Visual Prosthesis: Artificial device such as an externally-worn camera attached to a stimulator on the RETINA, OPTIC NERVE, or VISUAL CORTEX, intended to restore or amplify vision.Phosphenes: A subjective visual sensation with the eyes closed and in the absence of light. Phosphenes can be spontaneous, or induced by chemical, electrical, or mechanical (pressure) stimuli which cause the visual field to light up without optical inputs.Sensory Aids: Devices that help people with impaired sensory responses.Blindness: The inability to see or the loss or absence of perception of visual stimuli. This condition may be the result of EYE DISEASES; OPTIC NERVE DISEASES; OPTIC CHIASM diseases; or BRAIN DISEASES affecting the VISUAL PATHWAYS or OCCIPITAL LOBE.Prostheses and Implants: Artificial substitutes for body parts, and materials inserted into tissue for functional, cosmetic, or therapeutic purposes. Prostheses can be functional, as in the case of artificial arms and legs, or cosmetic, as in the case of an artificial eye. Implants, all surgically inserted or grafted into the body, tend to be used therapeutically. IMPLANTS, EXPERIMENTAL is available for those used experimentally.Electrodes, Implanted: Surgically placed electric conductors through which ELECTRIC STIMULATION is delivered to or electrical activity is recorded from a specific point inside the body.Prosthesis Design: The plan and delineation of prostheses in general or a specific prosthesis.Ancient Lands: Geographical sites known to be extant in a remote period in the history of civilization, familiar as the names of ancient countries and empires.Visual Cortex: Area of the OCCIPITAL LOBE concerned with the processing of visual information relayed via VISUAL PATHWAYS.Prosthesis Failure: Malfunction of implantation shunts, valves, etc., and prosthesis loosening, migration, and breaking.Evoked Potentials, Visual: The electric response evoked in the cerebral cortex by visual stimulation or stimulation of the visual pathways.Visual Perception: The selecting and organizing of visual stimuli based on the individual's past experience.Knee Prosthesis: Replacement for a knee joint.Hip Prosthesis: Replacement for a hip joint.Penile Prosthesis: Rigid, semi-rigid, or inflatable cylindric hydraulic devices, with either combined or separate reservoir and pumping systems, implanted for the surgical treatment of organic ERECTILE DYSFUNCTION.Visual Acuity: Clarity or sharpness of OCULAR VISION or the ability of the eye to see fine details. Visual acuity depends on the functions of RETINA, neuronal transmission, and the interpretative ability of the brain. Normal visual acuity is expressed as 20/20 indicating that one can see at 20 feet what should normally be seen at that distance. Visual acuity can also be influenced by brightness, color, and contrast.Heart Valve Prosthesis: A device that substitutes for a heart valve. It may be composed of biological material (BIOPROSTHESIS) and/or synthetic material.Visual Fields: The total area or space visible in a person's peripheral vision with the eye looking straightforward.Visual Pathways: Set of cell bodies and nerve fibers conducting impulses from the eyes to the cerebral cortex. It includes the RETINA; OPTIC NERVE; optic tract; and geniculocalcarine tract.Artificial Limbs: Prosthetic replacements for arms, legs, and parts thereof.Prosthesis Implantation: Surgical insertion of a prosthesis.Prosthesis Fitting: The fitting and adjusting of artificial parts of the body. (From Stedman's, 26th ed)Neural Prostheses: Medical devices which substitute for a nervous system function by electrically stimulating the nerves directly and monitoring the response to the electrical stimulation.Ossicular Prosthesis: An implant used to replace one or more of the ear ossicles. They are usually made of plastic, Gelfoam, ceramic, or stainless steel.Dental Prosthesis: An artificial replacement for one or more natural teeth or part of a tooth, or associated structures, ranging from a portion of a tooth to a complete denture. The dental prosthesis is used for cosmetic or functional reasons, or both. DENTURES and specific types of dentures are also available. (From Boucher's Clinical Dental Terminology, 4th ed, p244 & Jablonski, Dictionary of Dentistry, 1992, p643)Sexology: This discipline concerns the study of SEXUALITY, and the application of sexual knowledge such as sexual attitudes, psychology, and SEXUAL BEHAVIOR. Scope of application generally includes educational (SEX EDUCATION), clinical (SEX COUNSELING), and other settings.Retinitis Pigmentosa: Hereditary, progressive degeneration of the neuroepithelium of the retina characterized by night blindness and progressive contraction of the visual field.Retina: The ten-layered nervous tissue membrane of the eye. It is continuous with the OPTIC NERVE and receives images of external objects and transmits visual impulses to the brain. Its outer surface is in contact with the CHOROID and the