High prevalence of demodex brevis infestation in chalazia.

PURPOSE To investigate the correlation between demodicosis and chalazia in patients with the latter. DESIGN Prospective, observational, comparative study. METHODS Forty-four adult and 47 pediatric patients with chalazia and 34 adult and 30 pediatric age- and sex-matched patients without chalazia treated at an institutional referral eye center were included. All 155 patients underwent lash sampling followed by microscopic identification and counting of Demodex mites. All 91 patients with chalazia underwent surgical removal, and among them, 74 were followed up for 18 ± 4.3 months after surgery. Statistical correlation between ocular demodicosis and chalazia and its postoperative recurrence was performed. RESULTS Demodicosis was significantly more prevalent in chalazia patients than in control patients as a group (69.2% vs 20.3%) and when separated into pediatric (70.2% vs 13.3%) and adult (68.2% vs 26.5%) subgroups (all P < .001). Demodicosis was associated strongly with chalazia (odds ratio, 4.39; 95% confidence interval, 2.17 to 8.87; P < .001). D. brevis was significantly more prevalent (odds ratio, 18.21; 95% confidence interval, 2.22 to 149.74; P = .01) than D. folliculorum (odds ratio, 2.82; 95% confidence interval, 1.16 to 6.84, P = .02) in patients with chalazia. Patients with demodicosis tended to demonstrate recurrence (33.3% vs 10.3%; P = .02), especially in those with D. brevis (35.1% vs 13.5%; P = .03). CONCLUSIONS There is a high prevalence of demodicosis, especially cases of caused by D. brevis, in adult and pediatric patients with chalazia, suggesting that ocular demodicosis is a risk factor for chalazia.