In a person with “crossed-eyes,” one or both eyes point in different directions because the muscles in and around one or both eyes are not working in a coordinated manner. Causes of this defect are diverse, but in all cases, crossed-eyes should be treated as soon as possible after diagnosis to avoid any loss of vision!

Crossed-eyes (or "eye misalignment") is a common vision defect in which either one or both eyes are turned inward, outward, upward or downward, and one or both eyes may show irregular movement. People with misaligned eyes may have difficulty catching a ball, because they cannot judge distances. They may see double and/or find it difficult to focus on objects because their eyes are not working together properly. Apart from the abnormal appearance of one or both eyes, the symptoms of this defect include squinting, blinking, headaches, nausea, eye pain and abnormal head posture.

Misalignment of the eyes may be inherited and is especially common in children under 21 months old. Older children and adults may also develop this defect in association with an underlying disease, disorder or injury. The precise cause of eye misalignment is not always known. When our eyes are functioning normally, both eyes focus on the same object. But in some people, certain muscles simply do not function as they should and their eye(s) cannot be properly controlled. One or many factors can cause this defect, including the development and shape of the eye and its component parts, muscles within and around the eye, eye-brain functioning and the presence of disease or brain disorders.

Fortunately, crossed-eyes can be treated, improved upon and may even be permanently realigned. Whatever the cause of crossed-eyes, this defect should be treated as soon as possible after diagnosis to avoid vision loss. Treatment often involves a combination of elements. Because the causes of crossed-eyes are many and diverse, treatment often involves a combination of elements.

Glasses offer reliable and controllable treatment for a wide variety of alignment problems. Specially crafted glasses with bifocal, prism, concave or convex lenses are most commonly prescribed to redirect the line of sight, improve focusing ability and enable the eyes to straighten.

Vision therapy, or orthoptics, is another common treatment. In vision therapy, the eyes are trained to work together to achieve normal vision. An eye patch may be prescribed as part of the strengthening process. This therapy may take place both before and after surgery, since the reflexes and control in the muscles of the eye must be reinforced so that both eyes remain coordinated.

Surgery may be recommended to reposition muscles for greater control of one or both eyes.
Drugs such as botulinum toxin type A may be used as alternatives to eye-muscle surgery in selected cases. In selected cases, anticholinesterase miotic drugs may be taken to enhance the focusing mechanisms of the eye. These drugs may be used for children and adults alike in eyedrop or ointment form.

Newborn babies often experience temporary misalignment of their eyes when they first attempt to focus, but should outgrow their condition by six months of age at the latest. Since good vision is developed during childhood and basic skills (e.g. walking and talking) also depend heavily on good eyesight, parents should monitor the alignment of their children’s eyes. The turning or straying of one or both eyes may not be obvious to parents since it is not always readily visible or consistent. Some children may only experience eye turns when they are ill, stressed or fatigued. But even when eye turns only happen occasionally, they should be checked by an optometrist. When diagnosed early in children, correction is usually very successful. Left uncorrected, crossed-eyes can lead to lazy eye (see Lazy eye) and a permanent loss of depth perception.