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What is Crossed Eyes or Strabismus?

Crossed eyes or medically known as strabismus occurs when eyes are not aligned with each other. The brain is unable to coordinate eyes to work together. Strabismus can be categorized into four groups by the direction of the eye misalignment, namely esotropia (inward turning), exotropia (outward turning), hypertropia (upward turning) and hypotropia (downward turning).

How Common is Strabismus or Crossed Eyes?

Strabismus is a relatively common visual condition, affecting people of all ages, although it is more frequently diagnosed in children. According to the American Association for Pediatric Ophthalmology and Strabismus (AAPOS), approximately 4% of children under the age of six have crossed eyes.

While strabismus is often detected during childhood, it can also develop or persist into adulthood. Estimates suggest that around 2-4% of adults worldwide have some form of strabismus. However, due to underreporting and misconceptions surrounding adult strabismus, the actual prevalence may be higher.

Symptoms of Strabismus

In general, symptoms include:

  1. Visible Eye Misalignment: One eye turning inward, outward, upward, or downward.
  2. Double Vision: Seeing two images instead of one due to misaligned eyes.
  3. Head Tilting or Turning: Tilting the head to align the eyes and reduce double vision.
  4. Squinting or Closing Eyes in Bright Sunlight: Sensitivity to light may lead to squinting or discomfort, causing individuals to frequently close one eye in bright sunlight.
  5. Headaches: Straining to focus the misaligned eyes can result in frequent headaches, particularly after prolonged visual tasks.
  6. Eye Fatigue: Straining to focus the misaligned eyes can lead to eye fatigue and discomfort.
  7. Reduced Depth Perception: Difficulty judging distances accurately. Bumping into things because of limited depth perception can happen.

Causes of Strabismus

Normally, children do not realize any changes in their vision if they have crossed eyes. However, some complain about double vision or just general issues with seeing objects.

Strabismus can be present at birth or develop during childhood. The majority of strabismus is caused by abnormality of the neuromuscular control of eye movement which is the consequence of medical conditions, such as Down Syndrome and cerebral palsy. Furthermore, strabismus can be genetically related and run in the family.

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Types of Strabismus

Strabismus can be classified based on the direction of eye misalignment and the frequency of occurrence. Common types include:

  1. Esotropia: Inward turning of one or both eyes.
  2. Exotropia: Outward turning of one or both eyes.
  3. Hypertropia: Upward deviation of one eye.
  4. Hypotropia: Downward deviation of one eye.
  5. Intermittent vs. Constant: Strabismus may be intermittent, occurring occasionally, or constant, present at all times.

Two most common forms are accommodative esotropia and intermittent exotropia. Accommodative esotropia arises when a person has uncorrected farsightedness and a genetic predisposition for their eyes to turn inward. This type of strabismus usually develops throughout the first few years of a child’s life.

Intermittent exotropia refers to focusing with one eye on an object while the other eye is gazing outward. Intermittent exotropia happens at any age. 

Types of strabismus or crossed eyes.


The majority of children with strabismus are identified between the ages of one and four. After the age of six, a kid may also get crossed eyes. If this occurs, the child should consult a doctor right away to rule out any other conditions. If one or both eyes wander in, out, up, or down on a regular basis, it’s most probably due to strabismus.

Diagnosing strabismus involves a comprehensive evaluation conducted by an eye care professional, typically an ophthalmologist or optometrist specializing in pediatric or strabismus care. The diagnostic process may include a combination of the following assessments:

  1. Patient’s History: Gathering a detailed medical history, including any previous eye conditions, surgeries, or family history of strabismus, provides valuable insights into the potential causes and progression of the condition.
  2. Visual Acuity Testing: This test measures the clarity of vision in each eye using an eye chart. It helps identify any significant differences in visual acuity between the eyes.
  3. Cover Test: During a cover test, the eye care provider observes the movement and alignment of the eyes while one eye is covered and then uncovered. This test helps detect misalignment and determine the type of strabismus present.
  4. Refraction Test: Assessing refractive errors, such as nearsightedness, farsightedness, or astigmatism, is crucial as these conditions can contribute to strabismus or exacerbate existing misalignment.
  5. Ocular Motility Exam: Evaluating the range, coordination, and smoothness of eye movements helps assess the function of the eye muscles and detect any abnormalities.
  6. Focus Testing: Assessing the ability of the eyes to maintain focus and converge on a target, particularly at different distances, helps evaluate the coordination of eye movements and binocular vision.
  7. Assessment of Eye Alignment: Specialized tools and techniques, such as a prism cover test or Hirschberg test, may be used to measure the degree of eye misalignment accurately.
  8. Examination Under Anesthesia (EUA): In some cases, particularly with young children or individuals unable to cooperate fully during the examination, an EUA may be necessary. Under anesthesia, the eye care provider can thoroughly assess eye alignment and perform additional diagnostic procedures if needed.

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1. Eyeglasses or contact lenses: In some forms of strabismus, eyeglasses or contact lenses may be the only treatment that is needed to correct misalignment.

