By Dr. Charles J. Bock

Esotropia

Strabismus is the tern used to describe any type of misalignment of the eyes. Esotropia describes a misalignment of the eyes in which the eyes turn inward, toward the nose. There are several types of esotropia; some of the more common are described below.

Infantile Esotropia

Formerly called congenital esotropia, it is now known that most children with esotropia early in life are not actually born with it, but develop it within the first few months after birth. By definition, the term infantile esotropia is used to describe esotropia that is present before six months of age.

Infantile esotropia has several distinguishing characteristics. It is usually marked by very significant crossing of the eyes. Children with infantile esotropia tend to have very little hyperopia (farsightedness), and sometimes do not require glasses. Amblyopia (poor vision in one eye) is often not present, meaning that children with infantile esotropia often do not need to patch their eyes. Because there is equal vision in the two eyes, affected children will often alternate between using one eye and then the other, so that sometimes the right eye appears turned in and at other times the left eye appears turned in.

Infantile esotropia usually requires early surgical intervention because glasses rarely help to straighten the eyes. Early surgical intervention to straighten the eyes has been shown to increase the likelihood that the child's brain will "lock on" and begin to use the two eyes together. This allows for the possibility of the development of depth perception.

Children with infantile esotropia can develop other misalignment of the eyes. These problems occur in some children even after successful early surgery, and can include floating of one eye upward (called dissociated vertical deviation), pattern strabismus (marked by upward or downward turning of the eyes when looking in side gaze), and nystagmus (a back and forth wiggling of the eyes which may be present all of the time or only when one eye is covered).

Accommodative Esotropia

Accommodative Esotropia most commonly presents between 18 months and four years of age. There may be a brief period when it begins during which one eye appears to drift inward only intermittently followed by constant esotropia later on.

Unlike children with infantile esotropia, children with accommodative esotropia are often significantly farsighted. Whereas most children are a little bit farsighted, these children can be two or three times as farsighted as is normal. In order to overcome the farsightedness, these children must focus very hard, which stimulates the brain to converge (bring together) the eyes, causing them to cross.

To understand this, think of yourself when changing your focus from a distant to a near object. Your eyes must come together (converge) as you focus to see up close in order for them to continue to work together and see the object simultaneously. A child who is highly farsighted is focussing even harder than this all of the time. This focussing is enough to stimulate the brain's convergence, causing crossing of the eyes.

To treat children with accommodative esotropia, we must give them glasses for their farsightedness to help relax their focussing to help decrease their excess convergence. In other words, the glasses help to do the focussing in order to help relax the crossing of the eyes.

Despite wearing glasses and appropriate patching treatment for amblyopia, some children with accommodative esotropia may continue to have crossing of the eyes. In these cases, surgery is often recommended to straighten the eyes to help stimulate the brain to use the two eyes together. As with infantile esotropia, once the need for surgery has been identified, studies have shown that earlier surgery produces better results, in terms of development of depth perception, than delayed surgery.

Some children with accommodative esotropia will have straight eyes at distance with their glasses but continue to have crossing of the eyes at near. For these children, a bifocal is often needed to further relax their focussing at near.

Children with accommodative esotropia can develop many of the same associated problems as children with infantile esotropia, including dissociated vertical deviation, pattern strabismus, and nystagmus.

If you have questions

Gaining a complete understanding of the complexities of esotropia takes time. Every child is a little different, so the general information above may not cover all of the important issues regarding your child. We expect that you may need to call us after your visit, once you have had a chance to think of additional questions.

Please feel free to call our office 503-656-4221 at any time with any questions you may have. Our goal is that you understand completely your child's condition and treatment.