What is strabismus?
Strabismus refers to eye misalignment where the eyes point in different directions and are not working together. Normally, the eyes work together in aiming at the same spot to provide the brain with information to create a three dimensional image and allow depth perception. Although the word strabismus most often brings to mind crossed eyes (esotropia), it also means any misalignment and includes outward wandering (exotropia) or one eye turning up or down (hypertropia or hypotropia).
At what ages does strabismus occur?
Strabismus can begin in infancy, early childhood, or even in adulthood.
Does strabismus always cause double vision (diplopia)?
When strabismus begins in children before 6 years old, double vision rarely occurs because the brain is still able to shut off (or suppress) the vision in the deviating eye. When it begins at a later age, double vision is the rule if vision has developed normally.
What causes strabismus in children?
In young children, the two most common types of strabismus are accommodative esotropia, where the eyes cross due to excessive farsightedness, and infantile esotropia, where children are born with the tendency to cross their eyes. Strabismus in children is less commonly caused by head trauma and diseases that affect the brain or nerves that go to the eye, such as tumors, hydrocephalus (water on the brain), or cerebral palsy.
What are the complications of strabismus in children?
In any childhood strabismus, amblyopia may occur. Often called lazy eye, amblyopia occurs when the brain shuts off the image in one eye long enough that the vision is permanently decreased. In most cases, this condition is easily improved if treated early. (See amblyopia topic page)
What causes strabismus in adults?
Strabismus in adulthood may be simply due to decreased control of a prior tendency for eye wandering that the brain had always controlled previously. Other causes may include head trauma, diseases that affect the nerves (such as multiple sclerosis), long-standing high blood pressure or diabetes, or aneurysms in blood vessels supplying the brain or a tumor. Since some of these rare but potential causes can be quite serious or even life-threatening, a sudden onset of double vision in adulthood should prompt an immediate eye exam.
How is strabismus treated?
Different forms of strabismus must be dealt with differently. In many cases, the solution is as easy as wearing glasses to correct farsightedness and allow the eyes to focus correctly. Accommodative esotropia is generally treated in this manner.
Infantile esotropia, on the other hand, is usually caused by problems within the muscles that move the eye. These muscles must be operated upon to align the eyes. Often times, in cases of infantile esotropia when amblyopia (lazy eye) is also involved, the amblyopia might need to be treated first before proceeding to surgery.
Other treatments for strabismus that may sometimes be appropriate include eye exercises or an injection of a drug called Botox into the eye muscles. An injection of Botox into an eye muscle temporarily relaxes the muscle, allowing the opposite muscle to tighten and straighten the eye. Although the effects of the drug wear off after several weeks, the misalignment may be permanently corrected in some cases.
Early detection is key
In all strabismus, early diagnosis by a pediatric ophthalmologist (who also deal with adult strabismus) will allow proper treatment. Timely treatment by a trained physician offers the best chance of getting the eyes working together.