Aphakia: Absence of crystalline lens totally or partially from field of vision, from any cause except after cataract extraction. Aphakia is mainly congenital or as result of LENS DISLOCATION AND SUBLUXATION.Endophthalmitis: Suppurative inflammation of the tissues of the internal structures of the eye frequently associated with an infection.Aphakia, Postcataract: Absence of the crystalline lens resulting from cataract extraction.Contact Lenses: Lenses designed to be worn on the front surface of the eyeball. (UMDNS, 1999)Pseudophakia: Presence of an intraocular lens after cataract extraction.Cataract Extraction: The removal of a cataractous CRYSTALLINE LENS from the eye.Lenses, Intraocular: Artificial implanted lenses.Lens Implantation, Intraocular: Insertion of an artificial lens to replace the natural CRYSTALLINE LENS after CATARACT EXTRACTION or to supplement the natural lens which is left in place.Cataract: Partial or complete opacity on or in the lens or capsule of one or both eyes, impairing vision or causing blindness. The many kinds of cataract are classified by their morphology (size, shape, location) or etiology (cause and time of occurrence). (Dorland, 27th ed)Contact Lenses, Hydrophilic: Soft, supple contact lenses made of plastic polymers which interact readily with water molecules. Many types are available, including continuous and extended-wear versions, which are gas-permeable and easily sterilized.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.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.Microphthalmos: Congenital or developmental anomaly in which the eyeballs are abnormally small.Hyphema: Bleeding in the anterior chamber of the eye.Persistent Hyperplastic Primary Vitreous: A developmental ocular anomaly in which the primary VITREOUS BODY and its surrounding hyaloid vasculature failed to regress. It is usually unilateral and characterized by CATARACT; MICROPHTHALMOS (small eyeballs), and retrolenticular fibrovascular tissue. (from Yanoff: Ophthalmology, 2nd ed.)Refractive Errors: Deviations from the average or standard indices of refraction of the eye through its dioptric or refractive apparatus.Aniseikonia: A condition in which the ocular image of an object as seen by one eye differs in size and shape from that seen by the other.Eyeglasses: A pair of ophthalmic lenses in a frame or mounting which is supported by the nose and ears. The purpose is to aid or improve vision. It does not include goggles or nonprescription sun glasses for which EYE PROTECTIVE DEVICES is available.Nebulizers and Vaporizers: Devices that cause a liquid or solid to be converted into an aerosol (spray) or a vapor. It is used in drug administration by inhalation, humidification of ambient air, and in certain analytical instruments.Cerebral Aqueduct: Narrow channel in the MESENCEPHALON that connects the third and fourth CEREBRAL VENTRICLES.Malformations of Cortical Development: Abnormalities in the development of the CEREBRAL CORTEX. These include malformations arising from abnormal neuronal and glial CELL PROLIFERATION or APOPTOSIS (Group I); abnormal neuronal migration (Group II); and abnormal establishment of cortical organization (Group III). Many INBORN METABOLIC BRAIN DISORDERS affecting CNS formation are often associated with cortical malformations. They are common causes of EPILEPSY and developmental delay.Syndrome: A characteristic symptom complex.Language: A verbal or nonverbal means of communicating ideas or feelings.Aerosols: Colloids with a gaseous dispersing phase and either liquid (fog) or solid (smoke) dispersed phase; used in fumigation or in inhalation therapy; may contain propellant agents.Administration, Inhalation: The administration of drugs by the respiratory route. It includes insufflation into the respiratory tract.Research Support, U.S. Gov't, Non-P.H.S.Research Support, U.S. Gov't, P.H.S.Sister Mary Joseph's Nodule: Metastatic lesion of the UMBILICUS associated with intra-abdominal neoplasms especially of the GASTROINTESTINAL TRACT or OVARY.Concept Formation: A cognitive process involving the formation of ideas generalized from the knowledge of qualities, aspects, and relations of objects.Umbilicus: The pit in the center of the ABDOMINAL WALL marking the point where the UMBILICAL CORD entered in the FETUS.Authorship: The profession of writing. Also the identity of the writer as the creator of a literary production.Word Association Tests: Lists of words to which individuals are asked to respond ascertaining the conceptual meaning held by the individual.Publications: Copies of a work or document distributed to the public by sale, rental, lease, or lending. (From ALA Glossary of Library and Information Science, 1983, p181)Terminology as Topic: The terms, expressions, designations, or symbols used in a particular science, discipline, or specialized subject area.Intraocular Pressure: The pressure of the fluids in the eye.Trabeculectomy: Any surgical procedure for treatment of glaucoma by means of puncture or reshaping of the trabecular meshwork. It includes goniotomy, trabeculectomy, and laser perforation.Burial: The act or ceremony of putting a corpse into the ground or a vault, or into the sea; or the inurnment of CREMAINS.Congresses as Topic: Conferences, conventions or formal meetings usually attended by delegates representing a special field of interest.ItalyMass Vaccination: Administration of a vaccine to large populations in order to elicit IMMUNITY.TexasFaculty: The teaching staff and members of the administrative staff having academic rank in an educational institution.Faculty, Medical: The teaching staff and members of the administrative staff having academic rank in a medical school.Capsulorhexis: The making of a continuous circular tear in the anterior capsule during cataract surgery in order to allow expression or phacoemulsification of the nucleus of the lens. (Dorland, 28th ed)Lens Capsule, Crystalline: The thin noncellular outer covering of the CRYSTALLINE LENS composed mainly of COLLAGEN TYPE IV and GLYCOSAMINOGLYCANS. It is secreted by the embryonic anterior and posterior epithelium. The embryonic posterior epithelium later disappears.Phacoemulsification: A procedure for removal of the crystalline lens in cataract surgery in which an anterior capsulectomy is performed by means of a needle inserted through a small incision at the temporal limbus, allowing the lens contents to fall through the dilated pupil into the anterior chamber where they are broken up by the use of ultrasound and aspirated out of the eye through the incision. (Cline, et al., Dictionary of Visual Science, 4th ed & In Focus 1993;1(1):1)Rivers: Large natural streams of FRESH WATER formed by converging tributaries and which empty into a body of water (lake or ocean).Eye: The organ of sight constituting a pair of globular organs made up of a three-layered roughly spherical structure specialized for receiving and responding to light.Lens, Crystalline: A transparent, biconvex structure of the EYE, enclosed in a capsule and situated behind the IRIS and in front of the vitreous humor (VITREOUS BODY). It is slightly overlapped at its margin by the ciliary processes. Adaptation by the CILIARY BODY is crucial for OCULAR ACCOMMODATION.Night Blindness: Failure or imperfection of vision at night or in dim light, with good vision only on bright days. (Dorland, 27th ed)