Strabismus (Crossed Eyes): Types, Causes & How to Fix

Strabismus is an eye condition that affects babies, young children, and adults, in which the eyes cross or misalign. One eye points in one direction, whereas the other eye focuses. It occurs for multiple reasons, ranging from family history to stroke. 

Although there is no way to prevent being crossed-eyed, treatments can improve and correct vision.

What Is Strabismus?

Other names for strabismus include crossed eyes or walleye. It is a common eye condition that affects children and adults. However, the type of strabismus that kids and adults experience may differ, and it may occur for different reasons. 

The eyes may move in different directions, or they may be unable to line up at an early age. The eye condition may also develop over time following an injury or health problems. In some instances, it runs in families.

Strabismus is a relatively common eye condition, affecting 1 out of 20 kids. It is not always present at birth, as kids may develop strabismus around 3 or 4 years old. 

Children and adults may benefit from vision therapy, patching, medication, or surgery to help improve their eyesight. Usually, the six muscles attached to the eye allow it to move and line up without an issue. However, weak nerves or poor muscle control can lead to strabismus.

The most important thing is to get an examination and diagnosis as soon as possible. If a child or adult has strabismus, they should start treatment immediately to help correct vision impairments and reduce the risk of vision loss.

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Types of Strabismus

There are different types of strabismus. With each type, an eye may turn inward or outward, or vision may be fused or broken. 

Both children and adults may exhibit one of four common types of cross-eyedness or eye misalignment:

• Esotropia: The eyes turn inward toward the nose.
• Exotropia: This type is also known as walleye. One or both of the eyes turns outward toward the temple.
• Hypertropia: One eye turns upward toward the eyebrow. This type is less common.
• Hypotropia: One eye turns downward out of alignment.

Nearly 4 percent of adults will experience strabismus in some form within their lifetime. As the eye ages, the muscles don’t work as well. Hypertension, diabetes, or neurological problems can also exacerbate or trigger this eye condition.

For babies and young children, these are the most common types of strabismus:

• Accommodative esotropia
• Infantile esotropia
• Intermittent exotropia

Causes & Risk Factors

When a person develops crossed eyes, it’s not always present at birth. Various factors can cause someone to have strabismus. An early diagnosis can expedite a treatment plan to correct vision problems for children and adults.

Risk Factors for Child-Onset Strabismus

Certain behavior in pregnancy might increase the risk of a baby being born with strabismus.

The following can increase the chance that a baby will be born prematurely, before 37 weeks, or have a low birthweight. These two events may increase the risk of an infant being born with strabismus. If a pregnant person fits the following criteria, the baby is more likely to be born with crossed eyes:

• Smoking, drinking, and drug use during the prenatal period
• Poor nutrition or being underweight
• Living with a chronic health condition, such as lung, kidney, or heart problems or diabetes
• Being younger than 17 or older than 35

Although family history is a strong factor that may influence someone developing strabismus at birth or as a child, a healthy and stress-free pregnancy is very important.

Risk Factors for Adult-Onset Strabismus

For adults, various causes may lead to strabismus, such as these:

• Suffering a head injury
• Stroke
• Tumors
• Thyroid disease (Graves’ disease)

In addition, eye injuries or muscle or nerve disorders may contribute to the development of crossed eyes. Prevention and early diagnosis are the best medicine, so it is imperative to schedule medical checkups to screen for health problems that can lead to vision impairment.

Signs & Symptoms of Strabismus

Specific signs and symptoms may appear that indicate a child or adult has strabismus. Again, it is critical to undergo testing and receive a diagnosis from a medical professional. 

The following are signs of crossed eyes:

• The eyes don’t move together in alignment.
• You have to tilt or shift your head to see.
• You bump into objects because of poor depth perception.
• The eyes cannot look in the same direction simultaneously.

Besides these pressing issues, children and adults may complain about the following frequently:

• Blurry vision
• Seeing double
• Having to squint in bright light
• Eye fatigue

For a young child, signs and symptoms of strabismus may not appear consistently until 3 or 4 years old. For a teenager or adult, symptoms may develop over time following an injury, neurological disorder, or other problems.

Diagnosis

If you are concerned that you or your child may have strabismus, prompt diagnosis is important. Sometimes, it’s visibly evident that eyes have a severe misalignment, causing vision impairment.

