Walther Hendrik, Phan Chau-Minh, Subbaraman Lakshman N, Jones Lyndon
Centre for Ocular Research & Education (CORE) - formerly Centre for Contact Lens Research (CCLR), School of Optometry and Vision Science, Waterloo, Ontario, Canada.
Transl Vis Sci Technol. 2018 Apr 5;7(2):18. doi: 10.1167/tvst.7.2.18. eCollection 2018 Apr.
We evaluate the differences in lipid uptake and penetration in daily disposable (DD) contact lenses (CL) using a conventional "in-vial" method compared to a novel in vitro eye model.
The penetration of fluorescently labelled 22-(N-(7-Nitrobenz-2-Oxa-1,3-Diazol-4-yl)Amino)-23,24-Bisnor-5-Cholen-3beta-Ol (NBD)-cholesterol on three silicone hydrogel (SH) and four conventional hydrogel (CH) DD CLs were investigated. CLs were incubated for 4 and 12 hours in a vial, containing 3.5 mL artificial tear solution (ATS), or were mounted on an in vitro eye-blink platform designed to simulate physiologic tear flow (2 mL/24 hours), tear volume and "simulated" blinking. Subsequently, CLs were analyzed using laser scanning confocal microscopy and ImageJ.
Penetration depth and fluorescence intensities of NBD-cholesterol varied between the incubation methods as well as lens materials. Using the traditional vial incubation method, NBD-cholesterol uptake occurred equally on both sides of all lens materials. However, using our eye-blink model, cholesterol penetration was observed primarily on the anterior surface of the CLs. In general, SH lenses showed higher intensities of NBD-cholesterol than CH materials.
The traditional "in-vial" incubation method exposes the CLs to an excessively high amount of ATS, which results in an overestimation for cholesterol deposition. Our model, which incorporates important ocular factors, such as intermittent air exposure, small tear volume, and physiological tear flow between blinks, provides a more natural environment for in vitro lens incubation.
In vitro measurements of CLs are a common approach to predict their interactions and performance on the eye. Traditional methods, however, are rudimentary. Therefore, this study presents a novel in vitro model to evaluate CLs, which consequently will enhance elucidations of the interactions between CLs and the eye.
我们使用传统的“瓶内”方法与一种新型体外眼模型，评估日抛型（DD）隐形眼镜（CL）中脂质摄取和渗透的差异。
研究了荧光标记的22-（N-（7-硝基苯并-2-恶唑-1,3-二氮杂环丁烷-4-基）氨基）-23,24-双降-5-胆甾烯-3β-醇（NBD）-胆固醇在三种硅水凝胶（SH）和四种传统水凝胶（CH）日抛型隐形眼镜上的渗透情况。隐形眼镜在含有3.5毫升人工泪液（ATS）的小瓶中孵育4小时和12小时，或者安装在设计用于模拟生理泪液流动（2毫升/24小时）、泪液体积和“模拟”眨眼的体外眨眼平台上。随后，使用激光扫描共聚焦显微镜和ImageJ对隐形眼镜进行分析。
NBD-胆固醇的渗透深度和荧光强度在孵育方法以及镜片材料之间有所不同。使用传统的小瓶孵育方法，所有镜片材料两侧的NBD-胆固醇摄取情况相同。然而，使用我们的眨眼模型，主要在隐形眼镜的前表面观察到胆固醇渗透。一般来说，硅水凝胶镜片显示出比传统水凝胶材料更高的NBD-胆固醇强度。
传统的“瓶内”孵育方法使隐形眼镜暴露于过量的人工泪液中，这导致对胆固醇沉积的高估。我们的模型纳入了重要的眼部因素，如间歇性空气暴露、小泪液体积和眨眼之间的生理泪液流动，为体外镜片孵育提供了更自然的环境。
隐形眼镜的体外测量是预测其在眼部相互作用和性能表现的常用方法。然而，传统方法较为简陋。因此，本研究提出了一种评估隐形眼镜的新型体外模型，这将增强对隐形眼镜与眼睛之间相互作用的阐释。
