Standardization
The Standardization Task Forces within the Tear Research Network (TRN) bring together small groups of dedicated professionals to address key challenges in the field. By standardizing methodologies and practices, they enhance comparability and reproducibility, while reducing variability. In doing so, future research will be more streamlined, enabling meaningful conclusions and facilitating the translation of findings into clinical applications.
The need for standardization in tear fluid research.
Tear fluid is gaining recognition as a valuable biomarker source due to its quick, inexpensive, and non-invasive collection. However, variability in collection, processing, and analysis methods remains a challenge. To address this, the Tear Research Network Review Taskforce conducted an extensive review of 1,484 studies (published between 1974–2024)—a remarkable volume of research—to map trends in tear fluid biomarker studies.
The findings revealed an exponential increase in research on tear fluid biomarkers since 2015. Glass capillaries were the most commonly used collection method (45.2%) until 2019, after which Schirmer’s strips (25%) became the preferred technique. The majority of studies (65%) focused on tear fluid proteins, with 32.3% analyzing a single biomarker. More recently, there has been a noticeable shift toward examining a greater variety and number of analytes, reflecting the field’s rapid evolution.
These results underscore the urgent need for standardized protocols to minimize methodological differences, improve reproducibility, and enhance the clinical applications of tear fluid biomarkers.
Standardizing Tear Fluid Biobanking
Biobanking tear fluid offers a valuable opportunity to preserve samples for future research, yet there is no standardized approach for its organization, storage, and logistics. The Tear Research Network is exploring how to establish a properly structured tear fluid biobank, addressing key factors such as collection, storage conditions, sample processing, and accessibility to ensure high-quality, well-documented samples.
A well-organized biobank is crucial for future research, as analytical techniques are expected to become even more sensitive, allowing for the detection of biomarkers that may be undetectable today. Additionally, stored samples can help answer new research questions that may emerge over time, ensuring valuable resources are available for advancing tear fluid studies.
📌 More updates coming soon!
Establishing Tear Fluid Reference values
Tear fluid research currently lacks standardized reference values for commonly studied analytes, leading to repeated investigations in healthy populations. This results in a waste of time, costs, and resources, as researchers continuously measure the same analytes without a reliable baseline for comparison.
To address this, the Tear Research Network ‘reference values’ Taskforce is working to establish normative reference values by compiling existing literature and conducting a large-scale population study. In addition to establishing reference values, this effort will provide valuable insights into biomarker variability across individuals and conditions, helping to refine future research and diagnostic applications.
📌 Ongoing work
Establishing a Tear Fluid Biomarkers Database
The Tear Research Network ‘Databae’ Taskforce is working to create an open-access tear fluid biomarker database—a valuable resource for researchers worldwide. This database will provide insights into the presence, concentration, and prevalence of biomarkers in tear fluid, helping researchers design more informed and efficient studies.
By sharing and importing data, researchers can determine whether a biomarker has already been detected in tear fluid, in what concentration ranges, and across how many subjects. This will help avoid unnecessary sample collection for biomarkers that are undetectable or not present in meaningful amounts, ultimately saving time, resources, and effort.
Standardizing Tear Fluid Normalization
Tear fluid is a small-volume sample, making it highly sensitive to variations in collection. Even small differences in volume can introduce significant variability, affecting biomarker measurements. Additionally, the amount of tear fluid collected varies between individuals, making normalization essential to ensure accurate comparisons across samples.
Currently, several normalization methods are used in the literature, including adjusting for tear volume, total protein content, or specific protein-to-analyte ratios. While each approach has its own advantages and disadvantages, the lack of a standardized method leads to inconsistencies that hinder study comparisons and data interpretation.
To address this, the Tear Research Network ‘Normalization’ Taskforce is working to standardize tear fluid normalization. By establishing a unified approach, we aim to minimize volume-related errors, improve data comparability, and harmonize the literature, ultimately enhancing the reliability of tear fluid biomarker research.
📌 More updates coming soon!
Standardizing Tear Fluid extracellular vesicles
Extracellular vesicles (EVs) are an emerging area of interest in tear fluid research, offering exciting potential for biomarker discovery. Early findings suggest that tear fluid contains a high concentration of EVs, and their cargo—such as proteins, lipids, and RNA—may hold valuable insights into ocular and systemic diseases.
Despite their promise, no standardized protocols (SOPs) currently exist for the isolation, characterization, and analysis of EVs in tear fluid. To address this, the Tear Research Network ‘Extracellular vesicles’ Taskforce is working to establish best practices and harmonized methodologies to ensure consistency and comparability in tear-EV research.
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