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Updated: Jul 29, 2026
Effect of Artificial Tear Formulations on the Metabolic Activity of Human Corneal Epithelial Cells after Exposure to Desiccation
Published on: May 2, 2020
An improved fluorophotometric method for tear turnover assessment
E I Pearce1, B P Keenan, C McRory
1Department of Vision Sciences, Glasgow Caledonian University, Scotland, United Kingdom. Eipe@gcal.ac.uk
Purpose:
Scanning fluorophotometry is considered the "gold standard" to determine tear turnover rates (TTR). In this study, we attempted to improve the precision of basal TTR by fluorophotometry through a number of methodological changes.
Methods:
By means of a timer program that produces audio cues, a new methodology that ensures confluence and a constant thickness of the tear film and minimization of reflex lacrimation as a result of the inhibition of the blink reflex was developed. This was compared with the standard protocol, both in a paired study and by a review of unpaired data. The minimum length of time required to monitor TTR measurements was also investigated.
Results:
A significant improvement in correlation coefficient (r) of the log decay curve was observed as a result of changes in the protocol in both the paired (p = 0.016) and unpaired study (p < 0.0001). We determined that it was sufficient to monitor TTR for 10 min to obtain accurate results.
Conclusions:
We advocate that the changes be adopted as widely as possible for the precise and rapid measurement of basal tear turnover rates.
