If your eyes frequently feel gritty, itchy, burning, or irritated, you may have tried all kinds of over-the-counter eye drops looking for relief.
But sometimes dry-eye symptoms aren’t telling the whole story.
There is a common eyelid condition that can contribute to dry eye and irritation, and it has an unusual cause: microscopic mites that live naturally around our eyelashes.
Yes, mites.
Before you start scrubbing your face or throwing away your pillowcases, there’s an important distinction to understand. Demodex mites are normal inhabitants of human skin. Most people have them and never experience a problem. The issue is when they become associated with inflammation and a condition called Demodex blepharitis.
I’m Dr. Scott Spector, an eye surgeon, and I see this condition frequently. Understanding what to look for can help explain why some people continue to struggle with irritated, dry eyes despite using artificial tears.
What Is Demodex Blepharitis?
Demodex are microscopic mites that live in hair follicles and sebaceous structures on the skin. Two species commonly associated with humans are Demodex folliculorum and Demodex brevis.
Demodex folliculorum is commonly found around eyelash follicles, while Demodex brevis is associated more closely with sebaceous and meibomian glands.
Having Demodex does not mean that you have poor hygiene, an infection, or a dirty home.
They are part of the normal microscopic environment of human skin.
The concern is whether they are contributing to inflammation of the eyelids and ocular surface.
When Demodex is associated with eyelid inflammation, it can contribute to Demodex blepharitis.
What Does Demodex Blepharitis Feel Like?
The symptoms can look a lot like other common eye conditions, which is one reason Demodex blepharitis can be overlooked.
Some common symptoms include:
- Itchy eyelids
- Burning or irritated eyes
- A gritty or foreign-body sensation
- Redness along the eyelid margins
- Crusting around the eyelashes
- Excessive tearing
- Dry-eye symptoms
- Fluctuating or blurry vision
- Eyelashes that become thinner or fall out
These symptoms aren’t unique to Demodex. Dry eye, meibomian gland dysfunction, ocular rosacea, and other forms of blepharitis can cause similar complaints. That’s why a proper eye examination is important.
One Sign Your Eye Doctor Looks For: Collarettes
One of the most important clues is something called a collarette.
A collarette is a cylindrical cuff or collar of debris that forms around the base of an eyelash.
If you’ve never heard of them, that’s probably because they’re difficult to see without magnification. During an eye examination, an eye doctor can examine the eyelid margins and look closely at the bases of the lashes.
The presence of these cylindrical collarettes is considered a characteristic clinical sign of Demodex blepharitis.
Other findings can include redness along the eyelid margin, changes in the eyelashes, and problems involving the meibomian glands.
How Can Demodex Affect Dry Eye?
This is where the eyelids and the surface of your eye are closely connected.
Along the edges of your eyelids are tiny glands called meibomian glands. These glands produce the oily component of your tear film.
That oil helps slow evaporation of the tears covering the surface of your eye.
When the eyelid margins and meibomian glands become inflamed or dysfunctional, the tear film can become unstable. That can contribute to dry-eye symptoms and irritation.
Demodex has been associated with both anterior and posterior blepharitis and with dysfunction of the meibomian glands.
This is one reason someone can use artificial tears over and over again without addressing the underlying eyelid problem.
The drops may temporarily make the eye feel more comfortable, but they don’t necessarily address the source of the eyelid inflammation.
Why Artificial Tears May Not Be Enough
Artificial tears can be very helpful for dry-eye symptoms.
But think about the eye like a car with a windshield.
If the problem is the surface of the eye, adding moisture can help.
If the problem is inflammation along the eyelid margin that’s affecting the tear film, however, simply adding more moisture may not address everything that’s happening.
That’s why evaluating the eyelids can be an important part of evaluating someone with persistent dry-eye symptoms.
How Is Demodex Blepharitis Treated?
Treatment depends on the individual patient and the severity and cause of the eyelid inflammation.
Lid Hygiene
Keeping the eyelid margins clean is an important part of managing many forms of blepharitis.
Depending on the patient, an eye doctor may recommend warm compresses, eyelid cleansing, or other lid-hygiene measures.
These approaches can help remove debris and keep the eyelid margins cleaner.
Your eye doctor can recommend the appropriate technique and products for your particular condition.
Prescription Treatment for Demodex
There is also now an FDA-approved prescription medication specifically for Demodex blepharitis: XDEMVY (lotilaner ophthalmic solution) 0.25%.
The FDA approved XDEMVY in 2023 for the treatment of Demodex blepharitis. The labeled treatment is one drop in each eye twice daily, approximately 12 hours apart, for six weeks.
In the clinical trials used for FDA approval, XDEMVY was evaluated in 833 patients with Demodex blepharitis. Patients receiving XDEMVY showed greater improvement in the reduction of collarettes than those receiving the vehicle treatment.
Whether prescription treatment is appropriate depends on the findings of an eye examination.
Why This Matters Before Eye Surgery
As an eye surgeon, I pay particularly close attention to the health of the eyelids and ocular surface before performing eye surgery.
There are two important reasons.
First, if you’re having surgery on the eye, you want the surrounding eyelid margin and ocular surface to be as healthy as possible.
Second, many eye procedures depend on precise measurements of the eye.
The tear film forms the optical surface at the front of the eye, so instability or inflammation of that surface can affect the quality and reliability of measurements.
For patients considering vision correction or lens-based surgery, optimizing the ocular surface before taking measurements can therefore be an important part of the process.
A healthy “windshield” matters before you start making decisions about what’s happening inside the eye.
How Can You Tell If You Might Have Demodex Blepharitis?
Take a close look at the base of your eyelashes in a mirror.
You’re not looking at the eye itself. Look at the edge of the eyelid where the eyelashes emerge.
Do you notice:
- Redness along the eyelid margin?
- Crusting around the lashes?
- Small cylindrical collars of debris around the base of the lashes?
- Persistent itching or irritation?
Don’t try to diagnose yourself based on what you see in the mirror. Many eyelid conditions can look similar, and some of the most important findings require magnification during an eye examination.
If you’ve been treating dry-eye symptoms but continue to experience persistent irritation, it’s worth having your eyelid margins evaluated.
The Bottom Line
Almost everyone has microscopic organisms living on their skin, and the presence of Demodex mites doesn’t automatically mean that something is wrong.
The important question is whether they are contributing to inflammation and Demodex blepharitis.
If you’re experiencing itchy, irritated, gritty eyes, crusting around your eyelashes, or persistent dry-eye symptoms that don’t seem to improve with conventional treatment, your eyelids may be part of the problem.
A careful examination of the eyelid margins can help determine what’s actually causing your symptoms and whether Demodex blepharitis is involved.
And fortunately, we now have specific treatment options when it is.
If you’re experiencing persistent dry-eye or eyelid symptoms, talk with your eye doctor about having the surface of your eyes and your eyelid margins evaluated.
