Tear and Meibomian Gland Function in Blepharitis and Normals

Purpose: To determine the differential features of tear physiology and meibomian gland function in blepharitics for ascertaining the diagnostic potential of a number of clinical tests. Methods: Two groups Of subjects, 15 with clinically diagnosed blepharitis (11 women and 5 men mol/L; age 60.9 +/- 12.5; range 41-79) and 15 age- and sex-matched controls (11 women and 5 men mol/L; age 60.7 +/- 12.6; range 40-78), were included in the study. Tear physiology was assessed by evaporimetry and interferometry and the meibomian glands by expression and meibography. Results: Tear evaporation rate was significantly higher (P<0.001) ill blepharitics (46.3 +/- 22.9 g/m(2)/hr) than that in normals (18.0 +/- 10.7 g/m(2)/hr). The lipid pattern was found to be significantly less stable (P=0.001) in the blepharitic group compared with that in the normal group. By meibography, meibomian gland dropout was scored and found to be significantly greater (P=0.001) in blepharitics in both the upper eyelids (blepharitis 1.0 +/- 0.8 normal 0.1 +/- 0.3) and lower eyelids (blepharitis 2.1 +/- 8.3; normal 1.0 +/- 0.8). The dropout score was the same or greater for the lower lids than for the upper lids, in all cases. A significant difference (P=0.000) in meibomian gland expression was found between blepharitics and normals; meibum was significantly thicker and more opaque in blepharitics in both the upper (blepharitis 2.2 +/- 0.7; normal 1.0 +/- 0.2) and lower (blepharitis 2.6 +/- 0.7; normal 1.3 +/- 0.4) eyelids. Conclusions: There are significant differences in tear physiology and meibomian gland function in patients with blepharitis when compared with those without. All the tests employed would be useful as single tests in the diagnosis of blepharitis, with meibomian gland dropout of the lower eyelid offering the greatest effectiveness as a single measure.