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To examine the prevalence of Demodex Folliculorum (DF) on the eyelashes of symptomatic and asymptomatic patients. DF is an eight legged ectoparasite present in humans. It is most commonly found on the face; cheeks, nose, chin and eyelashes. Ocular symptoms of DF infestation on the eyelashes include itching, dryness, surface irritation, burning, foreign body sensation, photophobia and reduced vision1
Students and patients of the National Optometry Centre (NOC) (n=54), aged 19 – 78 years of age were assessed and sub-divided into 4 groups; Group (1) Control (n=12), Group (2) Signs, no symptoms (n = ?), Group (3) Symptoms, no signs (n = ?) and Group (4) Signs and symptoms (n = ?). Each subject completed a novel DF questionnaire on ocular symptoms and lifestyle. Habitual distance visual acuity was assessed and a slit lamp examination was conducted. 8 lashes – 2 from each eyelid were manipulated and epilated for microscopic examination. Presence of DF was noted and adult DF count was recorded using the modified Coston method2.
A two-way ANOVA was used to analyse the prevalence of DF (significance level p ≤ 0.05). The DF count significantly increased with age (p = 0.000), contact lens wear (p = 0.037), skin conditions (p = 0.025) and frequency of cleaning pillow case (p = 0.005). There was no significant link (p ≥ 0.05) between the DF count and gender, wearing make-up, allergies, the method of washing and drying pillow cases, method and frequency of lid hygiene routine. A two-way ANOVA was also used to analyse the age and lifestyle of patients who were more symptomatic (significance level p ≤ 0.05). Patient were more symptomatic with age (p = 0.000), contact lens wear (p = 0.032), less frequent lid hygiene routine (p = 0.001), method of lid hygiene (p = 0.000), less frequent pillow case cleaning (p = 0.032), air dried pillow case (p = 0.025), allergies (p = 0.000), skin conditions (p = 0.011), wearing mascara (p = 0.000).
The prevalence of DF and symptoms increase with age, contact lens wear, skin conditions and frequency of cleaning pillow cases. Whilst patients with less frequent lid hygiene routine, different method of lid hygiene routine, allergies and who air dried their pillow case were more symptomatic, the DF count did not increase. Therefore some patients can be symptomatic without an increase in DF count. Further data collection is ongoing.
Lloyd McKernan, A, O’Dwyer V. & Murphy, O. (2015) The Prevalence of Demodex Folliculorum on Eyelashes of Symptomatic and Asymptomatic Normal Patients. Poster presentation, European Academy of Optometry. Budapest, May 2015.