Relativity between demodex folliculorum in blepharitis patients and dry eyes

Objective To investigate the prevalence of Demodex folliculorum(DF) in blepharitis patients.To find the relationship between the presence of DF and Dry eye.Methods This retrospecctive study compromised patients with blepharitis and with itching symptom except blepharitis.Eyelash samples were collected from each patient and examined under the light microscope.At the same time,the three experiments were carried on,including Schirmer test,tear film break up time(BUT),filuorescein staining(FL).Results 156 patients were collected in this study,including 91 patients with blepharitis and 65patients with itching symptom except blepharitis.DF was found in 82 patients(90%) with blepharitis and in 21 patients(32.3%) of non-blepharitis group.The difference between the two groups was statistically significant.Besides,in the patients with blepharitis coexisting DF infection,59 patients(72.2%) had dry eye.In non-blepharitis group coexsting DF infection,3 patients(14.3%) had dry eye.The difference with dry eye between the two groups was statistically significant.Conclusion Our findings show a high DF prevalence in blepharitis patients and we presumed DF infection maybe one of the possible reason for the persistent blepharitis,and the increasing rate of dry eye.