After comparing existing and novel diagnostic methods for a confirming ocular Demodex infestation, a recent study suggests practitioners can incorporate a new technique into their clinical examination routines—one that only uses a biomicroscope and forceps and is painless for patients. The researchers determined that cylindrical dandruff removal and lateral eyelash traction techniques offer an accessible, less invasive and more clinically viable method for the assessment of Demodex than eyelash epilation.

The study examined 15 patients with a prior Demodex blepharitis diagnosis or featuring typical cylindrical dandruff collarettes as well as seven healthy patients. The researchers assessed five techniques, which were applied consecutively on a minimum of two different eyelashes on each eyelid of every participant for each test, in situ:

  1. Using fine-point forceps and 25x to 40x biomicroscopy magnification, with eyelash rotation (ROT).
  2. Removing cylindrical dandruff and exposing the eyelash insertion point at the lid margin (CDR).
  3. Laterally tensioning the eyelash (LET) following CDR.
  4. Lash epilation, and mite presence evaluated using bright-field microscopy at 10x to 40x magnification.
  5. Eyelash follicles were imaged using in vivo confocal microscopy, and the images visually inspected for mite presence.

In the Demodex group, the highest numbers of mites per eyelash were identified by the combination of LET and CDR (3.8±1.4), compared with CDR (2.4±1.6) and ROT (1.1±1.2) alone. Epilation only identified an average of 1.0±0.8 mites per lash. The study found that confocal microscopy failed to offer unequivocal evidence of Demodex presence even in confirmed cases.

The study concludes that doctors can easily integrate CDR and LET into their practice, as the precise manipulation of forceps and lashes under high-magnification observation proved to be a rapidly acquired skill for an eye care practitioner with biomicroscopy experience. The new methods also allowed the practitioner to inspect many lashes efficiently and painlessly.

Muntz A, Purslow C, Wolffsohn JS, Craig JP. Improved Demodex diagnosis in the clinical setting using a novel in situ technique. Cont Lens Anterior Eye. December 3, 2019. [Epub ahead of print].