Abstract:  Objective To compare the effects of defocus incorporated multiple segments spectacle lenses (referred to as defocus lenses) and single-vision lenses on astigmatism and myopia in children and whether defocus lenses increase the risk of astigmatism progression and their efficacy in myopia control.  Design Randomized controlled trial. Participants 102 Volunteers aged 6-12 years with myopia, recruited from University of Science and Technology of China Hospital between 2022 and 2023. Method Eligible children were randomly assigned to the defocus lens group (n=51) or single-vision lens group (n=51) for 12 months. Comprehensive ophthalmic examinations were performed, including slit-lamp microscopy, computer-assisted autorefraction under cycloplegia, retinoscopy, and subjective refraction to determine corrective prescriptions. Main Outcome Measures Changes in J0, J45, spherical equivalent refractive error (SER), and axial length. Results At baseline, there were no statistically significant differences between the defocus group and the single-vision group in terms of age, J0, J45, spherical equivalent refraction, or axial length. After 12 months of lens wear, the changes in J0 were (0.08±0.13) D and (0.08±0.13) D in the defocus and single-vision groups, respectively, with no statistically significant difference between the two groups (t=-0.193, P=0.424). The changes in J45 were (0.01±0.06) D and (-0.01±0.07) D, respectively, with no statistically significant difference between the two groups (t=0.029, P=0.977). The changes in spherical equivalent refraction were (-0.51±0.59) D and (-0.74±0.42) D, respectively, showing a statistically significant difference between the two groups (t=2.229, P=0.014). The progression of spherical equivalent refraction in the defocus group was reduced by 31.1% compared with the single-vision group. The axial elongation was (0.25±0.22) mm and (0.39±0.22) mm, respectively, showing a statistically significant difference between the two groups (t=-3.083, P=0.003). Axial elongation in the defocus group was reduced by 35.8% compared with the single-vision group. Conclusions The 12-month observation results show that compared to single-vision lenses, defocus incorporated multiple segments spectacle lenses do not increase the risk of astigmatism progression and demonstrate superior efficacy in controlling myopia progression of children aged 6-12 years.  

Key words: Defocus lenses, Single-vision lenses, Astigmatism, Myopia control