Tear Interferometric Patterns Reflect Clinical Tear Dynamics in Dry Eye Patients

Abstract

Purpose: We investigated whether the tear interferometric pattern was able to identify differences in tear film kinetics among clinical subtypes of dry eye.

Methods: A total of 138 eyes of 76 subjects (38 men and 38 women; mean age ± SD, 61.6 ± 16.2 years) with or without dry eye who visited Itoh Clinic from May to August 2015 were enrolled in a cross-sectional study. Clinical diagnosis of dry eye subtype was based on tear film parameters. The pattern of tear film kinetics determined by interferometry was classified as 0 (monotonous gray or multicolor interferometric fringe with a noninvasive breakup time [NIBUT] of ≥5 seconds), 1 (multicolor interferometric fringe with a NIBUT of <5 seconds), or 2 (grayish amorphous interferometric fringe with a NIBUT of <5 seconds), and reliability of classification was evaluated. Lipid layer thickness (LLT) for the tear film was also determined by interferometry.

Results: Interrater κ values for evaluation of interferometric patterns ranged from 0.57 to 0.94 for both physicians and nonphysicians with reference to a dry eye expert, the latter of whom showed an intrarater reliability of 0.90. The distribution of eyes among interferometric patterns 0, 1, and 2 coincided well with the clinical subgroups of normal tear condition, non-Sjögren syndrome aqueous-deficient dry eye, and meibomian gland dysfunction, respectively. A multicolor interferometric fringe was essentially observed only at an LLT of >70 nm.

Conclusions: Tear interferometry was able to reliably distinguish clinical subtypes of dry eye by reflecting the balance between the lipid and aqueous layers of the tear film.