Increase in myopia prevalence in clinic-based populations across a century.

Purpose: The study's aim was to report prevalence estimates and age-related trends in refractive error in a clinic-based series and compare them to results from studies of a similar nature conducted since 1892.

Methods: Refractive error, patient age, and sex were collected from the files of all patients seen at the University of Waterloo School of Optometry and Vision Science clinic between January 2007 and January 2008. Patients were categorized as having myopia (<-0.