Schirmer Strips in Tear Metabolomics of Dry Eye Disease: Pre-analytical and Analytical Considerations

We conclude that standardized guidelines for Schirmer strip use, covering material selection, sampling protocols, storage, and extraction, are urgently needed to advance tear metabolomics as a reliable clinical and research tool. Future research should focus on validating these recommendations in multi-center studies, exploring inter-individual variability, and developing innovative analytical workflows to optimize metabolite recovery and quantification. Such efforts will enhance the translational potential of tear metabolomics, paving the way for biomarker discovery and improved management of DED.