J Zhao1, P Wollmer. 1. Dept. of Clinical Physiology, Malmö University Hospital, Sweden.
Abstract
PURPOSE: The stability of the precorneal tear film is commonly assessed by measurement of its break-up time. An alternative, but less studied, approach is measurement of the surface tension of tear fluid samples. The aim of this study was to develop a clinical method for measurement of the surface activity of tear fluid. METHODS & RESULTS: Tear fluid was sampled from 20 normal subjects. Surface activity of the samples was measured on a Wilhelmy balance. Maximum and minimum surface tension of tear fluid samples was 71.5+/-1.3 mN/m and 46.6+/-3.8 mN/m, respectively. Surface tension was also recorded on solutions of bovine Meibomian lipids and bovine submaxillary mucin. The area/surface tension tracings obtained from solutions of lipids and mucin were qualitatively similar to those obtained from tear fluid samples. The effects of Meibomian lipids and mucin were additive. CONCLUSION: The technique for measurement of the surface activity of tear fluid is minimally invasive and easy to use. The inter-individual differences in surface tension of tear fluid are small in normal subjects. The technique may be a useful supplement to measurement of break-up time in the evaluation of patients with dry eyes.
PURPOSE: The stability of the precorneal tear film is commonly assessed by measurement of its break-up time. An alternative, but less studied, approach is measurement of the surface tension of tear fluid samples. The aim of this study was to develop a clinical method for measurement of the surface activity of tear fluid. METHODS & RESULTS: Tear fluid was sampled from 20 normal subjects. Surface activity of the samples was measured on a Wilhelmy balance. Maximum and minimum surface tension of tear fluid samples was 71.5+/-1.3 mN/m and 46.6+/-3.8 mN/m, respectively. Surface tension was also recorded on solutions of bovine Meibomian lipids and bovine submaxillary mucin. The area/surface tension tracings obtained from solutions of lipids and mucin were qualitatively similar to those obtained from tear fluid samples. The effects of Meibomian lipids and mucin were additive. CONCLUSION: The technique for measurement of the surface activity of tear fluid is minimally invasive and easy to use. The inter-individual differences in surface tension of tear fluid are small in normal subjects. The technique may be a useful supplement to measurement of break-up time in the evaluation of patients with dry eyes.
Authors: Tamsin Doll; Joshua Moore; Ahmad H Shihab; Bernardo T Lopes; Ashkan Eliasy; Osama Maklad; Richard Wu; Lynn White; Steve Jones; Ahmed Elsheikh; Ahmed Abass Journal: PLoS One Date: 2020-11-25 Impact factor: 3.240