Strabismus vs Amblyopia: What's the Difference

Strabismus vs Amblyopia: What's the Difference

April 5, 2023

Table of Content

Amblyopia (lazy eye) and strabismus (crossed eyes) are closely related, but different eye conditions. It's easy to get these two conditions confused because strabismus is the most common cause of amblyopia, and amblyopia often occurs along with strabismus.

Thankfully, your eyecare specialist can treat both amblyopia and strabismus. Different treatments such as surgery, or wearing glasses can improve these functional vision problems.  Let's take a look at strabismus vs. amblyopia side-by-side.

Core Differences Between Strabismus and Amblyopia

If you think your child may have amblyopia or strabismus, it's best to get a professional diagnosis. While an obvious symptom of strabismus is an observable misaligned eye(s), you can't detect amblyopia with a simple observation, as there are no outward physical signs.

Strabismus Amblyopia
Also Known As Crossed eyes, squint, wandering eye, deviating eye Lazy-eye
% of Population 4% 3% — 6%
Misconceptions Strabismus applies to any type of eye turn, not just crossed eyes.

Another misconception is that a child can outgrow strabismus. The opposite is actually true; strabismus can get worse without treatment, potentially leading to blindness.
Patients are often told that amblyopia can only be treated until a certain age, but this isn’t true. While early intervention is optimal, it’s never too late to seek treatment.

People often assume the amblyopic eye is the “bad eye”. This isn’t always the case. While it might not have the same level of eyesight as the non-amblyopic eye, its visual localization may be good, etc.

What Are Amblyopia and Strabismus?

Before researching treatment options, it's important to know the difference between lazy eye vs. strabismus:

What Is Amblyopia?

Amblyopia is also called lazy eye. So, what does lazy eye even mean? It's a condition that refers to reduced vision in one eye caused by abnormal visual development in childhood. This happens when there's a breakdown in how the brain and eye work together, and the brain can't recognize sight from one eye. Over time, the brain relies increasingly on the stronger eye.

As a result, the weaker (lazy) eye often wanders inward or outward and suffers poor visual acuity. Is lazy eye strabismus? No, it's not the same thing. It's only called lazy eye because the stronger eye works better, however, people with it are not lazy, and have no control over the way their weak eye muscles work.

What Is Strabismus?

lazy eye and strabismus

Strabismus is the medical term for cross-eyed. Is strabismus the same as lazy eye? No, it's not, it refers to a lack of alignment in one or both eyes, which results in them turning inwards (esotropia), or sometimes up and sideways.

This can happen constantly or intermittently and usually accompanies visual acuity issues that are treatable with prescription lenses. Strabismus occurs in infants and young children, typically before the age of three. However, older children and adults can develop the condition, although it is rare.

Cross Eyed vs. Lazy Eye: Symptoms

While some lazy eye vs. wandering eye symptoms overlap, there are a few marked differences:

Strabismus Symptoms

Patients with constant strabismus tend to be less symptomatic (but not asymptomatic) when compared to patients with non-strabismic functional vision problems. That’s because they often suppress the information from the eye that is turning, thus avoiding double vision and some accompanying symptoms of poor eye teaming.

Common symptoms include:

  • Observable eye turn
  • Poor depth perception
  • Eye strain and/or pain
  • Headaches
  • Blurry or double vision
  • Eye and/or general fatigue

Amblyopia Symptoms

wandering eye vs lazy eye

The difference between lazy eye and strabismus is that the former is more challenging to spot. If you or your child exhibit the following symptoms you should seek medical help:

  • Difficulty throwing and catching objects
  • Poor depth perception
  • Clumsiness
  • Shutting or squinting the eyes
  • Head turning or tilting
  • Eye strain
  • Fatigue with near-sighted work

Amblyopia vs. Strabismus: Causes

A range of factors can cause an imbalance in muscles that position the eyes as well as neurological communication which results in both types of vision problems:

Amblyopia Causes

There are several causes of amblyopia: refractive errors, strabismus, and cataracts. Refractive errors can occur when one eye has better focus than the other, or one eye is nearsighted and the other farsighted, or if a person has significant astigmatism. When the brain receives a blurry image from one eye,  and a clear one from the other eye, it will ignore the weaker eye's input.

Another cause of amblyopia is strabismus. Again, the brain ignores the weaker eye, in this case, the one that isn't aligned. Lastly, if ptosis (drooping or falling upper eyelids) is severe enough it can cover an eye's visual plane or alter its refractive power, resulting in amblyopia.

