Demodex may be small, but the little eyelash mites can’t easily hide from optometrists, a new report shows. The research found that Demodex infestation in blepharitis patients with cylindrical dandruff can be confirmed using only a slit lamp and common eye clinic equipment—no need to epilate and mount a specimen to a slide for ex vivo microscopy.

An Israeli research team evaluated 16 patients with blepharitis and cylindrical dandruff at a single medical center between November 2014 and February 2015. The team looked at two lashes from each lid of each eye (i.e., eight per patient) with cylindrical dandruff under light microscopy in the pathology laboratory. They also examined each lash under a slit lamp equipped with a 90D condensing lens. Mites were identified by their characteristic morphology and movement patterns.

All 16 patients were positive for Demodex infestation by either method. Researchers identified a mean total Demodex count per lash of 1.5±2.1 mites by using the slit lamp and 2±2.9 mites by light microscopy. Corresponding counts per patient were 11.7±9.4 and 16.1±12.4. The correlation between the slit lamp and microscopy results was statistically significant, both per lash and per patient. The accuracy of a slit-lamp examination was 91.4%. Slit lamps also had a specificity of 89% and a sensitivity 94%.

Man Peles I, Zahavi A, Chemodanova E, Vardizer Y. Novel in-office technique for visual confirmation of Demodexinfestation in blepharitic patients. Cornea. February 11, 2020. [Epub ahead of print].