Efficacy of tear eosinophil cationic protein level measurement using filter paper for diagnosing allergic conjunctival disorders

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 muL 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 < .01 for the Sjogren group and P < .001 for the control). Furthermore, the tear ECP level of each allergic disease subgroup in the allergic group was significantly higher than that in the control group. . Conclusions: This method of determining tear ECP concentration is useful not only to diagnose allergic conjunctival disorders but also to evaluate their clinical stages. Jpn J Ophthalmol 2003;47:64-68 (C) 2003 Japanese Ophthalmological Society.