Abstract
Purpose :
To investigate the repeatability of tear film measurements obtained in subjects with evaporative and non-evaporative dry eye, and to examine associations between tear film evaporation rate and other tear parameters.
Methods :
Forty non-contact lens wearing subjects with symptoms of dry eye (Ocular Surface Disease Index [OSDI] score >18) were enrolled. Subjects attended up to four visits, at which absolute tear evaporation rate (TER; Vapometer, Delfin Technologies), fluorescein tear film break-up time (TBUT), lipid layer thickness (LLT, Lipiview II, TearScience) and un-anaesthetized Schirmer I tear volume (TV) were measured for each eye. The right eye only was used for analysis and coefficient of repeatability (COR, 1.96*within-subjects standard deviation) was estimated for tear parameters. Associations were determined using parametric or non-parametric correlation tests. Variables associated at p<0.2 were included in a linear regression analysis to establish the tear parameters which best predicted tear evaporation rate.
Results :
Fourteen males and 26 females with average age 40.1±19.8 years and OSDI score 40.2±14.5 were enrolled. The mean LLT was 57.7±16.8μm (COR 19.1μm), TBUT 6.3±1.7s (COR 3.1s), TV 16.8±10.8mm (COR 11.2mm), TER 69.9±31.4 grams per square metre per hour (gm-2h) (COR 42.4 gm-2h). Tear evaporation rate was associated with tear break up time (r= -0.32, p<0.05), LLT (r=-0.32, p=0.05), and with OSDI score (r=0.38, p<0.02) and in the linear regression model was best predicted by OSDI and LLT (ANOVA, F = 4.94, p=0.013).
Conclusions :
In a mixed population with dry eye, LLT and TBUT were the most repeatable tear parameters. In regression analysis, TER was best predicted by OSDI score and LLT.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.