Contact Lenses: Lenses designed to be worn on the front surface of the eyeball. (UMDNS, 1999)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.Contact Lens Solutions: Sterile solutions used to clean and disinfect contact lenses.Keratitis: Inflammation of the cornea.Silicones: A broad family of synthetic organosiloxane polymers containing a repeating silicon-oxygen backbone with organic side groups attached via carbon-silicon bonds. Depending on their structure, they are classified as liquids, gels, and elastomers. (From Merck Index, 12th ed)Acanthamoeba Keratitis: Infection of the cornea by an ameboid protozoan which may cause corneal ulceration leading to blindness.Lenses: Pieces of glass or other transparent materials used for magnification or increased visual acuity.Acanthamoeba: A genus of free-living soil amoebae that produces no flagellate stage. Its organisms are pathogens for several infections in humans and have been found in the eye, bone, brain, and respiratory tract.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)Tears: The fluid secreted by the lacrimal glands. This fluid moistens the CONJUNCTIVA and CORNEA.Corneal Ulcer: Loss of epithelial tissue from the surface of the cornea due to progressive erosion and necrosis of the tissue; usually caused by bacterial, fungal, or viral infection.Prosthesis Fitting: The fitting and adjusting of artificial parts of the body. (From Stedman's, 26th ed)Disposable Equipment: Apparatus, devices, or supplies intended for one-time or temporary use.Keratoconus: A noninflammatory, usually bilateral protrusion of the cornea, the apex being displaced downward and nasally. It occurs most commonly in females at about puberty. The cause is unknown but hereditary factors may play a role. The -conus refers to the cone shape of the corneal protrusion. (From Dorland, 27th ed)Lenses, Intraocular: Artificial implanted lenses.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.Corneal Edema: An excessive amount of fluid in the cornea due to damage of the epithelium or endothelium causing decreased visual acuity.Corneal Topography: The measurement of curvature and shape of the anterior surface of the cornea using techniques such as keratometry, keratoscopy, photokeratoscopy, profile photography, computer-assisted image processing and videokeratography. This measurement is often applied in the fitting of contact lenses and in diagnosing corneal diseases or corneal changes including keratoconus, which occur after keratotomy and keratoplasty.Eye Infections, Bacterial: Infections in the inner or external eye caused by microorganisms belonging to several families of bacteria. Some of the more common genera found are Haemophilus, Neisseria, Staphylococcus, Streptococcus, and Chlamydia.Corneal Diseases: Diseases of the cornea.Hydrogel: A network of cross-linked hydrophilic macromolecules used in biomedical applications.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, Extended-Wear: Hydrophilic contact lenses worn for an extended period or permanently.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 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.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.Lens Nucleus, Crystalline: The core of the crystalline lens, surrounded by the cortex.Refraction, Ocular: Refraction of LIGHT effected by the media of the EYE.Lens DiseasesDisinfection: Rendering pathogens harmless through the use of heat, antiseptics, antibacterial agents, etc.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.Hydrogels: Water swollen, rigid, 3-dimensional network of cross-linked, hydrophilic macromolecules, 20-95% water. They are used in paints, printing inks, foodstuffs, pharmaceuticals, and cosmetics. (Grant & Hackh's Chemical Dictionary, 5th ed)Fusariosis: OPPORTUNISTIC INFECTIONS with the soil fungus FUSARIUM. Typically the infection is limited to the nail plate (ONYCHOMYCOSIS). The infection can however become systemic especially in an IMMUNOCOMPROMISED HOST (e.g., NEUTROPENIA) and results in cutaneous and subcutaneous lesions, fever, KERATITIS, and pulmonary infections.Myopia: A refractive error in which rays of light entering the EYE parallel to the optic axis are brought to a focus in front of the RETINA when accommodation (ACCOMMODATION, OCULAR) is relaxed. This results from an overly curved CORNEA or from the eyeball being too long from front to back. It is also called nearsightedness.