Lens Nucleus, Crystalline: The core of the crystalline lens, surrounded by the cortex.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)Lens Cortex, Crystalline: The portion of the crystalline lens surrounding the nucleus and bound anteriorly by the epithelium and posteriorly by the capsule. It contains lens fibers and amorphous, intercellular substance.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.Crystallins: A heterogeneous family of water-soluble structural proteins found in cells of the vertebrate lens. The presence of these proteins accounts for the transparency of the lens. The family is composed of four major groups, alpha, beta, gamma, and delta, and several minor groups, which are classed on the basis of size, charge, immunological properties, and vertebrate source. Alpha, beta, and delta crystallins occur in avian and reptilian lenses, while alpha, beta, and gamma crystallins occur in all other lenses.Presbyopia: The normal decreasing elasticity of the crystalline lens that leads to loss of accommodation.Two-Dimensional Difference Gel Electrophoresis: Methods of comparing two or more samples on the same two-dimensional gel electrophoresis gel.gamma-Crystallins: A subclass of crystallins that found in the lens (LENS, CRYSTALLINE) of VERTEBRATES. Gamma-crystallins are similar in structure to BETA-CRYSTALLINS in that they both form into a Greek key-like structure. They are composed of monomeric subunits.Cell Nucleus: Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (CELL NUCLEOLUS). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the ENDOPLASMIC RETICULUM. A cell may contain more than one nucleus. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)Lenses: Pieces of glass or other transparent materials used for magnification or increased visual acuity.Eye ProteinsContact Lenses: Lenses designed to be worn on the front surface of the eyeball. (UMDNS, 1999)Aging: The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.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.Lenses, Intraocular: Artificial implanted lenses.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.Lens DiseasesNucleus Accumbens: Collection of pleomorphic cells in the caudal part of the anterior horn of the LATERAL VENTRICLE, in the region of the OLFACTORY TUBERCLE, lying between the head of the CAUDATE NUCLEUS and the ANTERIOR PERFORATED SUBSTANCE. It is part of the so-called VENTRAL STRIATUM, a composite structure considered part of the BASAL GANGLIA.Contact Lenses, Extended-Wear: Hydrophilic contact lenses worn for an extended period or permanently.Lens Subluxation: Incomplete rupture of the zonule with the displaced lens remaining behind the pupil. In dislocation, or complete rupture, the lens is displaced forward into the anterior chamber or backward into the vitreous body. When congenital, this condition is known as ECTOPIA LENTIS.Contact Lens Solutions: Sterile solutions used to clean and disinfect contact lenses.Thalamic Nuclei: Several groups of nuclei in the thalamus that serve as the major relay centers for sensory impulses in the brain.Solitary Nucleus: GRAY MATTER located in the dorsomedial part of the MEDULLA OBLONGATA associated with the solitary tract. The solitary nucleus receives inputs from most organ systems including the terminations of the facial, glossopharyngeal, and vagus nerves. It is a major coordinator of AUTONOMIC NERVOUS SYSTEM regulation of cardiovascular, respiratory, gustatory, gastrointestinal, and chemoreceptive aspects of HOMEOSTASIS. The solitary nucleus is also notable for the large number of NEUROTRANSMITTERS which are found therein.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.Dictionaries, MedicalDictionaries as Topic: Lists of words, usually in alphabetical order, giving information about form, pronunciation, etymology, grammar, and meaning.Dictionaries, ChemicalTerminology as Topic: The terms, expressions, designations, or symbols used in a particular science, discipline, or specialized subject area.Patents as Topic: Exclusive legal rights or privileges applied to inventions, plants, etc.Corneal Edema: An excessive amount of fluid in the cornea due to damage of the epithelium or endothelium causing decreased visual acuity.Culture Media: Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.Salamandridae: A family of Urodela consisting of 15 living genera and about 42 species and occurring in North America, Europe, Asia, and North Africa.Fallopian Tubes: A pair of highly specialized muscular canals extending from the UTERUS to its corresponding OVARY. They provide the means for OVUM collection, and the site for the final maturation of gametes and FERTILIZATION. The fallopian tube consists of an interstitium, an isthmus, an ampulla, an infundibulum, and fimbriae. Its wall consists of three histologic layers: serous, muscular, and an internal mucosal layer lined with both ciliated and secretory cells.Blastocyst: A post-MORULA preimplantation mammalian embryo that develops from a 32-cell stage into a fluid-filled hollow ball of over a hundred cells. A blastocyst has two distinctive tissues. The outer layer of trophoblasts gives rise to extra-embryonic tissues. The inner cell mass gives rise to the embryonic disc and eventual embryo proper.Cornea: The transparent anterior portion of the fibrous coat of the eye consisting of five layers: stratified squamous CORNEAL EPITHELIUM; BOWMAN MEMBRANE; CORNEAL STROMA; DESCEMET MEMBRANE; and mesenchymal CORNEAL ENDOTHELIUM. It serves as the first refracting medium of the eye. It is structurally continuous with the SCLERA, avascular, receiving its nourishment by permeation through spaces between the lamellae, and is innervated by the ophthalmic division of the TRIGEMINAL NERVE via the ciliary nerves and those of the surrounding conjunctiva which together form plexuses. (Cline et al., Dictionary of Visual Science, 4th ed)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)Egg Shell: A hard or leathery calciferous exterior covering of an egg.International Council of Nurses: An international professional organization composed of one association per country for the purpose of improving and developing nursing's contribution to the promotion of health and care of the sick.Iodine: A nonmetallic element of the halogen group that is represented by the atomic symbol I, atomic number 53, and atomic weight of 126.90. It is a nutritionally essential element, especially important in thyroid hormone synthesis. In solution, it has anti-infective properties and is used topically.Ophthalmology: A surgical specialty concerned with the structure and function of the eye and the medical and surgical treatment of its defects and diseases.Eye Diseases: Diseases affecting the eye.United StatesInternational Cooperation: The interaction of persons or groups of persons representing various nations in the pursuit of a common goal or interest.Ophthalmologic Surgical Procedures: Surgery performed on the eye or any of its parts.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.Cataract Extraction: The removal of a cataractous CRYSTALLINE LENS from the eye.Drug Substitution: The practice of replacing one prescribed drug with another that is expected to have the same clinical or psychological effect.Refractive Errors: Deviations from the average or standard indices of refraction of the eye through its dioptric or refractive apparatus.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)Corneal Surgery, Laser: Surgical techniques on the CORNEA employing LASERS, especially for reshaping the CORNEA to correct REFRACTIVE ERRORS.ExhibitionsGreeceExhibits as Topic: Discussions, descriptions or catalogs of public displays or items representative of a given subject.MuseumsEducation, Medical, Continuing: Educational programs designed to inform physicians of recent advances in their field.