Critical period for restoration of normal stereoacuity in acute-onset comitant esotropia

We conducted a retrospective study of 25 patients with acute-onset comitant esotropia to evaluate whether the timing of the start of treatment is a critical factor in the development of normal stereopsis. The mean age at onset was 12 years 4 months, and mean age at the start of treatment was 17 years 9 months. Bifixation was defined as a stereoacuity threshold score that was numerically lower than 60 seconds of arc on stereotesting. An operation was performed on the nonfixating eye for the prism-adapted angle. At the final examination, bifixation was observed in four patients (16%) with the Randot test and in 15 patients (60%) with the Titmus test. No relationship was found between the time of the start of treatment and the postoperative development of stereopsis, nor was there a significant (P > .10) difference between the two groups with early and delayed start of treatment in the proportion of patients with bifixation.