June 2021
Volume 62, Issue 8
Open Access
ARVO Annual Meeting Abstract  |   June 2021
Prevalence of Demodex Colonization in Patients Presenting to an Outpatient Clinic
Author Affiliations & Notes
  • Alison Teo
    Ophthalmology, University of Michigan, Ann Arbor, Michigan, United States
  • Eric Rosenberg
    SightMD, Babylon, New York, United States
  • Adam Jacobson
    Ophthalmology, University of Michigan, Ann Arbor, Michigan, United States
  • Footnotes
    Commercial Relationships   Alison Teo, None; Eric Rosenberg, None; Adam Jacobson, None
  • Footnotes
    Support  Manhattan Eye Foundation, New York, NY, Unrestricted Research Grant
Investigative Ophthalmology & Visual Science June 2021, Vol.62, 1236. doi:
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      Alison Teo, Eric Rosenberg, Adam Jacobson; Prevalence of Demodex Colonization in Patients Presenting to an Outpatient Clinic. Invest. Ophthalmol. Vis. Sci. 2021;62(8):1236.

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      © ARVO (1962-2015); The Authors (2016-present)

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Purpose : Demodex follicularis and demodex brevis are microscopic ectoparasites known to cause blepharitis. However, there is limited knowledge regarding the prevalence of Demodex in asymptomatic healthy individuals versus those with symptomatic pathologic demodicosis.

Methods : This was a prospective, cross-sectional study examining the prevalence of and risk factors for Demodex colonization in all patients 18 years and older presenting to two large, tertiary care outpatient ophthalmology clinics. Demographic information, prescription and non-prescription ocular medications, and concurrent pathologies such as pterygia, blepharitis, and dry eye disease was also recorded. Each patient underwent epilation of four eyelashes, one from each eyelid. Each eyelash was examined underneath a compound light microscope looking for the presence of Demodex species or eggs. For patients positive for Demodex, appropriate treatment was initiated with routine follow up.

Results : 199 patients were examined, with an average patient age of 59.4 ± 2.1 years. Demodicosis was newly diagnosed in 55.3%, with 61.8% and 68.3% noted to have blepharitis and dry eye, respectively. Only 1% of those with confirmed Demodex were previously diagnosed and treated. The presence of Demodex was found to be independent of sex, number of clinic visits, self-administered lid hygiene regimen, or prescription ophthalmic drops. There were statistically significant associations noted between the presence of Demodex and age (p=0.005), history of pterygium surgery (p=0.01), dermatochalasis (p=0.001), blepharitis (p<0.001), and dry eye disease (p=0.001). Patients using alpha-agonist eyedrops showed a decreased risk of Demodex colonization (p<0.05).

Conclusions : In the clinical setting, Demodex is grossly under-diagnosed and responsible for both acute and refractory blepharitis in a large subset of patients. In agreement with prior studies, we found a positive correlation between presence of Demodex and age as well as presence of blepharitis and dermatochalasis. However, in contrast to previous studies, there was little association with pterygia and a decreased incidence of demodicosis in patients using alpha-agonist drops. Over 50% of the entire study population and over 60% of patients with blepharitis were found to have Demodex. Ongoing investigations into appropriate diagnosis and treatment regimens have great potential to improve quality of life for our patients.

This is a 2021 ARVO Annual Meeting abstract.


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