Dr. Burke is one of Cincinnati's most trusted resources concerning accommodative esotropia in children.
Esotropia is the medical term for crossed eyes. Accommodation is the powerful force that allows the eyes to focus. When we accommodate on a close target, this powerful focusing force also activates convergence, or turning inward of the eyes to look at or be aligned upon nearby objects. These 2 activities (focusing and turning the eyes inward) are both controlled by the same nerve and happen at the same time. This process is called accommodative convergence.
When these systems become imbalanced, a problem called accommodative esotropia may develop. This focusing related crossing problem occurs in about one out of every 100 children. The most common age of onset is after 12 months and before age 5 years. During the early stages, the child's eyes may cross only when looking at near targets and is especially noticeable when the child is fatigued or ill. As time passes the problem typically worsens causing the eyes to cross more often.
A child who has accommodative esotropia almost always chooses one eye to keep straight, the dominant eye. The crossed, non-dominant eye almost always loses vision because of disuse. This loss of vision is called amblyopia. Therapy to correct “the lazy eye” is imperative.
Accommodative esotropia is most always treated with glasses. Glasses will only help the child if they are prescribed accurately and worn full-time. The glasses relax the need to accommodate or focus that will reduce the convergence or crossing. Some children with accommodative esotropia may cross their eyes even more when they look at things close up than when they look at things far away. This excessive near crossing may require the use of bifocals to help straighten the eyes at near fixational distances.
Glasses alone may not be enough to straighten your child's eyes. In up to 30% of cases, eye muscle surgery may be required in addition to the use of glasses. Surgery is only used to treat the crossing that is left-over or not relaxed by the glasses.
Whenever an eye misalignment is suspected, your child should have a complete evaluation by a pediatric ophthalmology specialist.
What is accommodative esotropia?
Accommodative esotropia is a common form of crossed eyes occurring in up to 2% of children and typically developing after 12 months and before 5 years old. Accommodation refers to the powerful force that allows the eye to focus. When we accommodate on a close target, this powerful focusing force also activates convergence, or the turning inward of the eyes to look at or be aligned upon nearby objects. These two activities (focusing and turning the eyes inward) are both controlled by the same nerve and happen at the same time. This whole process is called accommodative convergence. Most children with accommodative esotropia are farsighted. Farsighted children have to use their focusing mechanism inside their eyes (accommodation) more powerfully than do most children. Because the same nerve controls focusing and turning the eye inward, the farsighted child who is working very hard to focus may cross (over-converge) the eyes at the same time. This is called accommodative esotropia or may also be described as focusing-related-crossing.
How is accommodative esotropia treated?
Most children with focusing-related-crossing, or accommodative esotropia, are treated with eyeglasses. The power of the eyeglasses is determined by performing a refraction. In most cases of accommodative esotropia, the focusing muscles inside the eye must be relaxed with eyedrops (cycloplegia) to accurately measure the full amount of the child's farsightedness (hyperopia). About 75% of children with accommodative esotropia will have straight eyes wearing eyeglasses. Glasses will only help the child if they are prescribed accurately and worn full-time. As soon as the glasses are removed, the eyes will cross again. For this reason your child must wear the glasses during all waking hours. In the remaining 25% of patients, glasses alone may not be enough to straighten your child's eyes. This type of strabismus is referred to as mixed mechanism esotropia. In these cases, eye muscle surgery may be required in addition to glasses. Eye muscle surgery is only used to treat the crossing that is not relaxed by the glasses (the non-accommodative component). That means your child will continue to need glasses to keep their eyes straight even after surgery (for their accommodative component).
What is mixed mechanism esotropia?
When the crossed eyes (esotropia) are caused by both focusing reason (accommodative) and by a muscular reason (non-accommodative), the crossing is referred to as mixed mechanism esotropia. The accommodative component requires to use of glasses. Surgery is often necessary for the muscular imbalance (non-accommodative) part.
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