Li Songhao, Kim Young Hyun, Li Wing, Lin Meng C, Radke Clayton J
Chemical and Biomolecular Engineering Department, University of California, Berkeley, Berkeley, California.
Vision Science Graduate Group, University of California, Berkeley, Berkeley, California.
Optom Vis Sci. 2018 Apr;95(4):343-348. doi: 10.1097/OPX.0000000000001196.
A simple methodology is presented to quantify basal tear production with a modified Schirmer-tear test.
We introduce a simple clinical procedure to measure quantitative basal tear-production flowrates, QL, from a modified Schirmer-tear test (STT).
Eight healthy subjects aged at least 18 years underwent modified STTs on both eyes for two visits each. Schirmer strips were sheathed with transparent tape before insertion. Topical anesthetic minimized reflex tearing. Wetting lengths were measured every 30 s for 5 min; QL was calculated from the linear slope of wetting length versus time. Determination of QL requires mass-balance equations on the tear prism and Schirmer strip with strip imbibition kinetics obeying Darcy and Young-Laplace laws.
Basal tear production rates varied from essentially 0 to about 2 μl/min. With some exceptions, right and left eyes showed similar tear production rates.
By following the modified STT, QL is established with minimal additional effort over a standard Schirmer test. We predict and observe four different subtypes of imbibition kinetics depending on how short or long the time is for first appearance of the wetting front and on how fast or slow is tear production. For slow lacrimal production rates, the standard 5-min wetting length does not correlate with basal tear production.
提出一种简单方法，通过改良的泪液分泌试验来量化基础泪液分泌量。
我们引入一种简单的临床程序，用于通过改良的泪液分泌试验（STT）测量基础泪液分泌的定量流速QL。
8名年龄至少18岁的健康受试者，每只眼睛进行两次改良的STT检查。插入前，将泪液分泌试纸条用透明胶带包裹。局部麻醉可使反射性流泪减至最少。每30秒测量一次湿润长度，持续5分钟；QL根据湿润长度与时间的线性斜率计算得出。确定QL需要泪膜和泪液分泌试纸条的质量平衡方程，试纸条的吸收动力学遵循达西定律和杨-拉普拉斯定律。
基础泪液分泌率从基本为0到约2微升/分钟不等。除了一些例外情况，右眼和左眼的泪液分泌率相似。
通过遵循改良的STT，在标准泪液分泌试验基础上只需付出极少额外努力就能确定QL。根据湿润前沿首次出现的时间长短以及泪液分泌的快慢，我们预测并观察到四种不同的吸收动力学亚型。对于泪液分泌缓慢的情况，标准的5分钟湿润长度与基础泪液分泌量不相关。
