Abstract
Abstract: :
Purpose:White light interferometric observations, while frequently used in dry eye investigations, have not been reported relative to specific dry eye sub–types. We undertook a systematic investigation of dry eye subjects to determine whether sub–type differentiation is possible using interferometry. Methods: A clinic–based sample of dry eye subjects was recruited and assessed using a standardized testing regimen as part of an ongoing dry eye characterization study. Forty–one subjects were screened for dry eye using a modified symptom questionnaire (Schein et al., 1997, Ophthalmol,104:1395,), noninvasive testing (lipid interferometry) and a battery of invasive (e.g., TBUT, fluorescein and rose bengal staining, Schirmer I) tests. Measures for dry eye diagnosis used three of the four NEI/Industry working group recommendations: symptoms, tear instability and surface damage (Lemp M., 1995, CLAO J, 21:221,). Specific diagnostic criteria were symptom score > 6/24, TBUT < 10 secs, and surface damage with fluorescein staining > 1.0 overall corneal grade (0–4 scale). . Subjects were classified as having atrophic meibomian gland disease (AMGD), blepharitis (Bleph), mixed aqueous tear deficiency with meibomian gland dysfunction (MIX), and a final grouping of non–specific dry eyes (DRY). White light inteferometric observations were quantified by comparison with previously published scale (Yokoi, N et al, 1996, Am J Ophthalmol, 122:818). Results: 35 of the 41 subjects screened were classified as dry based on the above diagnostic criteria. Analysis of interferometric observations of the atrophic MGD sub–group (n=16, mean = 2.95 ±0.80), blepharitis sub–group (n=6, mean =3.27±0.50), mixed sub–group (n=10, mean =3.00±0.90) and non–specific subgroup (n=3, mean=2.77±1.08) showed no significant differences (p=0.800, ANOVA).Conclusions: White light interferometry is a valuable tool in differentiating dry eye subjects from normal subjects. However, these observations may have limited efficacy in discriminating between dry eye sub–types.
Keywords: cornea: clinical science • cornea: tears/tear film/dry eye