inner surface with the VITREOUS BODY. The outer-most layer is pigmented, whereas the inner nine layers are transparent.Short-Wave Therapy: The use of focused short radio waves to produce local hyperthermia in an injured person or diseased body area.Cochlear Implants: Electronic hearing devices typically used for patients with normal outer and middle ear function, but defective inner ear function. In the COCHLEA, the hair cells (HAIR CELLS, VESTIBULAR) may be absent or damaged but there are residual nerve fibers. The device electrically stimulates the COCHLEAR NERVE to create sound sensation.Patents as Topic: Exclusive legal rights or privileges applied to inventions, plants, etc.Electrodes: Electric conductors through which electric currents enter or leave a medium, whether it be an electrolytic solution, solid, molten mass, gas, or vacuum.Epiretinal Membrane: A membrane on the vitreal surface of the retina resulting from the proliferation of one or more of three retinal elements: (1) fibrous astrocytes; (2) fibrocytes; and (3) retinal pigment epithelial cells. Localized epiretinal membranes may occur at the posterior pole of the eye without clinical signs or may cause marked loss of vision as a result of covering, distorting, or detaching the fovea centralis. Epiretinal membranes may cause vascular leakage and secondary retinal edema. In younger individuals some membranes appear to be developmental in origin and occur in otherwise normal eyes. The majority occur in association with retinal holes, ocular concussions, retinal inflammation, or after ocular surgery. (Newell, Ophthalmology: Principles and Concepts, 7th ed, p291)Dental Implantation: The grafting or inserting of a prosthetic device of alloplastic material into the oral tissue beneath the mucosal or periosteal layer or within the bone. Its purpose is to provide support and retention to a partial or complete denture.Vitrectomy: Removal of the whole or part of the vitreous body in treating endophthalmitis, diabetic retinopathy, retinal detachment, intraocular foreign bodies, and some types of glaucoma.Eye, Artificial: A ready-made or custom-made prosthesis of glass or plastic shaped and colored to resemble the anterior portion of a normal eye and used for cosmetic reasons. It is attached to the anterior portion of an orbital implant (ORBITAL IMPLANTS) which is placed in the socket of an enucleated or eviscerated eye. (From Dorland, 28th ed)Prosthesis Coloring: Coloring, shading, or tinting of prosthetic components, devices, and materials.RomeEye Enucleation: The surgical removal of the eyeball leaving the eye muscles and remaining orbital contents intact.Orbital Implants: Rounded objects made of coral, teflon, or alloplastic polymer and covered with sclera, and which are implanted in the orbit following enucleation. An artificial eye (EYE, ARTIFICIAL) is usually attached to the anterior of the orbital implant for cosmetic purposes.Encyclopedias as Topic: Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)Blood-Brain Barrier: Specialized non-fenestrated tightly-joined ENDOTHELIAL CELLS with TIGHT JUNCTIONS that form a transport barrier for certain substances between the cerebral capillaries and the BRAIN tissue.Microscopy, Electron: Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.United StatesMicroscopy, Electron, Scanning: Microscopy in which the object is examined directly by an electron beam scanning the specimen point-by-point. The image is constructed by detecting the products of specimen interactions that are projected above the plane of the sample, such as backscattered electrons. Although SCANNING TRANSMISSION ELECTRON MICROSCOPY also scans the specimen point by point with the electron beam, the image is constructed by detecting the electrons, or their interaction products that are transmitted through the sample plane, so that is a form of TRANSMISSION ELECTRON MICROSCOPY.Nucleic Acid Conformation: The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Central Nervous System: The main information-processing organs of the nervous system, consisting of the brain, spinal cord, and meninges.Electric Stimulation: Use of electric potential or currents to elicit biological responses.Probability: The study of chance processes or the relative frequency characterizing a chance process.Lymphocyte Activation: Morphologic alteration of small B LYMPHOCYTES or T LYMPHOCYTES in culture into large blast-like cells able to synthesize DNA and RNA and to divide mitotically. It is induced by INTERLEUKINS; MITOGENS such as PHYTOHEMAGGLUTININS, and by specific ANTIGENS. It may also occur in vivo as in GRAFT REJECTION.Kinetics: The rate dynamics in chemical or physical systems.Deep Brain Stimulation: Therapy for MOVEMENT DISORDERS, especially PARKINSON DISEASE, that applies electricity via stereotactic implantation of ELECTRODES in specific areas of the BRAIN such as the THALAMUS. The electrodes are attached to a neurostimulator placed subcutaneously.