Esotropia is when the eyes cross inward. This type of ocular deviation accounts for more than 50% of pediatric strabismus. The esotropia can be congenital or due to excessive accommodation, divergence insufficiency, or sensory deprivation; it can be consecutive following strabismus surgery or due to neurologic disorders. 

Congenital esotropia presents in infants by 6 months of age and is usually found in otherwise healthy children. There is often a family history of strabismus. Up to 30% of children with cerebral palsy, hydrocephalus, and other neurologic disorders also have congenital esotropia. It is associated with a large degree of deviation and sometimes inferior oblique overaction, nystagmus, and dissociated vertical deviation. 

Accommodative esotropia is another common cause of esotropia in children. Its onset is usually around 2 years of age, often intermittent at first; it may be associated with uncorrected hyperopia and is frequently associated with amblyopia. In the nonrefractive accommodative type of esotropia, the deviation is significantly worse at near than at distance because of excessive convergence tonus from accommodation.

While adults with acute onset of esotropia often complain of diplopia, children compensate by either ignoring the vision in one eye (leading to amblyopia) or alternating the eye that is being used. 

Esotropia may be seen in association with the following: Duane syndrome (type 1), sixth nerve palsy, sensory deprivation (secondary to cataract, retinal scars, orbital pseudotumor), thyroid disease with medial rectus restriction, and pterygia with restriction of lateral gaze.

Related topic: exotropia