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Cross Eyes - Eye Disorder
What do doctors call this condition?
Strabismus or squint
What is this condition?
Cross-eye is a misalignment of the eye caused by the absence of normal, parallel, or coordinated eye movement. In children, it may be concomitant, in which the degree of deviation doesn't vary with the direction of gaze; inconcomitant, in which the degree of deviation varies with the direction of gaze; congenital (present at birth or during the first 6 months); or acquired (present during the first 2½ years.)
Cross-eye can also be latent (phoria) - apparent only when the child is tired or sick - or manifest (tropia). In tropias, the eyes deviate in one of four ways: esotropia (eyes deviate inward), exotropia (eyes deviate outward), hyperrropia (eyes deviate upward), and hypotropia (eyes deviate downward).
The prognosis for correction varies with the timing of treatment and the onset of the disorder. Muscle imbalances may be corrected by glasses, patching, or surgery, depending on the cause. However, residual defects in vision and extraocular muscle alignment may persist even after treatment.
Cross-eye affects about 2% of the population. Its incidence is higher in people with central nervous system disorders, such as cerebral palsy, mental retardation, and Down syndrome.
What causes it?
Cross-eye is frequently inherited, but its cause is unknown. Controversy exists over whether or not amblyopia (lazy eye) causes or results from cross-eye. Strabismic amblyopia is characterized by loss of central vision in one eye that typically leads to esotropia. It may result from farsightedness or unequal refractive power. Esotropia may result from muscle imbalance and may be congenital or acquired. In accommodative esotropia, the child's attempt to compensate for farsightedness affects the convergent reflex, and the eyes cross.
Misalignment of the eyes suppresses vision in one of the eyes, causing amblyopia if it develops early in life.
What are its symptoms?
Misalignment of the eyes can be detected by an external eye exam when deviation is obvious or by ophthalmoscopic observation of the corneal light reflex in the center of the pupils. Cross-eye also causes double vision and other visual disturbances, which is often the reason the person seeks medical help.
How is it diagnosed?
Parents of children with cross-eye typically seek medical advice. Older people with cross-eye commonly seek treatment to correct double vision or improve their appearance. A detailed history is essential not only for the diagnosis but for treatment. Eye tests also help diagnose cross-eye.
How is it treated?
Initial treatment depends on the type of cross-eye. In strabismic amblyopia, therapy includes patching the normal eye and prescribing corrective glasses to keep the abnormal eye straight and to counteract farsightedness.
Surgery is often necessary for cosmetic and psychological reasons to correct cross-eye due to basic esotropia, or residual accommodative esotropia after correction with glasses. The timing of surgery varies from person to person.
Surgical correction consists of moving or shortening the muscle. A new procedure uses an adjustable suture. Eye exercises and corrective glasses may still be necessary; surgery may have to be repeated.
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