Incidence and types of childhood exotropia: a population-based study.

OBJECTIVE: To determine the incidence and types of childhood exotropia in a defined population.

DESIGN: Retrospective, population-based cohort.

PARTICIPANTS: All pediatric (<19 years old) residents of Olmsted County, Minnesota diagnosed with an exodeviation (>or=10 prism diopters) from January 1, 1985 through December 31, 1994.

METHODS: The medical records of all potential patients identified by the resources of the Rochester Epidemiology Project were reviewed.

MAIN OUTCOME MEASURES: Incidence and types of childhood exotropia.

RESULTS: Two hundred five cases of childhood exotropia were identified during the 10-year period, yielding an annual age- and gender-adjusted incidence of 64.1 (95% confidence interval: 55.2-72.9)/100,000 patients younger than 19 years. This rate corresponds to a prevalence of approximately 1.0% of all children younger than 11 years, with a significant decrease in the incidence during the second decade of life (P<0.001). Eighty-six percent of the children had intermittent exotropia, convergence insufficiency, or an exotropia in the setting of an abnormal central nervous system.

CONCLUSIONS: The incidence of childhood exotropia from this population-based study is comparable to the prevalence rates in prior reports. Exotropia is most prevalent during the first decade of life, with intermittent exotropia and convergence insufficiency occurring most frequently.