AIM: To investigate the Demodex infection in patients with recurrent chalazion and the possible related factors for Demodex infection.

METHODS: Patients diagnosed with "chalazion" in our ocular surface and cornea department from January 2019 to May 2019 were collected. 32 eyes in group A were patients with recurrent chalazion, 30 eyes in group B were patients with primary chalazion, and 35 eyes in group C were patients without eye disease. The positive infection rate of the roots of Demodex lashes was observed by biological optical microscopy. The infection of Demodex in the roots of the eyelashes and the opening of the meibomian glands was observed by vivo laser scanning confocal microscopy.

RESULTS: Observations by biological optical microscope: the detection rate of Demodex in the eyelashes of group A was 78%, which was significantly higher than that of group B(57%)and group C(34%). Observations by confocal microscopy: the detection rate of Demodex in the eyelashes of group A was 88%, which was significantly higher than that of group B(67%)and group C(37%). The detection rate of Demodex in the meibomian gland opening of group A was 69%, which was significantly higher than that of group B(23%)and group C(14%).

CONCLUSION: The rate of Demodex infection in patients with recurrent chalazion is obviously higher. Demodex infection may be one of the pathogenic reasons for recurrent chalazion.