Nitrogen Fixation: The process in certain BACTERIA; FUNGI; and CYANOBACTERIA converting free atmospheric NITROGEN to biologically usable forms of nitrogen, such as AMMONIA; NITRATES; and amino compounds.Fixation, Ocular: The positioning and accommodation of eyes that allows the image to be brought into place on the FOVEA CENTRALIS of each eye.Fracture Fixation: The use of metallic devices inserted into or through bone to hold a fracture in a set position and alignment while it heals.Complement Fixation Tests: Serologic tests based on inactivation of complement by the antigen-antibody complex (stage 1). Binding of free complement can be visualized by addition of a second antigen-antibody system such as red cells and appropriate red cell antibody (hemolysin) requiring complement for its completion (stage 2). Failure of the red cells to lyse indicates that a specific antigen-antibody reaction has taken place in stage 1. If red cells lyse, free complement is present indicating no antigen-antibody reaction occurred in stage 1.Tissue Fixation: The technique of using FIXATIVES in the preparation of cytologic, histologic, or pathologic specimens for the purpose of maintaining the existing form and structure of all the constituent elements.Ocular Hypertension: A condition in which the intraocular pressure is elevated above normal and which may lead to glaucoma.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.Bone Screws: Specialized devices used in ORTHOPEDIC SURGERY to repair bone fractures.Toxoplasmosis, Ocular: Infection caused by the protozoan parasite TOXOPLASMA in which there is extensive connective tissue proliferation, the retina surrounding the lesions remains normal, and the ocular media remain clear. Chorioretinitis may be associated with all forms of toxoplasmosis, but is usually a late sequel of congenital toxoplasmosis. The severe ocular lesions in infants may lead to blindness.Bone Plates: Implantable fracture fixation devices attached to bone fragments with screws to bridge the fracture gap and shield the fracture site from stress as bone heals. (UMDNS, 1999)External Fixators: External devices which hold wires or pins that are placed through one or both cortices of bone in order to hold the position of a fracture in proper alignment. These devices allow easy access to wounds, adjustment during the course of healing, and more functional use of the limbs involved.Fixatives: Agents employed in the preparation of histologic or pathologic specimens for the purpose of maintaining the existing form and structure of all of the constituent elements. Great numbers of different agents are used; some are also decalcifying and hardening agents. They must quickly kill and coagulate living tissue.Dominance, Ocular: The functional superiority and preferential use of one eye over the other. The term is usually applied to superiority in sighting (VISUAL PERCEPTION) or motor task but not difference in VISUAL ACUITY or dysfunction of one of the eyes. Ocular dominance can be modified by visual input and NEUROTROPHIC FACTORS.Fracture Fixation, Intramedullary: The use of nails that are inserted into bone cavities in order to keep fractured bones together.Albinism, Ocular: Albinism affecting the eye in which pigment of the hair and skin is normal or only slightly diluted. The classic type is X-linked (Nettleship-Falls), but an autosomal recessive form also exists. Ocular abnormalities may include reduced pigmentation of the iris, nystagmus, photophobia, strabismus, and decreased visual acuity.Refraction, Ocular: Refraction of LIGHT effected by the media of the EYE.Orthopedic Fixation Devices: Devices which are used in the treatment of orthopedic injuries and diseases.Tonometry, Ocular: Measurement of ocular tension (INTRAOCULAR PRESSURE) with a tonometer. (Cline, et al., Dictionary of Visual Science, 4th ed)Ocular Physiological Phenomena: Processes and properties of the EYE as a whole or of any of its parts.Eye Neoplasms: Tumors or cancer of the EYE.Internal Fixators: Internal devices used in osteosynthesis to hold the position of the fracture in proper alignment. By applying the principles of biomedical engineering, the surgeon uses metal plates, nails, rods, etc., for the correction of skeletal defects.Eye Movements: Voluntary or reflex-controlled movements of the eye.Bone Wires: Steel wires, often threaded through the skin, soft tissues, and bone, used to fix broken bones. Kirschner wires or apparatus also includes the application of traction to the healing bones through the wires.Ocular Motility Disorders: Disorders that feature impairment of eye movements as a primary manifestation of disease. These conditions may be divided into infranuclear, nuclear, and supranuclear disorders. Diseases of the eye muscles or oculomotor cranial nerves (III, IV, and VI) are considered infranuclear. Nuclear disorders are caused by disease of the oculomotor, trochlear, or abducens nuclei in the BRAIN STEM. Supranuclear disorders are produced by dysfunction of higher order sensory and motor systems that control eye movements, including