儿童配戴角膜塑形镜后早期角膜生物力学变化特征

目的：探讨近视儿童配戴角膜塑形镜后早期角膜生物力学变化特征及相关因素。方法：前瞻性临床 研究。收集山东第一医科大学附属眼科医院2018年6月至2019年12月配戴角膜塑形镜的中低度近 视患者55例（109眼）,男28例,女27例,年龄（12.1±3.7）岁,等效球镜度（SE）为（-2.97±1.56）D。 在配戴前及戴镜后1 d、1周、1个月,采用可视化角膜生物力学分析仪（Corvis ST）检查患者角膜生 物力学相关参数,如变形幅度比（DAR）、综合半径（IR）、水平方向Ambrosio相关厚度（ARTh）、硬 度参数（SP-A1）以及Corvis生物力学指数（CBI）;Pentacam检查角膜曲率;角膜光学相干断层扫描 （OCT）检查中央角膜厚度（CCT）和中央角膜上皮厚度（CET）。采用单因素方差分析比较不同时间 点角膜生物力学指标、屈光度和角膜形态的变化;采用Pearson检验进行各生物力学指标间的相关分 析。结果：所有患者在配戴角膜塑形镜后裸眼视力（UCVA）明显提高,1个月时均达到0 LogMAR。 CBI在配戴后1个月内逐渐上升,1个月时最高,配戴后1 d、1周、1个月较配戴前差异有统计学意义 （F=11.52, P<0.001）。IR在配戴后上升,1周时处于最高值,配戴前后比较差异有统计学意义（F=3.11, P=0.027）。ARTh在配戴后下降,1周时最低,配戴前后差异有统计学意义（F=29.82, P<0.001）。CBI 与SE呈正相关（r=0.21, P=0.003）,与CET呈负相关（r=-0.16,P=0.041）;与CCT无明显相关性。结论： 儿童配戴角膜塑形镜后1个月内,角膜生物力学特性有下降趋势,主要的变化指标为CBI。SE越低, CET越厚;CBI改变越小,角膜的安全性越高。

Analysis of Early Corneal Biomechanical Changes in Children after Wearing Orthokeratology Contact Lenses

Objective: To investigate the early changes in corneal biomechanical parameters in children after overnight wear of orthokeratology lenses (OK) and their associated factors. Methods: In this prospective clinical study, a total of 55 teenagers (109 eyes) with low to moderate myopia successfully wore OK lenses from June 2018 to December 2019. Twenty-eight males and 27 females with a mean age of (12.1±3.7) years and 1 d, 1 week and 1 month after first wearing the lenses. Corneal biomechanical parameters, including DA ratio (DAR), integrated radius (IR), Ambrosio relational thickness horizontal (ARTh), Stiffness parameter (SP-A1) and Corvis biomechanical index (CBI), were measured by Corvis ST. Corneal curvature was measured by Pentacam, and central corneal thickness (CCT) and central corneal epithelial thickness (CET) were measured by corneal OCT. One-way analysis of variance was used to compare changes in corneal biomechanics, refractive power, and corneal morphology at the different time points. A Pearson test was used to perform correlation analysis among various biomechanical indicators. Results: The uncorrected visual acuity (UCVA) of all patients improved significantly after wearing OK lenses, and reached 0 logMAR at 1 month. The CBI increased gradually after wearing OK lenses, the highest at 1 month. There was a statistically significant difference between before and 1 d, 1week, 1 month after wearing OK lens (F=11.52, P<0.001). IR increased after wearing the lenses, and the highest increase was at 1 week, which was a statistically significant increase at every time points compared to IR before wearing lens (F=3.11, P=0.027). ARTh decreased after OK lens and was lowest at 1 week, and there was statistically significant difference between before and 1 d, 1 week, 1 month after wearing the lenses (F=29.82, P<0.001). CBI was positively correlated with SE (r=0.21, P=0.003) and negatively correlated with CET (r=-0.16, P=0.041). And CBI was no significant correlation with CCT. Conclusion: Corneal biomechanical parameters show a downward trend within 1 month in the early stage of OK lens wearing in children; the main change is in the CBI index. The lower the SE is, the thicker the CET. The CBI change is smaller and the cornea is safer.