Prevalence and Incidence of Strabismus by Age Group in Japan: A Nationwide Population-Based Cohort Study

Manabu Miyata; Ai Kido; Masahiro Miyake; Hiroshi Tamura; Takuro Kamei; Saori Wada; Hiroaki Ueshima; Kentaro Kawai; Shinya Nakao; Akinari Yamamoto; Kenji Suda; Eri Nakano; Miho Tagawa; Akitaka Tsujikawa

doi:10.1016/j.ajo.2023.11.022

Prevalence and Incidence of Strabismus by Age Group in Japan: A Nationwide Population-Based Cohort Study

Am J Ophthalmol. 2023 Nov 30:262:222-228. doi: 10.1016/j.ajo.2023.11.022. Online ahead of print.

Authors

Affiliations

¹ From the Department of Ophthalmology and Visual Sciences, Graduate School of Medicine (M. Miyata, A.K., M. Miyake, H.T., T.K., S.W., K.K., S.N., A.Y., K.S., E.N., M.T., A.T.). Electronic address: miyatam@kuhp.kyoto-u.ac.jp.
² From the Department of Ophthalmology and Visual Sciences, Graduate School of Medicine (M. Miyata, A.K., M. Miyake, H.T., T.K., S.W., K.K., S.N., A.Y., K.S., E.N., M.T., A.T.).
³ From the Department of Ophthalmology and Visual Sciences, Graduate School of Medicine (M. Miyata, A.K., M. Miyake, H.T., T.K., S.W., K.K., S.N., A.Y., K.S., E.N., M.T., A.T.); Center for Innovative Research and Education in Data Science, Institute for Liberal Arts and Sciences (H.T., H.U.), Kyoto University, Kyoto City, Kyoto, Japan.
⁴ Center for Innovative Research and Education in Data Science, Institute for Liberal Arts and Sciences (H.T., H.U.), Kyoto University, Kyoto City, Kyoto, Japan.

PMID: 38040322
DOI: 10.1016/j.ajo.2023.11.022

Abstract

Purpose: To investigate the prevalence and incidence of strabismus in the Japanese population by age group and to estimate the subtype proportions.

Design: A nationwide population-based cohort study.

Methods: This study investigated the number of cases with previous and new diagnoses of strabismus by age group between 2009 and 2020 using the National Database of Health Insurance Claims and Specific Health Checkups of Japan, which includes almost all (≥95%) medical claims data. We calculated the strabismus prevalence and 1-year incidence in 2019 and analyzed the proportion of each strabismus subtype.

Results: The strabismus prevalence was 2.154% (2 709 207/125 708 000; 95% CI, 2.152%-2.157%). It showed a bimodal distribution, with a high proportion in school and old ages (especially ≥75 years). Exotropia, esotropia, and cyclovertical strabismus proportions were 67.3%, 26.0%, and 6.7%, respectively. Cyclovertical strabismus was uncommon in patients aged ≤18 years (1.4%) and more common (10.2%) in those aged >18 years. The strabismus incidence in 2019 was 321 per 100 000 person-years (403 093/125 708 000; 95% CI, 320-322). The annual incidence proportion of cyclovertical strabismus as opposed to whole strabismus subtypes in patients aged >18 years (13.1%) was higher than that in those aged ≤18 years (1.4%).

Conclusions: This is the first nationwide population-based cohort study to demonstrate strabismus's overall prevalence and incidence. The high prevalence of cyclovertical strabismus in adults compared with children may suggest that cyclovertical strabismus is a primarily age-related strabismus. The high prevalence of exotropia may indicate a genetic difference between Japanese and other ethnicities.