Demodex and eye disease: a review.

Demodex is the most common parasite living on humans and yet little is understood about its pathogenicity with respect to the ocular surface. An increasing interest in Demodex over the past 20-years has increased our understanding of this mite and its pathogenetic role. This article begins with a review of the anatomy, life cycle, mode of transmission and advances in genetics that can distinguish between Demodex folliculorum and Demodex brevis, the only two Demodex species in humans. Additionally, a review of diagnostic procedures and existing and emerging ocular and systemic management options are presented. Despite the increasing interest in Demodex in the literature, there remains numerous obstacles for future studies, hence a section of this review is dedicated to the identification and proposal for future considerations. The lack of uniformity with respect to terminology, diagnostic technique and management approach for Demodex remain as obstacles for future study comparisons. This review summarised the current knowledge on Demodex and hopes to offer some recommendations for future directions in the study of Demodex in humans.

Palpebral and facial skin infestation by Demodex folliculorum.

PURPOSE: To evaluate facial Demodex densities in participants with varying severities of blepharitis secondary to Demodex folliculorum assessed by the highest number of cylindrical dandruff on one lid. METHODS: This double masked cross-sectional study included 58 participants [19 control, 21 mild/moderate and 18 severe Demodex blepharitis] who underwent a standardized skin-surface biopsy and a lash epilation for each lid to obtain the forehead Demodex densities and the overall lash mite count, respectively. Also, facial photographs were taken to evaluate facial erythema and dermatological conditions. The Ocular Surface Disease Index [OSDI], non-invasive break-up time [NIBUT], tear meniscus height [TMH], bulbar conjunctival redness as well as additional questions on watery eyes, ocular itching and itching along the lids were assessed. RESULTS: Both mild/moderate and severe Demodex blepharitis groups were over the cut-off value [≥ 5 mites/cm2] that confirms a facial demodicosis (mild/moderate: 5 ± 1; severe: 6 ± 1) while the control group was below it (2 ± 1). Thereby, group comparisons showed that an increased severity of Demodex blepharitis was associated with higher forehead mite densities (p = 0.002) and increased lash mite count (p < 0.001). The degree of facial erythema was also positively correlated with forehead mite densities (rs = 0.31, p = 0.02). When compared to the controls, the mild/moderate group had more watery eyes (X2 = 6.54, p = 0.02), a lower TMH (U = 100.5, p = 0.006) and the severe group had more itching along the lids (X2 = 4.94, p = 0.04). The other ocular signs and symptoms [NIBUT, bulbar conjunctival redness, OSDI] were not affected by the severity of Demodex blepharitis (p > 0.05). CONCLUSION: Palpebral and facial Demodex infestation can co-exist, as the presence of blepharitis secondary to Demodex is associated with increased facial mite densities.

The eyelash follicle features and anomalies: A review / Características y anomalías del folículo de la pestaña: revisión

The primary role of eyelashes is to protect and maintain the health of the lid margin. However, the mechanisms to fulfill this role are not fully understood. Unraveling these mechanisms will stand to greatly improve the efficiency of eye care professionals’ interventions in anomalies of the eyelashes. The aim of this article is to provide a review on eyelashes including highlights and new avenues for research; the biology of both the lash and its follicle; the pathophysiology and management of lash anomalies by eye care professionals; and the effect of iatrogenic factors on lashes. Using the database of Ovid MEDLINE, we reviewed studies specifically directed on human/mammalian eyelashes and key articles on current trends in scalp hair methodologies that can be applicable to lash research. The eyelash morphology, pigmentation and growth rate have been documented using techniques ranging from lash imaging to follicle immunohistochemistry. Furthermore, studies have demonstrated that the lash follicle is sensitive to many factors of the external environment, a variety of systemic/topical medications and cosmetics. Recently, aerodynamic studies using a mammalian eye model confirmed that an optimal lash length was needed so that eyelashes serve a protective role in reducing the number of particles that can reach the eye. Despite recent advances in lash research, studies are still scarce, due to the limited availability of the human lid for sampling. This review brings awareness that further research is needed with respect to eyelashes and will hopefully reduce the gap with scalp hair research

La función principal de las pestañas es proteger y mantener la salud del margen palpebral. Sin embargo, los mecanismos de desempeño de esta función no se comprenden plenamente. Desentrañar estos mecanismos ayudará a mejorar la eficiencia de las intervenciones de los profesionales de cuidados oculares en cuanto a las anomalías de las pestañas. El objetivo de este artículo es aportar una revisión sobre las pestañas, incluyendo los aspectos más destacados y las nuevas aportaciones para la investigación, la biología de la pestaña y su folículo, la patofisiología y tratamiento de las anomalías de las pestañas por parte de los profesionales de cuidados oculares, y el efecto de los factores iatrogénicos sobre las pestañas. Utilizando la base de datos de Ovid MEDLINE, revisamos los estudios específicamente dirigidos a las pestañas humanas/de mamíferos, así como los artículos clave sobre las tendencias actuales en cuanto a las metodologías del cuero cabelludo, que pueden aplicarse a la investigación sobre las pestañas. Se han documentado la morfología de las pestañas, así como su pigmentación y tasa de crecimiento, utilizando técnicas que oscilan entre la imagen de las pestañas y la inmunohistoquímica del folículo. Además, los estudios han demostrado que el folículo de la pestaña es sensible a diversos factores del entorno externo, diversas medicaciones sistémicas/tópicas y cosméticos. Recientemente, los estudios aerodinámicos que han utilizando un modelo de ojo de mamífero, han confirmado que se precisaba una longitud de pestañas óptima para que éstas ejercieran su función protectora a la hora de reducir el número de partículas que pueden acceder al ojo. A pesar de los avances recientes de la investigación sobre las pestañas, los estudios son aún escasos, debido a la disponibilidad limitada de párpado humano para muestreo. Esta revisión sirve de concienciación acerca de la necesidad de investigación futura con respecto a las pestañas, que reducirá presumiblemente la brecha existente con respecto a la investigación sobre el cuero cabelludo

The eyelash follicle features and anomalies: A review.

The primary role of eyelashes is to protect and maintain the health of the lid margin. However, the mechanisms to fulfill this role are not fully understood. Unraveling these mechanisms will stand to greatly improve the efficiency of eye care professionals' interventions in anomalies of the eyelashes. The aim of this article is to provide a review on eyelashes including highlights and new avenues for research; the biology of both the lash and its follicle; the pathophysiology and management of lash anomalies by eye care professionals; and the effect of iatrogenic factors on lashes. Using the database of Ovid MEDLINE, we reviewed studies specifically directed on human/mammalian eyelashes and key articles on current trends in scalp hair methodologies that can be applicable to lash research. The eyelash morphology, pigmentation and growth rate have been documented using techniques ranging from lash imaging to follicle immunohistochemistry. Furthermore, studies have demonstrated that the lash follicle is sensitive to many factors of the external environment, a variety of systemic/topical medications and cosmetics. Recently, aerodynamic studies using a mammalian eye model confirmed that an optimal lash length was needed so that eyelashes serve a protective role in reducing the number of particles that can reach the eye. Despite recent advances in lash research, studies are still scarce, due to the limited availability of the human lid for sampling. This review brings awareness that further research is needed with respect to eyelashes and will hopefully reduce the gap with scalp hair research.