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.Equipment Contamination: The presence of an infectious agent on instruments, prostheses, or other inanimate articles.Presbyopia: The normal decreasing elasticity of the crystalline lens that leads to loss of accommodation.Fluorophotometry: Measurement of light given off by fluorescein in order to assess the integrity of various ocular barriers. The method is used to investigate the blood-aqueous barrier, blood-retinal barrier, aqueous flow measurements, corneal endothelial permeability, and tear flow dynamics.Polyhydroxyethyl Methacrylate: A biocompatible, hydrophilic, inert gel that is permeable to tissue fluids. It is used as an embedding medium for microscopy, as a coating for implants and prostheses, for contact lenses, as microspheres in adsorption research, etc.Astigmatism: Unequal curvature of the refractive surfaces of the eye. Thus a point source of light cannot be brought to a point focus on the retina but is spread over a more or less diffuse area. This results from the radius of curvature in one plane being longer or shorter than the radius at right angles to it. (Dorland, 27th ed)Eye Infections, Fungal: Infection by a variety of fungi, usually through four possible mechanisms: superficial infection producing conjunctivitis, keratitis, or lacrimal obstruction; extension of infection from neighboring structures - skin, paranasal sinuses, nasopharynx; direct introduction during surgery or accidental penetrating trauma; or via the blood or lymphatic routes in patients with underlying mycoses.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.Methylmethacrylates: The methyl esters of methacrylic acid that polymerize easily and are used as tissue cements, dental materials, and absorbent for biological substances.Epithelium, Corneal: Stratified squamous epithelium that covers the outer surface of the CORNEA. It is smooth and contains many free nerve endings.Eyelids: Each of the upper and lower folds of SKIN which cover the EYE when closed.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.Refractive Errors: Deviations from the average or standard indices of refraction of the eye through its dioptric or refractive apparatus.Disinfectants: Substances used on inanimate objects that destroy harmful microorganisms or inhibit their activity. Disinfectants are classed as complete, destroying SPORES as well as vegetative forms of microorganisms, or incomplete, destroying only vegetative forms of the organisms. They are distinguished from ANTISEPTICS, which are local anti-infective agents used on humans and other animals. (From Hawley's Condensed Chemical Dictionary, 11th ed)Eye Infections: Infection, moderate to severe, caused by bacteria, fungi, or viruses, which occurs either on the external surface of the eye or intraocularly with probable inflammation, visual impairment, or blindness.Corneal Stroma: The lamellated connective tissue constituting the thickest layer of the cornea between the Bowman and Descemet membranes.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.Orthokeratologic Procedures: An alternative to REFRACTIVE SURGICAL PROCEDURES. A therapeutic procedure for correcting REFRACTIVE ERRORS. It involves wearing CONTACT LENSES designed to force corrective changes to the curvature of the CORNEA that remain after the lenses are removed. The effect is temporary but is maintained by wearing the therapeutic lenses daily, usually during sleep.Hygiene: The science dealing with the establishment and maintenance of health in the individual and the group. It includes the conditions and practices conducive to health. (Webster, 3d ed)Silicone Elastomers: Polymers of silicone that are formed by crosslinking and treatment with amorphous silica to increase strength. They have properties similar to vulcanized natural rubber, in that they stretch under tension, retract rapidly, and fully recover to their original dimensions upon release. They are used in the encapsulation of surgical membranes and implants.Ophthalmic Solutions: Sterile solutions that are intended for instillation into the eye. It does not include solutions for cleaning eyeglasses or CONTACT LENS SOLUTIONS.Dry Eye Syndromes: Corneal and conjunctival dryness due to deficient tear production, predominantly in menopausal and post-menopausal women. Filamentary keratitis or erosion of the conjunctival and corneal epithelium may be caused by these disorders. Sensation of the presence of a foreign body in the eye and burning of the eyes may occur.Eye Diseases: Diseases affecting the eye.Hyperopia: A refractive error in which rays of light entering the eye parallel to the optic axis are brought to a focus behind the retina, as a result of the eyeball being too short from front to back. It is also called farsightedness because the near point is more distant than it is in emmetropia with an equal amplitude of accommodation. (Dorland, 27th ed)Endothelium, Corneal: Single layer of large flattened cells covering the surface of the cornea.Contact Tracing: Identification of those persons (or animals) who have had such an association with an infected person, animal, or contaminated environment as