A comprehensive exam with a vision specialist can determine if there are issues with the eye’s focus, poor eye muscle control, or vision loss. A medical professional may administer the following tests to check for crossed eyes:

• Retinal exam
• Visual acuity test
• Neurological exam

Children older than 3 months can undergo testing if they exhibit misaligned eyes consistently or infrequently. Older children and adults should seek testing to determine the cause of crossed eyes and seek ‌a treatment plan.

Treatment Options for Crossed Eyes

Strabismus is treatable. Both invasive and noninvasive procedures are available to improve eyesight and prevent vision loss. 

After treatment, most patients can expect a gradual improvement in eye muscle control, better depth perception, and other positive changes. These types of treatments are available for strabismus:

Eye Muscle Surgery

Surgery may be the best solution, depending on the type of strabismus and its severity. The surgery will tighten one or more eye muscles, aiming to improve alignment of the eyes. The patient may undergo vision therapy after surgery to prevent the eyes from becoming misaligned again and to improve eyesight.

Medications

A medical professional may prescribe medications for children or adults to stabilize the eye and reduce misalignment. These are often used in tandem with vision therapy. Medications range from eye drops to intermuscular eye injections.

Eyeglasses or Contacts

Prescription corrective eyeglasses or contacts may improve vision for children or adults with strabismus. Sometimes, this may be the only necessary treatment for mild cases of crossed eyes.

Vision Therapy

Vision therapy might involve patching a weak eye and practicing activities to help strengthen eye muscles, improve focus, and fortify the eye-brain connection. All these efforts help to improve vision. Many cases of strabismus show notable improvement after vision therapy.

Strabismus FAQs

What causes strabismus?

Crossed eyes or strabismus may happen at birth because of extreme farsightedness, a low birthweight, or a genetic predisposition to the condition. Adults may develop strabismus because of age-related health issues, an injury, or neurological disorders. 

Can crossed eyes be fixed?

Yes, strabismus or crossed eyes is a treatable condition. Patients may undergo vision therapy or corrective eye surgery. They can also use medications or wear prescription glasses or contacts to improve their vision.

What is the best treatment for strabismus?

For many cases of strabismus, noninvasive, nonsurgical treatment is the best solution. With vision therapy, patients can often achieve significant improvement in eye control, depth perception, and overall vision.

Can strabismus come back after surgery?

It is uncommon to develop strabismus again following surgery. After surgery, it is imperative to follow aftercare instructions, undergo therapy, and keep up with your eye doctor to ensure a successful recovery and long-term results.

Can you go blind from strabismus?

If left untreated, the non-dominant eye can experience vision difficulties, including eventual vision loss. Early diagnosis and treatment for strabismus can help reduce the chances of a patient experiencing this loss. 

What happens if you don’t treat crossed eyes?

When strabismus remains untreated, it will potentially lead to severe eye degeneration and poorer vision.

Is strabismus the same as lazy eye?

Some patients with strabismus may have a lazy eye, but it is not the same condition. Strabismus is when one or both eyes are out of alignment. A lazy eye is when there is poor visual acuity, and the person cannot see clearly out of one eye.

References

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2. Adult Strabismus. Yale Medicine.

3. Very Low Birthweight. Cedars Sinai.

4. Prevalence and Risk Factors of Strabismus in Children and Adolescents in South Korea: Korea National Health and Nutrition Examination Survey, 2008 – 2011. (February 2018). PLOS ONE.

5. Stanford Medicine Health Care: Strabismus (Crossed Eyes) Symptoms. Stanford Medicine Health Care.

6. Botulinum Toxin Injection for the Treatment of Strabismus: A Report by the American Academy of Ophthalmology. (December 2021). Ophthalmology.

7. Surgical Treatment for Residual or Recurrent Strabismus. (December 2014). International Journal of Ophthalmology.

8. Incidence, Types, and Lifetime Risk of Adult-Onset Strabismus. (April 2015). Ophthalmology.

9. Diagnosis and Management of Childhood Squints: Investigation and Examination With Reference to Red Flags and Referral Letters. (January 2017). British Journal of General Practice.

10. Understanding, Detecting, and Managing Strabismus. (March 2010). Community Eye Health Journal.

11. Management of Strabismus in Myopes. (July–September 2015). Middle East African Journal of Ophthalmology.

12. Vision Therapy for Intermittent Exotropia: A Case Series. (July–September 2021). Journal of Optometry.

13. Tests for Detecting Strabismus in Children Aged 1 to 6 Years in the Community. (November 2017). The Cochrane Database of Systematic Reviews.