Demodex and eye disease: a review

Prevalence and Risk Factors of Ocular Demodex at Ultra-High Altitude and Sea Level: A Cross-Sectional Study of Shigatse and Shanghai

Purpose: Demodex infestation is a risk factor for several ocular surface diseases. However, the prevalence of ocular Demodex infection in the ultra-high altitude population is not clear. This study aimed to compare the prevalence and factors associated with Demodex in populations residing in ultra-high altitude region and sea level areas. Methods: Consecutive patients who visited Shigatse People's Hospital (> 4,000 m) and Shanghai Tongren Hospital (sea level) for eye complaints between January 2023 and January 2024 were included. Subjects were divided into ultra-high altitude and sea level groups. All subjects underwent eyelash epilation for ocular Demodex identification and counting. Demographic and lifestyle information was also collected. Results: A total of 517 subjects were eligible, including 255 subjects in the ultra-high-altitude group and 262 subjects in the sea level group. In the overall analysis, the prevalence of ocular Demodex infection was significantly different between the ultra-high-altitude and sea level groups (15.7% vs. 33.2%, P < 0.001). Multiple logistic regression showed that age, time spent outdoors, and makeup were associated with ocular Demodex infection in both groups. In addition, in the ultra-high-altitude group, people who wear sun hats outdoors were more likely to be infected with Demodex. Conclusion: The infection rate of ocular Demodex in the residents of ultra-high altitude area was significantly lower than that in the residents of sea level area, which may be related to lower ambient temperature, lower humidity, and higher solar radiation. Additionally, age, time spent outdoors, and makeup may be associated with ocular Demodex infection.

Beyond the Surface: Understanding Demodex and Its Link to Blepharitis and Facial Dermatoses

Demodex represents the most frequent ectoparasite found in humans. Although Demodex mites are considered commensals of human pilosebaceous units, an abnormally high mite density can cause several ocular and cutaneous symptoms and signs, sometimes to a severe degree. Both Demodex spp. (folliculorum and brevis) play a significant part in eye pathology and facial dermatoses. These mites have been related to blepharitis, ocular rosacea, meibomian gland dysfunction and various skin diseases, including rosacea, demodicosis and seborrheic dermatitis. Understanding the importance of Demodex in both eye and skin conditions is crucial for accurate diagnosis and appropriate management strategies, which may involve targeted treatments to control the mite population and reduce associated symptoms.

"Demodicosis" Mimicking PreSeptal Cellulitis: Severe Periocular and Facial Inflammation Caused by "Normal" Skin Flora

Due to their relatively high prevalence and commensalism, the pathogenicity of Demodex mites has been debated. Recent data, however, show Demodex to be associated with skin and ocular surface diseases such as rosacea, blepharitis, and keratitis. Here the authors report the first known case, to the best of the their knowledge, of Demodex infestation mimicking preseptal cellulitis in an adult human. A 29-year-old male bilaterally blind from advanced retinopathy of prematurity presented with a 2-month history of right-greater-than-left upper eyelid and periocular/cheek swelling, redness, and ocular discharge that did not resolve with oral antibiotics or oral steroids. Based on MRI findings, biopsies of the right lacrimal gland, right orbital fat, and right upper eyelid preseptal skin were obtained which revealed marked intrafollicular Demodex mite density and budding yeasts in the upper eyelid skin. This case serves to alert clinicians to this entity that may not otherwise be usually considered in ophthalmic clinical practice.

Topical ivermectin ointment treatment of Demodex blepharitis: a 6-year retrospective study

BACKGROUND

To evaluate the efficacy of topical ivermectin 1% ointment, for the treatment of Demodex blepharitis.

METHODS

A retrospective study was designed to review electronic medical records of patients seen between January 2017 and December 2022, who had a diagnosis of Demodex blepharitis, treated with topical ivermectin 1% with at least 6 months of follow-up (Centro de Ojos Quilmes, Buenos Aires, Argentina). The presence of collarettes was graded from 0 to 4. An imaging system (Keratograph) was used, to evaluate tear meniscus height (TMH), non-invasive tear break-up time (NIKBUT), and degree of conjunctival redness. In addition, the ocular surface disease index (OSDI) test was performed. Results were compared before and after ivermectin treatment, which was performed once a day for 2 months.

