“Wall eyes” is a common, non-clinical term for Exotropia, a visual condition where the eyes do not look in the same direction at the same time. This misalignment, where one or both eyes turn outward, is one of the most prevalent forms of strabismus, a broader category of disorders involving eye movement and alignment.
Understanding Exotropia
Exotropia is a type of strabismus characterized by an outward deviation of the eye, turning away from the nose toward the ear. This outward drift prevents both eyes from focusing on the same target simultaneously, compromising binocular vision. The condition is classified based on how often the misalignment occurs, which influences the symptoms and potential complications.
The most common form is Intermittent Exotropia, where the outward turn is only noticeable sometimes. The eye may drift when a person is tired, stressed, or in bright sunlight, but the individual can usually correct the alignment themselves. In contrast, Constant Exotropia means the eye is always turned outward, making the misalignment a permanent feature. This constant deviation presents a greater risk to the visual system.
When the eyes are consistently misaligned, the brain may ignore the visual input from the deviating eye to avoid seeing double, a process called suppression. If suppression occurs during childhood, it can lead to Amblyopia (lazy eye), where the ignored eye fails to develop normal visual acuity. Constant Exotropia patients have a higher incidence of Amblyopia than those with the intermittent form, making early intervention important for preserving vision.
Why Eyes Drift Outward
Normal eye movement relies on the precise coordination of six extraocular muscles surrounding each eyeball. Exotropia results from a lack of proper balance or coordination between these opposing muscle groups, controlled by complex neurological signals. The underlying issue is often the brain’s inability to maintain the necessary convergence tone, the inward pull required to keep the eyes aligned for focus.
The cause of this coordination failure is often rooted in neurological or structural factors, though the exact cause is frequently unknown. Genetic predisposition plays a substantial role, as Exotropia commonly runs in families, suggesting an inherited component. Specific genetic duplications on chromosomes 2, 4, and 10 may also increase the risk of developing Exotropia.
Certain risk factors are associated with the development of the outward drift, particularly in children. These include prematurity, low birth weight, and the presence of systemic conditions, such as cerebral palsy or craniofacial anomalies. Ultimately, the outward drift occurs because the brain is unable to consistently command the eye muscles to hold the eye in the correct position.
Options for Correcting Misalignment
Correcting Exotropia begins with a comprehensive eye examination by an optometrist or ophthalmologist to measure the degree of deviation and assess visual acuity. Treatment depends on the frequency and angle of the misalignment, and the patient’s age. The primary goal of intervention is to restore binocular vision and ensure good sight.
For milder, intermittent forms, non-surgical methods are often the first line of management. Corrective lenses, such as glasses or contact lenses, may be prescribed to address underlying refractive errors like farsightedness, which can help control the outward turn. Vision therapy, a structured program of eye exercises, can also strengthen the patient’s ability to converge their eyes and maintain alignment.
If Amblyopia is present, patching the stronger eye for a period each day may be used to force the brain to rely on and improve vision in the misaligned eye. When non-surgical treatments are insufficient, or if the deviation is constant and severe, surgical intervention is considered. Eye muscle surgery involves adjusting the length or repositioning of the extraocular muscles to physically realign the eyes. This procedure aims to create a more stable alignment, allowing the eyes to work together and improving depth perception.