neural networks in the CEREBRAL CORTEX; BASAL GANGLIA; CEREBELLUM; and BRAIN STEM. Ocular torticollis refers to a head tilt that is caused by an ocular misalignment. Opsoclonus refers to rapid, conjugate oscillations of the eyes in multiple directions, which may occur as a parainfectious or paraneoplastic condition (e.g., OPSOCLONUS-MYOCLONUS SYNDROME). (Adams et al., Principles of Neurology, 6th ed, p240)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)Bone Nails: Rods of bone, metal, or other material used for fixation of the fragments or ends of fractured bones.Eye Injuries: Damage or trauma inflicted to the eye by external means. The concept includes both surface injuries and intraocular injuries.Fracture Healing: The physiological restoration of bone tissue and function after a fracture. It includes BONY CALLUS formation and normal replacement of bone tissue.Intraocular Pressure: The pressure of the fluids in the eye.Saccades: An abrupt voluntary shift in ocular fixation from one point to another, as occurs in reading.Tuberculosis, Ocular: Tuberculous infection of the eye, primarily the iris, ciliary body, and choroid.Tears: The fluid secreted by the lacrimal glands. This fluid moistens the CONJUNCTIVA and CORNEA.Ophthalmic Solutions: Sterile solutions that are intended for instillation into the eye. It does not include solutions for cleaning eyeglasses or CONTACT LENS SOLUTIONS.Fractures, Comminuted: A fracture in which the bone is splintered or crushed. (Dorland, 27th ed)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.Tibial FracturesEye Infections, Parasitic: Mild to severe infections of the eye and its adjacent structures (adnexa) by adult or larval protozoan or metazoan parasites.Conjunctival DiseasesVision, Ocular: The process in which light signals are transformed by the PHOTORECEPTOR CELLS into electrical signals which can then be transmitted to the brain.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.Uveitis: Inflammation of part or all of the uvea, the middle (vascular) tunic of the eye, and commonly involving the other tunics (sclera and cornea, and the retina). (Dorland, 27th ed)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.Sclera: The white, opaque, fibrous, outer tunic of the eyeball, covering it entirely excepting the segment covered anteriorly by the cornea. It is essentially avascular but contains apertures for vessels, lymphatics, and nerves. It receives the tendons of insertion of the extraocular muscles and at the corneoscleral junction contains the canal of Schlemm. (From Cline et al., Dictionary of Visual Science, 4th ed)ConjunctivitisOcular Hypotension: Abnormally low intraocular pressure often related to chronic inflammation (uveitis).Formaldehyde: A highly reactive aldehyde gas formed by oxidation or incomplete combustion of hydrocarbons. In solution, it has a wide range of uses: in the manufacture of resins and textiles, as a disinfectant, and as a laboratory fixative or preservative. Formaldehyde solution (formalin) is considered a hazardous compound, and its vapor toxic. (From Reynolds, Martindale The Extra Pharmacopoeia, 30th ed, p717)Fractures, Ununited: A fracture in which union fails to occur, the ends of the bone becoming rounded and eburnated, and a false joint occurs. (Stedman, 25th ed)Convergence, Ocular: The turning inward of the lines of sight toward each other.Femoral Fractures: Fractures of the femur.Nitrogenase: An enzyme system that catalyzes the fixing of nitrogen in soil bacteria and blue-green algae (CYANOBACTERIA). EC 126.96.36.199.Aqueous Humor: The clear, watery fluid which fills the anterior and posterior chambers of the eye. It has a refractive index lower than the crystalline lens, which it surrounds, and is involved in the metabolism of the cornea and the crystalline lens. (Cline et al., Dictionary of Visual Science, 4th ed, p319)Vitreous Body: The transparent, semigelatinous substance that fills the cavity behind the CRYSTALLINE LENS of the EYE and in front of the RETINA. It is contained in a thin hyaloid membrane and forms about four fifths of the optic globe.Anterior Eye Segment: The front third of the eyeball that includes the structures between the front surface of the cornea and the front of the VITREOUS BODY.Humeral FracturesCorneal Diseases: Diseases of the cornea.Iris: The most anterior portion of the uveal layer, separating the anterior chamber from the posterior. It consists of two layers - the stroma and the pigmented epithelium. Color of the iris depends on the amount of melanin in the stroma on reflection from the pigmented epithelium.Fractures, Closed: Fractures in which the break in bone is not accompanied by an external wound.Vision, Binocular: The blending of separate images seen by each eye into one composite image.Ciliary Body: A ring of tissue extending from the scleral spur to the ora serrata of the RETINA. It consists of the uveal portion and the epithelial portion. The ciliary muscle is in the uveal portion and the ciliary processes are in the epithelial portion.