to have had the opportunity to acquire the infection. Contact tracing is a generally accepted method for the control of sexually transmitted diseases.Interferometry: Measurement of distances or movements by means of the phenomena caused by the interference of two rays of light (optical interferometry) or of sound (acoustic interferometry).Conjunctiva: The mucous membrane that covers the posterior surface of the eyelids and the anterior pericorneal surface of the eyeball.Cataract Extraction: The removal of a cataractous CRYSTALLINE LENS from the eye.Accommodation, Ocular: The dioptric adjustment of the EYE (to attain maximal sharpness of retinal imagery for an object of regard) referring to the ability, to the mechanism, or to the process. Ocular accommodation is the effecting of refractive changes by changes in the shape of the CRYSTALLINE LENS. Loosely, it refers to ocular adjustments for VISION, OCULAR at various distances. (Cline et al., Dictionary of Visual Science, 4th ed)Eye ProteinsCorneal Transplantation: Partial or total replacement of the CORNEA from one human or animal to another.Amebiasis: Infection with any of various amebae. It is an asymptomatic carrier state in most individuals, but diseases ranging from chronic, mild diarrhea to fulminant dysentery may occur.Dermatitis, Contact: A type of acute or chronic skin reaction in which sensitivity is manifested by reactivity to materials or substances coming in contact with the skin. It may involve allergic or non-allergic mechanisms.Ophthalmodynamometry: Measurement of the blood pressure of the retinal vessels. It is used also for the determination of the near point of convergence (CONVERGENCE, OCULAR). (From Cline, et al., Dictionary of Visual Science, 4th ed)Equipment Design: Methods of creating machines and devices.BiguanidesSerratia Infections: Infections with bacteria of the genus SERRATIA.Optics and Photonics: A specialized field of physics and engineering involved in studying the behavior and properties of light and the technology of analyzing, generating, transmitting, and manipulating ELECTROMAGNETIC RADIATION in the visible, infrared, and ultraviolet range.Pseudophakia: Presence of an intraocular lens after cataract extraction.Keratoplasty, Penetrating: Partial or total replacement of all layers of a central portion of the cornea.Dermatitis, Allergic Contact: A contact dermatitis due to allergic sensitization to various substances. These substances subsequently produce inflammatory reactions in the skin of those who have acquired hypersensitivity to them as a result of prior exposure.Ophthalmology: A surgical specialty concerned with the structure and function of the eye and the medical and surgical treatment of its defects and diseases.Radiation ProtectionMethacrylates: Acrylic acids or acrylates which are substituted in the C-2 position with a methyl group.Lasers, Excimer: Gas lasers with excited dimers (i.e., excimers) as the active medium. The most commonly used are rare gas monohalides (e.g., argon fluoride, xenon chloride). Their principal emission wavelengths are in the ultraviolet range and depend on the monohalide used (e.g., 193 nm for ArF, 308 nm for Xe Cl). These lasers are operated in pulsed and Q-switched modes and used in photoablative decomposition involving actual removal of tissue. (UMDNS, 2005)Pseudomonas aeruginosa: A species of gram-negative, aerobic, rod-shaped bacteria commonly isolated from clinical specimens (wound, burn, and urinary tract infections). It is also found widely distributed in soil and water. P. aeruginosa is a major agent of nosocomial infection.ConjunctivitisAcanthamoeba castellanii: A species of free-living soil amoebae in the family Acanthamoebidae. It can cause ENCEPHALITIS and KERATITIS in humans.Amebicides: Agents which are destructive to amebae, especially the parasitic species causing AMEBIASIS in man and animal.Fluorescein: A phthalic indicator dye that appears yellow-green in normal tear film and bright green in a more alkaline medium such as the aqueous humor.Fusarium: A mitosporic Hypocreales fungal genus, various species of which are important parasitic pathogens of plants and a variety of vertebrates. Teleomorphs include GIBBERELLA.Meibomian Glands: The sebaceous glands situated on the inner surface of the eyelids between the tarsal plates and CONJUNCTIVA.Eye Injuries: Damage or trauma inflicted to the eye by external means. The concept includes both surface injuries and intraocular injuries.