What is an eye mite in humans? - briefly
Eye mites, primarily Demodex folliculorum and Demodex brevis, are microscopic ectoparasites that reside in the hair follicles and sebaceous glands of human eyelids. In normal numbers they are harmless, but over‑population can lead to irritation, blepharitis, or contribute to rosacea.
What is an eye mite in humans? - in detail
Eye mites, medically known as Demodex spp., are microscopic ectoparasites that inhabit the hair follicles and sebaceous glands of the human ocular region. Two species are most commonly associated with the eye: Demodex folliculorum and Demodex brevis. Both are elongated, cigar‑shaped organisms measuring 0.2–0.4 mm in length, invisible to the naked eye and detectable only with microscopy.
The life cycle consists of egg, larva, protonymph, nymph and adult stages. Females lay eggs at the base of hair shafts; development to maturity occurs over approximately two weeks. Adults survive for five to six weeks before dying, after which the cycle repeats. Transmission occurs through direct contact with contaminated skin or eyelashes, and prevalence increases with age, reaching near‑ubiquity in individuals over 60 years.
Clinical manifestations include:
- Redness and irritation of the eyelid margin
- Presence of cylindrical dandruff at the base of eyelashes (collarettes)
- Burning or itching sensations
- Fluctuating visual acuity due to tear film instability
- In severe cases, blepharitis, meibomian gland dysfunction and secondary bacterial infection
Diagnosis relies on microscopic examination of epilated eyelashes or lid scrapes. A count of more than three mites per five lashes typically indicates pathological infestation.
Management strategies focus on reducing mite load and alleviating inflammation:
- Lid hygiene: warm compresses followed by gentle cleaning with diluted tea tree oil or commercial lid scrub solutions.
- Topical acaricidal agents: ointments containing 1 % ivermectin or 0.1 % metronidazole applied to the lid margin.
- Systemic therapy: oral ivermectin in refractory cases, administered under medical supervision.
- Environmental measures: regular laundering of pillowcases, towels and avoidance of shared cosmetics.
Prevention emphasizes consistent eyelid hygiene, especially in individuals with chronic blepharitis or ocular rosacea, and periodic screening for mite presence in at‑risk populations.