Abstract
Purpose :
The upper cut-off value of 100 nm in lipid layer thickness (LLT) with a LipiView II automated-interferometer (TearScience Inc, Morrisville, NC) makes its interpretation difficult in patients with dry eye disease (DED). The purpose of this study was to investigate the characteristics of patients with DED whose LLT is reported as 100 nm and to compare the DED parameters of them and those of patients with LLT below 100 nm.
Methods :
We performed a retrospective analysis of 101 patients (201 eyes, age range = 23–84, mean = 56.4 ± 11.8 years, 87 females and 14 males) with DED. Patients completed ocular surface disease index (OSDI) questionnaires. The LLT was measured using LipiView II interferometer. Slit lamp examination, Schirmer I test, tear film break-up time (TBUT), meiboscore and ocular surface staining (OSS) were also evaluated. Patients were classified into three groups according to average LLT; < 60 as thin-LLT (n = 49), ≥ 60, < 100 as normal-LLT (n = 77), and 100 as thick-LLT (n = 75). The Pearson correlations, Kruskal-Wallis test and Fisher-exact test were used for statistical analysis and P < 0.05 was considered statistically significant.
Results :
Mean age of patients with thick-LLT (57.8 ± 10.3 years) was significantly higher than thin-LLT (49.6 ± 12.7), but not different with normal-LLT (59.4 ± 10.9). The proportion of female was significantly higher in thick-LLT (93%) than normal-LLT (84%) and thin-LLT (77%). The LLT showed significant positive correlation with age, OSDI, and OSS (r = 0.229, P = 0.001; r = 0.328, P = 0.002; and r = 0.168, P = 0.018, respectively). The OSDI of thick-LLT (61.1 ± 18.2) was significantly higher than that of thin-LLT (44.1 ± 24.6, P = 0.006). The OSS was significantly worse in thick-LLT (1.7 ± 2.0) than in normal-LLT (0.9 ± 1.6, P = 0.020). The TBUT was significantly shorter in thick-LLT (1.9 ± 1.0 s) than in normal-LLT (2.4 ± 1.6 s, P = 0.028).
Conclusions :
Thin LLT has been associated with severe symptoms of patients with DED in previous studies. However, this study results suggest that thick LLT of 100 nm or over with LipiView II interferometer should not be regarded as normal value of LLT. Furthermore, above a certain range of LLT may be considered to be related to more severe symptoms or signs. Further studies are required to determine the normal range of LLT with LipiView II interferometer in DED patients.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.