International Ophthalmology

, Volume 39, Issue 2, pp 405–417 | Cite as

Ocular Demodex folliculorum: prevalence and associated symptoms in an Irish population

  • Orla MurphyEmail author
  • Veronica O’Dwyer
  • Aoife Lloyd-McKernan
Original Paper



To investigate the prevalence of ocular Demodex folliculorum (DF) in an Irish population. To validate a modified Ocular Surface Disease Index questionnaire and employ it to evaluate the relationship between dry eye symptoms and the presence of DF.


One hundred and fifty-six subjects were enrolled in an epidemiological cross-sectional prevalence study. Each subject completed a novel questionnaire on ocular symptoms and was assessed for the presence of DF. Data was analysed to assess prevalence and to search for significant links between each symptom and DF.


An overall prevalence of 68% was found. Total mean number of DF found on microscopic examination was 3.83 mites per subject (range 0–25). The presence of symptoms was higher among individuals with DF (P = 0.04). Itch was found to be the symptom most significantly associated with the presence and number of DF (P = 0.025 and P = 0.035, respectively). The questionnaire showed good internal consistency (Cronbach’s alpha; α > 0.7) and good reliability (Intra-class Correlation Co-efficient; ICC > 0.7). The sensitivity and specificity of a positive symptom result using the questionnaire were 70.8% and 46.9%, respectively.


There is a strong association between the prevalence of DF and symptoms, in particular itchy eyes. However, not all patients with DF will be symptomatic. The newly developed questionnaire is a reliable instrument for measuring change in symptoms over a period of time and suitable for observing patient reported outcomes in interventional treatment studies.


Demodex folliculorum Prevalence Dry eye symptoms Blepharitis 



The authors’ thanks the management and staff of the National Optometry Centre for providing use of the premises and equipment, and helping with diary management and subject recruitment. The final year Optometry students assisted with data collection and subject recruitment.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest. This research was conducted as part of a self-funded postgraduate research degree.

Human and animal rights

All procedures performed in this study involving human participants were in accordance with the ethical standards of Dublin Institute of Technology and with the Tenets of Helsinki Declaration of Human Studies [29].

Informed consent

Informed consent was obtained from all individual participants included in the study.

Supplementary material

10792_2018_826_MOESM1_ESM.docx (15 kb)
Supplementary material 1 (DOCX 14 kb)