RESULTS

A total of 2157 patients (4314 eyes) were included. The mean age was 50.43 ± 15.3 years, and the follow-up time was 26.1 ± 8.5 months. No one discontinued treatment due to intolerance, although 14 cases (0.6 %) reported occasional discomfort. The grade of collarettes decreased with statistical significance, from 3.37 ± 0.7 to 0.1 ± 0.3 (p < 0.01), as well as conjunctival redness from 1.32 ± 0.3 to 0.94 ± 0.4 (p < 0.01) and OSDI score from 58.74 ± 17.9 to 17.1 ± 10.5 (p = 0.02). TMH and NIKBUT improved without statistical difference.

CONCLUSION

Treatment with ivermectin 1% topical ointment, once daily for 2 months, was effective in reducing the presence of collarettes and in improving symptoms in patients with Demodex blepharitis.

A Delphi approach to establishing consensus on best practice for the diagnosis and treatment of Demodex blepharitis

Demodex blepharitis does not have agreed standardized guidelines. The aim of this study was to classify signs and symptoms and to develop appropriate management strategies for Demodex blepharitis from a consensus of expert advice.

METHODS

A total of 11 anterior segment experts (ophthalmologists, optometrists and a contact lens optician) working in the United Kingdom participated in a modified 2-round Delphi panel. A mixed-methods approach was adopted and a survey questionnaire for round 1 was formulated, constructed from information in the available literature. Based on panel responses from round 1, feedback was provided and a round 2 questionnaire was formulated. More than two-thirds majority (72%) was used for consensus building.

RESULTS

Based on the clinical presentation of signs and symptoms along with associated conditions and risk factors, a diagnostic algorithm was proposed for the clinical investigation of Demodex blepharitis. A treatment algorithm was also proposed with first-line and second-line treatment recommendations for Demodex blepharitis.

CONCLUSION

The recommendation from this study provides the first effort in formulating clinical diagnostic algorithm and management guidelines for Demodex blepharitis. The guidelines include appropriate magnification on the slit lamp, associated signs, symptoms, risk factors and suggested management options. These guidelines can be used in a routine eyecare setting to encourage eyecare practitioners in tailoring the investigation and management of Demodex blepharitis.

Chicago sky blue gel for better visualization of Demodex in patients with Demodex blepharitis

Background

Demodex blepharitis is a common chronic disease. The number of mites is associated with ocular discomfort. The accurate number derived from well-stained specimens is, hence, in favor of diagnosing, monitoring, and determining treatment responses.

Methods

A cross-sectional study was conducted between April and July 2022 at the dermatology and ophthalmology clinic, Walailak University, Thailand. Adult participants with clinical suspicion of Demodex blepharitis were recruited. We examined eyelashes under light microscopy to quantify the number of Demodex mites before and after adding CSB gel. The mite counts, evaluated by an untrained investigator and an experienced investigator, were recorded and compared.

Results

A total of 30 participants were included for final analysis, among which 25 (83.3%) were female. The median age was 64.0 years (IQR, 61.0-68.0). The median Demodex counts evaluated by the experienced investigator before and after adding CSB gel were 1.0 (IQR, 0.0-1.0) and 2.5 (IQR, 2.0-3.0), respectively (p < 0.001). Moreover, the median Demodex counts evaluated by the untrained investigator before and after adding CSB gel were 1.0 (IQR, 0.0-1.0) and 2.0 (IQR, 1.0-3.0), respectively (p < 0.001). The correlation coefficient between Demodex counts after the addition of CSB counted by the experienced investigator and those counted by the untrained investigator was 0.92 (p < 0.001). CSB gel is a promising product to identify and quantify the number of Demodex mites. The findings supported the consideration of CSB gel as one of the diagnostic stains.

Routine eyelid care for those without dermatitis

The eye is a unique structural and functional anatomic unit of the face and requires specific care and attention. Often, dermatologists are not familiar with the routine needs of the eyelid area. Despite evidence showing that lid hygiene may serve as an important supplement to therapeutic management of eyelid disorders, lid hygiene is often overlooked. Ophthalmologists and dermatologists have an important role to play in educating patients on the importance of proper eyelid hygiene and ensuring patient compliance. We review eyelid anatomy and function to better understand how these structures relate to potential disease processes. We also review current recommendations for routine eyelid care and discuss the need for further advancements in promoting eyelid health.

Demodex Blepharitis: A Survey-Based Approach to Investigate Knowledge, Attitudes, and Practices Among Optometrists in India

PURPOSE

To investigate the knowledge, attitudes, and practice towards Demodex blepharitis among optometrists in India.

