Pacific University College of Optometry, Forest Grove, OR, USA; Eye-Contact-Lens Research & Education, Amsterdam, The Netherlands.
Pacific University College of Optometry, Forest Grove, OR, USA.
Cont Lens Anterior Eye. 2021 Dec;44(6):101386. doi: 10.1016/j.clae.2020.11.006. Epub 2021 Jan 8.
While knowledge of the ocular surface sagittal height (OC-SAG) is increasing with newer instrumentation, understanding of soft lens sag values (CL-SAG) in daily clinical practice is limited. This study aimed to report the differences in CL-SAG of a large collection of daily disposable (DD), reusable (2-week and 4-week replacement) and toric lens designs.
12 different spherical DD and 15 reusable lens types were analysed (labelled power -3.00D); 17 different toric lens types analysed (6 DD and 11 reusable) in -3.00D =C 0.75 × 180. Posterior CL-SAG was measured directly using a spectral domain OCT-based instrument (Optimec is830).
The range in CL-SAG for DDs was 3,398-3,912 microns, for reusable lenses 3,372-4,004 microns and for toric lenses 3,536-4,157 microns. Lens diameter and BC together influence CL-SAG values. For lenses with the same labelled base curve (BC), the maximum difference in the DD group was 264 microns, in the reusable group 418 microns and in the toric group 345 microns. Three lens designs within the DD group and five in the reusable group offer two BCs, with an average variation (±SD) in CL-SAG of 276 ± 39 microns; one toric lens with two BCs showed a 377-micron difference.
Marked differences in CL-SAG values were found in this study, also between lenses of the same BC. While ECPs should be aware that diameter and BC together influence CL-SAG, this also indicates that lens substitution based on BC alone could result in substantial differences in CL-SAG, with a potential impact on lens fit. Lens designs offering two BCs showed a somewhat narrow band in absolute terms in CL-SAG, and switching from a spherical to a toric lens of the same lens manufacturer could result in a significant change in CL-SAG.
随着新型仪器的出现，人们对眼表矢高（OC-SAG）的认识不断提高，但在日常临床实践中对软性隐形眼镜矢高（CL-SAG）的理解有限。本研究旨在报告大量日抛型（DD）、可重复使用型（2 周和 4 周更换）和散光隐形眼镜设计的 CL-SAG 差异。
分析了 12 种不同的球面 DD 和 15 种可重复使用的镜片类型（标记为-3.00D 视力）；分析了 17 种不同的散光镜片类型（6 种 DD 和 11 种可重复使用镜片），均为-3.00D =C 0.75 × 180。使用基于光谱域 OCT 的仪器（Optimec is830）直接测量后 CL-SAG。
DD 的 CL-SAG 范围为 3,398-3,912 微米，可重复使用镜片的 CL-SAG 范围为 3,372-4,004 微米，散光镜片的 CL-SAG 范围为 3,536-4,157 微米。镜片直径和基弧（BC）共同影响 CL-SAG 值。对于具有相同标记基弧（BC）的镜片，DD 组的最大差异为 264 微米，可重复使用组为 418 微米，散光组为 345 微米。DD 组中有 3 种镜片设计，可重复使用组中有 5 种镜片设计提供两种 BC，CL-SAG 的平均变化（±SD）为 276 ± 39 微米；一种散光镜片有两种 BC，相差 377 微米。
本研究发现 CL-SAG 值存在明显差异，即使是相同 BC 的镜片也是如此。虽然 ECP 应该意识到直径和 BC 共同影响 CL-SAG，但这也表明仅基于 BC 进行镜片替代可能会导致 CL-SAG 出现实质性差异，从而对镜片适配产生潜在影响。提供两种 BC 的镜片设计在 CL-SAG 方面显示出一定的窄带，从同一镜片制造商的球面镜片切换到散光镜片可能会导致 CL-SAG 发生显著变化。
