Tear Film Osmolarity Measurement in Japanese Dry Eye Patients Using a Handheld Osmolarity System.

Jun Shimazaki,Miki Iwasaki,Ikuko Toda,Seika Den,Miki Sakata

doi:10.3390/diagnostics10100789

Abstract

We studied the efficacy and safety of a handheld osmolarity measurement system (I-PEN) in Japanese patients with dry eye disease (DED) and non-DED subjects. In this prospective, multicenter study, tear osmolarity was examined using the I-PEN in a total of 122 eyes divided into DED (n = 71) and non-DED (n = 51) groups. Subjective symptoms were assessed using the Dry Eye-Related Quality-of-Life Score (DEQS) questionnaire. Ocular surface condition was evaluated in terms of fluorescein tear breakup time (FBUT) and tear breakup pattern (TBUP), and by fluorescein staining and Schirmer’s test. The I-PEN measurements were performed safely in the majority of cases. There was no statistically significant difference in mean tear film osmolarity between the DED and non-DED groups (294.76 ± 16.39 vs. 297.76 ± 16.72 mOsms/L, respectively, p = 0.32). No significant correlations were observed between osmolarity values and DEQS score, FBUT, or the Schirmer score. Osmolarity did not differ among TBUP subgroups. This prospective clinical study found no correlations between the tear film osmolarity values obtained with the I-PEN system and any subjective or objective parameters of DED. Further studies are required to determine the utility of the I-PEN system in other settings.

Highlights

Dry eye disease (DED) is one of the most common ophthalmic disorders in Japan, with a reported prevalence of 12.5% in men and 21.6% in women aged over 40 years [1,2]
Ocular surface condition was evaluated in terms of fluorescein tear breakup time (FBUT) and tear breakup pattern (TBUP), and by fluorescein staining and Schirmer’s test
This prospective clinical study found no correlations between the tear film osmolarity values obtained with the I-PEN® Osmolarity System (I-PEN) system and any subjective or objective parameters of DED

Summary

Introduction

Dry eye disease (DED) is one of the most common ophthalmic disorders in Japan, with a reported prevalence of 12.5% in men and 21.6% in women aged over 40 years [1,2]. The main diagnostic tests are tear secretion tests, such as Schirmer’s test, the vital staining test, and the tear stability test, which includes a measurement of fluorescein tear breakup time (FBUT). These tests do not have sufficient sensitivity and specificity, and more reliable biomarkers are needed. Tear osmolarity is one of the most promising biomarkers for diagnosis and monitoring of DED [3,4,5], and is considered to be involved in the pathogenesis of DED [6]. Hyperosmolarity of tears is considered to cause inflammation and damage of the ocular surface, irritating symptoms, and compensatory mechanism in DED. While a number of clinical studies based on osmolarity have been conducted, the diagnostic value of this measurement remains controversial [9,10]

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Discussion

Conclusion