Objective: To evaluate the effect of using the amount of base-out (BO) recovery point as the surgical target for acute acquired comitant esotropia (AACE). Methods: Patients with AACE underwent surgery based on the target angle of the base-out recovery point and were followed up at least 4 months. The deviation, binocular functions before and after the surgery were analyzed and the factors related the post-operative stereopsis were evaluated. Results: Totally 43 patients were included in the study, including 27 males (63%) and 16 females (37%), aged from 9 to 53 years (23.7±11.4 years), duration of preoperative strabismus ranged from 3 months to 11 years (24.8±24.5 months), and postoperative follow-up ranged from 4 to 62 (15.8±14.5 months). Both distant and near pre-operative Base-out recovery point were larger than the angle of esotropia [(9.3±6.9) PD for distant; (11.4±6.7) PD for near, both P<0.001]. The pre-operative esotropia for distant and near viewing were (38.4±13.2) PD and (37.6±13.7) PD respectively and reduced to (0.74±2.4) PD and (0.70±2.4) PD at the last visit time (P<0.001). Thirty-eight cases were orthosia without any phoria and five cases still had some esophoria or minimal esotropia at the last visit. The stereoacuity improved significantly after the surgery. The post-operative stereopsis significantly correlated with the pre-operative stereopsis and the duration from onset of esotropia to the time of surgery. Conclusion: The acute acquired comitant esotropia can be corrected with strabismus surgery based on the target angle of base-out recovery point. The post-operative stereopsis correlated with the pre-operative stereo function and the time of esotropia lasting. It suggested the earlier esotropia was corrected the better the stereopsis recovered.
