Comparative study between phenol red thread test and the Schirmer's test in the diagnosis of dry eyes syndrome.

Objective: To investigate the correlation between phenol red test and Schirmer tear test on tear quantification together with a questionnaire to detect symptoms of dry eye. Methods: A total of 49 patients were enrolled at this study. Each participant had its eyes examined by the two tests. The dry eye symptoms were evaluated by a total of 5 questions. The data were collected and analysed by Kappa statistical method to check the concordance between the tests. Results: A sum of 65.3% of the patients referred dry eye symptoms. When grouping them by age, 70.5% of the patients older than 60 years had symptoms, while in the group of 40-59 years, 59.3% reported symptoms. Schimer tear test was positive for dry eye in 51%(25) of the patients, against 65.3%(32) in the phenol red test. Kappa value between the tests were 0.548, which indicates a moderate agreement of the them. Conclusion: The symptomatic questionnaire showed a higher frequency of dry eye in the elderly. Kappa value displayed an moderate agreement, which is relevant, specially because neither of the tests are the gold standard for the diagnosis of dry eye, and for the variability of results that testing can bring. [ABSTRACT FROM AUTHOR]