The Changing Profile of Astigmatism in Childhood: The NICER Study.

PURPOSE We performed a prospective study of the changing profile of astigmatism in white school children in Northern Ireland. METHODS Of the 399 6- to 7-year-old and 669 12- to 13-year-old participants in Phase 1 of the Northern Ireland Childhood Errors of Refraction (NICER) study, 302 (76%) of the younger and 436 (65%) of the older cohort were re-examined three years later (Phase 2). Stratified random cluster sampling was used. Following cycloplegia (cyclopentolate HCl 1%) refractive error was recorded by the Shin-Nippon-SRW-5000 autorefractor. Astigmatism is defined as ≥ 1.00 diopters cylinder (DC). Right eye data only are presented. RESULTS The prevalence of astigmatism was unchanged in both cohorts: younger cohort 17.1% (95% confidence intervals [CIs], 13.3-21.6) were astigmatic at 9 to 10 years compared to 22.9% (95% CIs, 18.3-28.2) at 6 to 7 years; older cohort, 17.5% (95% CIs, 13.9-21.7) of participants were astigmatic at 15-16 years compared to 18.4% (95% CIs, 13.4-24.8) at age 12 to 13 years. Although prevalence remained unchanged, it was not necessarily the same children who had astigmatism at both phases. Some lost astigmatism (10.0%; CIs, 7.5-13.3 younger cohort and 17.4%; CIs, 13.5-22.2 older cohort); others became astigmatic (9.1%; CIs, 6.7-12.2 younger cohort and 11.6%; CIs, 8.4-15.8 older cohort). CONCLUSIONS This study presents novel data demonstrating that the astigmatic error of white children does not remain stable throughout childhood. Although prevalence of astigmatism is unchanged between ages 6 and 7 to 15 to 16 years; during this time period individual children are developing astigmatism while other children become nonastigmatic. It is difficult to predict from their refractive data who will demonstrate these changes, highlighting the importance of all children having regular eye examinations to ensure that their visual requirements are met.