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.Glaucoma: An ocular disease, occurring in many forms, having as its primary characteristics an unstable or a sustained increase in the intraocular pressure which the eye cannot withstand without damage to its structure or impairment of its function. The consequences of the increased pressure may be manifested in a variety of symptoms, depending upon type and severity, such as excavation of the optic disk, hardness of the eyeball, corneal anesthesia, reduced visual acuity, seeing of colored halos around lights, disturbed dark adaptation, visual field defects, and headaches. (Dictionary of Visual Science, 4th ed)Eye Abnormalities: Congenital absence of or defects in structures of the eye; may also be hereditary.Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.Glutaral: One of the protein CROSS-LINKING REAGENTS that is used as a disinfectant for sterilization of heat-sensitive equipment and as a laboratory reagent, especially as a fixative.Osmium: Osmium. A very hard, gray, toxic, and nearly infusible metal element, atomic number 76, atomic weight 190.2, symbol Os. (From Dorland, 28th ed)Fractures, Bone: Breaks in bones.Strabismus: Misalignment of the visual axes of the eyes. In comitant strabismus the degree of ocular misalignment does not vary with the direction of gaze. In noncomitant strabismus the degree of misalignment varies depending on direction of gaze or which eye is fixating on the target. (Miller, Walsh & Hoyt's Clinical Neuro-Ophthalmology, 4th ed, p641)Spinal Fusion: Operative immobilization or ankylosis of two or more vertebrae by fusion of the vertebral bodies with a short bone graft or often with diskectomy or laminectomy. (From Blauvelt & Nelson, A Manual of Orthopaedic Terminology, 5th ed, p236; Dorland, 28th ed)Choroid: The thin, highly vascular membrane covering most of the posterior of the eye between the RETINA and SCLERA.Oculomotor Muscles: The muscles that move the eye. Included in this group are the medial rectus, lateral rectus, superior rectus, inferior rectus, inferior oblique, superior oblique, musculus orbitalis, and levator palpebrae superioris.Histological Techniques: Methods of preparing tissue for examination and study of the origin, structure, function, or pathology.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)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)Femoral Neck Fractures: Fractures of the short, constricted portion of the thigh bone between the femur head and the trochanters. It excludes intertrochanteric fractures which are HIP FRACTURES.Carbon Cycle: The cycle by which the element carbon is exchanged between organic matter and the earth's physical environment.Administration, Ophthalmic: Application of pharmaceutically active agents on the tissues of the EYE.AcetyleneEyelids: Each of the upper and lower folds of SKIN which cover the EYE when closed.DislocationsEye 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.Refractive Errors: Deviations from the average or standard indices of refraction of the eye through its dioptric or refractive apparatus.Surgical Fixation Devices: Devices used to hold tissue structures together for repair, reconstruction or to close wounds. They may consist of adsorbable or non-adsorbable, natural or synthetic materials. They include tissue adhesives, skin tape, sutures, buttons, staples, clips, screws, etc., each designed to conform to various tissue geometries.Symbiosis: The relationship between two different species of organisms that are interdependent; each gains benefits from the other or a relationship between different species where both of the organisms in question benefit from the presence of the other.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.Eye Movement Measurements: Methods and procedures for recording EYE MOVEMENTS.Visual Fields: The total area or space visible in a person's peripheral vision with the eye looking straightforward.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Range of Motion, Articular: The distance and direction to which a bone joint can be extended. Range of motion is a function of the condition of the joints, muscles, and connective tissues involved. Joint flexibility can be improved through appropriate MUSCLE STRETCHING EXERCISES.Fractures, Open: Fractures in which there is an external wound communicating with the break of the bone.Onchocerciasis, Ocular: Filarial infection of the eyes transmitted from person to person by bites of Onchocerca volvulus-infected black flies. The microfilariae of Onchocerca are thus deposited beneath the skin. They migrate through various tissues including the eye. Those persons infected have impaired vision and up to 20% are blind. The incidence of eye lesions has been reported to be as high as 30% in Central America and parts of Africa.Pemphigoid, Benign Mucous Membrane: A chronic blistering disease with predilection for mucous membranes and less frequently the skin, and with a tendency to scarring. It is sometimes called ocular pemphigoid because of conjunctival mucous membrane involvement.Ophthalmologic Surgical