A Comparison Of Dry Eye Diagnostic Tests Within An Optometric Population

Abstract

Purpose: : The aims of this study were to provide clinicians and researchers with an overview of the variety of dry eye diagnostic tests now available and to assess concordance between tests to allow an informed choice on the most suitable and accurate tests for use in dry eye diagnosis.

Methods: : Dry eye symptoms were assessed in an optometric population of 101 participants using both the McMonnies dry eye questionnaire (McMQ) and a short frequency questionnaire (SFQ). The tear film and ocular surface was assessed by measuring tear osmolarity (TO) using the TearLab^TM system; biomicroscopic examination of meibomian glands, lids, conjunctiva and tear film; measuring fluorescein tear break up time (FTBUT); viewing ocular surface staining with lissamine green and fluorescein; the Schirmers test and assessment of conjunctival goblet cells using impression cytology. Cohen’s Kappa was used to compute the agreement between tests and univariate analysis was used to compare each test with the dry eye diagnosis.

Results: : Cohen’s Kappa was cross calculated for each test to determine a weak or strong concordance. There was over 70% agreement between SFQ and McMQ with a Kappa value of 0.460 indicating moderate agreement between the questionnaires. TO 308+ agreed to a higher degree with SFQ than McMQ with more than 50% agreement displayed. TO 308+ also strongly agreed with FTBUT also with more than 50% concordance. FTBUT and SFQ displayed significant agreement with p=0.008.Using these to define dry eye we found the agreement to be strong enough so that in a univariate analysis these 3 tests had p<0.001 when tested against the overall positive or negative dry eye diagnosis.

Conclusions: : Dry eye diagnostic tests are not all equal, with only a small number of test combinations showing strong concordance. Based on strong concordance data we would recommend the use of TO 308+, SFQ and FTBUT as reliable tests for dry eye. With standardisation of tests in place the comparison of data will be easier and more meaningful enabling other variable factors to be studied.

Keywords: cornea: tears/tear film/dry eye • cornea: epithelium • cornea: surface mucins