Blepharitis is a disease characterized by inflammation of the eyelid margins. Participants with blepharitis often experience lid margin itching, burning, or stinging in the eyes, foreign body sensation, as well as redness of the eyes and eyelids. In the United States, blepharitis is estimated to affect as many as 19 million people and is most common in individuals over the age of 50 (Schaumberg et al., 2011). One of the most common causes of blepharitis can be attributed to Demodex mites. Demodex mites (Demodex folliculorum or Demodex brevis) are microscopic, obligate ectoparasites (Fromstein et al., 2018) that inhabit the base of eyelashes, Meibomian glands, and sebaceous glands. Demodex are the only mites that are known to affect the human eye (Luo et al., 2017). A recent meta-analysis of 11 clinical studies has shown that Demodex is associated with 45% of blepharitis cases (Zhao et al., 2012). The density of Demodex is correlated with the signs of blepharitis and other ocular complications (Liu et al., 2010; Luo et al., 2017). In Demodex blepharitis, mites inhabit the lash follicles where they feed on sebum and cause epithelial abrasions, resulting in epithelial hyperplasia and reactive hyperkeratinization (Fromstein et al., 2018; Liu et al., 2010). Undigested material, combined with epithelial cells, keratin, and eggs lead to the formation of collarettes (also known as cylindrical dandruff), which are pathognomonic for Demodex blepharitis (Fromstein et al., 2018). Lashes with collarettes have been demonstrated to contain 2-4 mites/lash on average, compared with only 0.2 mites/lash without collarettes (Gao et al., 2005). Demodex infestations can also lead to swelling and irritation, as well as enlargement of the meibomian glands. A localized granulomatous reaction associated with the chitinous exoskeleton and waste products of Demodex may mechanically block the meibomian glands (English and Nutting, 1981; Yam et al., 2014). In addition to surface irritation and inflammation, the mites may also activate inflammatory cascades by introducing bacteria harbored on and within the mites (Liu et al., 2010). Finally, the lid collarettes caused by Demodex infestation can themselves trigger an immune response and have been shown to increase the number of CD4+ T cells, macrophages, and Langerhans in participants (Fromstein et al., 2018; Liu et al., 2010). There are currently no therapeutics approved to treat Demodex blepharitis (Fromstein et al., 2018). The most effective and commonly used treatments include at-home remedies to remove Demodex from the lid through lid scrubs and removal of the eyelash collarettes/cylindrical dandruff (Fromstein et al., 2018). Demodex mites are resistant to a wide range of antiseptics, including 75% alcohol, 10% povidone iodine, and antibiotics such as erythromycin (Gao et al., 2007). Some clinicians recommend use of tea tree oil for amelioration of Demodex blepharitis, despite the ocular discomfort that it causes (Fromstein et al., 2018). However, none of these remedies effectively improve Demodex infestation or treat blepharitis (Fromstein et al., 2018; Tighe et al., 2013). Thus, there remains an unmet medical need for an efficacious treatment option for individuals with Demodex blepharitis. The objective of this study is to determine the Demodex density count in eyelashes of patients presenting with blepharitis.
Inclusion Criteria Each patient must:
a. Be at least 18 years of age;
b. Provide written informed consent;
c. Have a self-reported history of eyelid problems or clinician diagnosis of blepharitis;
d. Be able and willing to follow instructions, including participation in all study assessments.
Exclusion Criteria Each patient may not:
a. Have used artificial eyelashes or eyelash extensions within the last 7 days;
b. Have lid structural abnormalities (e.g. ectropion, entropion, etc.) that, in the opinion of the investigator, may impact the outcome of the study;
c. Have an acute ocular infection or have an active ocular inflammation other than blepharitis in either eye;
d. Have, in the opinion of the investigator, severe dry eye in either eye;
e. Have an uncontrolled systemic disease;
f. Be currently enrolled in an investigational drug or device study;
g. Be a female who is currently pregnant, planning a pregnancy, or lactating;
h. Have a corrected visual acuity greater than or equal to logMAR+0.7 as assessed by the Early Treatment of Diabetic Retinopathy Study (ETDRS) scale in either eye at Visit 1; or i. Have a condition or be in a situation which the investigator feels may put the patient at significant risk, may confound the study results, or may interfere significantly with the patient’s participation in the study.