Incidence and Prevalence of Keratoconus in Taiwan During 2000–2018 and Their Association With Topography Use

Abstract Purpose The aim of this study was to determine the age- and sex-specific incidence and prevalence of keratoconus (KC) in Taiwan and explore their association with computerized corneal topography use. Design: This nationwide population-based retrospective study included the data of the Taiwanese population (N = 27,540,859) from the National Health Insurance Research Database (NHIRD) from 2000 to 2018. Method We estimated the incidence of KC by identifying patients with newly diagnosed KC and estimated its prevalence by identifying the total number of patients who had the ICD-9-CM code 371.6 or ICD-10-CM code H18.609 twice or more in NHIRD during 2000–2018. Results The incidence of KC in Taiwan during 2000–2018 was 7,075, with the incidence rate being 1.56 (95% confidence interval [CI]: 1.53–1.60) per 100,000 person-years. The prevalence of KC was 4.29 (95% CI: 4.23–4.35) per 100,000 person-years. The KC incidence rate peaked in patients aged 21–25 years (6.40 in male patients and 3.19 in female patients). The overall incidence rates in male and female patients were 2.01 and 1.35, respectively (incidence rate ratio: 1.46), indicating that KC had a significant male predisposition. Moreover, we noted a linear correlation ( R 2 = 0.7488) between the proportion of computerized corneal topography use and the incidence of KC in our study. Conclusion Estimates of nationwide population-based incidence and prevalence can contribute to better understanding of the risk of ethnic groups and geographic locations in the pathophysiology of KC, and the trend can help physicians improve the general vision health of the population.