METHODS

The study was conducted in the form of an online survey using Research Electronic Data Capture (REDCap). The survey link was distributed via direct e-mail and social media platforms, and it was comprised of 20 questions divided into two sections. The first section focused on the practitioners' demographics and their views on the general health of the eyelid. The second section of the survey was specific and aimed at obtaining information on identifying and treating Demodex blepharitis, and was only completed by those respondents who looked for Demodex mites.

RESULTS

The survey was completed by 174 optometrists. The prevalence of blepharitis in the general population was judged by the respondents to be 40%, whereas the prevalence of Demodex mites was estimated to be 29%. Interestingly, the prevalence of Demodex mites in people with blepharitis was estimated to be 30%. This estimated prevalence was substantially lower than that reported in the literature on the subject. 66% of participants believed Demodex mites to be a significant cause of ocular discomfort, whereas only 30% of participants would intervene to diagnose and manage Demodex blepharitis in their patients. Optometrists differed in their preferred method of diagnosis and management of Demodex infestation in eyelids.

CONCLUSION

The result of this survey suggests that Demodex blepharitis is a highly under-diagnosed condition in India, with nearly 30% of surveyed optometrists managing this condition. The study also observed a lack of awareness and consensus among surveyed optometrists with regards to diagnosis and appropriate treatment methods to control Demodex infestation in eyelids.

Lotilaner Ophthalmic Solution, 0.25%, for the Treatment of Demodex Blepharitis: Results of a Prospective, Randomized, Vehicle-Controlled, Double-Masked, Pivotal Trial (Saturn-1)

PURPOSE

The purpose of this study was to evaluate the safety and efficacy of lotilaner ophthalmic solution, 0.25%, compared with vehicle for the treatment of Demodex blepharitis.

METHODS

In this prospective, randomized, controlled, double-masked, phase 2b/3 clinical trial, 421 patients with Demodex blepharitis were randomly assigned in a 1:1 ratio to receive either lotilaner ophthalmic solution, 0.25% (study group), or vehicle without lotilaner (control group) bilaterally, twice daily for 43 days. Patients were evaluated at days 8, 15, 22, and 43. Outcome measures were complete collarette cure (collarette grade 0), clinically meaningful collarette cure (grade 0 or 1), mite eradication (0 mites/lash), erythema cure (grade 0), composite cure (grade 0 for collarettes/erythema), and drop comfort. Adverse events were also evaluated.

RESULTS

At day 43, the study group achieved a statistically significantly higher proportion of patients with clinically meaningful collarette cure (81.3% vs. 23.0%; P < 0.0001), complete collarette cure (44.0% vs. 7.4%; P < 0.0001), mite eradication (67.9% vs. 17.6%; P < 0.0001), erythema cure (19.1% vs. 6.9%; P = 0.0001), and composite cure (13.9% vs. 1.0%; P < 0.0001) than the control group. Nearly 92.0% of patients rated the study drop as neutral to very comfortable. All ocular adverse events in the study group were mild, with the most common being instillation site pain.

CONCLUSIONS

Twice-daily treatment with a novel lotilaner ophthalmic solution, 0.25% for 43 days, is safe and effective for the treatment of Demodex blepharitis compared with the vehicle control.

Prevalence of Demodex folliculorum and Demodex brevis in patients with blepharitis and chalazion

PURPOSE

Demodex folliculorum and Demodex brevis are common ectoparasites on skin that also can lead to blepharitis and chalazion. The aim of our study is to determine the prevalence of Demodex spp. in eyelashes of patients diagnosed with chronic blepharitis and chalazion.

METHODS

This study included 330 patients diagnosed with chronic blepharitis, 70 patients diagnosed with chalazion and 130 volunteers without any ocular problems. Patient eyelashes were examined under a light microscope at magnifications of × 40, × 100 and × 400. Demodex spp. were determined.

RESULTS

Parasite prevalence was significantly higher in blepharitis (75.5%) and chalazion groups (70%) compared to the control group (16.2%) (p < 0.001). The prevalence of D. folliculorum in the blepharitis group and D. brevis in the chalazion group was found to be significantly higher compared to other groups (p < 0.05). The average number of mites per eyelash was found to be significantly higher in patients with Demodex positive blepharitis (p = 0.001) and in chalazion patients (p = 0.047) than in the control group. It has been determined that mite positivity increases with age in blepharitis and control groups (p < 0.05). In the group with blepharitis, it was found that mite positivity was significant in the presence of symptoms (p = 0.0001) and Demodex positivity decreased as the education level of individuals increased (p = 0.039).

CONCLUSION

The results of the study show that Demodex spp infestations should be considered in chronic blepharitis and chalazion.

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

Purpose

Patients and Methods

Results

Conclusion