State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China .
Eye Contact Lens. 2024 Oct 1;50(10):432-438. doi: 10.1097/ICL.0000000000001119. Epub 2024 Aug 23.
To determine the relationship between regional summed corneal refractive power changes (CRPCs) in myopic orthokeratology and axial elongation.
This retrospective study included 70 eyes of 70 patients aged 8 years to 13 years who underwent orthokeratology lens (OK lens) treatment, and all patients underwent regular follow-ups at 1 week, 1 month, 6 months, and 12 months at Zhongshan Ophthalmic Center between January 2019 and May 2021.
Axial length (AL) was measured at baseline and 12 months by an IOLmaster 5.0. Refractive error power was measured using cycloplegia. Regional summed CRPCs were calculated by MATLAB software using difference tangential power maps at the sixth month acquired by corneal topography measurements (Medmont E300 Corneal Topographer; Medmont Pty, Victoria, Australia) and defined as changes in corneal refractive power at the sixth month from baseline. The regional summed CRPCs were then subdivided into 4-mm diameter circles, 4- to 5-mm diameter chords, and 5- to 6-mm diameter chords according to the distance from the central of the pupil and into negative, positive, and total according to the values. Pearson correlation, multiple linear regression analysis, and stepwise multiple linear regression analysis were performed to analyze the relationships among these parameters.
Axial elongation had a negative relationship with positive regional summed corneal refractive power in the central 4-mm diameter circle and age (r=-0.282, P =0.018; r=-0.473, P <0.001, respectively) and a positive relationship with negative regional summed corneal refractive power in the 5- to 6-mm diameter chord (r=0.361, P =0.002). Stepwise multiple linear regression analysis identified age (standardized β =-0.434, P <0.001) and negative regional summed corneal refractive power in the 5- to 6-mm diameter chord (standardized β =0.305, P =0.004) as factors influencing AL elongation.
Negative regional summed corneal refractive power in a 5- to 6-mm diameter chord after OK lens treatment may be an important index for evaluating the control effects of axial elongation.
确定近视角膜塑形术（orthokeratology）中角膜整体离焦量（corneal refractive power changes，CRPCs）的区域变化与眼轴增长之间的关系。
本回顾性研究纳入了 2019 年 1 月至 2021 年 5 月期间在中山大学中山眼科中心接受角膜塑形镜治疗的 70 名 8 至 13 岁患者的 70 只眼，所有患者均在 1 周、1 个月、6 个月和 12 个月进行了定期随访。
采用 IOLMaster 5.0 测量眼轴长度（axial length，AL）。使用睫状肌麻痹剂进行屈光不正力测量。采用 MATLAB 软件根据角膜地形图（Medmont E300 角膜地形图仪；Medmont Pty，澳大利亚维多利亚州）在第 6 个月获得的差异切线屈光力图计算角膜整体离焦量，定义为从基线开始的第 6 个月时角膜屈光力的变化。然后根据距离瞳孔中心的距离将角膜整体离焦量分为 4mm 直径圆、4-5mm 直径弦和 5-6mm 直径弦，并根据数值分为负值、正值和总和。采用 Pearson 相关分析、多元线性回归分析和逐步多元线性回归分析来分析这些参数之间的关系。
眼轴增长与中央 4mm 直径圆的正值角膜整体离焦量和年龄呈负相关（r=-0.282，P=0.018；r=-0.473，P<0.001），与 5-6mm 直径弦的负值角膜整体离焦量呈正相关（r=0.361，P=0.002）。逐步多元线性回归分析发现年龄（标准化β=-0.434，P<0.001）和 5-6mm 直径弦的负值角膜整体离焦量（标准化β=0.305，P=0.004）是影响眼轴增长的因素。
角膜塑形术后 5-6mm 直径弦的负值角膜整体离焦量可能是评估眼轴增长控制效果的重要指标。
