[PREVALENCE OF DEMODEX PARASITES IN PATIENTS WITH CHRONIC BLEPHARITIS AND HEALTHY CONTROLS IN ISRAEL].

INTRODUCTION: Previous studies demonstrated the potential pathogenic relationship between infestation of the eyelashes by the parasite Demodex and chronic blepharitis, whereas other studies did not demonstrate such relations and concluded that Demodex is a normal eyelid flora. AIMS: This study examines the prevalence of Demodex in patients with blepharitis compared to a healthy control group in Israel, in order to further explore and establish its pathogenic role in cases of chronic blepharitis. METHODS: A case-control study was conducted including 110 participants: 60 patients with chronic blepharitis attending a tertiary medical center and 50 subjects with no signs of blepharitis. Six to eight eyelashes were epilated from each participant and studied microscopically for the presence of Demodex by a blinded examiner. Fluorescein stain was added to the "clean" samples in order to reduce the false negative results. RESULTS: Demodex were identified on the eyelashes of 44 patients with blepharitis (73.3%) and 20 controls (40%) (p<0.001). After adjusting for age, blepharitis was still a significant risk factor for the presence of Demodex (OR=2.96, CI 95% 1.2-7.3). CONCLUSIONS: This study supports previous studies demonstrating pathogenic relationship between Demodex infestation of the eyelashes to chronic blepharitis. The authors recommend epilating 6-8 lashes of patients with blepharitis for microscopic identification of these parasites. Fluorescein stain may have a limited role in the recognition of Demodex in parasite free samples.