ABSTRACT
It is well established that Demodectic mites can infest the meibomian glands, eyelash and hair follicles of the eyelid. In this study, scanning electron microscopy revealed Demodex folliculorum occurring freely on the skin surface of the eyelid. This indicates some mobility and implies further vector potential. Exoskeletons from these parasites also occur on the eyelid.
Subject(s)
Eyelids/ultrastructure , Mites/ultrastructure , Animals , Arachnid Vectors/ultrastructure , Humans , Microscopy, Electron, Scanning , Middle AgedSubject(s)
Cysts/etiology , Eyelid Diseases/etiology , Mite Infestations , Foreign-Body Reaction/etiology , HumansABSTRACT
The normally torpid existence of demodectic mites of the eyelid changes with the onset of oviposition. There occurs a burst of activity characterized by flexion, extension and rotation.
Subject(s)
Eyelids , Mites/anatomy & histology , Oviposition , Animals , Female , HumansSubject(s)
Eyelashes/parasitology , Eyelid Diseases/parasitology , Mite Infestations/parasitology , Mites/physiology , Animals , Female , Humans , MaleABSTRACT
Hair-follicle mites are the only metazoan organism commonly found in the pilosebaceous components of the eyelid of man. Our study showed that Demodex folliculorum in all stages is found in the small hair follicles and the eyelash hair follicles. This species, in adult and immature forms, consumes epithelial cells, produces follicular distension and hyperplasia, and increases keratinization leading, in eyelashes, to cuffing consisting of keratin and lipid moieties. Demodex brevis (in all stages) is present in the eyelash sebaceous glands, small hair sebaceous glands, and in the lobules of the meibomian glands. Adults and immature forms consume the gland cells in all of these loci and, when infestations are heavy, can affect the formation of the superficial lipid layer of the tear film coacervate. Comparative studies of demodicids from man and other mammals suggest that keratinization, hyperplasia, distension, and melanocyte aggregation may be even more extensive if large populations of D. folliculorum build up in the follicles of the eyelid. Large populations of D. brevis may destroy the glandular cells, produce granuloma in the eyelid, and plug the ducts of the meibomian or sebaceous glands. Further studies may incriminate either or both species, in conjunction with microorganisms, as transfer agents or synergists, or both, in producing ocular disease in man. Prevention and control of these mites must await experimental studies with infested laboratory animals (such as the squirrel monkey, Saimiri sciureus). These mites are probably most vulnerable during transfer stages, when they leave their glandular or follicular habitats.
Subject(s)
Eyelashes/parasitology , Eyelid Diseases/parasitology , Mite Infestations , Eyelid Diseases/pathology , Hair Diseases/parasitology , Humans , Meibomian Glands/parasitology , Meibomian Glands/pathology , Mite Infestations/parasitology , Mite Infestations/pathologyABSTRACT
Histological studies of pterygium pathology, reveals the presence of goblet cells liberally distributed throughout the epithelial surface. This feature poses medical and surgical implications which are discussed.
Subject(s)
Conjunctiva/ultrastructure , Pterygium/pathology , Epithelium/ultrastructure , Humans , Microscopy, ElectronABSTRACT
The full-thickness eyebrow graft constitutes a valuable technique in restoring resected or devitalized brow tissue. Proper brow appearance may be obtained with this technique.