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Pseudomonas Infections: Infections with bacteria of the genus PSEUDOMONAS.Corneal Endothelial Cell Loss: Loss of CORNEAL ENDOTHELIUM usually following intraocular surgery (e.g., cataract surgery) or due to FUCHS' ENDOTHELIAL DYSTROPHY; ANGLE-CLOSURE GLAUCOMA; IRITIS; or aging.Diagnostic Techniques, Ophthalmological: Methods and procedures for the diagnosis of diseases of the eye or of vision disorders.Blinking: Brief closing of the eyelids by involuntary normal periodic closing, as a protective measure, or by voluntary action.Conjunctival DiseasesFungi: A kingdom of eukaryotic, heterotrophic organisms that live parasitically as saprobes, including MUSHROOMS; YEASTS; smuts, molds, etc. They reproduce either sexually or asexually, and have life cycles that range from simple to complex. Filamentous fungi, commonly known as molds, refer to those that grow as multicellular colonies.Epithelium: One or more layers of EPITHELIAL CELLS, supported by the basal lamina, which covers the inner or outer surfaces of the body.Epithelial Cells: Cells that line the inner and outer surfaces of the body by forming cellular layers (EPITHELIUM) or masses. Epithelial cells lining the SKIN; the MOUTH; the NOSE; and the ANAL CANAL derive from ectoderm; those lining the RESPIRATORY SYSTEM and the DIGESTIVE SYSTEM derive from endoderm; others (CARDIOVASCULAR SYSTEM and LYMPHATIC SYSTEM) derive from mesoderm. Epithelial cells can be classified mainly by cell shape and function into squamous, glandular and transitional epithelial cells.Colony Count, Microbial: Enumeration by direct count of viable, isolated bacterial, archaeal, or fungal CELLS or SPORES capable of growth on solid CULTURE MEDIA. The method is used routinely by environmental microbiologists for quantifying organisms in AIR; FOOD; and WATER; by clinicians for measuring patients' microbial load; and in antimicrobial drug testing.
Fairness to Contact Lens Consumers Act: The Fairness to Contact Lens Consumers Act (, 117 Stat. 2025, 2026, 2027, 2028 and 2029, codified at et seq.List of soft contact lens materials: * Alphafilcon AAdvanced Medical OpticsChronic superficial keratitisSilicone resin: rightMicromirror device: Micromirror devices are devices based on microscopically small mirrors. The mirrors are Microelectromechanical systems (MEMS), which means that their states are controlled by applying a voltage between the two electrodes around the mirror arrays.Acanthamoeba infection: Acanthamoeba infection is a cutaneous condition resulting from Acanthamoeba that may result in various skin lesions. Acanthamoeba strains can also infect human eyes causing acanthamoebic keratitis.AlachrymaCorneal ulcerSingle-use bioreactor: A single-use bioreactor or disposable bioreactor is a bioreactor with a disposable bag instead of a culture vessel. Typically, this refers to a bioreactor in which the lining in contact with the cell culture will be plastic, and this lining is encased within a more permanent structure (typically, either a rocker or a cuboid or cylindrical steel support).KeratoconusIntraocular lens power calculation: The aim of an accurate intraocular lens power calculation is to provide an intraocular lens (IOL) that fits the specific needs and desires of the individual patient. The development of better instrumentation for measuring the eye's axial length (AL) and the use of more precise mathematical formulas to perform the appropriate calculations have significantly improved the accuracy with which the surgeon determines the IOL power.AphakiaRobert Atkyns (topographer): Sir Robert Atkyns (1647–1711) was a topographer, antiquary, and Member of Parliament. He is best known for his county history, the Ancient and Present State of Gloucestershire.Bullous keratopathyCongenital cataractAlta Eficacia MethodCapsulotomyRimless eyeglasses: Rimless eyeglasses, are a type of eyeglasses in which the lenses are mounted directly to the bridge and/or temples. The style is divided into two subtypes: three piece glasses are composed of lenses mounted to a bridge and two separate temple arms, while rimways (also called cortlands) feature a supporting arch that connects the temples to the bridge and provides extra stability for the lenses.LenticonusFull mouth disinfection: Full mouth disinfection typically refers to an intense course of treatment for periodontitis typically involving scaling and root planing in combination with adjunctive use of local antimicrobial adjuncts to periodontal treatment such as chlorhexidine in various ways of application. The aim is to complete debridement of all periodontal pocket areas within a short time frame such as 24 hours, in order to minimize the chance of reinfection of the pockets with pathogens coming from another oral niches like the tongue, tonsils and non-treated periodontal pocket.Fusariosis: Fusariosis is an infection seen in neutropenic patients, and is a significant opportunistic pathogen in patients with hematologic malignancy.Sustainability marketing myopia: Sustainability marketing myopia is a term used in sustainability marketing