Look Again! Demodex Blepharitis in Closer Focus

By David Lockington

Twenty years ago, when I was beginning my ophthalmology training, Demodex blepharitis (DB) was traditionally viewed as boring and a bit irritating to both the patient and the eye doctor. Now, in my role as a complex cataract and corneal surgeon, blepharitis is not really my priority – until it comes to eye surgery, when it suddenly is! Patients with DB have a higher number and variety of bacteria on their lids, and there is a realworld incentive to look at the lids ‘properly’ before surgery (1)… and then you become aware of what you have been overlooking.

Recently, I was part of a group of key opinion leaders who looked specifically for signs of DB as part of routine clinical examinations. DB was identified on average in about 54% of patients (804 patients screened across 15 unique clinics in six countries) (2) – a much higher proportion than I had expected.

Who gets DB?

Patients with DB often report redness, irritation, and itchiness, particularly affecting their upper lids (3). When these symptoms occur in a patient without atopy (asthma/ eczema/hay fever), think blepharitis as the potential source of their ocular surface discomfort and itch. One study of 1032 patients (mean age: 60.2 ± 17.8 years) showed a higher overall prevalence of dry eye disease in patients with Demodex blepharitis (69.1%) (4). In a Chinese review of 103 eyes of 52 patients with meibomian gland dysfunction (MGB) and 62 eyes of 31 non-MGD patients, the rate of Demodex infestation in MGDs was 89.32% (5). Further, a Polish study of eyelashes from 73 patients selected for cataract surgery found Demodex mites in 48% of patients (6). Those figures mean many of our cornea/cataract/ anterior segment patients will have DB. Furthermore, a study of 62 contact lens users revealed Demodex infections in 93% of patients with intolerance to contact lenses. (7).

What does DB look like?

Demodex mites are a natural part of the skin microbiome. A couple of collarettes (cylindrical dandruff at the base of the lashes) are a clinical sign of the mites, which at low levels may or may not cause symptoms. However, when there is an overgrowth of Demodex mites it causes inflammation and disruption of the eyelid margin. This can happen for many reasons, some of which include aging and weakened immune response or other skin conditions. As 100% of patients with collarettes have Demodex mites, collarettes = DB.

How to diagnose DB

We are so used to looking at the more visible lower lids as part of our routine clinical examinations. In busy clinics, it’s tempting to fall into the trap of not specifically looking at the upper lids in great detail. All you need to do is ask your patients to look down, ensuring you have 10x or 16x magnification, and any collarettes become immediately visible. It literally takes a few seconds to do. No need for invasive tests, the cause of the patient’s symptoms may be hiding in plain sight.

Why is DB underdiagnosed?

Clinicians may be unaware of the significance of DB, and the relevance of collarettes, so they have not been specifically documenting their presence or absence. In the world of busy sub-specialty eye clinics, some may view all forms of blepharitis and meibomian gland dysfunction as one big entity with unsatisfactory, complex treatment regimes.

What difference does treating Demodex Blepharitis make for cataract patients?

Traditionally, blepharitis was seen as an inconvenience, but no one was going to lose vision from it. However, post op endophthalmitis has been linked to lid margin disease, so all eye surgeons and staff should be primed to examine the upper and lower lids properly. People are now becoming more aware that the ocular surface has a significant impact on vision, and the lids contribute to the tear film and ocular health. Inaccurate biometry, poor healing due to inflammation and fluctuations in vision can all cause patient dissatisfaction, which could have been avoided through proactive identification and management.

How is DB currently managed?

Commonly used approaches include lid hygiene, tea tree oil-based lid wipes, topical and oral antibiotics, and warm compresses, supplemented with ocular lubricants. These relieve symptoms but don’t eliminate mites – so recurrence is common. Lid hygiene measures require a degree of dexterity and ongoing diligence, which may discourage continued treatment, leading to persistence of symptoms due to untreated mite overgrowth.

Final thoughts

I would say to my ophthalmic colleagues, “The more you look, the more you find.” Just ask the patient to look down, and any collarettes become immediately visible. It literally takes a few seconds to do as part of your routine exam. Your patients will thank you for looking at the lids properly. You never see what you don’t look for!

Dr. David Lockington is Consultant Ophthalmologist with subspecialty interest in cataract and cornea at the Tennent Institute of Ophthalmology, NHS Greater Glasgow & Clyde, Scotland, UK, and Visiting Professor at VUB, Brussels, Belgium.

David Lockington is a paid consultant of Tarsus Pharmaceuticals Inc.

Technology and Management Advances

By Mario Nubile

One of the main challenges in shifting clinical practice toward routine testing for DB lies in increasing physicians’ awareness of the disease, its clinical features, and the implications of early diagnosis and management. As with many ocular conditions, it is often true that “the eyes see what the mind knows.”

Key opinion leaders (KOLs) are instrumental in raising awareness and improving clinical practices related to DB and overall eyelid health. Through peerreviewed publications, scientific congress presentations, keynote lectures, and educational webinars, they have brought attention to the high prevalence of DB and the need for routine lid margin evaluation.

By sharing real-world cases, promoting the value of a simple slit-lamp eyelash and lash-base examination, and emphasizing hallmark signs such as collarettes, KOLs are encouraging clinicians to integrate Demodex screening into the routine anterior segment assessment. This process takes only seconds and should be as routine as examining the inferior lid margin, fornices, conjunctiva, tear film, and cornea.

Additionally, KOL support for new diagnostic tools and therapeutic strategies is helping to legitimize and standardize DB management.

Emerging techniques

In most cases, DB can be diagnosed through a high-magnification slit-lamp examination of the lid margins and lashes. This simple, quick technique allows clinicians to identify collarettes the pathognomonic sign at the base of the eyelashes, a highly specific marker of Demodex infestation.

Emerging technologies, however, are adding the ability to objectively assess the ocular surface environment, where DB often coexists with other conditions like meibomian gland dysfunction and chronic inflammation. These comorbidities may be either triggered or worsened by Demodex. Advanced diagnostics – such as meibography and ocular surface imaging systems – can help clinicians evaluate the relative contribution of each factor and better personalize management strategies.

In addition, dermoscopy, in-office macro photography, and innovations in point-of-care diagnostics are being explored as non-invasive and timeefficient tools to support DB diagnosis.

Patient profiles

Patients presenting with chronic eyelid discomfort, itching, foreign body sensation, fluctuating vision or persistent dry eye symptoms should be prioritized for DB screening. DB is especially prevalent among individuals with anterior blepharitis, MGD, or recurrent chalazia.

Additionally, DB screening is recommended for patients who are unresponsive to conventional dry eye or MGD treatments, or in patients who have tried several lubricating or topical anti-inflammatory approaches without significant benefits. Elderly patients, due to increased mite prevalence with age, and pre-surgical patients should also be routinely evaluated.

Early identification in these subgroups supports targeted management, helps break the cycle of inflammation and infestation, and ultimately can support patient satisfaction.

Mario Nubile MD, Ophthalmology Clinic, Department of Medicine and Aging Science, “G. d’Annunzio” of Chieti-Pescara, Chieti, Italy

Mario Nubile is a paid consultant of Tarsus Pharmaceuticals Inc.