The Prevalence of Demodex Blepharitis in US Eye Care Clinic Patients as Determined by Collarettes: A Pathognomonic Sign

Abstract

Purpose To evaluate the prevalence of Demodex blepharitis by its pathognomonic sign, collarettes, in patients presenting for any reason to eye care clinics in the United States. Patients and Methods In this retrospective study by 7 investigators at 6 eye care clinics, case records of consecutive patients who underwent a slit-lamp examination, regardless of chief complaint, were reviewed for Demodex blepharitis, as identified by the presence of collarettes. Patient characteristics, including age, gender, race, relevant ocular and systemic diagnoses, ocular medications, lid hygiene practices and contact lens wear, were also recorded. Results Of 1032 patients (mean age: 60.2 ± 17.8 years), 57.7% had Demodex blepharitis. While the prevalence of Demodex blepharitis in patients with dry eye disease (DED) (58.9%) and cataract (55.7%) was similar to the overall prevalence of Demodex blepharitis, it was higher in patients with blepharitis (69.1%) and glaucoma (64.8%). Among patients with collarettes, 44.0% had never been diagnosed with blepharitis. Among those on anti-inflammatory DED treatment, 60.0% had Demodex blepharitis. Demodex blepharitis prevalence was significantly higher among those using topical tea tree oil versus those who were not (74.5% versus 56.7% p = 0.014); prevalence was comparable among those using/not using lid wipes (56.9% versus 55.5%). Conclusion Demodex blepharitis, based on the pathognomonic finding of collarettes, is common and likely underdiagnosed among patients seeking eye care. These collarettes are still found in patients using over-the-counter treatments for blepharitis. The present study highlights the importance of screening patients for collarettes and Demodex blepharitis as part of every slit-lamp examination.

Psychosocial Impact of Demodex Blepharitis

“…Lost work days and reduced productivity add another $55.4 billion in indirect costs. 42 Since Demodex blepharitis is as common as DED and there is substantial overlap of symptoms and clinical presentation with DED, 9 Demodex blepharitis is also expected to have a similar socioeconomic impact. 15 Although the economic burden of Demodex blepharitis was not evaluated, the findings related to multiple visits to eye care professionals and myriad treatments used, even if ineffective, suggest considerable direct costs.…”

“…[2][3][4][5][6][7] Two recent US studies have reported Demodex infestation rates of 55% and 58% based on the detection of mites following lash epilation or presence of collarettes (cylindrical dandruff), respectively, among patients presenting for eye examinations for varying reasons. 8,9 Since approximately 45 million US patients visit eye care professionals annually; it is estimated that 25 million Americans may have Demodex blepharitis. 10,11 Despite the high prevalence of Demodex blepharitis, patients with the condition may go undiagnosed or misdiagnosed for years.…”

“…This may be due to the substantial overlap of symptoms with dry eye disease (DED) and other ocular surface or lid margin disorders, as well as a general lack of awareness among eye care professionals to actively look for collarettes (waxy, translucent, solidified excretions that form a cylindrical collar around the base of the eyelash follicle), the pathognomonic sign of Demodex blepharitis. 9,[12][13][14] These can be readily identified by asking patients to look down during a standard slit-lamp examination. 12,15 Even when Demodex blepharitis is diagnosed, inconsistent and typically suboptimal efficacy with over-the-counter and other management options and the absence of an FDA-approved prescription therapeutic disincentivizes treatment.…”

Should ocular Demodex be checked and treated in refractory keratitis patients without blepharitis?

“…In 2005, Gao et al [2] found that 100% of the people with cylindrical dandruff in the eyelash had Demodex mites. There has been an increasing amount of evidence to support that Demodex is an important cause of blepharitis and related ocular surface diseases [3][4][5][6][7][8][9][10][11] . In 2018, Liang et al [12] reported that Demodex caused blepharitis-associated keratoconjunctivitis, and the extent of keratopathy was related to the severity of blepharitis.…”

Novel Molecule Lotilaner Could Potentially Offer Relief to Long-suffering Demodex Blepharitis Patients

“…13 Fifty-six percent of cataract patients in the Titan study had Demodex blepharitis. 14 Given the higher bacterial load in Demodex blepharitis patients compared with patients without the disease, 15 minimizing the risk of DOI: https://doi.org/10.17925/USOR.2022. 16.1.2 touchREVIEWS in Ophthalmology bacterial infection prior to surgery by screening for Demodex blepharitis is also important.…”