In vivo tear-film thickness determination and implications for tear-film stability
In vivo tear-film thickness determination and implications for tear-film stability
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DOI：
10.1076/ceyr.17.11.1058.5233
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发表时间：
1998-11-01
影响因子：
2
通讯作者：
Radke, CJ
中科院分区：
文献类型：
--
作者：
Creech, JL;Do, LT;Radke, CJ
目的.以前的泪膜厚度在体内的测量是有限的，不能很容易地应用于临床设置。本文介绍了一种新的间接测量泪膜厚度的方法，该方法只需要裂隙灯、摄像机和计算机。最近的流体力学理论将泪膜厚度h与泪液弯月面半径R、泪液表面张力σ、泪液粘度μ和上眼睑速度U联系起来。该理论得出的结果是h/R = 2.12（μ U/sigma）（2/3）。除h/R外的所有参数均视为已知的物理常数，并测量每个受试者的R，允许上述方程建立h。泪膜破裂也进行了评估，并与泪膜厚度相关。进行了一项临床研究，其中测定了45名受试者的水性泪膜厚度，包括24名非透镜受试者、15名水凝胶接触透镜配戴者和6名RGP透镜配戴者。通过滴眼液形式的荧光素染料并拍摄泪液半月板的轮廓来测量R。泪膜破裂通过裂隙灯的目镜口进行录像，并根据严重程度量表进行评估。水泪膜的测量是在与文献值相同的范围内，大多数测量值落在6和12 μ m之间。非晶状体、水凝胶和RGP受试者的平均泪膜厚度分别为10.4、6.5和5.8 μ m。泪膜破裂在泪膜较薄的受试者中最为严重，尤其是戴隐形眼镜者。撕裂厚度是一个重要的参数，个体之间的差异。这些变化与泪膜稳定性的差异相关。
Purpose. Previous measurements of tear-film thickness in vivo are limited and cannot be easily applied in a clinical setting. A novel technique to measure tear-film thickness indirectly is introduced here, requiring only a slit lamp, video camera, and computer. A recent fluid mechanical theory relates tear-film thickness h, to the tear meniscus radius R, tear surface tension sigma, tear viscosity mu, and upper lid velocity U. This theory yields the result that h/R = 2.12 (mu U/sigma)(2/3). All parameters except h/R are taken as known physical constants, and R was measured for each subject, allowing the above equation to establish h. Tear-film breakup was also evaluated and correlated with tear-film thickness.Methods. A clinical study was performed in which aqueous tear-film thickness was determined for 45 subjects, including 24 non-lens subjects, 15 hydrogel contact lens wearers, and 6 RGP lens wearers. R was measured by instilling fluorescein dye in the form of an eyedrop and videotaping the tear meniscus in profile. Tear-film breakup was videotaped through the ocular port of the slit lamp and evaluated based on a severity scale.Results. Aqueous tear-film measurements are in the same range as literature values, with most measured values falling between 6 and 12 mu m. Average tear-film thicknesses for non-lens, hydrogel, and RGP subjects are 10.4, 6.5, and 5.8 mu m, respectively. Tear-film breakup is most severe in subjects with thin tear films, especially in contact-lens wearers.Conclusions. Tear-him thickness is an important parameter that varies among individuals. These variations correlate with differences in tear-film stability.