Esotropia with High AC/A Ratio

Updated: Sep 16, 2021
  • Author: Sharmila Segar, MD; Chief Editor: Hampton Roy, Sr, MD  more...
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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.



Esotropia with high AC/A ratio generally presents by the age of 2 years. [1]  Esodeviations are intermittent initially and usually decompensate to become constant. Sometimes there is trauma or illness related to onset. There is no sex predilection for esotropia with high AC/A ratio.



In esotropia with high AC/A ratio, patients have an excessive convergence response to accommodation while wearing their full cycloplegic correction. These patients most commonly have low hyperopia, while some have high hyperopia, myopia or emmetropia (no refractive error). Consecutive esotropia with high AC/A ratio has also been identified in patients after surgical correction for intermittent exotropia. [2]