Blepharitis is one of the most common ocular conditions that we encounter. It can result in significant discomfort for patients, often causing symptoms of burning, itching, epiphora, photophobia, dryness, foreign body sensation, blurred vision, and a decreased ability to wear contact lenses comfortably. These symptoms can affect a person’s quality of life and can cause undesirable effects on overall cosmesis, such as chronic redness, swollen lids, and short, brittle eyelashes.
Studies tend to report a fairly strong association between Demodex and various forms of blepharitis. In one study of 150 patients, Demodex was found in 60% of those who had meibomian gland dysfunction and in 90% of those who had anterior and mixed blepharitis (Bhandari and Reddy, 2014). So which came first, the Demodex or the blepharitis? Although it’s been suggested that Demodex may have a hand in causing other forms of blepharitis, it still isn’t clear whether it truly plays an etiological role or whether it is simply a co-factor (Gao et al, 2007).
An Option on the Horizon
With the Phase 3 trial of a topical ophthalmic formulation of lotilaner for the human treatment of Demodex expected to conclude in the first quarter of 2022, we may be close to having the first U.S. Food and Drug Administration-approved therapeutic treatment for Demodex blepharitis. In its Phase 2b/3 trial, the drug met all primary and secondary endpoints without any serious adverse events or treatment-related discontinuations (Tarsus Pharmaceuticals, 2021; Salinas et al, 2021).
Lotilaner is a selective inhibiter of parasitic gamma-aminobutyric acid-gated chloride channels, which ultimately results in parasite death (www.parasitipedia.net ). It is approved commercially as an oral treatment to eradicate fleas and ticks in cats and dogs, and it is sometimes used off-label to treat Demodex infestation in animals. It has also shown some potential for treating human lice (Lamassiaude et al, 2021).
Don’t Forget Other Therapies
Although lotilaner could become a welcome addition to our therapeutic toolbox for managing Demodex blepharitis, it appears to be a narrowly targeted therapy. Lid hygiene will likely remain essential for maintaining and improving overall lid and ocular surface health.
The ocular surface is anatomically and functionally complex. Pathology in one structure can affect the health and performance of other structures in due time. For example, overcolonization of bacteria on the lids and lashes, stasis of meibomian gland secretions, and allergic eye disease can induce a state of chronic ocular surface inflammation, which in turn can lead to deleterious effects on the stability of the entire lacrimal system unit (Baudouin et al, 2016). Routine lid care is still generally regarded as the mainstay of clinical treatment and prevention for various forms of blepharitis, especially when ocular surgery is proposed (Song et al, 2019; Eom et al, 2020; Jones et al, 2017). Lid care may include at-home daily heat and cleansing with ophthalmic preparations as well as in-office treatments such as lid debridement/exfoliation, meibomian gland expression, intense pulsed light therapy, and low-level light therapy, to name a few. A very broad range of research evidence exists for these various therapies, especially in terms of disease prevention. This is not to say that some of these therapies are without merit; I mention it only to emphasize the need for large-scale, prospective, randomized, head-to-head studies to truly determine best evidence-based practices and to standardize optimal techniques.
A prevention-based approach, combined with the targeted and appropriate use of medication and other treatments, should enable us to optimally care for our patients. This requires a commitment on our part to routinely educate patients on their ocular surface health status and to encourage them to persist with their home care regimens. We have only to look to our colleagues in dentistry and dermatology to appreciate the colossal impact that patient education, routine hygiene, and prevention strategies can have. CLS
For references, please visit www.clspectrum.com/references and click on document #315.