Purpose: Demodex folliculorum and Demodex brevis are ectoparasites with an astounding prevalence of 100% in patients aged 70 years and older. Every person in this age group is estimated to carry a colony of 1000 to 2000 mites. With such a high prevalence, little attention has been paid to the mite among eye care practitioners. We demonstrate a clinical sequence in a set of case reports to identify the mite. The clinical sequence includes a clinical history of blepharitis, dry eyes, and/or ocular allergy; slit lamp examination of cylindrical dandruff; and confirmation using light microscope evaluation of epilated lashes.
Case reports: Patient 1 was a 68-year-old woman who demonstrates associations with dry eyes and diabetes. Patient 2 was a 44-year-old man with uncommonly seen D. brevis present. Patient 3 was a 40-year-old woman with dry eyes and allergy, showing mite tails protruding from base of lashes. Patient 4 was a 60-year-old woman who demonstrates the association with rosacea. Patient 5 was a 53-year-old woman intermittently taking topical steroid and antibiotic combination medications, with an actual mite photographed on the surface.
Conclusions: Following a clinical sequence helps identify Demodex, the underdiagnosed, undertreated, and underappreciated ocular surface disease.