The below video snippet is an example of dead Demodex mites on a lash. We see no leg movement on video microscopy and presume mite death. Demodex mites are parasites with a length ranging from 200-400 microns (1) . One study suggests that six or more Demodex mites per 16 lashes is clinically significant (2). 4 mites on a single lash is likely a pathologic level as is the case here. There are many treatment options including but not limited to oral or topical Ivermectin, IPL, and tree tea oil. Dr. Fishman recently published a paper showing for the first time Demodex death by IPL.
This patient used tea tree oil lid scrubs to kill the parasites which is a nice first-line option. While the active ingredient in tree tea oil is Terpinen-4-ol, the mechanism of death is not fully established. The mites still need removal from lashes with effective lid scrubbing. Often this requires in-office lid debridement.
(1) “Human Demodex Mite: The Versatile Mite of Dermatological Importance. Parvaiz Anwar Rather, Iffat Hassan.” Indian J Dermatol. 2014 Jan-Feb; 59(1): 60–66.
(2) “Demodex blepharitis: clinical perspectives.” Stephanie R Fromstein, Jennifer S Harthan, Jaymeni Patel, and Dominick L Opitz. Clin Optom (Auckl). 2018; 10: 57–63.