Prevalence of Demodex Folliculorum in a Dry Eye Clinic Setting

Title Prevalence of Demodex Folliculorum in a Dry Eye Clinic Setting
Author, Co-Author Michelle Zakem, Etty Bitton
Topic Cornea/anterior segment/external/dry eye
Program Number
Ballroom A-B

PURPOSE:Anterior blepharitis has many causative factors, including Demodex folliculorum, a common ectoparasite on humans. True prevalence of Demodex infestation of the eyelashes (EL) is unknown, however its occurrence is known to increase with age. Demodex infestation can manifest itself as ocular discomfort, irritation and itching along the lid margin, all symptoms similar to ocular surface disease, which can lead to an unstable tear film and dry eye (DE). Hence this report investigated the prevalence of Demodex in patients referred to a University DE clinic. METHODS:A retrospective record review over the past 2 years (2014-2016) gathered patient demographics and identified those who presented with a positive ocular sign of cylindrical dandruff (+CD) along the base of the EL. The presence of +CD typically initiated a protocol whereby EL epilation and confirmation of Demodex by microscopic evaluation was performed. RESULTS: Patients (n=205) were referred by ODs (93.7%), Ophthalmologists (1.5%), MDs (3.4%) and others (1.5%). Patient demographics revealed 46M: 158F, ages 18-86, avg 53.3 ± 16.4SD. From the 205 referrals, 45 (22%) had +CD. Epilation and microscopic confirmation was not always documented. Two records had negative confirmation despite +CD. Thirty-four (75.6%) with +CD were confirmed for Demodex under the microscope. Demographics of the +Demodex group were 14M:20F, age 34-84, avg 59.3 ± 14.3SD. Demodex was observed increasingly over the age of 50. No Demodex was found in patients < 30 yrs, despite a referral of 9.3% (n=19) in that age group. CONCLUSION: Practitioners need to recognize CD and differentiate them from other debris so that appropriate management can be initiated. Although CD are pathognomonic for Demodex, the choice of eyelash and epilation method may not always reveal Demodex. A better understanding of the prevalence of Demodex in a DE clinic setting may bring further awareness as to its role in ocular discomfort and irritation.

Affiliation of Co-Authors École d'Optométrie, Université de Montréal