Delphi Methodology Establishes Consensus About Demodex Blepharitis Signs, Symptoms, and Diagnosis

The Delphi methodology effectively establishes consensus on the diagnosis of Demodex blepharitis (DB), including signs and symptoms, but does not determine the best course of treatment or how to grade the severity of the disease, according to a study published in Eye.

“This study is the first to show that the Delphi methodology is effective in establishing consensus surrounding various aspects of DB,” wrote Brandon Ayres, Wills Eye Hospital in Philadelphia, PA, and coauthors.

Demodex Expert Panel on Treatment and Eyelid Health (DEPTH) included 12 practitioners: 9 ophthalmologists and 3 optometrists. The panelist's mean age was 53.7 years, and the average number of years in practice was 23.9. The panelists deemed DB to be chronic and recurrent. They see Demodex in all age groups, but it is mostly seen in people 60 or older. The panelists agreed that inflammation is a key result of DB, with Demodex mites and their byproducts triggering the inflammatory cascade. The consensus agreed that disease progression starts with increased collarettes leading to inflammation and lid erythema, followed by conjunctival injection, then lid margin thickening/notching/oedema, followed by lash loss/irregularity and potential corneal staining. The panelists agreed that Demodex is a common parasite found on the skin, and when overgrowth occurs, it can cause blepharitis.

The experts at DEPTH identified collarettes as the most common and definitive sign of DB. They also agreed that inflammation is the driving force behind the symptoms, and itching is the most common symptoms reported by patients. Mornings are usually the time when patients experience the most discomfort. The experts also agreed that the slit lamp examination is the most used method for diagnosing DB, and visualizing the mites is not necessary to make a diagnosis. Counting individual mites is also not required. Grading the severity of DB is important and helpful for clinical purposes. The experts agreed that collarettes with symptomatic blepharitis are indicative of DB and should be treated. However, there is no consensus on the most effective over-the-counter treatment for DB. The panel was evenly split between blepharoexfoliation and tea tree oil as their primary strategy.

“Overall, consensus was obtained across numerous aspects of the disease including signs, symptoms, diagnosis, and associated ocular conditions,” concluded the study authors. “Consensus was not reached on other factors, such as the best therapeutic option and the best way to grade DB,” they added.

Increasing awareness of blepharitis in the eyecare community can improve patient care and improve treatment outcomes.

Reference

Ayres BD, Donnenfeld E, Farid M, et al. Clinical diagnosis and management of Demodex blepharitis: the Demodex Expert Panel on Treatment and Eyelid Health (DEPTH). Eye (Lond). 2023;37(15):3249-3255. doi:10.1038/s41433-023-02500-4