Tear film biomarker testing from Schirmer strips as a clinical tool in autoimmune ocular surface disease

National Eye Institute

Investigators

Linked publications & trials

Abstract

We established a method on how to extract tears from Schirmer strips reliably and measure biomarkers with an ELISA assay. We discovered significant differences in moisture migration levels in Schirmer strips for the same tear volume attributed to inconsistencies in strip standardization and variations in paper properties. To address this issue, we developed a calibration formula and a conversion table to standardize results in microliters, regardless of the strip brand. This calibration enabled accurate calculation of extracted volume and protein concentrations from the extracted tear volume. Impact: This is significant not only for the accuracy of tear volume and millimeter migration values in tear extraction, but also in clinical care, disease criteria (e. g. OGVH, SD), and in clinical research where the Schirmer’s test is used as an outcome measure. After the method was established we extracted tear samples of healthy volunteers and measured levels of biomarkers associated with dry eye disease. Collections were performed on different days at the same times to evaluate for consistency. Additionally, we started measurements in patients with Sjogrens syndrome and plan to correlate the results with the clinical parameters of ocular surface inflammation. We believe that our innovative approach will allow insight into the pathophysiology of diseases that affect millions of patients (dry eye disease, oGVHD, Sjogrens Disease). If successful, our clinical method will advance the field of ocular surface inflammatory disease significantly and allow for more accurate study results and clinical care.