Correlation of Tear Osmolarity With Ocular Symptoms and Ocular Surface Parameters in Dry Eye Disease: A Systematic Review and Meta-analysis

Abstract

Introduction: This systematic review and meta-analysis aimed to assess the correlations of tear osmolarity (TO) with ocular symptoms and ocular surface parameters in dry eye disease (DED). Materials and methods: A literature search was conducted in PubMed, ScienceDirect, and Google Scholar databases up to 31 December 2022. Observational studies were included if they reported Pearson’s-r or Spearman’s-ρ of TO with ocular symptoms and/or ocular surface parameter(s) in DED patients without or with other underlying diseases. The r or ρ values were extracted and assessed using a random effect of meta-analysis. Results: Twelve studies were included in the qualitative synthesis and meta-analysis. Overall weighted summary-r values amounted to 0.17, -0.35, and -0.29 for the correlations of TO with ocular symptoms, fluorescein break-up time (FBUT), and Schirmer I, respectively. In the DED subgroup, the weighted summary-r values amounted to 0.11, -0.32, and -0.12 for the correlations of TO with ocular symptoms, FBUT, and Schirmer I, respectively. Greater weighted summary-r values were found in the autoimmune disease-related DED (AID-DED) subgroup for the correlations of TO with ocular symptoms (weighted summary-r, 0.38), FBUT (weighted summary-r, -0.39), Schirmer I (weighted summary-r, -0.47), and corneal staining (weighted summary-r, 0.38). The I² values were 36% to 92.4%. Conclusion: This systematic review and meta-analysis reveal weak to fair correlations between TO and clinical parameters in DED, with stronger correlations in AID-DED. The findings underscore the need for standardised diagnostic methods and further research to explore the distinct mechanisms of AID-DED. Future studies should focus on longitudinal assessments, advanced diagnostic tools, and patient-centred outcomes to enhance understanding and management of DED, ultimately informing clinical guidelines and improving patient care.