Systemic evaluation of the risk of reoperations in pediatric populations with exotropia and esotropia: nested case–control study

The study aimed to assess the risk of reoperations for strabismus in the pediatric population and to identify high-risk groups. This was a nationwide population-based study that used data from the Korean National Health Claims Database from 2008 to 2020. Two major cohorts were established based on initial strabismus: age-, sex-, and recruitment year-matched controls were randomly selected. Patients aged ≤ 9 years who underwent initial strabismus surgery for exotropia and esotropia were included, resulting in a total of 24,816 patients included to this study. The cumulative incidence of reoperations was 843 per 10,000 persons for exotropia, 1559 per 10,000 persons for esotropia. To assess the significant exposure factors, conditional logistic regression was performed to obtain odds ratio (OR) in each cohort. In patients with exotropia, the OR of reoperations was 4.26 times higher when the initial surgery is performed at younger age (earlier than 3-year-old) and 6.49 times higher when only one eye underwent than two eye. Similarly, in patients with esotropia, younger age (6.57 times) and unilateral surgery (7.20 times) were identified as common factors that increase the risk of reoperations. Based on the findings, special attention is recommended for patients younger than 3 years, especially those performed unilateral surgery as initial intervention in practical settings.