Outcomes of Early Surgery in Children under Four Years Old with Large Angle Intermittent Exotropia

Purpose: To find out the significance of early surgery in children of 4 years old and under with large angle intermittent exotropia of 35 prism diopters (PD) and more by examining the results of bilateral lateral rectus recession surgery and factors influencing the surgical outcome.Methods: It was a retrospective study of patients who underwent bilateral lateral rectus muscle recession surgery between 2006 to 2016 with intermittent exotropia greater than or equal to 35 PD and who were able to follow-up for at least 2 years after surgery were divided into two groups based on age of 4 years old. The surgical motor success was defined as exodeviation less than 10 PD, esodeviation less than 8 PD. The angle of deviation, binocular function, best corrected visual acuity, and amount of corrected PD per lateral recession (PD/mm) were compared at each observation point after surgery.Results: The motor success of bilateral rectus muscle recession surgery was 85% in children of age 4 years and under, 65.5% in age over 4 years. Success rate of early surgery was 1.3 times higher in younger age group, but there was no statistical meaning. The complication of surgery after 2 years of follow up was less in younger group-the rate of recurrent exotropia was 15% in younger group, 31.3% in older group and the rate of consecutive esotropia was 0% and 3.1%, respectively. Stereoacuity after 2 years of surgery was not fall behind in younger group compared to older group.Conclusions: It is possible to obtain good surgical results by performing early surgery rather than hesitating to operate due to the younger age in patients younger than 4 years old with large angle exotropia of 35 PD and more for long-term follow up and efficient patient management.