Value of lipid layer thickness and blinking pattern in approaching patients with dry eye symptoms

Objective: To analyze the relationship between dry eye symptoms and modern dry eye tests, including the Schirmer I test, lipid layer thickness (LLT), and blinking pattern by LipiView interferometer. Design: Cross-sectional study. Participants: 115 dry eye outpatients. Methods: Dry eye symptoms were quantified by questionnaire scores, such as Ocular Surface Disease Index (OSDI) and Standard Patient Evaluation of Eye Dryness (SPEED). LLT, complete, and incomplete blinking rate were recorded by the LipiView interferometer. Results: 115 patients (229 eyes, mean age = 60.5 +/- 13.6 years) were enrolled in this study. The mean value of the SPEED and OSDI scores was 9.5 and 10.2, respectively. A total of 44.3% of all subjects had severe dry eye syndrome (SPEED, OSDI >= 10). LLT (mean = 71.2 nm) was inversely correlated with both the SPEED and OSDI (p = 0.003 and 0.004, respectively). The incomplete-to-complete ratio of blinking rate (i/c ratio) was correlated with both the SPEED and OSDI (p = 0.0048 and 0.0234, respectively). Patients with LLT less than 69 nm were more likely to have severe dry eye syndrome. There was no significant relationship between the Schirmer I test and the SPEED or OSDI. However, LLT was inversely related to the Schirmer I test (linear regression, p = 0.0002, r= -0.1857). Conclusions: LLT and the i/c ratio were significantly correlated to dry eye symptoms. Eyes with thinner LLT are more likely to have better aqueous tear production. The role of the reciprocal influence between each tear component in the maintenance of tear function warrants further investigation.