The Clinical Feature and Surgical Outcome of Infantile Exotropia

Purpose: To investigate the clinical features and treatment of infantile exotropia which developed in the first year of life. Methods: The medical records of infantile exotropia operated on in our hospital were reviewed for preoperative and postoperative deviation, cycloplegic refraction, Worth 4-dot test and Titmus stereo acuity test. Results: Preoperative mean deviation was 37 prism diopters. The average post-operative follow-up period was 26.5 months (1286 months). Twelve patients (71%) had successful horizontal alignment with final horizontal deviations of less than 8 prism diopters, and five patients were undercorrected between 10 and 20 prism diopters. None were overcorrected. Six patients (35%) had fusion at distance and near as well as stereoacuity of 200 seconds of arc or less. Both preoperative and postoperative associated anomalies were inferior oblique muscle overaction (35%), dissociated vertical deviation (18%), both inferior oblique muscle overaction and dissociated vertical deviation (18%), nystagmus (12%) and V-pattern (6%). Conclusion: Although infantile exotropia is rare, it has similarities to infantile esotropia. Infantile exotropia features a large-angle deviation, accompanied with inferior oblique muscle overaction and dissociated vertical deviation. After operation, no cases were overcorrected, while high levels of binocular function, and stereoacuity developed in some cases.