Clinical characteristics of demodectic blepharitis

Abstract

Objective To investigate the clinical characteristics of demodectic blepharitis. Methods The study included patients with chronic blepharitis who presented to our clinic. Patients were divided into Demodex (+) group and Demodex (-) group according to the Demodex infestation. Symptoms, cylindrical dandruff in the eyelash follicles, tear film breakup time (TBUT), corneal and conjunctival staining, Schirmer I test and expressivity of meibum from five glands of two groups were compared. Results Seventy-six patients were collected, while 45 Demodex (+), 31 Demodex (-). The prevalence of Demodex infection was 59.21%. The incidence of itching and dry felling were significantly higher in the Demodex (+) group than in the Demodex (-) group (P =0.016, 0.036, respectively). There was no statistic difference between other clinical symptoms. The incidence of cylindrical eyelash dandruff was significantly higher in the Demodex (+) patients (62.6%) than in Demodex (-) patients (6.45%) (χ2 =23.9 and P<0.0001). TBUT in the Demodex (+) patients (6.13s) was shorter than in the Demodex (-) patients (8.62s), and 48.9% Demodex (+) patients’ TBUT was lower than 5s, versus 12.9% in Demodex (-) patients (χ2 and P value was 10.56, 0.001, respectively). Corneal and conjunctival staining score was higher in the Demodex (+) patients (1.42) than in Demodex (-) patients (0.87) (P =0.004). There was no significant difference in Schirmer I test and expressivity of meibum. Conclusions Demodex infestation must be investigated in patients with advanced stage blepharitis, itching, dry felling, cylindrical dandruff in the eyelash follicles, shorter than normal TBUT and ocular surface staining. Key words: Blepharitis; Demodex; Clinical characteristic