Seeing esotropia? Take fast action: Q&A with ophthalmologist

Diagram showing esotropia, aka an inward-turning crossed eye
Esotropia is the term used to describe an inward-turning crossed eye.


According to the American Academy of Ophthalmology, about 4 percent of children have some form of strabismus (crossed eye). In infants, the most common type of crossed eye is known as esotropia, which is when the eye or eyes turn inward.

Although it can sometimes be as simple as prescribing glasses to correct the eye’s alignment, it’s important to seek expert care early.

Early intervention can:

  • rule out any potentially serious underlying disease
  • identify appropriate treatment to quickly correct the crossed eye and
  • prevent lingering long-term effects.

Boston Children’s Ophthalmologist-in-Chief, David Hunter, MD, PhD, offers advice to pediatricians on what to do when a patient suddenly develops esotropia.

When should a pediatrician refer a patient with a crossed eye to an ophthalmologist?

Infants and young children don’t have many ways to tell us that there is a problem with their eyesight. So, one way we can detect a problem is when esotropia develops.

While it is common for an infant’s eye to drift outward within the first three months of life, it is uncommon for the eye to cross noticeably inward. In infants, crossing of the eye(s) is called “infantile esotropia.” This can often appear spontaneously and for unknown reasons. It can develop as early as a few weeks of age. Usually, surgery is required to correct infantile esotropia.

In older children, it can be a red flag when a child suddenly describes having double vision.

Watch the video and learn more about Dr. Hunter’s approach to strabismus.

If esotropia occurs at any age, the child should be referred to an ophthalmologist who has experience working with children. The ophthalmologist will administer dilating drops. This will help determine whether the child needs a prescription for corrective lenses. It will also allow the ophthalmologist to check the retinas and optic nerves for signs of underlying disease.

Regardless of the cause, the longer esotropia goes untreated, the harder it is to regain stereopsis (depth perception) and prevent amblyopia (commonly called “lazy eye”).

What is the difference between ‘comitant’ and ‘incomitant’ esotropia?

When the eyes are misaligned, ophthalmologists don’t just measure the angle of alignment in a straight-ahead gaze. We also check alignment with gaze right, left, up and down. We describe it as “comitant esotropia” when the misalignment measurements are the same in all directions.

If esotropia occurs at any age, the child should be referred to an ophthalmologist who has experience working with children.

When a child aged 2 or older develops comitant esotropia, it can be a sign that the child is farsighted and simply needs glasses. This can correct the crossing while the glasses are worn. But, when comitant esotropia doesn’t respond to glasses and isn’t associated with other systemic or structural disease, we call that “acute comitant esotropia.” This latter condition is quite rare, and usually requires prompt surgical intervention. Comitant esotropia is generally not associated with any acute medical or neurologic illness, although there are exceptions.

In contrast, when the gaze alignment measurement is significantly different in at least one other direction, that’s called “incomitant esotropia.” Often, one eye can seem to get stuck when it is trying to move in one direction. Incomitant esotropia is more concerning because it can be associated with other diseases, such as sixth cranial nerve palsy, high intracranial pressure or even tumors.

What are the current treatment options for a child with acute comitant esotropia?

Diagram of the eye showing the medial rectus muscle, which can be surgically recessed to correct esotropia
Corrective procedures, targeting the medial rectus muscle, are sometimes necessary to treat esotropia.
David Hunter
David Hunter, MD, PhD

Traditionally, the only treatment for these children has been strabismus surgery. During surgery, the medial rectus muscle of each eye is recessed 4 to 6 mm to reduce the tension on the eye and reduce or eliminate the eye’s deviation.

More recently, we have found that many of these children respond to injection of botulinum toxin (Botox) into the medial rectus muscles. Botox is a commercial grade of the toxin known to cause botulism, a poisoning that causes all muscles in the body to become extremely weak. The required amount of Botox is a tiny fraction of what could cause any sort of systemic reaction, but it is just enough to weaken that one muscle.

Above all, it’s important that kids who develop a crossed eye are seen by a pediatric ophthalmologist right away, even if they are just a few weeks or months old. This can rule out any serious underlying diseases, prevent long-term “lazy eye” and help get these kids back to seeing straight as soon as possible.

Learn more about the Department of Ophthalmology at Boston Children’s Hospital.