June 2022
Volume 63, Issue 7
Open Access
ARVO Annual Meeting Abstract  |   June 2022
Sensitivity and specificity for the detection of Demodex mites with slit-lamp in patients with blepharitis.
Author Affiliations & Notes
  • RUTH ESKENAZI
    cornea, Instituto de Oftalmologia Fundacion Conde de Valenciana IAP, Mexico City, Mexico City, Mexico
  • Nicolás Kahuam-López
    cornea, Instituto de Oftalmologia Fundacion Conde de Valenciana IAP, Mexico City, Mexico City, Mexico
  • Alejandro Navas
    cornea, Instituto de Oftalmologia Fundacion Conde de Valenciana IAP, Mexico City, Mexico City, Mexico
  • Carlos Adolfo Müller-Morales
    cornea, Instituto de Oftalmologia Fundacion Conde de Valenciana IAP, Mexico City, Mexico City, Mexico
  • Enrique O Graue-Hernandez
    cornea, Instituto de Oftalmologia Fundacion Conde de Valenciana IAP, Mexico City, Mexico City, Mexico
  • Footnotes
    Commercial Relationships   RUTH ESKENAZI None; Nicolás Kahuam-López None; Alejandro Navas None; Carlos Müller-Morales None; Enrique Graue-Hernandez None
  • Footnotes
    Support  None
Investigative Ophthalmology & Visual Science June 2022, Vol.63, 3963 – A0243. doi:
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      RUTH ESKENAZI, Nicolás Kahuam-López, Alejandro Navas, Carlos Adolfo Müller-Morales, Enrique O Graue-Hernandez; Sensitivity and specificity for the detection of Demodex mites with slit-lamp in patients with blepharitis.. Invest. Ophthalmol. Vis. Sci. 2022;63(7):3963 – A0243.

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

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Abstract

Purpose : Demodex mites are the most common microscopic ectoparasite found in human skin, affecting 84% of the population older than 60 years. It is a common cause of chronic blepharitis. The gold standard for diagnosing a Demodex infestation is the visualization of the mite with light-microscopy examination. We tested the hypothesis that the detection of Demodex infestation in blepharitic patients by silt-lamp is a comparable tool for the detection of the pathogen.

Methods : Demodex infestation was evaluated in 22 patients with blepharitis. Two lashes with cylindrical dandruff were epilated from each lid. They were mounted on a glass slide with a drop of saline, a coverslip was mounted on each slide then placed on a strip of white paper and examined on a slit lamp (magnification x25) with a 90D lens attached. Mites were identified by their morphology and movement patterns. The number of mites per lash were documented. Thereafter the slides were transferred to the pathology laboratory to examined them under a light microscope, and the results were documented. The same procedure was followed with a control group (22 patients). The results were evaluated both per lash and per patient. The findings were expressed in number of mites and in positive (at least 1 mite identified per lash) or negative (no mite identified).

Results : 22 patients were included in the cohort, 11 men and 11 women with an average age of 54.8 years. A total of 176 epilated lashes were examined. The mean total Demodex count per lash was 0.9 ±1.3 mites by slit-lamp examination and 1.22 ±1.73 mites by light-microscopy. Corresponding values per patient were 7.3 ±4.4 and 9.7 ±7.18. The correlation between Demodex counts by using the slit lamp and light microscopy was midly-positive and statistically significant per patient (8 lashes, r= 0.69, P<0.001). Analysis of positive/negative results yielded 43.2% with a positive result for slit lamp and 51.7% for light-microscopy. The sensitivity of the slit lamp examination for the presence of Demodex per patient was 96.6%, with a specificity of 90.9%; the positive predictive value was 91.6% and the negative predictive value was 95.2%.

Conclusions : Our results are consisting with our hypothesis that Demodex infestation in patients with blepharitis and cylindrical dandruff can be confirmed using a slit lamp, and this technique is non-inferior than the light-microscopy examination.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.

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