referring to a distortion stemming from the overlooking of socio-environmental attributes of a sustainable product or service at the expenses of customer benefits and values. The idea of sustainability marketing myopia is rooted into conventional marketing myopia theory, as well as green marketing myopia.LogMAR chart: A LogMAR chart comprises rows of letters and is used by ophthalmologists and vision scientists to estimate visual acuity. This chart was developed at the National Vision Research Institute of Australia in 1976, and is designed to enable a more accurate estimate of acuity as compared to other charts (e.Dispomix Technology: The Dispomix Technology is used for the homogenization of a chemical sample.PresbyopiaPolyhydroxyethylmethacrylateAstigmatism: An optical system with astigmatism is one where rays that propagate in two perpendicular planes have different focus. If an optical system with astigmatism is used to form an image of a cross, the vertical and horizontal lines will be in sharp focus at two different distances.Hay–Wells syndromeIridodonesis: Iridodonesis () is the vibration or agitated motion of the iris with eye movement. This may be caused by lens subluxation, the incomplete or partial dislocation of the lens; or by aphakia, the absence of a lens.Autorefractor: An autorefractor or automated refractor is a computer-controlled machine used during an eye examination to provide an objective measurement of a person's refractive error and prescription for glasses or contact lenses. This is achieved by measuring how light is changed as it enters a person's eye.Virkon: Virkon is a multi-purpose disinfectant. It contains oxone (potassium peroxymonosulfate), sodium dodecylbenzenesulfonate, sulfamic acid, and inorganic buffers.Guiding Eyes for the Blind: Yorktown Heights, New YorkHygiene: Hygiene is a set of practices performed for the preservation of health.Silastic: Silastic (a portmanteau of 'silicone' and 'plastic') is a trademark registered in 1948 by Dow Corning Corporation for flexible, inert silicone elastomer.Artificial tearsNeuro-ophthalmology: Neuro-ophthalmology is an academically-oriented subspecialty that merges the fields of neurology and ophthalmology, often dealing with complex systemic diseases that have manifestations in the visual system. Neuro-ophthalmologists initially complete a residency in either neurology or ophthalmology, then do a fellowship in the complementary field.Contact tracing: In epidemiology, contact tracing is the identification and diagnosis of persons who may have come into contact with an infected person. For sexually transmitted diseases, this is generally limited to sexual partners and can fall under the heading of partner services.Angle-resolved low-coherence interferometry: Angle-resolved low-coherence interferometry (a/LCI) is an emerging biomedical imaging technology which uses the properties of scattered light to measure the average size of cell structures, including cell nuclei. The technology shows promise as a clinical tool for in situ detection of dysplatic, or precancerous tissue.Conjunctiva: The conjunctiva lines the inside of the eyelids and covers the sclera (white part of the eye). It is composed of non-keratinized, stratified columnar epithelium with goblet cells, and also stratified columnar epithelium.Cataract surgerySpasm of accommodation: A spasm of accommodation (also known as an accommodation, or accommodative spasm) is a condition in which the ciliary muscle of the eye remains in a constant state of contraction. Normal accommodation allows the eye to "accommodate" for near-vision.Corneal transplantationGranulomatous amoebic encephalitisNon-invasive intracranial pressure measurement methods: Increased intracranial pressure (ICP) is one of the major causes of secondary brain ischemia that accompanies a variety of pathological conditions, most notably, traumatic brain injury (TBI), stroke, and intracranial hemorrhages. Increased intracranial pressure can cause such complications as VIIP, death, permanent neurological problems, reversible neurological problems, seizures, stroke.Beta encoder: A beta encoder is an analog to digital conversion (A/D) system in which a real number in the unit interval is represented by a finite representation of a sequence in base beta, with beta being a real number between 1 and 2. Beta encoders are an alternative to traditional approaches to pulse code modulation.Wound bed preparationSerratia infection: Serratia infection refers to a disease caused by a species in the genus Serratia.Avo PhotonicsAutomated lamellar keratoplasty: Automated Lamellar Keratoplasty, commonly abbreviated to ALK uses a device called a microkeratome to separate a thin layer of the cornea and create a flap. The flap is then folded back, and the microkeratome