Aqueous-Deficient Dry Eye Increases Lipid Layer Thickness Measured by Dynamic Tear Interferometry

Purpose: To investigate the impact of aqueous deficiency on lipid layer thickness (LLT) measurement in dry eye disease before and after treatment of aqueous-deficient dry eye (ADDE) using dynamic tear interferometry. Methods: This prospective comparative study included 230 eyes from 230 patients with ADDE. The treatment group with punctal plug insertion was compared with the control group. The average LLT (LLT_ave) was measured with a LipiView II tear interferometer at baseline and after 1 month. Correlation analyses were performed with the indices of the dynamics of the tear film lipid layer (TFLL). Results: Baseline LLT_ave values were 116.1 6 26.7 and 112.3 6 27.6 nm in the treatment group (n = 121) and the control group (n = 109), respectively. At 1 month, LLT_ave significantly decreased in the treatment group (difference 241.8 [95% confidence interval (CI) 247.2 to 236.3], P = 0.003). The values of tear meniscus height (TMH) at baseline and 1-month follow-up were negatively correlated with LLT_ave (both P, 0.001). Spreading time of TFLL to equilibrium and the deviation of TFLL were positively correlated with LLT_ave (all P, 0.001) and negatively correlated with TMH (P, 0.001 and 0.009). In multivariate analysis (adjusted R² = 0.411, P, 0.001), LLT_ave was associated with TMH (B = 21.068; P, 0.001), adjusting for age, sex, and meibomian gland expressibility. Conclusions: In ADDE, the TFLL was measured to be thicker than the normal range of 60 to 99 nm and became thinner with treatment. LLT was affected by not only meibum secretion but also aqueous status due to changes in the dynamics of TFLL.