Screening for Demodex blepharitis: Integrating best practices into routine eye care

Demodex blepharitis is more common than previously thought, and proper diagnosis and management are important for effective patient care. Anne M. Zaki, MD, a cornea specialist in private practice at Desert Eye Specialists in Peoria, Arizona, moderated a recent Ophthalmology Times Case-Based Round-
table on diagnosing and effectively treating Demodex blepharitis. Approximately 58% of patients presenting for an ocular examination have Demodex blepharitis, Zaki noted.

Zaki explained that in her practice, a thorough ocular surface examination is the standard of care for every patient, regardless of their presenting problem. Her typical dry eye evaluation includes a close assessment of the eyelids and eyelid margins for notching or irregularities, telangiectasia, posterior displacement of gland orifices, margin thinning or thickening, and the presence of collarettes on the inferior eyelid margin. After measuring tear breakup time, she applies pressure to the lids to assess the amount of expression, the force needed for expression, and the quality of the meibum. She also looks for lid laxity, inferior scleral show, and lagophthalmos.

A key change Zaki has incorporated into her examination is instructing the patient to look down when assessing the upper eyelids.

“It was not until I had the patients look down that I was adequately screening for Demodex,” she said. This facilitates a view of the eyelid margin and the lash base for collarettes, as well as misdirected lashes, lash loss, or engorged vessels on the upper eyelid. “Demodex definitely impacts the ocular surface health of patients,” she said.

Zaki also examines the conjunctiva for punctate staining, irregularities, conjunctival chalasis, and corneal staining patterns.
Meibography and tear osmolarity testing are performed before she sees the patient.

“Before I changed my examination, I considered Demodex to develop in only 5% to 10% of patients,” Zaki said, now realizing that percentage is much higher.

Changes in treatment

“The frequent recognition of Demodex has impacted my overall dry eye management,” Zaki said. “We previously treated blepharitis and meibomian gland dysfunction with oral agents, lid hygiene or scrubs, hypochlorous acid, pulsed light therapy, LipiFlow [TearScience], or [artificial] tears.” For collarettes, the therapy is lotilaner ophthalmic solution (Xdemvy; Tarsus Pharmaceuticals, Inc), she added.

A Demodex case report

A woman was referred to Zaki for a cataract evaluation. Her vision was 20/50 bilaterally and had been declining, possibly due to droopy eyelids. Upon examination, Zaki observed sparse lashes and collarettes along the inferior eyelid margin. Slit lamp evaluation revealed corneal punctate staining in the inferior and superior regions, as well as clinically significant cataracts. Zaki described “massive collarettes” along the eyelid margin and noted lash misdirection and engorged blood vessels.

The first step involved initiating lotilaner therapy to eliminate Demodex mites before cataract surgery. After 8 weeks, the patient returned with marked improvement following 4 weeks of lotilaner use. Based on the phase 2/3 Saturn-1 (NCT04475432) and Saturn-2 (NCT04784091) studies, Zaki did not implement lid hygiene. Cataract surgery was subsequently performed without complications.

The patient said Zaki was the fourth doctor she had seen, including a dermatologist and ophthalmologists, all of whom told her to “scrub harder” and said lid hygiene was the only treatment.

Saturn-1 and Saturn-2 studies

The Saturn-1 and Saturn-2 studies included patients with grade 3 and 4 disease, defined as having more than one-third or more than two-thirds of the upper eyelashes affected by collarettes, along with mite infestation on lashes that were pulled. The primary end point, Zaki explained, was achieving fewer than 2 collarettes on the upper lid.

About 80% of patients had fewer than 10 collarettes. “With lotilaner alone, the results were very impressive,” she said.

Although Zaki does not use lid hygiene when prescribing lotilaner, she noted she may prescribe other dry eye treatments 2 to 3 months after starting lotilaner to address other ocular surface issues.

Key takeaways

The roundtable participants agreed that there must be a lower threshold for treating patients, especially those who present preoperatively, because the Demodex mites can create lid inflammation and increase the bacterial load on the lids, Zaki noted.

Another takeaway was the recognition that when clinicians see collarettes and Demodex mites, they start with lid hygiene instead of lotilaner. “Lid hygiene does not kill the Demodex or treat the root of the problem but may only remove some collarettes. The mites get into the hair follicles,” Zaki said.

A third takeaway is that not all clinicians routinely look for Demodex mites, which are far more common than previously realized, she added.

The most important point regarding the patient examination is to have the patient look down while using higher slit lamp magnification to inspect the lash base for collarettes. “It is really that simple,” Zaki said.