How is a test for eye mite performed? - briefly
A clinician gently plucks a few eyelashes from the suspected eye, mounts them on a slide with saline, and inspects the preparation under a light microscope for Demodex mites. Identification is confirmed by visualizing the mites’ elongated bodies and four pairs of legs.
How is a test for eye mite performed? - in detail
Detecting ocular Demodex mites requires a systematic approach that combines clinical observation with laboratory analysis. The procedure begins with a thorough ocular examination. The examiner looks for signs such as cylindrical dandruff at the lash base, blepharitis, or irritation that suggest mite infestation.
If suspicion remains, sample collection follows. A sterile, fine‑toothed forceps or a single‑use cotton swab is used to grasp several eyelashes—typically five to ten—from the affected lid. The lashes are placed on a glass slide with a drop of non‑oil‑based mounting medium (e.g., saline or a mild potassium hydroxide solution). The slide is covered with a coverslip, ensuring the lashes lie flat.
Microscopic evaluation proceeds next. The slide is examined under a light microscope at 100×–400× magnification. Demodex mites appear as elongated, translucent organisms with a characteristic segmented body and four pairs of legs near the anterior end. The observer counts the number of mites per lash to assess infestation severity. In some laboratories, a wet mount is replaced by a KOH preparation to clear debris and enhance visibility.
When microscopy is unavailable, a confocal laser scanning device or in‑vivo laser scanning ophthalmoscopy can be employed. These imaging systems capture high‑resolution cross‑sections of the lid margin, allowing direct visualization of mites without extracting lashes.
After identification, results are recorded, and treatment recommendations are formulated based on mite density. A low count may warrant topical tea‑tree oil or ivermectin; a high count often requires a combination of lid hygiene, pharmacologic agents, and follow‑up examinations.
Key steps summarized:
- Clinical inspection for characteristic signs.
- Collection of 5–10 eyelashes with sterile forceps or swab.
- Placement on slide with saline or mild KOH solution.
- Microscopic examination at 100×–400× magnification.
- Counting and documentation of mites per lash.
- Optional imaging with confocal or laser scanning devices when microscopy is not feasible.
- Interpretation of density and initiation of appropriate therapy.
Adherence to sterile technique, accurate magnification, and precise counting are essential for reliable diagnosis.