What is the test for an eye mite called? - briefly
The diagnosis is made by microscopic examination of epilated eyelashes or conjunctival scrapings, commonly referred to as a Demodex test.
What is the test for an eye mite called? - in detail
The diagnostic procedure for ocular Demodex infestation involves microscopic analysis of eyelashes. A clinician removes several lashes, typically from the lower lid, using fine forceps. The collected hairs are placed on a glass slide with a drop of saline or oil, covered with a coverslip, and examined under a light microscope at 100–400× magnification. Demodex mites appear as elongated, translucent organisms with a characteristic gnathosoma and segmented body; one to two mites per lash indicate infestation.
Alternative imaging techniques include in‑vivo confocal microscopy of the lid margin, which visualizes mites within follicles without sampling. This method provides real‑time, high‑resolution images but requires specialized equipment. Polymerase chain reaction (PCR) assays have been described for research settings, allowing species identification (D. folliculorum vs. D. brevis) from eyelash extracts.
Key steps for the standard microscopic test:
- Sample acquisition: 4–6 lashes from each eye, avoiding damage to the follicle.
- Slide preparation: Place lashes in a drop of sterile saline or mineral oil; add a coverslip.
- Staining (optional): Apply a few drops of 0.1 % potassium hydroxide or methylene blue to enhance contrast.
- Microscopic examination: Scan each lash for mites, noting count, location (root vs. shaft), and any accompanying bacterial debris.
- Interpretation: ≥1 mite per lash is considered positive; higher counts correlate with more severe blepharitis.
Clinical relevance: identification of mites guides treatment decisions, such as tea‑tree oil lid scrubs, ivermectin therapy, or topical metronidazole. Accurate microscopy remains the reference standard because it directly confirms the presence of the organism and allows quantification for monitoring therapeutic response.