Esotropia is an eye condition where either one or both of your eyes turn inward. This causes the appearance of crossed eyes. This condition can develop at any age.

Esotropia also comes in different subtypes:

  • constant esotropia: eye is turned inward at all times
  • intermittent esotropia: eye turns inward but not all the time

With esotropia, your eyes don’t direct themselves at the same place or at the same time on their own. You may notice this when you’re trying to look at an object in front of you but can only fully see it with one eye.

The symptoms of esotropia can also be noticeable by others. You may not be able to tell by looking in the mirror on your own, due to misalignment.

One eye may be crossed more than the other. This is often colloquially referred to as “lazy eye.”

Esotropia is caused by eye misalignment (strabismus). While strabismus can be hereditary, not all family members will develop the same type. Some people develop esotropia, while others might develop eyes that turn outward instead (exotropia).

According to the College of Optometrists in Vision Development, esotropia is the most common form of strabismus. Overall, up to 2 percent of people have this condition.

Some people are born with esotropia. This is called congenital esotropia. The condition can also develop later in life from untreated farsightedness or other medical conditions. This is called acquired esotropia. If you are farsighted and don’t wear glasses, the constant strain on your eyes can eventually force them into a crossed position.

The following may also increase your risk for esotropia:

  • diabetes
  • family history
  • genetic disorders
  • hyperthyroidism (overactive thyroid gland)
  • neurological disorders
  • premature birth

Sometimes esotropia may be caused by other underlying conditions. These include:

  • eye problems caused by thyroid disease
  • horizontal eye movement disorders (Duane syndrome)
  • hydrocephalus (excess fluid on the brain)
  • poor vision
  • stroke

Treatment measures for this type of eye condition depend on the severity, as well as how long you’ve had it. Your treatment plan can also vary based on whether misalignment affects one or both eyes.

People with esotropia, especially children, may wear prescription eyeglasses to help correct misalignment. In some cases, you might need glasses for farsightedness.

Surgery may be an option for severe cases. However, this treatment plan is mostly used for infants. Surgery focuses on straightening the eyes by adjusting the length of the muscles around the eyes.

Botulinum toxin (Botox) injections may be used in some cases. This helps to reduce small amounts of esotropia. In turn, your vision could become aligned. Botox is not used as much as other treatment options for esotropia.

Certain types of eye exercises can also help. These are often referred to as vision therapy. For example, your doctor may recommend placing an eye patch over the unaffected eye. This forces you to use the misaligned eye, which strengthens it and helps to improve vision. Eye exercises can also strengthen the muscles around the eye to improve alignment.

Infants with esotropia may have one eye that visibly aligns inward. This is called infantile esotropia. As your child gets older, you may notice issues with binocular vision. This can cause difficulties with measuring the distance of toys, objects, and people.

According to the University of Texas Southwestern Medical Center, infants with this condition usually get diagnosed between 6 and 12 months of age. Surgery can be required.

If strabismus runs in your family, you might consider having your child’s eyes checked out as a precaution. This is done by a specialist called a pediatric ophthalmologist or optometrist. They will measure your child’s overall vision, as well as look for any form of misalignment in one or both eyes. It’s important, especially in children, to treat the strabismus as early as possible to prevent any possible vision loss in the turned eye.

If one eye is stronger than another, the doctor may conduct further tests. They may also measure your child for astigmatism, as well as near or farsightedness.

People who develop crossed eyes later in life have what’s called acquired esotropia. Adults with this type of esotropia frequently complain of double vision. Often, the condition presents itself when everyday visual tasks become more difficult. These include:

  • driving
  • reading
  • playing sports
  • doing work-related tasks
  • writing

Adults with acquired esotropia may not need surgery. Glasses and therapy may be enough to help straighten your vision.

Left untreated, esotropia may lead to other complications of the eyes, such as:

  • binocular vision problems
  • double-vision
  • loss of 3-D vision
  • vision loss in one or both eyes

The overall outlook for this eye condition depends on the severity and type. Since infantile esotropia is often treated at a young age, such children may experience few vision problems in the future. Some might need glasses for farsightedness. Adults with acquired esotropia may need treatment for an underlying condition or special glasses to help with eye alignment.