  1. 1.
    Spickett SG (1961) Studies on Demodex folliculorum Simon (1842). I. Life history. Parasitology 51:181–192CrossRefGoogle Scholar
  2. 2.
    Rufli T, Mumcuoglu Y (1981) The hair follicle mites Demodex folliculorum and Demodex brevis: biology and medical importance. Dermatologica 162:1–11CrossRefGoogle Scholar
  3. 3.
    English FP, Nutting WB (1981) Demodicosis of ophthalmic concern. Am J Ophthalmol 91:362–372CrossRefGoogle Scholar
  4. 4.
    Aylesworth R, Vance JC (1982) Demodex folliculorum and Demodex brevis in cutaneous biopsies. J Am Acad Dermatol 7:583–589. CrossRefGoogle Scholar
  5. 5.
    Lacey N, Kavanagh K, Tseng S (2009) Under the lash: Demodex mites in human diseases. Biochem (Lond) 31:2–6Google Scholar
  6. 6.
    Coston T (1967) Demodex folliculorum blepharitis. Trans Am Ophthalmol Soc 65:361–392Google Scholar
  7. 7.
    Liu J, Sheha H, Tseng SCG (2010) Pathogenic role of Demodex mites in blepharitis. Curr Opin Allergy Clin Immunol 10:505–510CrossRefGoogle Scholar
  8. 8.
    Schear MJ, Milman T, Steiner T et al (2015) The association of Demodex with chalazia: a histopathologic study of the eyelid. Ophthalmic Plast Reconstr Surg 32:275–278. CrossRefGoogle Scholar
  9. 9.
    English F (1971) Demodex folliculorum and oedema of the eyelash. Br J Ophthal 55:742–746CrossRefGoogle Scholar
  10. 10.
    Nicholls SG, Oakley CL, Tan A, Vote BJ (2017) Demodex species in human ocular disease: new clinicopathological aspects. Int Ophthalmol 37:303–312. CrossRefGoogle Scholar
  11. 11.
    Gao YY, Di Pascuale MA, Li W et al (2005) High prevalence of Demodex in eyelashes with cylindrical dandruff. Investig Ophthalmol Vis Sci 46:3089–3094CrossRefGoogle Scholar
  12. 12.
    Solomon A, Dursun D, Liu Z et al (2001) Pro- and anti-inflammatory forms of interleukin-1 in the tear fluid and conjunctiva of patients with dry-eye disease. Invest Ophthalmol Vis Sci 42:2283–2292Google Scholar
  13. 13.
    De Paiva C, Pflugfelder S (2008) Rationale for anti-inflammatory therapy in dry eye syndrome. Arq Bras Oftalmol 71:89–95CrossRefGoogle Scholar
  14. 14.
    Savini G, Prabhawasat P, Kojima T et al (2008) The challenge of dry eye diagnosis. Clin Ophthalmol 2:31–55CrossRefGoogle Scholar
  15. 15.
    Koo H, Kim TH, Kim KW et al (2012) Ocular surface discomfort and Demodex: effect of tea tree oil eyelid scrub in Demodex blepharitis. J Korean Med Sci 27:1574–1579CrossRefGoogle Scholar
  16. 16.
    Sullivan BD, Crews L, Messmer EM et al (2014) Correlations between commonly used objective signs and symptoms for the diagnosis of dry eye disease: clinical implications. Acta Ophthalmol 92:161–166CrossRefGoogle Scholar
  17. 17.
    Nichols K, Nichols J, Mitchell G (2004) The lack of association between signs and symptoms in patients with dry eye disease. Cornea 23:762–770CrossRefGoogle Scholar
  18. 18.
    Sullivan BDBD, Whitmer D, Nichols KKK et al (2010) An objective approach to dry eye disease severity. Investig Ophthalmol Vis Sci 51:6125–6130. CrossRefGoogle Scholar
  19. 19.
    Pult H, Purslow C, Murphy PJ (2011) The relationship between clinical signs and dry eye symptoms. Eye (Lond) 25:502–510. CrossRefGoogle Scholar
  20. 20.
    Achtsidis V, Kozanidou E, Bournas P et al (2014) Dry eye and clinical disease of tear film, diagnosis and management. Eur Ophthalmic Rev 8:17–22. CrossRefGoogle Scholar
  21. 21.
    Kim JT, Lee H, Chun YS, Kim JC (2011) Tear cytokines and chemokines in patients with Demodex blepharitis. Cytokine 53:94–99CrossRefGoogle Scholar
  22. 22.
    Kabataş N, Doğan AŞ, Kabataş EU et al (2017) The effect of Demodex infestation on blepharitis and the ocular symptoms. Eye Contact Lens 43:64–67CrossRefGoogle Scholar
