Sorbara Luigina, Simpson Trefford, Vaccari Stephanie, Jones Lyndon, Fonn Desmond
Centre for Contact Lens Research, School of Optometry, University of Waterloo, 200 University Avenue, Waterloo, Ont., Canada N2L 3G1.
Cont Lens Anterior Eye. 2004 Mar;27(1):15-20. doi: 10.1016/j.clae.2003.10.001.
Tear turnover rate (TTR) is defined as the percent decrease of fluorescein concentration in the tears per minute after the instillation of fluorescein. The purpose of this study was to examine differences in TTR in a sample with symptoms of dry eye and an asymptomatic control sample using the Fluorotron Master Fluorophotometer.
TTR was measured using the OcuMetrics Fluorotron Master. It measures the decay of the fluorescence of high molecular weight fluorescein FITC Dextran instilled into the tear film. Twenty participants (post-menopausal women) were enrolled in the study (10 asymptomatic (age 64.7 +/- 6.99) and 10 symptomatic (age 61.5 +/- 7.98)). Participants were grouped according to either a positive (symptomatic) or negative (asymptomatic) McMonnies Dry Eye Questionnaire, i.e., an indication of self-reported ocular dryness and the use of rewetting/lubricating drops (questions 4 and 5). TTR was measured in the afternoon only. Measurements were made on the right eye with a controlled blink rate (15 blinks/min), for up to 30 min, post-insertion of 2 microl of 2% FITC Dextran (MW 9500). The scan data were used to construct a graph of log fluorescein concentration (ng/ml) as a function of time and the TTR calculated (%/ min = (1- ln (slope)) x 100).
There was a significant difference in the TTR between symptomatic and asymptomatic subjects. Mean TTR (symptomatic) was 4.89 +/-2.74%/min (range, 2.04-11.81) and mean TTR (asymptomatic) was 11.85 +/- 3.31%/min (range, 5.76-16.45) (P < 0.0001).
Fluorophotometry may be used to demonstrate differences in the tear turnover rate in this post-menopausal group of women, with patients experiencing symptoms of dry eye having a lower TTR than the normals.
泪液更新率（TTR）定义为滴入荧光素后每分钟泪液中荧光素浓度降低的百分比。本研究的目的是使用荧光素眼底血管造影仪（Fluorotron Master Fluorophotometer）检测干眼症状样本与无症状对照样本中TTR的差异。
使用OcuMetrics Fluorotron Master测量TTR。它测量滴入泪膜中的高分子量荧光素异硫氰酸荧光素葡聚糖（FITC Dextran）荧光的衰减。20名参与者（绝经后女性）被纳入研究（10名无症状者（年龄64.7±6.99岁）和10名有症状者（年龄61.5±7.98岁））。参与者根据McMonnies干眼问卷的阳性（有症状）或阴性（无症状）进行分组，即自我报告的眼部干燥以及使用润眼/润滑滴眼液（问题4和5）。仅在下午测量TTR。在滴入2微升2% FITC Dextran（分子量9500）后，以受控的眨眼频率（15次/分钟）对右眼进行测量，最长测量30分钟。扫描数据用于构建荧光素浓度对数（纳克/毫升）随时间变化的图表，并计算TTR（%/分钟 = (1 - ln(斜率))×100）。
有症状和无症状受试者的TTR存在显著差异。有症状者的平均TTR为4.89±2.74%/分钟（范围2.04 - 11.81），无症状者的平均TTR为11.85±3.31%/分钟（范围5.76 - 16.45）（P < 0.0001）。
荧光光度法可用于证明该绝经后女性群体中泪液更新率的差异，干眼症状患者的TTR低于正常人。
