Crossed eyes (strabismus) is a vision condition in which the eyes are not properly aligned with each other. For a variety of reasons, one or both eyes turn inward, outward, upward, or downward. The condition occurs in childhood, but is relatively rare.
Crossed eyes affects five percent of all children. The earlier treatment is initiated, the easier it is to correct.
A vision therapy program called orthoptics has been used by optometrists for decades to treat crossed eyes.
Causes of Crossed Eyes
There are different causes of crossed eyes, but the most common is poor eye muscle control. It is not that the muscles are weak. Actually, the muscles on the outside of the eyes are 100 times stronger than they need to be. What has happened is that the child has not learned how to use those muscles properly to make the two eyes work together as a team.
Crossed eyes can also develop during toddler and preschool years as a result of stress. These periods of stress on the nervous and vision system are part of normal development, but can adversely affect some children, even those whose vision has been fine.
Eyes that are crossed do not function properly. The messages each sends to the brain are so different that the brain cannot fuse them into one image, as occurs with normal two-eyed vision. This can result in double vision or in difficulty doing tasks that require two-eye coordination. It also can interfere with the development of other vision skills.
Symptoms of Crossed Eyes
It is normal for an infant's eyes to appear crossed or out of alignment for brief moments during the first five or six months of life, when he or she is learning to use the eyes together as a team.
If by age 3-1/2 months, the misalignment appears to be frequent or long-lasting or is always with the same eye, the infant should be examined by a doctor of optometry. In some cases, the optometrist, using a simple test, will find that a fold of skin across the inner part of the eye opening makes the eye appear to be turned when in fact it is not.
In toddlers and preschoolers, crossed eyes is usually but not always obvious. Sometimes the turned eye is present only part of the time. Clumsiness or accident proneness may be symptoms of crossed eyes that are not visibly apparent.
When to Begin Treatment of Crossed Eyes
The earlier treatment is begun for crossed eyes the better. A child will not outgrow the condition.
If treatment of crossed eyes is delayed, the problem may become more deeply imbedded or secondary complications may develop. Then treatment is likely to take longer and may be less successful.
Treatment of crossed eyes in infants can begin as early as age 3-1/2 months and certainly should be underway by the time the child is six months old. Toddlers and preschoolers should receive care as soon as symptoms are noticed.
Treating Crossed Eyes
Surgery is often suggested for crossed eyes, but it does not usually offer a total solution to the problem. Vision therapy can offer a more complete solution and is, therefore, often the preferred method of treatment.
During surgery, eye muscles are cut so that the eyes look straight. Since no effort is made, however, to teach the eyes how to work together as a team, the underlying cause remains and there is a tendency for the eyes to turn again. In many cases, repeated operations must be performed, with no guarantee of permanent results.
A review of 22 studies involving 1,490 persons who underwent surgery for crossed eyes found that:
- One-third achieved straight eyes and normal vision.
- One-third achieved straight eyes but did not attain normal vision.
- One-third either experienced no change in vision and appearance or were worse after surgery than they were before.
With vision therapy, optometrists get at the underlying cause of the crossed eyes. They usually are able to solve the problem permanently because, once the eyes learn how to work together as a team, there is no longer a tendency for them to turn.
Optometrists begin by breaking the bad seeing habits the child has developed—habits that have taught the eyes to work separately rather than together. Then they teach the child how to use his or her eyes as a team, proceeding sequentially through all the steps a child should go through in order to achieve normal eye teaming. The process takes three months to one year, depending upon the severity of the problem.
A review of five studies involving 439 persons who underwent vision therapy for crossed eyes found that 76 percent attained normal two-eyed vision and 86 percent achieved straight eyes. The remainder experienced some degree of improved vision and/or straightening of the eyes.
Another study, which followed up on persons in an earlier study, found that results achieved with vision therapy are long-term, not short-term. Of 81 patients who had been successfully treated for crossed eyes with vision therapy three to seven years earlier, 96 percent still had straight eyes and 89 percent had normal two-eyed vision.
Seven other patients from the original study did not participate in the reexamination because their eyes were so normal that they did not want to bother or did not want to be reminded that they once had a problem.
Source for portions of information in this article: American Optometric Association | This information is in no way a substitute for a personal examination by an eyecare professional. To find a certified Carl ZEISS Vision practice near you, use our
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