Estimation of cycloplegic spherical refraction from non-cycloplegic clinical and biometric data in children using...

To develop and evaluate non-cycloplegic clinical and biometric models for estimating cycloplegic spherical power (DS), spherical equivalent (SE), and astigmatic power-vector components (J0 and J45) in children, and to assess their utility as a preliminary screening-triage aid rather than a substitute for cycloplegic refraction.

This retrospective pilot study included 590 children aged 2.4-14.8 years who underwent cycloplegic refraction at the Children's Hospital, Zhejiang University School of Medicine. The children were randomly divided at the patient level into training and held-out test sets at a ratio of 7:3, ensuring that both eyes from the same child remained in the same set. Astigmatism was expressed using J0 and J45. Power-vector components were calculated separately for non-cycloplegic and post-cycloplegic refraction, and post-cycloplegic J0/J45 served as prediction targets. Seven algorithms were screened; DT, BPNN, GPR, and LR were selected for clinically oriented evaluation using regression metrics, error thresholds, screening indices, subgroup analyses, GEE analysis, and Bland-Altman plots.

Age, axial length, corneal astigmatism, corneal power, and UCVA were the main predictors for spherical refraction. After patient-level splitting, DT, BPNN, GPR, and LR showed moderate performance for DS and SE. DT achieved RMSE/R² values of 0.776 D/0.819 for DS and 0.781 D/0.823 for SE; BPNN achieved 0.752 D/0.802 for DS and 0.759 D/0.798 for SE. GPR achieved 0.921 D/0.806 for DS and 0.941 D/0.800 for SE, while LR achieved 0.876 D/0.824 for DS and 0.949 D/0.797 for SE. The vector-based analysis showed interpretable J0 outputs for several models, including GPR (R² = 0.671), but J45 was weak across models (R² approximately - 0.08 to 0.06). For SE-based screening, GPR achieved sensitivity/specificity of 94.09%/86.46% for myopia and 80.00%/98.20% for hyperopia. Only 53.75% of GPR SE estimates were within +/-0.50 D.

Non-cycloplegic clinical and biometric variables provided moderate estimates of cycloplegic DS and SE after patient-level data partitioning. The J0/J45 vector analysis indicated partial predictability of J0, whereas J45 prediction was clinically unreliable. This approach should be regarded as an exploratory triage aid for spherical refractive estimation rather than a substitute for cycloplegic refraction.