Correlation between ocular biological parameters and cycloplegic refractive shift in pediatric myopia

AIM: To analyze the correlation between ocular biometric parameters and cycloplegic refractive shift (ΔSE) and to provide evidence for clinical decision-making regarding cycloplegic refraction in pediatric myopia management. METHODS: This retrospective study enrolled myopic patients aged 5-17y between July 2022 and November 2023. Data collected included age, gender, pre-cycloplegic spherical equivalent (SE1), axial length (AL), average corneal curvature (K), lens thickness (LT), anterior chamber depth (ACD), central corneal thickness (CCT), positive relative accommodation (PRA), negative relative accommodation (NRA), and post-cycloplegic spherical equivalent (SE2). Only right eyes were analyzed. Participants were divided into three groups by ΔSE: Group A (ΔSE≤0.25 D), Group B (0.25<ΔSE<0.75 D), and Group C (ΔSE≥0.75 D). Based on SE2, subjects were classified into pre-myopia (−0.50<SE2≤+0.75 D), low myopia (−3.00<SE2≤−0.50 D), and moderate myopia (−6.00<SE2≤−3.00 D). RESULTS: A total of 996 myopic patients (455 boys, 541 girls) with a mean age of 9.97±0.83y were included. Groups A, B, and C comprised 544, 284, and 168 eyes, respectively. Post-cycloplegic stratification identified 94 pre-myopic eyes, 797 low myopic eyes, and 105 moderate myopic eyes. Significant inter-group differences were observed in AL, CCT, ACD, LT, NRA, and axial length/corneal radius (AL/CR; all P<0.05). LT was positively correlated with ΔSE (P=0.003), while NRA was negatively correlated with ΔSE (P=0.049). AL/CR showed the strongest negative association (P<0.001). ROC curve analysis yielded area under the curve (AUC) values of 0.551 for LT, 0.447 for NRA, and 0.441 for AL/CR. For LT, the optimal cutoff was 3.39 mm, with 65.4% sensitivity and 44.2% specificity. Mean LT was 3.438±0.168 mm in the 5-7-year group, significantly thicker than in 8-10y (3.360±0.145 mm), 11-13y (3.353±0.158 mm), and 14-17y (3.336±0.155 mm; all P<0.001). Median AL/CR ratios were 3.02 (2.95, 3.08) in pre-myopia, 3.10 (3.06, 3.14) in low myopia, and 3.21 (3.15, 3.28) in moderate myopia. Linear regression produced the model: AL/CR=3.025-0.051×SE2 (R²=0.462, F=854.081, P<0.001). Receiver operating characteristic (ROC) analysis for moderate myopia detection showed an AUC of 0.851 with an optimal AL/CR cutoff of 3.15. CONCLUSION: In myopic patients aged 5-17y, ΔSE is negatively correlated with NRA and positively correlated with LT. Cycloplegic refraction is recommended when LT exceeds 3.39 mm, but interpretation must account for age-related variations in lens thickness. Using the formula AL/CR=3.02-0.05×SE2, cycloplegic refraction is advised when a marked discrepancy exists between pre-cycloplegic refraction and AL/CR.