Amblyopia vs. Strabismus

Don’t be “lazy,” learn which is which and how you can correct the problem!

There is often confusion between amblyopia and strabismus because people mistakenly call a crossed or turned eye a “lazy eye,” but the two are not the same.

Strabismus is the medical term for a “crossed eye,” when there is a problem with the eye alignment and the eyes do not look at the same place at the same time. Amblyopia is the medical term for a “lazy eye,” when one eye has less visual acuity than the other eye. This can be further confused because someone could have both amblyopia and strabismus!

Strabismus is easier to recognize, because the eye actually turns in, out, up, or down. Amblyopia’s symptoms are more subtle, but can seriously impact a child’s life. Both conditions can be diagnosed by a developmental optometrist and helped by a program of optometric vision therapy.

Read on to learn more about both of these conditions!



Also Known As

Crossed-eyes, Squint, Wandering eye, Deviating eye, Walleye

Lazy eye

Most Common Symptom

Visual acuity is less in one eye

Eye teaming and alignment



Causes and Risk Factors

According to the AOA:

  • A high prescription that has gone uncorrected with glasses or contacts
  • Family history
  • Premature birth
  • Developmentally disabled
  • Eye turn—also referred to as strabismus (one eye turned out or in)
  • Visual deprivation of one eye—congenital cataract, ptosis and/or corneal opacities
  • Large refractive errors

According to the AOA:

  • Family history- People with a parent or sibling who have strabismus are more likely to develop it
  • Refractive error- People who have a significant amount of uncorrected farsightedness (hyperopia) may develop strabismus because of the additional eye focusing they must do to keep objects clear
  • Medical conditions- People with conditions such as Down Syndrome and cerebral palsy or who have suffered a stroke or head injury are at a higher risk for developing strabismus

All three types of amblyopia result from suppression of vision in one or both eyes. The difference is in the root cause of the suppression.

  • Refractive amblyopia 
  • Strabismic amblyopia 
  • Deprivation amblyopia

There are several types of strabismus, determined by the following:

  • Which eye turns
  • Direction of the eye turn
  • Frequency of the eye turn
  • Amount of eye turn
  • Whether the turn is the same in all positions of gaze



% of Population

3% – 6% (About 1 in 25 people)

4% (About 1 in 25 people)

  • Noticeably favoring one eye
  • Tendency to bump into objects on one side
  • Poor depth perception
  • Difficulty judging distances
  • Difficulty catching and throwing objects
  • Clumsiness
  • Squinting or shutting an eye
  • Head turn or tilt
  • Eye strain
  • Fatigue with near work
  • Eyes that look misaligned
  • Eyes that do not move together
  • Frequent blinking or squinting, especially in bright sunlight
  • Tilting the head to look at things
  • Faulty depth perception
  • Double vision

Complete correction possible. 

Children will not grow out of amblyopia naturally. If left undiagnosed, treatment becomes more complex and can take longer.

Can be corrected, better results for earlier detection.

  • Prescription lenses or prisms can help
  • Vision therapy treats the underlying problem of binocular vision dysfunction, ensures that relapses don’t happen, and prevents vision from worsening
  • Prescription lenses or prisms can help
  • Vision therapy
  • Surgery*

* Surgery cuts the muscles, but doesn’t actively develop binocular vision. Most of vision occurs in the brain and surgery ignores this, meaning eye muscle surgery is only successful 60-80% of the time. Vision therapy is an effective, non-surgical way to manage strabismus.

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If you suspect that you or a loved one have amblyopia or strabismus, they should be evaluated by a developmental optometrist to prevent the lifelong struggles that come with amblyopia and strabismus. A developmental optometrist, like Dr. Jesse Willingham, can diagnose them during a thorough evaluation that goes beyond a routine eye exam. This additional testing allows the doctor to fully understand the underlying problem and better address the issue. Based on the diagnosis, he can recommend a treatment that best meets the patient’s needs.

Optometric vision therapy is an effective, non-invasive method for treating both amblyopia and strabismus. Vision therapy teaches your brain to better communicate with your eyes to more efficiently understand and navigate your world. It gets to the root of the problem and teaches the eyes to work together, with the brain. Someone can take steps to correct amblyopia/strabismus at any age, but younger children are more adaptable. Older patients may have longer programs than children. Each person and program is unique!

Connect with us to see if we can open up a whole new world for you or your loved one!

vision therapy - red green wall binocular vision