2. Prism lenses: However, in other cases, other treatment approaches are needed such as prism lenses, vision therapy or eye muscle surgery. Prism lenses are lenses that are thicker on one side than the other. The prisms change the way light enters the eye, reducing the amount of turning required to perceive objects. The prisms can sometimes obviate the need to turn your head.

3. Vision therapy: Vision therapy is a type of therapy that involves structured programs including exercises that teach the eyes and brain to work together more efficiently. Exercises aid with eye movement, concentrating, and teaming, as well as strengthening the eye-brain relationship. Treatment can take place both in the office of your optometrist and at home.

4. Eye muscle surgery: Eye muscle surgery alters the length of muscles and corrects misalignment of the eyes. Prior to surgery, it is most important to rehabilitate any vision loss from amblyopia. After eye muscle surgery, vision therapy is often required to improve eye coordination and prevent the eyes from becoming misaligned again.

AmblyoPlay is Treating Strabismus or Crossed Eyes

AmblyoPlay is a vision therapy performed with a combination of anaglyph/red and green filter glasses. Using different exercises and activities, we can improvemild forms of strabismus and train the visual system to develop a healthy vision. In cases of strabismus, AmblyoPlay is efficient for exotropia (outward) or esotropia (inward) form of deviation.

Enhancing Vision Therapy Effectiveness Through Engaging Activities and Binocular Stimulation

Vision therapy is performed through playing therapeutic games and exercises on your tablet or computer. What is more, the use of red and green lenses allows excellent control over stimulus characteristics. When a red filter is placed over the right eye and a green filter is placed over the left eye, the right eye sees only red targets and the left eye sees only blue/green targets, allowing you to see with both eyes at the same time.

Researchers found that treatments that include fun activities have a higher percentage of compliance. As games are very engaging, a greater compliance is achieved. Therapy programs with a high degree of compliance have relatively large treatment effects.

AmblyoPlay can treat exotropia strabismus
Volos, Greece

Panagiotis: “The games are really fun!”

I‘ve been using AmblyoPlay for over the past 6 months, after my doctor’s recommendation. I have exotropia strabismus. I’ve really noticed an improvement in my eyes, they feel stronger and I am waiting now for the official examination and measurement by my doctor. The games are really fun and I enjoy playing them and collecting gems.

Treating crossed eyes with AmblyoPlay.
Kecamatan Kuta Utara, Indonesia

Tom: “My daughter likes completing the training!”

AmblyoPlay has proved to be a fun and successful way to help our daughter’s left eye realign. She really enjoys the rewards, like getting new costumes for her character and she likes completing the training because it makes her feel “satisfied”.

The charts are really good as we can watch how her eyes are improving by checking the training efficiency chart and the regular eye screening test results.

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Adults disorders that cause strabismus include trauma, neurological problems, Graves’ disease, diabetes, stroke, tumor and other.

Generally speaking, adults with strabismus will have symptom of double vision. Adults may possess misalignment as a result of residual childhood strabismus or as a result of adults-onset strabismus. Strabismus in adults can be treated. The most qualified specialist to treat adults with misaligned eyes is an ophthalmologist who specializes in strabismus. Other specialists can be used to figure out what’s causing the misalignment.

Frequently Asked Questions

What are the common signs and symptoms of strabismus?

Strabismus, also known as “crossed eyes” or “squint,” presents with various symptoms indicating eye misalignment and coordination issues. These symptoms may include visible eye misalignment, double vision, head tilting, eye fatigue, and reduced depth perception.

How is strabismus diagnosed?

Strabismus diagnosis involves a comprehensive evaluation conducted by an eye care professional. This evaluation includes gathering the patient’s medical history, performing visual acuity testing, cover testing, assessing refractive errors, evaluating eye muscle function, conducting focus testing, and assessing eye alignment using specialized techniques.

What treatment options are available for strabismus?

Treatment options for strabismus depend on factors such as severity, underlying causes, age, and individual preferences. Common treatments include corrective lenses, vision therapy, prism lenses, eye muscle surgery, and botulinum toxin injections. Early detection and intervention are crucial for optimizing treatment outcomes.

Can strabismus affect people of all ages?

Yes, while strabismus is commonly diagnosed in children, it can affect individuals of all ages. It may develop or persist into adulthood and can have significant impacts on visual function and quality of life if left untreated.

What should I do if I suspect strabismus in myself or my child?

If you suspect strabismus or notice any symptoms, it’s essential to consult an eye care professional for a comprehensive evaluation and personalized treatment plan. Early detection and intervention can help manage strabismus effectively, improve eye alignment, and enhance overall visual function and quality of life.

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Why Do We Suggest a Minimum Time of 6 Months for Success?

Based on the data from over 15,000 patients using AmblyoPlay, improvements start within 4 months, while optimal results take anywhere between 6-18 months on average. The duration of required training depends on the patient’s age, the severity of the problem, accompanying diseases, and adherence to the training program.

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