The diagnosis and characteristics of moderate dry eye in non-contact lens wearers

Purpose. To identify and characterize moderate dry eye in non-contact lens wearers with a new scoring system-based dry eye questionnaire and to determine which objective tests better differentiate patients with moderate dry eye from healthy patients. Methods. Fifty-two healthy subjects (21 women and 31 men with a mean age of 27.8 ± 9.2 years) and 37 subjects with moderate dry eye (33 women and 4 men with a mean age of 36.4 ± 12.9 years) completed a 42-item dry eye questionnaire. Seventeen healthy subjects (11 women and 6 men with a mean age of 30.5 ± 9.7 years) and 28 subjects with moderate dry eye (24 women and 4 men with a mean age of 38.50 ± 3.8 years) underwent additional objective assessment of ocular surface health, tear osmolality, tear stability, and tear volume. Results. Subjects with moderate dry eye scored significantly higher (49.8 ± 20.3, P<0.0001) on the dry eye questionnaire than did normal subjects (11.7 ± 10.3). Ocular irritation symptoms worsened with progression of time of day in both groups of subjects. Internal reliability (0.95 Cronbach α) was excellent, and concurrent validity (Spearman ρ 0.507) was acceptable when compared to the McMonnies and Ho dry eye questionnaire. Significant differences in tear osmolality (P<0.00001), invasive tear breakup time (P<0.034), and corneal vital dye staining (P<0.0001) were detected between the two groups of subjects. A stepwise linear regression on objective clinical tests, however, did not account for 77% of the total variance in the questionnaire scores. Conclusions. A unique scoring system-based dry eye questionnaire was validated to separate non-contact lens wearers with moderate dry eye from healthy subjects. Objective tests of tear osmolality and stability and ocular surface integrity were better than other clinical measures at identifying differences between the two subject groups. The results strongly support the evidence that the diagnosis and treatment of moderate dry eye requires a detailed assessment of self-perceived symptoms and that objective clinical testing alone may be insufficient.