Key points are not available for this paper at this time.
PURPOSE: To characterize longitudinal astigmatism changes and their interaction with spherical equivalent (SE) progression in Chinese school-age children. METHODS: We retrospectively reviewed medical records of patients with long-term follow-up data from 2008 to 2022. Patients aged 6-10 years at initial visit and 16 years at last assessment, with a cylinder refraction of 0.75 D or greater, were selected. Astigmatism was analyzed in clinical notation and vector notation (J0, J45). Factors related to annual changes in astigmatism and SE and their interaction were analyzed. RESULTS: A total of 2946 patients (mean age 8.72 ± 1.21 years at initial visit) were followed up for 7.40 ± 1.23 years. In low astigmatism (≤1.50 D), cylinder power increased by 0.018 D/y with age, whereas in high astigmatism (≥3.00 D), it decreased by 0.048 D/y (p < 0.001). Oblique astigmatism (J45) increased by 0.008 D/y, and with-the-rule (WTR) astigmatism (J0) decreased by 0.005 D/y (p < 0.001). A more negative baseline SE at initial visit was associated with greater increase in astigmatism magnitude (β = -0.004, p < 0.001), and higher baseline astigmatism magnitude was associated with less SE progression (β = 0.047, p < 0.001). CONCLUSION: In this large longitudinal cohort of Chinese school-age children, astigmatism progression exhibited a baseline-dependent pattern. Myopia was associated with a modest acceleration of astigmatism progression, whereas higher astigmatism conferred a slight protective effect against myopic shift. This study demonstrates these refractive interactions, though their clinical applicability is limited by small effect sizes.
Qin et al. (Fri,) studied this question.