Characteristics of dry eye patients with thick tear film lipid layers evaluated by a LipiView II interferometer

Hyun Sun Jeon,Joon Young Hyon,Yunjin Lee

doi:10.1007/s00417-020-05044-5

Abstract

PurposeTo investigate the characteristics of eyes with dry eye disease (DED) whose lipid layer thickness (LLT) measured 100 nm on a LipiView II interferometer and compare the DED parameters of them to those with LLT below 100 nm.MethodsA total of 201 eyes of 102 enrolled DED patients (mean age 56.4 ± 11.8 years) were classified into 3 groups according to their average LLT; < 60 nm as thin-LLT (n = 49), 60–99 nm as normal-LLT (n = 77), and 100 nm as thick-LLT (n = 75). LLT, meiboscore, Schirmer I test, tear film break-up time (TBUT), ocular surface staining (OSS), and ocular surface disease index (OSDI) were assessed.ResultsThe OSS and TBUT were significantly worse in the thick-LLT group than in the normal-LLT group (p = 0.020, and p = 0.028, respectively). The OSDI was significantly higher in the thick-LLT group than in the thin-LLT group (p = 0.006). However, the meiboscore was not different among the three groups (p = 0.33). Age, OSS, and OSDI showed a positive correlation with LLT (r = 0.16, p = 0.023; r = 0.213, p = 0.003; and r = 0.338, p = 0.001, respectively). In sensitivity analyses, eyes with corneal erosions had a significantly higher average LLT (p = 0.015), higher OSDI (p = 0.009), shorter TBUT (p < 0.001), and shorter Schirmer I value (p = 0.024) than those with clear corneas.ConclusionThe average LLT of eyes with corneal erosions was thicker than those without erosions, suggesting that the LLT of 100 nm in the eyes with corneal erosions should not be regarded as a stable physiologic condition. Cautious interpretation of LLT along with other dry eye parameters is required.

Highlights

The classic model of the tear film originated in the 1950s and separated the tear film into three layers: the glycocalyx layer, the intermediate aqueous layer, and the outermost tear film lipid layer (TFLL) [1]
The average lipid layer thickness (LLT) of eyes with corneal erosions was thicker than those without erosions, suggesting that the LLT of 100 nm in the eyes with corneal erosions should not be regarded as a stable physiologic condition
Key messages: Previous studies have reported that a thin tear film lipid layer (TFLL) is related to tear film instability and severe dry eye symptoms

Summary

Introduction

The classic model of the tear film originated in the 1950s and separated the tear film into three layers: the glycocalyx (mucin) layer, the intermediate aqueous layer, and the outermost tear film lipid layer (TFLL) [1]. The outermost TFLL is formed almost exclusively from lipids and attached and/or intercalated proteins. It is a two-layered structure consisting of an inner polar layer and an outer nonpolar lipid layer that is in contact with the air [1, 2]. Blackie et al found that 3 of 4 patients reporting severe dry eye symptoms had relatively thin lipid layers (less than 60 nm), while Finis et al suggested that a lipid layer thickness (LLT) of less than or equal to 75 nm could be used to detect obstructive meibomian gland dysfunction (MGD) with a sensitivity of 65.8% and a specificity of 63.4% [6, 7]. There is a paucity of data that evaluates the characteristics of dry eye patients with thicker LLT values

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