Evaluation of tear osmolarity measured by I-Pen osmolarity system in patients with dry eye

Jongyeop Park,Jisang Han,Dong Hui Lim,Gyule Han,Youngjoo Choi,Eunhae Shin,Tae-Young Chung

doi:10.1038/s41598-021-87336-2

Abstract

This retrospective comparative study was to evaluate tear osmolarity measured by I-Pen osmolarity system (I-MED Pharma Inc, Dollard-des-Ormeaux, Quebec, Canada) in healthy subjects without dry eye disease (DED) and patients with DED, and its association with other ocular surface parameters. This study comprised 65 eyes of 65 patients. The ocular surface parameters including tear osmolarity with I-Pen osmometer of the patients who visited the refractive surgery center of Samsung Medical Center between January 1, 2020 and May 31, 2020 were retrospectively collected. The subjects were divided as asymptomatic normal group and symptomatic dry eye group. The distribution of tear osmolarity and its association with other ocular surface parameters were evaluated. Total thirty-two patients (32 eyes) were included in the control group, and 33 patients (33 eyes) were included in the DED group. Tear osmolarity was significantly higher in the DED group. Tear osmolarity was negatively correlated with tear break-up time, and the Schirmer test, and was positively correlated with Ocular Surface Disease Index symptom score. The cut-off value of 318 mOsm/L showed a sensitivity of 90.9% and specificity of 90.6% for diagnosing DED. The I-Pen osmometer can be considered suitable for use in the clinical setting, with good performance in DED diagnosis.

Highlights

This retrospective comparative study was to evaluate tear osmolarity measured by I-Pen osmolarity system (I-MED Pharma Inc, Dollard-des-Ormeaux, Quebec, Canada) in healthy subjects without dry eye disease (DED) and patients with DED, and its association with other ocular surface parameters
The ocular surface evaluation was performed in the same order as follows: tear film osmolarity measurement with an I-Pen osmometer, tear film lipid layer thickness (LLT) measurement with a Lipiview interferometer (TearScience Inc, Morrisville, NC), non-invasive tear break-up time (NIBUT), tear meniscus height (TMH) measured with a Keratograph 5M (Oculus Optikgerate GmbH, Wetzlar, Germany), fluorescein tear break-up time (TBUT) measurement, corneal/conjunctival fluorescein staining scoring, and the anesthetized Schirmer test
Thirty-three patients (33 eyes) who had an Ocular Surface Disease Index (OSDI) score ≥ 13 with either fluorescein TBUT < 8 s or Schirmer test < 10 mm/5 min were included in the DED group

Summary

Introduction

This retrospective comparative study was to evaluate tear osmolarity measured by I-Pen osmolarity system (I-MED Pharma Inc, Dollard-des-Ormeaux, Quebec, Canada) in healthy subjects without dry eye disease (DED) and patients with DED, and its association with other ocular surface parameters. Tear film hyperosmolarity induces an inflammatory cascade at the ocular surface which initiates cytokine release, causing corneal epithelial damage and loss of goblet c ells[1,2,5,6] These lead to ocular discomfort and blurred vision in DED patients. Considering the difference in measurement site between the two osmometers (tear meniscus vs palpebral conjunctiva), and the different operative mechanisms of the two devices, it is necessary to evaluate the clinical performance of I-Pen osmometer in DED patients[11,13]. Normal healthy controls and DED patients, and to investigate the correlation between tear osmolarity with the I-Pen and other subjective and objective parameters in DED

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Conclusion