Procedures: Surgery performed on the eye or any of its parts.Retinal DiseasesEpithelium, Corneal: Stratified squamous epithelium that covers the outer surface of the CORNEA. It is smooth and contains many free nerve endings.Retrospective Studies: Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.Photic Stimulation: Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light flashes or visual patterns are used to elicit brain activity.Chorioretinitis: Inflammation of the choroid in which the sensory retina becomes edematous and opaque. The inflammatory cells and exudate may burst through the sensory retina to cloud the vitreous body.Rabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.Prosthesis Design: The plan and delineation of prostheses in general or a specific prosthesis.Glaucoma, Open-Angle: Glaucoma in which the angle of the anterior chamber is open and the trabecular meshwork does not encroach on the base of the iris.Administration, Topical: The application of drug preparations to the surfaces of the body, especially the skin (ADMINISTRATION, CUTANEOUS) or mucous membranes. This method of treatment is used to avoid systemic side effects when high doses are required at a localized area or as an alternative systemic administration route, to avoid hepatic processing for example.Keratitis: Inflammation of the cornea.Pelvic Bones: Bones that constitute each half of the pelvic girdle in VERTEBRATES, formed by fusion of the ILIUM; ISCHIUM; and PUBIC BONE.Osteotomy: The surgical cutting of a bone. (Dorland, 28th ed)Foreign-Body Migration: Migration of a foreign body from its original location to some other location in the body.Atlanto-Axial Joint: The joint involving the CERVICAL ATLAS and axis bones.Bone Transplantation: The grafting of bone from a donor site to a recipient site.Nystagmus, Pathologic: Involuntary movements of the eye that are divided into two types, jerk and pendular. Jerk nystagmus has a slow phase in one direction followed by a corrective fast phase in the opposite direction, and is usually caused by central or peripheral vestibular dysfunction. Pendular nystagmus features oscillations that are of equal velocity in both directions and this condition is often associated with visual loss early in life. (Adams et al., Principles of Neurology, 6th ed, p272)Osseointegration: The growth action of bone tissue as it assimilates surgically implanted devices or prostheses to be used as either replacement parts (e.g., hip) or as anchors (e.g., endosseous dental implants).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.Eye Infections, Viral: Infections of the eye caused by minute intracellular agents. These infections may lead to severe inflammation in various parts of the eye - conjunctiva, iris, eyelids, etc. Several viruses have been identified as the causative agents. Among these are Herpesvirus, Adenovirus, Poxvirus, and Myxovirus.Clavicle: A bone on the ventral side of the shoulder girdle, which in humans is commonly called the collar bone.Follow-Up Studies: Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.Root Nodules, Plant: Knobbed structures formed from and attached to plant roots, especially of LEGUMES, which result from symbiotic infection by nitrogen fixing bacteria such as RHIZOBIUM or FRANKIA. Root nodules are structures related to MYCORRHIZAE formed by symbiotic associations with fungi.Blepharitis: Inflammation of the eyelids.Fundus Oculi: The concave interior of the eye, consisting of the retina, the choroid, the sclera, the optic disk, and blood vessels, seen by means of the ophthalmoscope. (Cline et al., Dictionary of Visual Science, 4th ed)Vision Disorders: Visual impairments limiting one or more of the basic functions of the eye: visual acuity, dark adaptation, color vision, or peripheral vision. These may result from EYE DISEASES; OPTIC NERVE DISEASES; VISUAL PATHWAY diseases; OCCIPITAL LOBE diseases; OCULAR MOTILITY DISORDERS; and other conditions (From Newell, Ophthalmology: Principles and Concepts, 7th ed, p132).Fovea Centralis: An area approximately 1.5 millimeters in diameter within the macula lutea where the retina thins out greatly because of the oblique shifting of all layers except the pigment epithelium layer. It includes the sloping walls of the fovea (clivus) and contains a few rods in its periphery. In its center (foveola) are the cones most adapted to yield high visual acuity, each cone being connected to only one ganglion cell. (Cline et al., Dictionary of Visual Science, 4th ed)Suture Techniques: Techniques for securing together the edges of a wound, with loops of thread or similar materials (SUTURES).AxisProsthesis Failure: Malfunction of implantation shunts, valves, etc., and prosthesis loosening, migration, and breaking.Vision, Monocular: Images seen by one eye.Postoperative Complications: Pathologic processes that affect patients after a surgical procedure. They may or may not be related to the disease for which the surgery was done, and they may or may not be direct results of the surgery.Biomechanical Phenomena: The properties, processes, and behavior