Esotropia means one of the eyes turns in, as in the left eye of the photo on the left. Accomodation means the act of focusing. The term “accomodative esotropia” refers to a child whose eyes turn in because farsightedness (hyperopia). This is the most common type of eye misalignment in young children, and the most common type of esotropia. The onset is usually in children about ages 2 to 4. Early detection and treatment is very important for a good outcome.
Why does farsightedness cause esotropia?
A child who is farsighted needs to focus very hard to see clearly. A normal side effect of a strong focusing effort is that the eyes will turn in. This normal response ensures that when we focus to read up close, our eyes turn in slightly. In a child with accomodative esotropia, this normal response creates a turned-in eye even when looking in the distance.
How is accomodative esotropia treated?
The treatment is prescribing farsighted glasses. The glasses do the job of focusing, so accomodation can relax. When accomodation relaxes, the eyes will straighten, as is illustrated on the photo on the right.
The goals of therapy are to:
- Detect and treat amblyopia. Amblyopia is also very common in accomodative esotropia. When one eye turns in, the child’s brain essentially turns off the vision in that eye.
- Straighten the eyes to allow the eyes to work together and develop depth perception. Usually glasses do this. If glasses don’t completely align the eyes, then a non-accomodative component to the esotropia may be present which may require eye muscle surgery.
- Detect an abnormal accomodative/convergence amplitude. If present, the esotropia will be worse at near than in the distance. The treatment is bifocals.
When children reaches age 8 or so, the vision and depth perception present will usually remain for life. Close follow-up and treatment is required until that time.
Will my child wear glasses forever?
In many cases children will outgrow their need for glasses by age 10 or so. This is because farsighteness typically decreases with age. However, some children will not outgrow their need for glasses.
