Marcotte-Collard Rémy, Simard Patrick, Michaud Langis
École d'optométrie, l'Université de Montréal, Montréal, QC, Canada.
Eye Contact Lens. 2018 Sep;44(5):322-329. doi: 10.1097/ICL.0000000000000495.
This study aims to analyze two commercial orthokeratology lens designs and compare their optical effects at the corneal level.
This is a retrospective study on subjects seeking an orthokeratology fitting for myopia management at the Université de Montréal clinic between January 2013 and August 2015. Group A included the first 64 subjects fitted with a 4-curve lens design (Paragon CRT; Paragon) who met the inclusion criteria, whereas group B included the same number of subjects fitted with a 5-curve lens design (Dreamlens; Polymer Technology, Rochester, NY). Topographic tangential maps were collected at baseline and 3 months after fitting. The differential map was generated for each patient and analyzed, which involved determining the radius of the central distance zone (CDZ) and the power and width of the high convex zone (HCZ). Results were compared between the two groups, taking baseline refraction into account. Finally, a correlation was estimated between topographic data and corneal parameters (flat and steep K, the corneal eccentricity of each principal meridian).
The CDZ for group A is significantly larger than the one generated for group B both horizontally (t(126)=12.12, P<0.01) and vertically (t(126)=15.690, P<0.01). However, there was no significant difference regarding the HCZ power generated. The only correlations found were a strong positive association between CDZ radius and HCZ power generated by lens A nasally (r=0.450; P=0.000) and temporally (r=0.558; P=0.000), and a weaker association between the baseline refractive error, along with the nasal (r=0.237; P=0.033) and temporal (r=0.288; P=0.028) HCZ power for lens B.
The four- and five-curve orthokeratology lens designs generate significantly different optical modifications on the cornea. This can affect reports on orthokeratology efficacy for myopia management as well as the lens selection when used for myopia correction.
本研究旨在分析两种商业角膜塑形镜设计，并比较它们在角膜层面的光学效果。
这是一项回顾性研究，研究对象为2013年1月至2015年8月期间在蒙特利尔大学诊所寻求角膜塑形镜近视控制治疗的患者。A组包括首批64名符合纳入标准且佩戴4弧镜片设计（Paragon CRT；Paragon）的患者，而B组包括相同数量佩戴5弧镜片设计（Dreamlens；Polymer Technology，罗切斯特，纽约州）的患者。在基线期和配镜后3个月收集角膜地形图切线图。为每位患者生成并分析差异图，包括确定中央距离区（CDZ）的半径以及高凸区（HCZ）的度数和宽度。在考虑基线屈光不正的情况下，比较两组结果。最后，评估地形数据与角膜参数（平坦和陡峭角膜曲率、每个主子午线的角膜偏心率）之间的相关性。
A组的CDZ在水平方向（t(126)=12.12，P<0.01）和垂直方向（t(126)=15.690，P<0.01）均显著大于B组产生的CDZ。然而，所产生的HCZ度数没有显著差异。唯一发现的相关性是A组镜片鼻侧（r=0.450；P=0.000）和颞侧（r=0.558；P=0.000）的CDZ半径与所产生的HCZ度数之间存在强正相关，以及B组基线屈光不正与鼻侧（r=0.237；P=0.033）和颞侧（r=0.288；P=0.028）的HCZ度数之间存在较弱的相关性。
4弧和5弧角膜塑形镜设计在角膜上产生显著不同的光学改变。这可能会影响关于角膜塑形镜近视控制疗效的报告以及用于近视矫正时的镜片选择。
