The condition can be constantly present, or occur intermittently, and can give the affected individual a "cross-eyed" appearance.

Amblyopia can, however, arise as a result of esotropia occurring in childhood: In order to relieve symptoms of diplopia or double vision, the child's brain will ignore or "suppress" the image from the esotropic eye, which when allowed to continue untreated will lead to the development of amblyopia.

The over-convergence associated with the extra accommodation required to overcome a hyperopic refractive error can precipitate a loss of binocular control and lead to the development of esotropia.

[4] The chances of an esotropia developing in a hyperopic child will depend to some degree on the amount of hyperopia present.

Where the degree of hyperopia is large, the child may not be able to produce clear vision no matter how much extra-accommodation is exerted and thus no incentive exists for the over-accommodation and convergence that can give rise to the onset of esotropia.

However, where the degree of error is small enough to allow the child to generate clear vision by over-accommodation, but large enough to disrupt their binocular control, esotropia will result.

[5] Where the esotropia is solely a consequence of uncorrected hyperopic refractive error, providing the child with the correct glasses and ensuring that these are worn all the time, is often enough to control the deviation.

In such cases an additional hyperopic correction is often prescribed in the form of bifocal lenses, to reduce the degree of accommodation, and hence convergence, being exerted.

It is, however, associated with other ocular dysfunctions including oblique muscle over-actions, dissociated vertical deviation (DVD), manifest latent nystagmus, and defective abduction, which develops as a consequence of the tendency of those with infantile esotropia to 'cross fixate'.

The origin of the condition is unknown, and its early onset means that the affected individual's potential for developing binocular vision is limited.

Incomitant esotropias occur both in childhood and adulthood as a result of neurological, mechanical or myogenic problems affecting the muscles controlling eye movements.