Purpose: This study aimed, using a large sample size, to determine the long-term results of standard treatment of accommodative esotropia and identify predictors of outcome while minimizing bias in data collection and analysis.

Methods: Data from all the files of a large, long-established pediatric ophthalmology practice were collected and analyzed using a masked protocol. The study included every esotropic patient who had been prescribed glasses. Criteria for patient inclusion were designed to conform to earlier studies by the authors.

Results: The database totaled 1307 patients, of who 354 met inclusion criteria. A greater difference between near and distance esodeviation (AC/A relationship) correlated with a higher rate of deterioration of accommodative esotropia control (P < 0.0001). Deterioration also positively correlated with earlier age of onset (P < 0.0001), inferior oblique overaction (P = 0.0005), and amblyopia (P < 0.005).

Conclusions: This study demonstrates that a high AC/A relationship increases the likelihood of deterioration of accommodative esotropia, supporting the earlier studies, as well as the accuracy of this database. It also represents a new model for the utilization of clinical trials' bias-reduction principals in the analysis of retrospective data.