removes a thin disc of corneal stroma below.Contact dermatitisPediatric ophthalmology: Pediatric ophthalmology is a sub-speciality of ophthalmology concerned with eye diseases, visual development, and vision care in children.Radiation protection of patients: Patients are exposed to ionizing radiations when they undergo diagnostic examinations using x-rays or radiopharmaceuticals, therapy of cancer or benign lesions using radiations emitted by radioisotopes or those by radiation generators; and in interventional procedures using fluoroscopy. There has been a tremendous increase in the use of ionizing radiation in medicine during recent decades.Poly(methacrylic acid)Photoablation: Photoablation is the use of light or lasers to destroy tissues. The excimer laser of deep ultra-violet light is mainly used in Photoablation.GyrA RNA motif: The gyrA RNA motif is a conserved RNA structure identified by bioinformatics. The RNAs are present in multiple species of bacteria within the order Pseudomonadales.Ligneous conjunctivitis: Ligneous conjunctivitis is a rare form of chronic conjunctivitis characterized by recurrent, fibrin-rich pseudomembranous lesions of wood-like consistency that develop mainly on the underside of the eyelid (tarsal conjunctiva). It is generally a systemic disease which may involve the periodontal tissue, the upper and lower respiratory tract, kidneys, middle ear, and female genitalia.FluoresceinFusarium ear blight: 180px|thumb|right|Symptom on wheat caused by F. graminearum (right:inoculated, left:non-inoculated)Meibomian gland: The meibomian glands (or tarsal glands) are a special kind of sebaceous gland at the rim of the eyelids inside the tarsal plate, responsible for the supply of meibum, an oily substance that prevents evaporation of the eye's tear film. Meibum prevents tear spillage onto the cheek, trapping tears between the oiled edge and the eyeball, and makes the closed lids airtight.Eye injuryTemporal analysis of products: Temporal Analysis of Products (TAP), (TAP-2), (TAP-3) is an experimental technique for studyingPseudomonas infectionConjunctivochalasisMarine fungi: Marine fungi are species of fungi that live in marine or estuarine environments. They are not a taxonomic group but share a common habitat.Stratified squamous epithelium: A stratified squamous epithelium consists of squamous (flattened) epithelial cells arranged in layers upon a basal membrane. Only one layer is in contact with the basement membrane; the other layers adhere to one another to maintain structural integrity.Squamous epithelial cell: In anatomy, squamous epithelium (squama- + -ous) is that whose outermost (apical) layer consists of thin, flat cells called squamous epithelial cells. The epithelium may be composed of one layer of these cells, in which case it is referred to as simple squamous epithelium, or it may possess multiple layers, referred to then as stratified squamous epithelium.
(1/407) Estimation of corneal endothelial pump function in long-term contact lens wearers.
PURPOSE: To study the effects of long-term contact lens wear on morphologic and physiologic properties of corneal endothelial cells. METHODS: The endothelial permeability to fluorescein and the rate of corneal deswelling from hypoxia-induced edema were measured in 20 long-term (mean, 17+/-9 years; range, 5-33 years) contact lens wearers and 20 age-matched control subjects. From these data, the relative endothelial pump rate in each subject was estimated, based on the pump-leak hypothesis of corneal hydration control. Corneal autofluorescence and the aqueous humor flow rate were determined by fluorescein fluorophotometry. Images of corneal endothelial cells were recorded by using specular microscopy, and morphologic indices (cell density, coefficient of variation of cell area, percentage of hexagonal cells, and skewness) were determined. RESULTS: No statistically significant differences were found between the contact lens and control groups in endothelial permeability, corneal deswelling, relative endothelial pump rate ([mean +/- SD] 1.07+/-0.33 relative pump units versus 1.01+/-0.25 relative pump units; contact lens versus control; P = 0.57), and endothelial cell density. Contact lens wearers had a significantly higher aqueous humor flow rate (3.57+/-1.03 microl/min versus 2.77+/-0.51 microl/min; P = 0.005), coefficient of variation of cell area (0.35+/-0.09 versus 0.28+/-0.04; P = 0.006), and corneal autofluorescence (3.1+/-0.6 ng/ml versus 2.3+/-0.3 ng/ml fluorescein equivalents; P < 0.001) than did non-contact lens wearers. CONCLUSIONS: Despite the known effects of long-term contact lens wear on corneal endothelial morphometry, no effect on endothelial function was found. (+info)
(2/407) Contact lens-induced infection--a new model of Candida albicans keratitis.
