Purpose
Dry eye disease (DED) is associated with epithelial desiccation and therefore methods of quantifying tear production are critical to the clinician. The Schirmer’s test has remained the gold standard for evaluating tear production despite the fact that it has been shown to be crude, non-reproducible, and invasive to the tear film. Fluorophotometry measures tear production in a less invasive manner by accurately capturing the rate of fluorescien dye dilution from the tear film. Still, methods for performing fluorophotometry assessments vary between investigators, and the value of the metric for use clinically has been disputed. In this study, we compared an improved fluorophotometry technique to the Schirmer’s test to evaluate correlations of these measures with traditional signs and symptoms of dry eye disease (staining, ocular discomfort).
Methods
The following endpoints were assessed and correlations calculated on data from 11 subjects with DED: demographics, symptoms, quality of life (QoL), tear film break up time, Schirmer’s test scores (ST), improved tear fluorophotometry (F), fluorescein staining, corneal sensitivity, lid redness, and meibomian gland measurements. This fluorophotometry method varies from previously reported procedures through alterations in fluorescien drop volume, fluorescien drop concentration, and scan initiation in relation to the subject’s blink.
Results
Fluorophotometry scores correlated well with both signs and symptoms of dry eye in this study, while Schirmer’s test did not correlate with any signs or symptoms measured. Higher flow rates (tear turnover rates) were associated with lower ocular discomfort scores and lower fluorescein staining (R=-0.81, p=0.005 for ocular discomfort. R=-0.17, p=0.05 for central staining).
Conclusions
Results suggest that when using this modified methodology, fluorophotometry may be a better tool for measuring aqueous secretion than the Schirmer’s test, based on superior correlations with traditional signs and symptoms of dry eye disease. Improving the methodology for performing fluorophotometry assessments is important to ensuring the greatest possible accuracy of the measurement.
Keywords: 486 cornea: tears/tear film/dry eye