An eye condition known as strabismus can result in misaligned eyes and can cause vision problems such as eye strain, headaches, decreased vision, or double vision. In strabismus, one eye is aligned and looking straight ahead, while the other eye is turned inward towards the nose, or outwards towards the ear. It can be caused by weak eye muscles, or by problems with the nerves that control the eye muscles. In most cases, strabismus onsets early in life during childhood. However, some cases of strabismus can arise in adulthood. The treatment for strabismus depends on many factors, including how often it occurs, if it affects one or both eyes, and how large the misalignment is.
Understanding Strabismus
In most cases of strabismus, one eye turns inward towards the nose, or outward towards the ear, though in some cases the misaligned eye can deviate up or down. If the misaligned eye is turned in and gives a cross-eyed appearance, the condition is called an esotropia. If the eye turns out and appears “lazy,” it is called an exotropia. The deviation of the eye can come and go throughout the day (which is known as an intermittent strabismus), or it can be constant. In many cases, the strabismic eye alternates, meaning that sometimes the right eye is misaligned, while other times the left eye is misaligned. However, some people can experience a “unilateral” strabismus, where only one eye is affected. Children who are affected by unilateral constant strabismus, meaning one eye is constantly misaligned, are at risk for a vision condition called amblyopia. The brain can begin to ignored the misaligned eye in order to prevent double vision, and the visual development to that eye can be delayed. If it is not diagnosed and treated early in childhood, a unilateral constant strabismus can result in permanently decreased vision due to these visual development issues.
Treating Strabismus and “Lazy Eye”
Once a strabismus has been identified, there may be several different approaches to treating the condition. The goals of these treatment options are to promote the best possible visual development, improve coordination and depth perception, and relieve eye strain. In some cases of strabismus, a simple glasses or contact lens prescription is enough to improve alignment and treat the condition. Sometimes special prism glasses can be made to help eliminate or reduce double vision or eye strain. Other cases of strabismus may require vision therapy, which is a series of specialized eye exercises that aim to strengthen eye muscles and prevent misalignment. In cases of unilateral strabismus, a “patching” treatment may be recommended. This means that the “good” eye is covered so the brain is forced to communicate with and strengthen the muscles for the misaligned eye. In some severe cases of strabismus, treatment may include surgery on the eye muscles. This surgical technique can adjust the muscles that control eye movements so that the eye is no longer misaligned. These are more commonly performed on children, where there is good potential for visual outcome if the eyes are better aligned. Adults can also choose to have eye muscle surgery for cosmetic reasons.