PURPOSE: A model of experimental keratomycosis was established that mimics human disease in which the only fungi present are those that are actively growing within the cornea. METHODS: Dutch-belted rabbits received a subconjunctival injection of triamcinolone acetonide to one eye. One day later the epithelium was removed from the central cornea and a standardized inoculum of Candida albicans blastoconidia was placed on the corneal surface and covered with a contact lens. The lids were closed with a lateral tarsorrhaphy. After 24 hours, the lid sutures and contact lens were removed. Five days later the animals were killed, and their corneas were subjected to separate isolate recovery and histology studies. A group of similarly infected rabbits without corticosteroid injection served as controls. RESULTS: Both groups developed invasive corneal disease. Although isolate recovery was not significantly different from corticosteroid-treated rabbits compared with controls, fungal biomass was increased. Hyphal invasion was limited to the anterior cornea in control eyes, but penetrated deep stroma in most of the corticosteroid-treated rabbits. CONCLUSIONS: Invasive corneal disease can be established with a surface inoculum. Corticosteroid administration increased corneal penetration of hyphae. Quantitative isolate recovery is not a reliable measure of the fungal load within the cornea. (+info)
(3/407) Clinical estimation of corneal endothelial pump function.
PURPOSE: To develop a technique to estimate the corneal endothelial pump rate in human subjects. METHODS: Corneal hydration control is thought to be maintained by a pump-leak mechanism whereby the leak of solutes and fluid across the endothelial barrier into the stroma is, in the steady state, exactly balanced by the pumping of solutes and passive fluid transfer across the endothelium to the aqueous humor. Overall corneal hydration control can be measured from the rate at which the swollen cornea thins (deswells), and a measure of the leak can be obtained simultaneously from the endothelial permeability to fluorescein. From the pump-leak hypothesis, the deswelling rate is directly proportional to the pump rate and inversely proportional to the leak rate. The relative endothelial pump rate can be estimated as the product of the normalized deswelling rate and the normalized endothelial permeability. This procedure was used to obtain the relative endothelial pump rate in 41 patients with diabetes mellitus, 12 patients with long-term corneal transplants, 20 long-term wearers of contact lenses, and 19 normal volunteer subjects after the short-term administration of topical dorzolamide. RESULTS: The relative endothelial pump rate did not differ significantly from that of control subjects in diabetics, in contact lens wearers, and after dorzolamide administration, but was markedly decreased in the patients with corneal transplants, despite a reduction in permeability (reduced leak). CONCLUSIONS: This method allows the estimation of both the barrier and pump arms of corneal endothelial function and should be useful in the investigation of causes and mechanisms of functional endothelial insufficiency. (+info)
(4/407) Rehabilitation of children with cataracts.
Over a period of 10 years, 160 children with cataracts underwent operation at the University of Tennessee Medical Center, Memphis. The surgical, optical, and psychosocial rehabilitation of these patients was analyzed and studied. The optical rehabilitation included patients with glasses, intraocular lens implants, epikeratophakia, and contact lenses. Seventy three of these patients were chosen at random and reevaluated as to visual outcome, and 46 were subjected to a psychosocial test to evaluate their quality of life and their rehabilitation. Eighteen of these were also given a psychosocial test to evaluate the quality of life enjoyed by these children at an older age following treatment for the cataract. Surgical, optical, and psychosocial rehabilitation of such children is also discussed. This is the first report of the psychological evaluation of such children. The further needs of these children as they approach adulthood are discussed in detail. (+info)
(5/407) Rapid improvement in the acuity of infants after visual input.
Visual acuity was assessed in 28 human infants who had been deprived of all patterned visual input by cataracts in one or both eyes until they were treated at 1 week to 9 months of age. Immediately after treatment, acuity was no better than that of normal newborns. Acuity improved significantly over the next month, with some improvement apparent after as little as 1 hour of visual input. Unlike findings at older ages, the pattern of results was the same for eyes treated for monocular and for binocular deprivation. The results indicate that patterned visual input is necessary for the postnatal improvement of human visual acuity and that the onset of such input initiates rapid functional development. (+info)
(6/407) Measurement of post-lens tear thickness.
