Ácaros del género Demodex: ¿parásitos colonizadores de personas sanas o asociados a patología ocular? / Demodex genus: colonizing parasites of healthy people or mites associated with ocular pathology?

Las especies Demodex folliculorum y Demodexbrevis, responsables de la demodicosis humana, afectan la piel y en ocasiones están vinculadas con afecciones oculares. El objetivo de este trabajo fue conocer si existe asociación significativa entre la presencia del ácaro y de patologías palpebrales, y el papel de factores como la edad y el sexo de los pacientes. Se analizaron las pestanas de un conjunto de pacientes sintomáticos y asintomáticos (n = 72) de entre 9 y 82 años. El 53% de los pacientes fueron positivos para la presencia del ácaro Demodex. De ellos, el 66% manifestó síntomas o patologías oculares, dentro de las cuales la blefaritis y el ojo seco resultaron prevalentes. Se observaron asociaciones significativas tanto entre la presencia de este ácaro y una edad mayor de 60 años (p < 0,001), como entre la presencia del ácaro y ojo seco o blefaritis o ambos (p <0,001). Consideramos necesaria la búsqueda de Demodex sp. en pacientes con síndrome de ojo seco o blefaritis, especialmente durante la inmunosenescencia, a fin de instaurar tratamientos antiparasitarios específicos.

Demodex folliculorum and Demodex brevis are mites that are responsible for human demodicosis affecting skin and frequently linked to ocular diseasess. The aim of this work was to determine the association between Demodex sp. and eyelid and eyelash diseases and to establish the predisposing factors for acquiring this parasitic disease. Eyelashes from symptomatic and asymptomatic patients (n = 72) between 9 and 82 years old were analyzed, where 53% were positive for Demodex sp., of which 66% manifested ocular symptoms and pathologies, blepharitis and dry eye being prevalent. Significant correlations between Demodex and patients over 60 years of age (p <0.001) and between Demodex sp. and dry eye patients / blepharitis (p <0.001) were observed. We consider that it is necessary to search for Demodex sp. especially in those patients suffering from dry eye and blepharitis and/or during immunosenescence in order to implement specific antiparasitic treatments.

Toxic effects of selected proprietary dry eye drops on Acanthamoeba.

Amoebae of the genus Acanthamoeba are ubiquitous protists that have been isolated from many sources such as soils, water and the air. They are responsible for infections including fatal encephalitis and a severe keratitis in humans. To date, there is no satisfactorily effective therapeutic agent against this pathogen and the infections it causes are exacerbated by the existence of a resistant cyst stage produced by this amoeba. As dry eye syndrome is a risk factor for Acanthamoeba keratitis, we aimed to evaluate the anti-Acanthamoeba activity of a variety of proprietary eye drops intended to treat dry eye syndrome. From the nine eye drop formulations tested, "Systane Ultra" was determined to be the most active against all tested Acanthamoeba strains. During our investigations into the mode of action of Systane Ultra, we discovered that it decreases mitochondrial membrane potential and ATP levels, induces chromatin condensation, and increases the permeability of the plasma-membrane.

[Demodex genus: colonizing parasites of healthy people or mites associated with ocular pathology?] / Ácaros del género Demodex: ¿parásitos colonizadores de personas sanas o asociados a patología ocular?

Demodex folliculorum and Demodex brevis are mites that are responsible for human demodicosis affecting skin and frequently linked to ocular diseasess. The aim of this work was to determine the association between Demodex sp. and eyelid and eyelash diseases and to establish the predisposing factors for acquiring this parasitic disease. Eyelashes from symptomatic and asymptomatic patients (n=72) between 9 and 82 years old were analyzed, where 53% were positive for Demodex sp., of which 66% manifested ocular symptoms and pathologies, blepharitis and dry eye being prevalent. Significant correlations between Demodex and patients over 60 years of age (p<0.001) and between Demodex sp. and dry eye patients / blepharitis (p<0.001) were observed. We consider that it is necessary to search for Demodex sp. especially in those patients suffering from dry eye and blepharitis and/or during immunosenescence in order to implement specific antiparasitic treatments.

Demodex treatment in external ocular disease: the outcomes of a Tasmanian case series.

Demodex species (spp.) have previously been implicated in the pathogenesis of blepharitis. This study aims to correlate improvement in symptoms of external ocular disease with treatment of underlying Demodex spp. This is a prospective, observational case series of patients with chronic external ocular disease. Demodicosis was confirmed by microscopic examination of epilated eyelashes. The main outcome measure was response to the treatment (5 % tee tree oil) in regard to change in subjective symptoms utilising a symptom-based patient questionnaire assessment. Overall patients had a good response to the treatment in terms of improvement or resolution of symptoms, with 91 % of patients reporting at least some improvement in symptoms. The treatment of underlying Demodex spp. appears to result in improvement of symptoms in patients with long standing external ocular disease and underlying Demodex spp. infestation.

In vivo confocal microscopy as a novel and reliable tool for the diagnosis of Demodex eyelid infestation.

AIMS: Demodex mites are implicated in several ocular surface diseases such as blepharitis, ocular rosacea and dry eye syndrome. Demodex eyelid infestation is classically diagnosed by analysing depilated eyelashes under the light microscope. The use of in vivo confocal microscopy (IVCM) could be an easy way to improve its diagnosis. The ability of IVCM to identify Demodex was evaluated and compared with the classic depilation method. METHODS: Eight healthy subjects, 22 patients with dry eye syndrome without anterior blepharitis and 18 patients with anterior blepharitis were examined using lower eyelid IVCM (lash follicles and meibomian glands (MGs)). Twenty-five of the 48 subjects underwent both an IVCM examination and classic depilation to compare the two methods. Ex vivo Demodex obtained from lash depilation were also analysed using the confocal microscope. RESULTS: IVCM found 100% of the mite infestations among patients with anterior blepharitis, 60% among dry eye patients without blepharitis and 12% in healthy subjects, whereas the depilation technique found 100%, 50% and 0%, respectively. Demodex brevis and Demodex larvae inside the lash follicles were better detected by IVCM. In symptomatic patients, the Demodex infestation was often associated with MG dysfunction, which was better characterised using IVCM in symptomatic patients (60% and 40% of meibomianitis and gland fibrosis, respectively). CONCLUSIONS: IVCM is an efficient and reliable tool for the diagnosis of eyelid mite infestation and may also provide an evaluation of MGs.

Demodex.

PURPOSE: Demodex folliculorum and Demodex brevis are ectoparasites with an astounding prevalence of 100% in patients aged 70 years and older. Every person in this age group is estimated to carry a colony of 1000 to 2000 mites. With such a high prevalence, little attention has been paid to the mite among eye care practitioners. We demonstrate a clinical sequence in a set of case reports to identify the mite. The clinical sequence includes a clinical history of blepharitis, dry eyes, and/or ocular allergy; slit lamp examination of cylindrical dandruff; and confirmation using light microscope evaluation of epilated lashes. CASE REPORTS: Patient 1 was a 68-year-old woman who demonstrates associations with dry eyes and diabetes. Patient 2 was a 44-year-old man with uncommonly seen D. brevis present. Patient 3 was a 40-year-old woman with dry eyes and allergy, showing mite tails protruding from base of lashes. Patient 4 was a 60-year-old woman who demonstrates the association with rosacea. Patient 5 was a 53-year-old woman intermittently taking topical steroid and antibiotic combination medications, with an actual mite photographed on the surface. CONCLUSIONS: Following a clinical sequence helps identify Demodex, the underdiagnosed, undertreated, and underappreciated ocular surface disease.