  23. 23.
    Sędzikowska A, Osęka M, Grytner-Zięcina B (2016) Ocular symptoms reported by patients infested with Demodex mites. Acta Parasitol 61:808–814Google Scholar
  24. 24.
    Jarmuda S, O’Reilly N, Zaba R et al (2012) Potential role of Demodex mites and bacteria in the induction of rosacea. J Med Microbiol 61:1504–1510CrossRefGoogle Scholar
  25. 25.
    Sahai Malik P, Sahai A, Malik P (2005) Dry eye: prevalence and attributable risk factors in a hospital-based population. Indian J Ophthalmol 53:87–91. CrossRefGoogle Scholar
  26. 26.
    Pesudovs K, Burr JM, Harley C, Elliott DB (2007) The development, assessment, and selection of questionnaires. Optom Vis Sci 84:663–674CrossRefGoogle Scholar
  27. 27.
    Willke RJ (2008) Measuring the value of treatment to patients: patient-reported outcomes in drug development. Am Heal Drug Benefits 1:34–40Google Scholar
  28. 28.
    Schaumberg DA, Nichols JJ, Papas EB et al (2011) The international workshop on meibomian gland dysfunction: report of the subcommittee on the epidemiology of, and associated risk factors for, MGD. Investig Ophthalmol Vis Sci 52:1994–2005CrossRefGoogle Scholar
  29. 29.
    World Medical Association (2013) World Medical Association declaration of Helsinki ethical principles for medical research involving human subjects. JAMA 310:2191–2194CrossRefGoogle Scholar
  30. 30.
    Gao YY, Di Pascuale MA, Li W et al (2005) In vitro and in vivo killing of ocular Demodex by tea tree oil. Br J Ophthalmol 89:1468–1473. CrossRefGoogle Scholar
  31. 31.
    Mastrota KM (2013) Method to identify Demodex in the eyelash follicle without epilation. Optom Vis Sci 90:e172–e174. CrossRefGoogle Scholar
  32. 32.
    Wolffsohn JS, Arita R, Chalmers R et al (2017) TFOS DEWS II diagnostic methodology report. Ocul Surf 15:539–574. CrossRefGoogle Scholar
  33. 33.
    Tomlinson A, Bron AJ, Korb DR et al (2011) The international workshop on meibomian gland dysfunction: report of the diagnosis subcommittee. Investig Ophthalmol Vis Sci 52:2006–2049CrossRefGoogle Scholar
  34. 34.
    Schiffman RM, Christianson MD, Jacobsen G et al (2000) Reliability and validity of the ocular surface disease index. Arch Ophthalmol 118:615. CrossRefGoogle Scholar
  35. 35.
    Jalbert I, Rejab S (2015) Increased numbers of demodex in contact lens wearers. Optom Vis Sci 92:671–678Google Scholar
  36. 36.
    Lee SH, Chun YS, Kim JH et al (2010) The relationship between demodex and ocular discomfort. Investig Ophthalmol Vis Sci 51:2906–2911CrossRefGoogle Scholar
  37. 37.
    Walt J (2004) Ocular surface disease index (OSDI) administration and scoring manualGoogle Scholar
  38. 38.
    Mathews PM, Ramulu PY, Friedman DS et al (2013) Evaluation of ocular surface disease in patients with glaucoma. Ophthalmology 120:2241–2248. CrossRefGoogle Scholar
  39. 39.
    Miller KL, Walt JG, Mink DR et al (2010) Minimal clinically important difference for the ocular surface disease index. Arch Ophthalmol 128:94–101. (Chicago, Ill 1960) CrossRefGoogle Scholar
  40. 40.
    Smith JA, Albenz J, Begley C et al (2007) The epidemiology of dry eye disease: report of the epidemiology subcommittee of the international dry eye workshop (2007). Ocul Surf 5:93–107CrossRefGoogle Scholar
  41. 41.
    Bland JM, Altman DG (1997) Statistics notes: Cronbach’s alpha. BMJ. Google Scholar
  42. 42.
    Tavakol M, Dennick R (2011) Making sense of Cronbach’s alpha. Int J Med Educ 2:53–55CrossRefGoogle Scholar
  43. 43.
    Hallgren KA (2012) Computing inter-rater reliability for observational data: an overview and tutorial. Tutor Quant Methods Psychol 8:23–34CrossRefGoogle Scholar
  44. 44.
    Rosner B (2011) Fundamentals of biostatistics, 7th edn. Brooks/Cole, BostonGoogle Scholar
