The medical term for misaligned eyes is strabismus. There are six different muscles that are attached to each eye to help it turn and rotate. The eyes may not appear straight because one or more muscles are pulling too hard or other muscles are too weak. If the eyes turn inward leading to “crossed eyes” we call it esotropia. If they turn outward, called “wall eyes,” then the condition is labeled exotropia. There are different treatments for strabismus depending on the specific cause. Some cases are managed with eye muscle surgery, some simply need glasses.
Crossed eyes (esotropia) needs to be treated early to prevent vision impairment later in life. As a baby grows and develops, so do his or her eyes. During the first few months of life, an infant does not have crisp, clear vision. Thereafter, the eye’s focusing mechanisms and eye movements rapidly develop as the eye and brain develop the visual apparatus. By about the age of 6 months, both eyes should consistently work together, allowing a baby to see both near and far away targets. The infant’s eyes should be aligned, both looking at the same object.
However, in some situations the eyes do not appear to work together. One eye may tend to drift inward or outward some or all of the time. Prompt evaluation by an eye specialist is essential to determine whether any suspected drifting is due to a muscle imbalance or an internal eye problem that interferes with good eyesight. Simply stated, the eye doctor needs to determine how well each eye sees and why the eyes do not appear straight. Parents will be relieved to know that the eye doctor’s exam can find the answers without any help from the baby. Any problems that are identified need to be addressed in order to preserve good eyesight in both eyes.
Maintaining proper eye alignment is important to avoid seeing double, for good depth perception, and to prevent the development of poor vision in the turned eye. When the eyes are misaligned, the brain receives two different images. At first, this may create double vision and confusion, but over time the brain will learn to ignore the image from the turned eye. If the eye turning becomes constant and is not treated, it can lead to permanent reduction of vision in one eye, a condition called amblyopia or lazy eye. Put simply, amblyopia is a healthy eye that does not see. Only infants and children develop amblyopia; and the vision loss can be reversed with therapy if the contributing eye problem is corrected early enough during childhood — typically before the age of 7.
According to the American Optometric Association, people with strabismus have several treatment options available to improve eye alignment and coordination. They include:
- Eyeglasses or Contact Lenses: may be prescribed for patients with uncorrected farsightedness. This may be the only treatment needed for some patients with accommodative esotropia. Once the farsightedness is corrected, the eyes require less focusing effort and may remain straight.
- Prism Lenses: special lenses that have a prescription for prism power in them. The prisms alter the light entering the eye and assist in reducing the amount of turning the eye has to do to look at objects. Sometimes the prisms are able to fully compensate for and eliminate the eye turning.
- Vision Therapy: a structured program of visual activities prescribed to improve eye coordination and eye focusing abilities. Vision therapy trains the eyes and brain to work together more effectively. These eye exercises help remediate deficiencies in eye movement, eye focusing and eye teaming and reinforce the eye-brain connection. Treatment may include office-based as well as home training procedures.
- Eye Muscle Surgery: can change the length or position of the muscles around the eye in an attempt to better align the eyes. Eye muscle surgery may be able to physically align the eyes so they appear straight. Often a program of vision therapy may also be needed to develop a functional improvement in eye coordination and to keep the eyes from reverting back to their previous condition of misalignment.