Esotropia is a type of strabismus, or ocular misalignment, characterized by nasal deviation of the eye. High AC/A ratio accommodative esotropia is also called non-refractive accommodative esotropia. The accommodative convergence/accommodation (AC/A) ratio gives the relationship between the amount of convergence, or inward turning of the eyes, that is generated by a given amount of accommodation, or focusing of the lens. This ratio is numerically represented by the amount of convergence in prism diopters per unit change in accommodation in diopters. Amblyopia can occur in untreated patients, which is decreased vision due to a failure of normal neural development of the eye not in normal alignment.