PURPOSE: A method to measure the tear film beneath a soft contact lens, referred to as post-lens tear thickness (PLTT), would have many applications to contact lens research. In this study a noninvasive technique for measuring the PLTT is presented. METHODS: The feasibility of measuring the tear layer by optical pachometry was first assessed using a model eye. The baseline corneal thickness (B) of both eyes of 21 subjects was measured, etafilcon-A ionic disposable soft contact lenses (58% water) were inserted, and the total thickness (T) of the cornea, contact lens, and PLTT were measured. After the pachometry readings the lenses were removed and their center thickness (C) determined. The PLTT was calculated using the equation: PLTT = T-(B+C). Two sets of measurements of T were performed at 15 and 25 minutes after lens insertion. The entire procedure was repeated at a second visit. RESULTS: The pachometry measurements of the small aqueous reservoir between the model eye and the lens closely matched those obtained by direct microscopic measurement. For human PLTT, the mean values (and 95% confidence intervals) for right eyes on visits 1 and 2 were 11 (8, 13) and 12 (10, 15) microm, respectively, and for left eyes were 12 (10, 15) and 11 microm (8, 14) microm, respectively. CONCLUSIONS: It is possible to measure the post-lens tear thickness using optical pachometry. The variability between repeated measurements suggests that with careful sample size planning, the technique is sufficiently precise to be useful in group assessments of PLTT. (+info)
(7/407) Isoenzyme patterns and phylogenetic relationships in Acanthamoeba spp. isolated from contact lens containers in Korea.
In order to refer to the basic information regarding the identification of isolates obtained from a contact lens container in Korea, the isoelectric focusing gel electrophoresis was employed to compare the isoenzyme band patterns among Acanthamoeba spp. including eight isolates and the simple pairwise dissimilarity analysis was carried out. For an alkaline phosphate development, isolate 7 and Acanthamoeba polyphaga showed homologous band patterns, and isolates 1, 2, and 3 showed the same patterns. For lactate dehydrogenase, similar patterns were observed in isolates 2 and 3. Isolates 3 and 5 showed homologous band patterns for malate dehydrogenase and glucose phosphate isomerase. For hexokinase, isolates 4, 7, and A, hatchetti showed the same band patterns. In others, a considerable number of interstrain polymorphisms was observed in nine isoenzyme band patterns. In Acanthamoeba group II, genetic distances among isolates 1, 2, 3, 4, and 5 ranged from 0.104 to 0.200. In comparison to A. castellanii, A. hatchetti, and A. polyphaga, genetic distances of isolates 7 and 8 were 0.254 and 0.219, respectively. In Acanthamoeba group III, including A. culbertsoni, A. healyi, and A. royreba, isolate 6 had genetic distances which ranged from 0.314 to 0.336. Finally, when comparing to the six reference Acanthamoeba, it was possible to classify isolates 1, 2, 3, 4, and 5, as genetically close-related species and as independent species group. Furthermore, isolates 6, 7 and 8 were identified as independent species as well. (+info)
(8/407) Clinical course of hurricane keratopathy.
BACKGROUND/AIMS: "Hurricane keratopathy" is the name given to the whorl pattern, highlighted with fluorescein, seen in situations where corneal epithelial cell turnover is exaggerated. Although the condition is well described, follow up data on patients with this condition and its sequelae have only been reported in corneal graft patients. The aim was to study the clinical course of hurricane keratopathy in corneal graft patients and contact lens wearers, and to document any sequelae of this condition. METHODS: Hurricane keratopathy, occurring in 20 eyes with corneal grafts and 16 eyes (six bilateral) wearing rigid gas permeable contact lenses, was studied and followed. The occurrence, pattern, progress, resolution, and residual effects of the whorls were noted. RESULTS: Hurricane keratopathy was noted to occur in grafts as previously reported and also in contact lens wearers, which has hitherto not been reported. The whorls usually appeared within the first 3 weeks postoperatively and persisted up to 4 months. A small epithelial defect (11.1%), heaped epithelial cells (5.6%), and a nebular grade opacity (2.8%), were the only significant sequelae noted at the epicentre of the whorls. Resolution occurred from the periphery towards the centre of the cornea. CONCLUSIONS: The whorl pattern is sustained as long as the stimulus for increased cell turnover is maintained. Once this stimulus is eliminated, the pattern tends to resolve spontaneously. (+info)