Efficacy of Tear Eosinophil Cationic Protein Level Measurement Using Filter Paper for Diagnosing Allergic Conjunctival Disorders

Abstract Purpose: We investigated the efficacy of the tear sampling method using a filter paper to evaluate eosinophil cationic protein (ECP) levels in patients with allergic disorders. Methods: Subjects were an allergic group comprising patients with allergic conjunctivitis, vernal keratoconjunctivitis, or atopic keratoconjunctivitis, a Sjogren group comprising patients with secondary Sjogren syndrome, and a control group comprising healthy volunteers. Tears were sampled using the Schirmer Method I and the sample was eluted from the filter paper in 50 μL of elution solution containing phosphate buffer solution with 0.5 M NaCl + 0.1% Tween 20. Then the ECP concentration in the elution sample was determined by the enzyme-linked immunosorbent assay method. Results: Tear ECP level in the allergic group was significantly higher than the levels in the other two groups ( P P Conclusions: This method of determining tear ECP concentration is useful not only to diagnose allergic conjunctival disorders but also to evaluate their clinical stages.