Assessment of Transepidermal Water Loss From the Ocular Area in Dry Eye Disease

PURPOSE. To investigate transepidermal water loss (TEWL) from the ocular area in dry eye disease (DED) and evaluate the correlation between ocular TEWL and other DED parameters. METHODS. Transepidermal water loss from the ocular area in 56 eyes with DED and 38 healthy eyes was measured using a Tewameter TM300 that was equipped with custom made goggles (measuring temperature 24 degrees C-26 degrees C and relative humidity 35%-45%). The DED group was classified into two subgroups, aqueous deficient dry eye (ADDE) and evaporative dry eye (EDE). Correlations between ocular TEWL and other DED parameters, such as tear osmolarity, tear break-up time (TBUT), corneal staining, conjunctival staining, Schirmer I test, Ocular Surface Disease Index (OSDI), and Visual Analogue Scale score were evaluated. RESULTS. Ocular TEWL was significantly higher in the DED group (63.0 +/- 12.2 g/h/m(2)) than in the control group (54.7 +/- 14.2 g/h/m(2); P < 0.003). Although there was no significant difference, TEWL was higher in the ADDE subgroup (64.0 +/- 10.7 g/h/m(2)) compared with the EDE subgroup (61.1 +/- 14.9 g/h/m(2)). Tear break-up time, corneal staining score, and OSDI were significantly correlated with ocular TEWL (P < 0.05) in all participants. Ocular TEWL loss was negatively correlated with Schirmer I test value in the DED group. CONCLUSIONS. Ocular TEWL was significantly higher in DED patients compared with controls, reflecting higher tear evaporation in DED patients. Patients who have shorter Schirmer I test values tend to have higher TEWL values. Not only EDE but also ADDE patients may have increased tear evaporation.