Provocation of the ocular surface to investigate the evaporative pathophysiology of dry eye disease.

Abstract Purpose To investigate whether standard clinical measures of tear film stability, meniscus height and symptomology reflect changes in evaporation rate induced by ocular surface provocations. Methods Forty participants (23.8 ± 4.5 years, 53 % female) with healthy to mild dry eyes underwent two tear film provocations in random sequence on separate occasions: playing a tablet computer high concentration game ( http://slither.io/ ) for 30 min; and receiving treatment with humidity goggles for 10 min followed by liposomal spray application. Measures at baseline and 30 min later were: Symptom Assessment iN Dry Eye (SANDE) questionnaire, tear film lipid layer thickness (LLT), non-invasive tear film break-up time (NIBUT), tear meniscus height (TMH), dynamic tear film lipid layer pattern (DLP) and tear film evaporation (TFE). Results There were no differences in the baseline measurements before each provocation (p > 0.05). Dry eye symptoms significantly worsened with concentration task (p 0.05). NIBUT declined with the concentration task (p = 0.015), but was not enhanced with treatment (p = 0.142). TMH increased after treatment (p = 0.001) and decreased with the concentration task (p = 0.006). While evaporation decreased with the concentration task (p Conclusions Sub-classifying dry eye based on an ‘evaporative’ component to inform treatment seems over-simplistic. However objective TMH, NIBUT and LLT seem to be the key clinical metrics that drive ocular comfort.