  45. 45.
    Costello AB, Osborne JW, Costello AB (2009) Best practices in exploratory factor analysis: four recommendations for getting the most from your analysis. Pan Pacific Manag Rev 12:131–146Google Scholar
  46. 46.
    Roth AM (1979) Demodex folliculorum in hair follicles of eyelid skin. Ann Ophthalmol 11:37–40Google Scholar
  47. 47.
    Forton F, Seys B (1993) Density of Demodex folliculorum in rosacea: a case-control study using standardized skin-surface biopsy. Br J Dermatol 128:650–659CrossRefGoogle Scholar
  48. 48.
    Randon M, Liang H, El Hamdaoui M et al (2015) In vivo confocal microscopy as a novel and reliable tool for the diagnosis of Demodex eyelid infestation. Br J Ophthalmol 99:336–341. CrossRefGoogle Scholar
  49. 49.
    Kemal M, Sümer Z, Toker MI et al (2005) The prevalence of Demodex folliculorum in blepharitis patients and the normal population. Ophthalmic Epidemiol 12:287–290CrossRefGoogle Scholar
  50. 50.
    Baima B, Sticherling M (2002) Demodicidosis revisited. Acta Derm Venereol 82:3–6CrossRefGoogle Scholar
  51. 51.
    Elston DM (2010) Demodex mites: facts and controversies. Clin Dermatol 28:502–504CrossRefGoogle Scholar
  52. 52.
    Lacey N, Ní Raghallaigh S, Powell FC (2011) Demodex mites–commensals, parasites or mutualistic organisms? Dermatology 222:128–130CrossRefGoogle Scholar
  53. 53.
    de Venecia AB, Lim Bon Siong R (2011) Demodex sp. infestation in anterior blepharitis, meibomian-gland dysfunction, and mixed blepharitis. Philipp J Ophthalmol 36:15–22Google Scholar
  54. 54.
    Bhandari V, Reddy JK (2014) Blepharitis: always remember demodex. Middle East Afr J Ophthalmol 21:317–320CrossRefGoogle Scholar
  55. 55.
    Forton F, Germaux M-A, Brasseur T et al (2005) Demodicosis and rosacea: epidemiology and significance in daily dermatologic practice. J Am Acad Dermatol 52:74–87CrossRefGoogle Scholar
  56. 56.
    Villani E, Magnani F, Viola F et al (2013) In vivo confocal evaluation of the ocular surface morpho-functional unit in dry eye. Optom Vis Sci 90:576–586CrossRefGoogle Scholar
  57. 57.
    Hoşal BM, Örnek N, Zilelioğlu G, Elhan AH (2005) Morphology of corneal nerves and corneal sensation in dry eye: a preliminary study. Eye 19:1276–1279CrossRefGoogle Scholar
  58. 58.
    Bourcier T, Acosta MC, Borderie V et al (2005) Decreased corneal sensitivity in patients with dry eye. Investig Ophthalmol Vis Sci 46:2341CrossRefGoogle Scholar
  59. 59.
    Lemp MA, Baudouin C, Baum J et al (2007) The definition and classification of dry eye disease: report of the definition and classification subcommittee of the international dry eye work shop (2007). Ocul Surf 55:75–92Google Scholar
  60. 60.
    Gao YY, Di Pascuale MA, Elizondo A, Tseng SC (2007) Clinical treatment of ocular demodicosis by lid scrub with tea tree oil. Cornea 26:136–143CrossRefGoogle Scholar
  61. 61.
    Kheirkhah A, Casas V, Li W et al (2007) Corneal manifestations of ocular Demodex infestation. Am J Ophthalmol 143:743–749CrossRefGoogle Scholar
  62. 62.
    Kojima T, Ishida R, Sato EA et al (2011) In vivo evaluation of ocular demodicosis using laser scanning confocal microscopy. Investig Ophthalmol Vis Sci 52:565–569CrossRefGoogle Scholar
  63. 63.
    Georgala S, Katoulis AC, Kylafis GD et al (2001) Increased density of Demodex folliculorum and evidence of delayed hypersensitivity reaction in subjects with papulopustular rosacea. J Eur Acad Dermatol Venereol 15:441–444CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V., part of Springer Nature 2018

Authors and Affiliations

  1. 1.The National Optometry CentreDublin Institute of TechnologyDublin 8Ireland

Personalised recommendations