Also called squint, heterotropia, crosseye, or walleye, strabismus is a condition of eye malalignment that results from the absence of normal, parallel, or coordinated eye movement. it can be congenital (present at birth) or during the first 6 months); or acquired (present during the first 2.5 years).
strabismus can also be latent, apparent when the child is tired or sick, or manifest (tropia). Tropias are categorized into four types:
- esotropia - eyes deviate inward
- exotropia - eyes deviate outward
- hypertropia - eyes deviate upward
- hypotropia - eyes deviate downward
Strabismus affects about 25% of the population. Incidence of this condition is higher in people with CNS disorders, such as cerebral palsy, mental retardation, and Down syndrome.
The prognosis for correction varies with the timing of treatment and the onset of the disease. Muscle imbalances may be corrected by glasses, patching or surgery, depending on the cause. However, defects in vision and muscle alignment may persist even after treatment.
CAUSES
Strabismus is frequently inherited, but its cause is unknown. esotropia may result from muscle imbalance and may be congenital or acquired. Malalignment of the eyes leads to suppression of vision in one of the eyes.
TREATMENT
Initial treatment depends on the type of strabismus. It may include patching the normal eye and prescribing corrective glasses to keep the eyes straight and to counteract farsightedness (especially accomodative esotropia).
surgery is often necessary for cosmetic and psychological reasons to correct strabismus that results from basic esotropia after correction with glasses.
Timing of surgery varies with individual circumstances. For example, a 6-month old infant with equal visual acuity and a large esotropia will have the deviation corrected surgically. but a child with unequal visual acuity and an acquired deviation will have the affected eye patched until visual acuity is equal, then undergo surgery.
Possible complications include overcorrection or undercorrection, slipped muscle and perforation of the globe.