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.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.Artificial Lens Implant Migration: The shifting and or tilting of implanted artificial lens resulting in impaired vision.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)Pupil: The aperture in the iris through which light passes.Posterior Capsular Rupture, Ocular: A breach in the continuity of the posterior chamber of the eyeball.Anterior Chamber: The space in the eye, filled with aqueous humor, bounded anteriorly by the cornea and a small portion of the sclera and posteriorly by a small portion of the ciliary body, the iris, and that part of the crystalline lens which presents through the pupil. (Cline et al., Dictionary of Visual Science, 4th ed, p109)Anterior Capsular Rupture, Ocular: A breach in the continuity of the ANTERIOR CHAMBER of the eyeball.Aphakia, Postcataract: Absence of the crystalline lens resulting from cataract extraction.Research Support, U.S. Gov't, Non-P.H.S.Research Support, U.S. Gov't, P.H.S.Copyright: It is a form of protection provided by law. In the United States this protection is granted to authors of original works of authorship, including literary, dramatic, musical, artistic, and certain other intellectual works. This protection is available to both published and unpublished works. (from Circular of the United States Copyright Office, 6/30/2008)Vision, Entoptic: Visual sensation derived from sensory stimulation by objects or shadows inside the eye itself, such as floating vitreous fibers, tissues, or blood.Periodicals as Topic: A publication issued at stated, more or less regular, intervals.Ophthalmology: A surgical specialty concerned with the structure and function of the eye and the medical and surgical treatment of its defects and diseases.Publishing: "The business or profession of the commercial production and issuance of literature" (Webster's 3d). It includes the publisher, publication processes, editing and editors. Production may be by conventional printing methods or by electronic publishing.Neuromyelitis Optica: A syndrome characterized by acute OPTIC NEURITIS; MYELITIS, TRANSVERSE; demyelinating and/or necrotizing lesions in the OPTIC NERVES and SPINAL CORD; and presence of specific autoantibodies to AQUAPORIN 4.Optic Neuritis: Inflammation of the optic nerve. Commonly associated conditions include autoimmune disorders such as MULTIPLE SCLEROSIS, infections, and granulomatous diseases. Clinical features include retro-orbital pain that is aggravated by eye movement, loss of color vision, and contrast sensitivity that may progress to severe visual loss, an afferent pupillary defect (Marcus-Gunn pupil), and in some instances optic disc hyperemia and swelling. Inflammation may occur in the portion of the nerve within the globe (neuropapillitis or anterior optic neuritis) or the portion behind the globe (retrobulbar neuritis or posterior optic neuritis).Laser Coagulation: The use of green light-producing LASERS to stop bleeding. The green light is selectively absorbed by HEMOGLOBIN, thus triggering BLOOD COAGULATION.Tomography, Optical Coherence: An imaging method using LASERS that is used for mapping subsurface structure. When a reflective site in the sample is at the same optical path length (coherence) as the reference mirror, the detector observes interference fringes.Aquaporin 4: Aquaporin 4 is the major water-selective channel in the CENTRAL NERVOUS SYSTEM of mammals.Vision Tests: A series of tests used to assess various functions of the eyes.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)Tonometry, Ocular: Measurement of ocular tension (INTRAOCULAR PRESSURE) with a tonometer. (Cline, et al., Dictionary of Visual Science, 4th ed)Ophthalmoscopy: Examination of the interior of the eye with an ophthalmoscope.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.Photopheresis: A process in which peripheral blood is exposed in an extracorporeal flow system to photoactivated 8-methoxypsoralen (METHOXSALEN) and ultraviolet light - a procedure known as PUVA THERAPY. Photopheresis is at present a standard therapy for advanced cutaneous T-cell lymphoma; it shows promise in the treatment of autoimmune diseases.PUVA Therapy: Photochemotherapy using PSORALENS as the photosensitizing agent and ultraviolet light type A (UVA).Methoxsalen: A naturally occurring furocoumarin compound found in several species of plants, including Psoralea corylifolia. It is a photoactive substance that forms DNA ADDUCTS in the presence of ultraviolet A irradiation.Graft vs Host Disease: The clinical entity characterized by anorexia, diarrhea, loss of hair, leukopenia, thrombocytopenia, growth retardation, and eventual death brought about by the GRAFT VS HOST REACTION.Extracorporeal Circulation: Diversion of blood flow through a circuit located outside the body but continuous with the bodily circulation.Lymphoma, T-Cell, Cutaneous: A group of lymphomas exhibiting clonal expansion of malignant T-lymphocytes arrested at varying stages of differentiation as well as malignant infiltration of the skin. MYCOSIS FUNGOIDES; SEZARY SYNDROME; LYMPHOMATOID PAPULOSIS; and PRIMARY CUTANEOUS ANAPLASTIC LARGE CELL LYMPHOMA are the best characterized of these disorders.Sezary Syndrome: A form of cutaneous T-cell lymphoma manifested by generalized exfoliative ERYTHRODERMA; PRURITUS; peripheral lymphadenopathy, and abnormal hyperchromatic mononuclear (cerebriform) cells in the skin, LYMPH NODES, and peripheral blood (Sezary cells).Comparative Effectiveness Research: Conduct and synthesis of systematic research comparing interventions and strategies to prevent, diagnose, treat, and monitor health conditions. The purpose of this research is to inform patients, providers, and decision-makers, responding to their expressed needs, about which interventions are most effective for which patients under specific circumstances. (hhs.gov/recovery/programs/cer/draftdefinition.html accessed 6/12/2009)Macular Edema: Fluid accumulation in the outer layer of the MACULA LUTEA that results from intraocular or systemic insults. It may develop in a diffuse pattern where the macula appears thickened or it may acquire the characteristic petaloid appearance referred to as cystoid macular edema. Although macular edema may be associated with various underlying conditions, it is most commonly seen following intraocular surgery, venous occlusive disease, DIABETIC RETINOPATHY, and posterior segment inflammatory disease. (From Survey of Ophthalmology 2004; 49(5) 470-90)Intravitreal Injections: The administration of substances into the VITREOUS BODY of the eye with a hypodermic syringe.Diabetic Retinopathy: Disease of the RETINA as a complication of DIABETES MELLITUS. It is characterized by the progressive microvascular complications, such as ANEURYSM, interretinal EDEMA, and intraocular PATHOLOGIC NEOVASCULARIZATION.Angiogenesis Inhibitors: Agents and endogenous substances that antagonize or inhibit the development of new blood vessels.Triamcinolone Acetonide: An esterified form of TRIAMCINOLONE. It is an anti-inflammatory glucocorticoid used topically in the treatment of various skin disorders. Intralesional, intramuscular, and intra-articular injections are also administered under certain conditions.