Strabismus Causes

strabismus vs lazy eye

“What causes crossed eyes in babies?” is a question we're often asked. It's typically genetic and can be the result of an underlying systemic condition like Down syndrome, from refractive errors like farsightedness,  or other vision problems such as a congenital cataract.

Illnesses that affect muscles and nerves, premature birth, and head injuries also make people more prone to developing crossed eyes. Adults may develop intermittent or constant strabismus from eye or blood vessel damage, Grave's disease, a stroke, and various other muscle and nerve disorders.

How to Know If I Have a Lazy Eye or Crossed Eyes

If you have any of the symptoms we've mentioned, you should undergo a Functional Vision Exam. Unlike a routine eye test, a Functional Vision Exam diagnoses visual difficulties that detrimentally impact your quality of life and learning.

These exams are performed by eye doctors who know how to identify the subtle and sometimes obvious difference between a lazy eye and squinting. Functional Vision Exams take between 60-90 minutes and include additional testing to assess the visual skill areas of eye teaming, eye alignments, eye focusing, and eye movements.

As leading optometrists in the Chicago area, we offer Functional Vision Exams. If you haven't had an eye test in the past two years, we recommend booking one to ensure your eyes are healthy.

Treatment for Amblyopia and Strabismus

lazy eye vs strabismus

Learn what the difference is between strabismus and amblyopia treatments:

Amblyopia Treatment

Amblyopia treatment can greatly improve your vision or your child’s vision. When caught early,  its impact can be significantly mitigated. All children should have their eyes checked before their 4th birthday, so whether you’re concerned about the condition or not it’s important for you to arrange an appointment for an eye exam.

Amblyopia treatment for adults and children focuses on encouraging a child to use their weaker eye, which might include wearing an eye patch over their stronger eye. It may also include eye drops to blur the vision in the stronger eye. This is how to correct a lazy eye and in most cases, work extremely well.

Can LASIK Fix Amblyopia?

No. However, the chances of developing amblyopia can be reduced by using LASIK to treat shortsightedness and farsightedness.

Strabismus Treatment

Strabismus treatment may vary. Your eye doctor will determine which course of treatment is best depending on the cause of the condition. It may include prescribing prescription eyeglasses and/or eye muscle surgery.

In some cases, eye muscle surgery is necessary. The main thing to remember is that catching this condition early can often completely resolve the issue. So don’t be shy about reaching out to an eye doctor.

Can Glasses Fix Strabismus?

medical term for cross eyed

Yes, depending on what causes it.


Strabismus and amblyopia can be corrected, but it’s critical to catch them early. Be sure to schedule an appointment with your eye doctor for your young children, particularly before they reach the age of four, in hopes of catching any potential issues early.

If you experience any of the symptoms described above, or if you notice them in your child, be sure to reach out to our team at the Kraff Eye Institute. We’re Chicago’s trusted specialists in eyecare, and we offer a range of vision correction and treatment options.

Call us now at (312) 444-1111 to schedule an appointment.


How common is strabismus?

Expand F.A.Q.

Strabismus is a common eye condition affecting between 2%—4% of adults and children. It usually appears in infants and young children by the time they are three to four years old. However, older children and adults can also develop it.

Does amblyopia get worse with age?

Expand F.A.Q.

Without treatment, an amblyopic eye will get worse over time. While treatment can happen at any age to restore binocular vision, it's ideal before the age of seven when the connections between the brain and the eyes are still developing.

Is amblyopia genetic?

Expand F.A.Q.

Yes, amblyopia may be genetic. If you have a family history of lazy eyes consult an eye doctor to make sure your eyes are in good health. If you have amblyopia and you suspect your child may have it, taking them to see an eye care professional is recommended.

How long does it take to correct a lazy eye?

Expand F.A.Q.

It depends on the treatment. For most patients, vision improves within a few weeks to a few months.

Can you go blind from strabismus?

Expand F.A.Q.

Yes, the deviating eye becomes weak from not being used, which may eventually lead to blindness if strabismus isn't treated properly. This is because over time the brain will learn to ignore the image from the turned eye.

Dr. Colman R. Kraff

Committed to advancing new technologies in the field of ophthalmology, Dr. Colman Kraff helped to pioneer laser vision correction. In February of 1991, as part of a five-site, U.S., FDA clinical trial team, Dr. Kraff successfully performed the first excimer laser procedures in the Chicagoland area using the VISX Excimer Laser.

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