as the doctor advises is key to helping vision get better.

The doctor may also want to help the eyes learn how to work together again. This may be done with special games or videos.


There are no known ways to prevent this health problem. Getting regular eye exams can help find the problem early.


Eye Smart—American Ophthalmology 

National Eye Institute 


Canadian National Institute for the Blind 

Canadian Ophthalmological Society 


Amblyopia. EBSCO DynaMed website. Available at: Accessed March 22, 2022.

Amblyopia (lazy eye). National Eye Institute website. Available at: Accessed March 22, 2022.

Birch, E.E., Kelly, K.R., et al. Recent advances in screening and treatment for amblyopia. Ophthalmol Ther, 2021; 10(4): 815-830.

Levi, D. Rethinking amblyopia 2020. Vision Res, 2020; 176: 118-129.

Park, S.H. Current management of childhood amblyopia. Korean J Ophthalmol, 2019; 33(6): 557-568.

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