Abstract:AIM: To analyze the risk factors for pre-myopia among school-aged children, develop a nomogram model based on these factors, and explore the efficacy of plano defocus lenses on myopia prevention and control.
METHODS: A prospective randomized controlled clinical trial. School-aged children receiving physical examinations in the hospital between July 2024 and January 2025 were enrolled. All subjects were divided into the experimental group(children with pre-myopia)and the control group(children with normal refraction)according to the results of cycloplegic refraction and axial length measurement. Clinical data of the two groups were collected. Logistic regression analysis was adopted to identify the risk factors for pre-myopia, and a corresponding nomogram model was constructed. The children in the experimental group were further assigned to Group A(standard behavioral intervention+plano defocus lenses)and Group B(standard behavioral intervention alone)via the random number method. Ocular biological parameters and refractive indices before and after intervention were compared between groups.
RESULTS: A total of 236 school-aged children were enrolled in this study, including 80 children in the experimental group(40 cases in group A and 40 cases in group B)and 156 children in the control group. The age of children in the experimental group was 8.88±1.11 y, with 27 males and 53 females. The age of children in the control group was 8.92±1.05 y, with 91 males and 65 females. Group A had an average age of 8.79±1.22 y(14 males and 26 females), and group B had an average age of 8.91±1.07 y(13 males and 27 females). Multivariate Logistic regression analysis revealed that parental myopia history, pencil-grip posture and duration of electronic device use were risk factors for pre-myopia among school-aged children(all P<0.05); daily outdoor activity duration and daily sleep duration were protective factors(all P<0.05). The nomogram model yielded an AUC of 0.970(95%CI: 0.951-0.990), with a sensitivity of 0.900 and specificity of 0.942. The calibration curve indicated nearly perfect linear calibration and good fitting performance. Decision curve analysis demonstrated high clinical applicability. SHAP summary plots showed that daily outdoor activity duration was the most critical factor affecting the onset of pre-myopia in school-aged children. After intervention with plano defocus spectacles, the axial length elongation in group A was significantly lower than that in group B(P<0.05). Choroidal thickness and cycloplegic spherical refraction were significantly higher, and uncorrected distance visual acuity(LogMAR)was significantly lower in group A compared with group B(all P<0.05).
CONCLUSION: Parental myopia history, pencil-grip posture, and duration of electronic device use are risk factors for pre-myopia in school-aged children, while daily outdoor activity duration and daily sleep duration are protective factors. The nomogram constructed based on the above factors exhibits favorable predictive accuracy and can be applied for early screening of high-risk children. Plano defocus spectacles can slow axial length progression, stabilize refractive status, and exert positive effects on myopia prevention in school-aged children with pre-myopia.
