Demodex
What Is Demodex?
Demodex are microscopic mites that live naturally on human skin, especially around hair follicles and oil glands. There are two main types that affect the eyes — Demodex folliculorum, which lives in eyelash follicles, and Demodex brevis, which burrows into oil glands near the lashes. In small numbers, they usually don’t cause any harm. However, when they multiply excessively, they can cause inflammation and irritation of the eyelids and eyes — a condition known as Demodex blepharitis.
What Are the Symptoms?
Demodex can cause a variety of eye and eyelid symptoms, including:
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Itchy or burning eyelids
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A gritty or sandy feeling in the eyes
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Red, swollen, or crusty eyelids (especially in the morning)
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Flaking or “dandruff-like” debris around the lashes
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Dry or watery eyes
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Lashes that fall out, stick together, or grow in the wrong direction
These symptoms can be mild at first but may become more uncomfortable over time if not treated.
What Causes Demodex?
Demodex mites are extremely common and are typically spread through skin-to-skin contact or by sharing personal items such as towels, bedding, or pillowcases. Everyone has a small number of these mites, but they tend to multiply when there is more oil on the skin or a weakened immune system. As we age, the likelihood of having Demodex increases — studies show that about 50% of adults over age 20 and up to 80–100% of people over age 60 have them.
Who Gets Demodex?
Anyone can have Demodex, but it’s most common in:
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Older adults
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People with oily skin or rosacea
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Individuals with chronic eyelid inflammation or dry eye
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Contact lens wearers who don’t clean their lids regularly
Having Demodex doesn’t mean you’re unclean — these mites are part of the natural skin ecosystem. Problems only arise when their population grows too large.
How Is Demodex Diagnosed?
Your optometrist can diagnose Demodex during an eye exam by carefully examining your eyelids and lashes with a slit lamp microscope. They may also gently remove one or two eyelashes to look for mites or their eggs under magnification. Often, the presence of collarettes — tiny waxy or sleeve-like buildups around the base of lashes — is a telltale sign of Demodex infestation.
How Is It Treated?
Treatment focuses on reducing the number of mites and keeping the eyelids clean. Your optometrist may recommend:
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A prescription eyedrop, called Xdemvy, used twice daily for 6 weeks.
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In-office treatments, which deep-clean the eyelid margins
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IPL (Intense Pulsed Light) Therapy, applied to the eyelids
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Eyelid scrubs or wipes containing tea tree oil or other anti-mite ingredients
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Warm compresses and gentle massage to remove debris and oils
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Artificial tears or dry eye treatments to improve comfort
Most patients begin to feel relief within a few weeks of starting treatment. For best results, it’s important to continue daily eyelid hygiene even after symptoms improve, since Demodex can return if not kept under control.
What Is the Prognosis?
With consistent treatment and good eyelid hygiene, the outlook for Demodex is excellent. Once the mite population is reduced and inflammation is controlled, symptoms usually resolve and the eyelids feel more comfortable. However, maintenance care is often needed to prevent recurrence.
When Should You See Your Optometrist?
You should schedule an appointment if you experience:
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Persistent itching, redness, or crusting of your eyelids
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A gritty or burning sensation in your eyes
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Lashes that frequently fall out or stick together
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Symptoms of dry eye that don’t improve with artificial tears
Early diagnosis and treatment can help prevent long-term irritation and protect your eyelid health.
Healthy Lids, Healthy Eyes
Regular eyelid hygiene and routine eye exams are key to preventing Demodex-related problems. If you suspect you may have Demodex or experience ongoing eyelid discomfort, talk with your optometrist — there are safe, effective treatments that can restore comfort and keep your eyes healthy.