Abstract
Purpose: :
The purpose of this study was to evaluate the relationship between signs and symptoms of dry eye disease in a general patient population.
Methods: :
In a retrospective analysis of data obtained in two cross-sectional observational studies (ClinicalTrials.gov number, NCT00848198), seven tests for clinical signs and symptoms were evaluated for 598 eyes in the general patient population (n=164 Normal, n=434 dry eye), across 11 sites from the E.U. and U.S. Tear osmolarity, tear film breakup time (TBUT), Schirmer test, corneal and conjunctival staining, and meibomian gland dysfunction grading (Foulks/Bron scoring) were tested, and the Ocular Surface Disease Index (OSDI) questionnaire was performed (value used for each eye). A full matrix of squared Pearson correlation coefficients of determination (r2) and an independent components analysis (ICA) mixing matrix were derived from the dataset.
Results: :
No correlations above r2=0.20 were found between any of the signs or symptoms, except for corneal and conjunctival staining, which reported an r2=0.34 (and measure similar events). The average r2 for osmolarity (0.04), TBUT (0.12), Schirmer test (0.08), corneal (0.15) and conjunctival staining (0.16), meibomian grading (0.10) and OSDI (0.11) were consistently low. Similarly, each component of the ICA mixing matrix exhibited minimal residual information.
Conclusions: :
No correlation was found between any of the common signs and symptoms of dry eye disease. Given that independent measurements are necessarily uncorrelated, it was concluded that each type of measurement reveals unique information about the status of the ocular surface. The fact that some of the traditional signs only reflect one subtype of DED or may not reflect the central pathogenetic mechanisms of the disease may help explain the lack of correlation between the various clinical techniques. Overall, the clinical presentation of dry eye disease is multifactorial, with each test contributing different information, thus correlation between different tests should not be expected.
Keywords: cornea: tears/tear film/dry eye • cornea: clinical science