Analysis of the Factors Influencing the Treatment Zone Area after Overnight Orthokeratology Lens Wearing

Purpose To validate the agreement between R language (R) and MATLAB for measuring orthokeratology (OK) lens treatment zone parameters, and identify the influencing factors of the treatment zone area (TZA). Methods A retrospective study included 239 children (7–16 years) who wore OK lenses continuously for 12 months. Two OK lens designs were used: 1) Vision Shaping Treatment (VST) lenses, with back optic (BC) zone diameters of 5.5 mm or 6.0 mm; 2) Corneal Refractive Therapy (CRT) lenses, with BC zone diameters of 5.0 mm or 6.0 mm. Patients were divided into four groups based on lens design and BC zone diameter: VST-S (5.5 mm, n = 61), VST-L (6.0 mm, n = 66), CRT-S (5.0 mm, n = 59), and CRT-L (6.0 mm, n = 53). Treatment zone parameters were quantified using R and MATLAB. Spearman correlation analysis and multiple linear regression were applied to explore factors influencing TZA. Results R and MATLAB showed high agreement in measuring treatment zone parameters: Cronbach’s alpha values were 0.993 for treatment zone decentration (TZD) and 0.991 for TZA; intraclass correlation coefficient values were 0.986 for TZD and 0.983 for TZA. Post hoc comparisons revealed VST-L group had significantly larger TZA than the other three groups (all P  < 0.001); TZA of VST-L group was significantly larger than that of CRT-L group (U = 719.000, P  < 0.001). Lens design, BC zone diameter, preoperative p value, corneal mean keratometry change (Δkm), and p value change (Δp) were independent predictors of TZA ( R ² = 0.629), with Δkm showing the strongest correlation ( ρ  = 0.623). Conclusion R is reliable for measurement of treatment zone parameters, with results consistent with MATLAB. Dynamic corneal remodeling parameters (Δkm, Δp) and static factors (lens design, BC zone diameter, preoperative p) jointly regulate TZA. These findings provide guidance for personalized OK lens fitting to optimize myopia control by regulating TZA.