The common term “wall eyed” refers to a medical condition where one or both eyes turn outward, away from the nose, a misalignment known as Exotropia. Exotropia is a type of strabismus, which is the general medical term for eyes that do not align or work together as a unit. This condition is caused by a failure in the complex system that coordinates eye movement and binocular vision. It can affect people of any age, but it is frequently diagnosed in childhood. Treatment is available and often successful, particularly when detected and managed early in life.
Defining Exotropia
Exotropia is defined as the outward turning, or divergence, of one or both eyes. This outward turn is the opposite of Esotropia, which is an inward turning of the eyes, commonly called “crossed eyes.” The mechanism behind Exotropia involves a disruption in the brain’s ability to fuse the two images received from each eye into a single, three-dimensional image. When binocular vision fails, the eye that is not focusing on the target object drifts outward.
The most common form is intermittent Exotropia, where the eye only drifts outward some of the time. This temporary misalignment often occurs when an individual is tired, sick, stressed, or focusing on distant objects. When the eye remains deviated outward constantly, it is classified as constant Exotropia, a less common but more severe form. Sensory Exotropia develops when one eye has poor vision and can no longer work with the other eye, causing it to drift.
Underlying Factors and Risk
The exact cause of Exotropia is often unknown, especially in the most prevalent intermittent type. However, the condition results from an underlying problem with the neuromuscular control of the eye muscles. The six extraocular muscles surrounding each eye must work in precise coordination, and a signaling issue between the brain and these muscles can lead to misalignment.
Neurological factors can disrupt this coordination, such as certain cranial nerve palsies or conditions like cerebral palsy or Down syndrome. Trauma to the head or orbit, or conditions like stroke in adults, can also impair the brain’s control over eye movement. Anatomical factors, such as issues with the structure of the eye muscles or the shape of the eye sockets, may also play a role in the development of the condition.
A significant risk factor is a genetic predisposition, as Exotropia and other forms of strabismus often run in families. If one eye has very poor vision due to cataracts or other conditions, it may lose its ability to maintain alignment, leading to sensory Exotropia. Preterm birth and uncorrected refractive errors are additional factors that increase the likelihood of developing Exotropia.
Identifying Signs
The most distinguishing sign of Exotropia is the visible outward divergence of one or both eyes. This misalignment may be subtle and only noticeable when the affected individual is feeling unwell or is distracted. The deviation can also alternate, with one eye turning out at one moment and the other eye turning out at another.
Individuals with Exotropia often exhibit behavioral symptoms that indicate a struggle to maintain binocular vision. A common sign is frequent squinting or closing one eye, particularly when exposed to bright sunlight or intense light. This action is a coping mechanism to eliminate the double image that occurs when the eyes are misaligned, a phenomenon known as diplopia.
Subjective symptoms may include eye strain, headaches, and general discomfort during or following extended visual tasks. Patients whose brains have not adapted to ignore the image from the deviating eye may report double vision. Difficulty with depth perception, or stereopsis, is another frequent complaint, as the eyes are not working together to accurately judge spatial relationships.
Therapeutic Approaches
Treatment for Exotropia aims to reduce the outward turning, restore proper eye alignment, and improve binocular function, especially in children to ensure normal visual development. The approach varies depending on the type and severity of the deviation, starting with the least invasive methods.
Non-Surgical Options
Non-surgical options include corrective lenses, which may involve prescription glasses to address refractive errors that contribute to the misalignment.
For some patients, especially those with convergence insufficiency, vision therapy—a program of eye exercises—is recommended. These exercises are designed to improve the brain’s ability to maintain alignment and strengthen the muscles responsible for inward eye movement.
Occlusion therapy is another non-surgical method, where a patch is placed over the stronger, straight eye for a period each day. This part-time patching forces the deviating eye to work harder and helps to improve its visual acuity and control.
Surgical Intervention
In cases where non-surgical treatments are insufficient, or the deviation is constant and severe, surgical intervention is necessary. Strabismus surgery involves carefully adjusting the tension of the extraocular muscles to physically reposition the eye. The surgeon may tighten or loosen specific muscles in one or both eyes to achieve better alignment. The goal of this procedure is not only cosmetic alignment but also to bring the eyes close enough to straight so that the patient can maintain binocular vision and depth perception.