Crossed Eyes in Babies
(Congenital Esotropia)

Crossed eyes is a common condition in children. Among the many questions parents have are:

  • What does my child with crossed eyes actually see?
  • Does the vision improve with surgery?
  • Why does my child need to be seen on a regular basis after the surgery, if the surgery is successful?

What is Congenital Esotropia?

Congenital esotropia is the most common type of crossed eyes occurring in babies. It always develops before six months of age. Although the term esotropia means crossed eyes, there children may also have a mild vertical imbalance to the eyes (one eye drifting upward). Sometimes they also develop an unsteady to-and-fro movement of the eyes (nystagmus).

The important fact to bear in mind, however, is that children with this type of eye crossing have absolutely normal development and normal intelligence.

What is the Cause of Congenital Esotropia?

The cause is unknown. Some researchers believe it is due to an inborn inability of the brain’s vision center to use the two eyes together; other believe that there are a number of causes, some of which may be partially genetic.

Congenital esotropia is not due to anything that happened during pregnancy.

What Does My Child See?

A child with congenital esotropia uses basically just one eye to see, but he or she does see just fine! Unlike an adult with crossed eyes, your child does not see double — the brain protects these children from seeing two images at the same time.

There is an important reason for this: Imagine what it would be like for a child just starting to learn to do all sorts of things — walk, tie the shoelaces, dress oneself — if there were constant double vision. The complex circuitry of the brain automatically protects the child from double vision by suppressing one of the images (at an unconscious level), so that the child’s development will not be held back.

If you want to experience what your child sees, just cover one eye. Notice that you can still see very well, but that somehow your environment looks a bit different — you have lost “true” depth perception. You can still judge the distance of objects, but you do not have true depth perception using just one eye.

If Only One Eye Is Being Used,
Won’t The Other Eye Get Lazy?

Probably not. It all depends on whether each eye is being used at least some of the time every day. Even though children usually have a favored eye, they will usually switch eyes and use the opposite eye at least part of every day. In that case, the eye probably won’t become lazy.

If the child has a very strong preference for one eye, the other eye may be lazy. We treat this by patching the favored eye to force the non-preferred eye to be used.

What Is The Treatment?

The treatment of congenital esotropia is surgical. Glasses do not improve the eye crossing, and eye exercises are ineffectual.

The surgery either weakens the in-turning eye muscles, or tightens the out-turning eye muscles.

I usually prefer to operate on the two in-turning eye muscles (one in each eye). I sometimes operate on additional eye muscles, depending on how much eye crossing there is. The more the eyes cross, the more surgery is done on each muscle and the greater the number of eye muscles operated.

The purpose of surgery to straighten the eyes is not just to improve the cosmetic appearance of the child, but to give the child the opportunity to develop true depth perception.

If My Child Has A Good Result From The Surgery,
Why Does He Or She Need To Be Seen Periodically Afterwards?

In the majority of children, the eyes are straightened with one operation. However, surgery is not the end of treatment. Children may still develop lazy vision (amblyopia), vertical deviations of the eyes, re-crossing of the eyes, and the need for glasses, even years following an excellent surgical result. Thus, all children who have had surgery for crossed eyes should be followed closely by an ophthalmologist, at least until their vision is fully developed (about age 10) and, preferably, through their entire childhood.

David Reese, MD



The Pediatric Ophthalmology and Strabismus Service is located in the same office as the Electrophysiology Service, which measures vision in preverbal children using visual evoked potentials and preferential looking techniques.

Pediatric patients with cataracts, glaucoma, corneal and retinal disorders are provided a full range of diagnostic and therapeutic services in conjunction with other New England

New England Eyeware Optical Shop

Visual Electrophysiology, ERG & Psychophysics

Eye Plastics and Orbital Services

Schedule an appointment or contact us at 617-636-6769.


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