What Are Eye Mites?

LM of Demodex folliculorum
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If you have red, irritated eyes or scratchy, crusting eyelids, it could be caused by excessive growth of eye mites.

Demodex folliculorum and Demodex brevis are two types of mites that many of us have living on our skin. You can’t see them without a microscope, but they’re common to have on hair follicles, including our eyelashes. They also seem to be present in greater numbers on our skin as we get older.

Most of the time, these eye mites won’t cause noticeable problems. In large quantities, they can cause symptoms of infestation. These infestations can occur not only around the eyes but other areas of the skin as well, and are collectively recognized as a condition called demodicosis or demodicidosis.

Symptoms

Eye mites don’t cause any symptoms with mild cases. However, if the numbers of them start to grow, that infestation can lead to ocular conditions, including blepharitis, which is inflammation of the eyelids, and keratitis, or inflammation of the cornea.

Symptoms of blepharitis caused by eye mites include:

  • Itching
  • Burning feeling in eye
  • Blurry vision
  • Feeling of something in the eye
  • Crusting or redness around eyelid
  • Blurry vision
  • Misdirected or missing eyelashes

Inflammation from blepharitis may also impact the cornea. Symptoms of keratitis include:

  • Redness in the eye
  • Irritation
  • Eye pain
  • Sensitivity to light
  • Watery eyes
  • Blurred vision

Inflammation from eye mites has also been linked to other eye conditions, including conjunctivitis, chalazia, rosacea, and recurrent trichiasis.

Causes

Demodex mites are most prevalent on the face. They can be transferred from contact with another person who has them. Because your eyelids are difficult to clean routinely, the mites can easily multiply and spread.

Two Demodex species have been identified to cause blepharitis – Demodex folliculorum and Demodex brevis. Demodex folliculorum tends to be found in the lash follicle and uses skin cells and sebum (an oily substance) for nourishment. Demodex brevis feeds on gland cells, including those in your eyelids, called meibomian glands.

Demodex mites can cause eye conditions by consuming the lining of eyelash follicles to lay eggs, blocking the sebaceous ducts in the eyelid, or inducing an inflammatory response to the exoskeleton of the mites.

Some health conditions may be connected to an overgrowth of these eye mites. If you have rosacea, you may be more likely to develop blepharitis from Demodex. According to the National Rosacea Society, rosacea patients have been found to have 15 to 18 times greater amounts of Demodex than patients without rosacea. Researchers have theorized that Demodex could be one cause of rosacea’s inflammatory reactions.

Infestations may also be more likely if you have a weakened immune system or a condition like leukemia or HIV.

Demodex is thought to be acquired shortly after birth through breastfeeding. The numbers of Demodex increase with puberty as sebaceous glands produce extra oil, and the numbers continue to increase as you age. Infestation is present in 84% of the population at age 60, and 100% in patients older than 70.

Diagnosis

Your doctor will start with a physical exam to learn more about your symptoms. Demodex infestation may be suspected if you have symptoms that don't respond to traditional treatments for other eye conditions.

An ophthalmologist may use a slit-lamp exam to look at your eye. This magnifies your eye and uses a bright light to examine your eye structures. If the doctor detects cylindrical dandruff on the eyelash, it can be a sign of Demodex infestation.

Getting a sample of your eyelashes can provide microscopic evidence of Demodex eggs, larvae, and adult mites. Your doctor will place the lashes on a glass slide, put a dye called fluorescein on top, cover it with a thin piece of glass called a cover slip, and examine the sample to look for mites.

Treatment

While you can’t completely get rid of eye mites, the goal of treatment is to reduce the growth to improve symptoms. Tea tree oil has been found to be an effective therapy. One treatment is a daily lid scrub with a 50% solution of tea tree oil to apply to the lids and the base of the eyelash follicles.

While 50% tea tree oil can reduce symptoms and inflammation, it may cause irritation in some patients. Therefore, the active ingredient in tea tree oil, 4-Terpineol, is often used as an effective therapy that can be used at lower concentrations.

A 2013 study showed that 4-Terpineol, one of 15 components in tea tree oil, was effective in eliminating Demodex. The researchers found that 4-Terpineol was more effective when used alone than when combined with the other components of tea tree oil. The other tea tree oil components had antagonistic effects that reduced the effectiveness in killing the mites.

Cliradex, an eyelid scrub cleansing pad, contains 4-Terpineol and is available in a single-use, disposable cleansing pad. The pads can be used for six weeks, which is about two life cycles of Demodex.

Good hygiene can help prevent a recurrence of an eye mite infestation. That can include cleaning the skin around the eye area twice daily with a non-soap cleanser, being careful not to get it in your eyes. You should also try to avoid oil-based cleaners and greasy makeup.

A Word From Verywell

It can be unnerving to hear that your eye condition is caused by eye mites. Keep in mind that it’s normal for everyone to have these mites on their skin. However, there are ways to treat them to help limit their growth so that they don’t cause symptoms.

Make an appointment with your doctor if you’re experiencing any of the above eye symptoms. Eye mites can’t be seen without a microscope, so a doctor’s diagnosis is vital in getting the right treatment.

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