of biological systems under the action of mechanical forces.Wrist Injuries: Injuries to the wrist or the wrist joint.Scotoma: A localized defect in the visual field bordered by an area of normal vision. This occurs with a variety of EYE DISEASES (e.g., RETINAL DISEASES and GLAUCOMA); OPTIC NERVE DISEASES, and other conditions.Shoulder Fractures: Fractures of the proximal humerus, including the head, anatomic and surgical necks, and tuberosities.Scleritis: Refers to any inflammation of the sclera including episcleritis, a benign condition affecting only the episclera, which is generally short-lived and easily treated. Classic scleritis, on the other hand, affects deeper tissue and is characterized by higher rates of visual acuity loss and even mortality, particularly in necrotizing form. Its characteristic symptom is severe and general head pain. Scleritis has also been associated with systemic collagen disease. Etiology is unknown but is thought to involve a local immune response. Treatment is difficult and includes administration of anti-inflammatory and immunosuppressive agents such as corticosteroids. Inflammation of the sclera may also be secondary to inflammation of adjacent tissues, such as the conjunctiva.Carbon Dioxide: A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.Intra-Articular Fractures: Fractures of the articular surface of a bone.Cadaver: A dead body, usually a human body.Pupil: The aperture in the iris through which light passes.Timolol: A beta-adrenergic antagonist similar in action to PROPRANOLOL. The levo-isomer is the more active. Timolol has been proposed as an antihypertensive, antiarrhythmic, antiangina, and antiglaucoma agent. It is also used in the treatment of MIGRAINE DISORDERS and tremor.Keratitis, Herpetic: A superficial, epithelial Herpesvirus hominis infection of the cornea, characterized by the presence of small vesicles which may break down and coalesce to form dendritic ulcers (KERATITIS, DENDRITIC). (Dictionary of Visual Science, 3d ed)Reoperation: A repeat operation for the same condition in the same patient due to disease progression or recurrence, or as followup to failed previous surgery.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)Spinal Fractures: Broken bones in the vertebral column.Prostaglandins F, Synthetic: Analogs or derivatives of prostaglandins F that do not occur naturally in the body. They do not include the product of the chemical synthesis of hormonal PGF.Coloboma: Congenital anomaly in which some of the structures of the eye are absent due to incomplete fusion of the fetal intraocular fissure during gestation.Sutures: Materials used in closing a surgical or traumatic wound. (From Dorland, 28th ed)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.Conjunctival Neoplasms: Tumors or cancer of the CONJUNCTIVA.Sensory Deprivation: The absence or restriction of the usual external sensory stimuli to which the individual responds.Femur: The longest and largest bone of the skeleton, it is situated between the hip and the knee.Odontoid Process: The toothlike process on the upper surface of the axis, which articulates with the CERVICAL ATLAS above.ReadingEye ProteinsOphthalmoscopy: Examination of the interior of the eye with an ophthalmoscope.Recovery of Function: A partial or complete return to the normal or proper physiologic activity of an organ or part following disease or trauma.Rotation: Motion of an object in which either one or more points on a line are fixed. It is also the motion of a particle about a fixed point. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Fractures, Malunited: Union of the fragments of a fractured bone in a faulty or abnormal position. If two bones parallel to one another unite by osseous tissue, the result is a crossunion. (From Manual of Orthopaedic Terminology, 4th ed)Corneal Opacity: Disorder occurring in the central or peripheral area of the cornea. The usual degree of transparency becomes relatively opaque.Uvea: The pigmented vascular coat of the eyeball, consisting of the CHOROID; CILIARY BODY; and IRIS, which are continuous with each other. (Cline et al., Dictionary of Visual Science, 4th ed)Visual Perception: The selecting and organizing of visual stimuli based on the individual's past experience.Titanium: A dark-gray, metallic element of widespread distribution but occurring in small amounts; atomic number, 22; atomic weight, 47.90; symbol, Ti; specific gravity, 4.5; used for fixation of fractures. (Dorland, 28th ed)Pursuit, Smooth: Eye movements that are slow, continuous, and conjugate and occur when a fixed object is moved slowly.Eye Burns: Injury to any part of the eye by extreme heat, chemical agents, or ultraviolet radiation.Bone Cements: Adhesives used to fix prosthetic devices to bones and to cement bone to bone in difficult fractures. Synthetic resins are commonly used as cements. A mixture of monocalcium phosphate, monohydrate, alpha-tricalcium phosphate, and calcium carbonate with a sodium phosphate solution is also a useful bone paste.Lacrimal Apparatus: The tear-forming and tear-conducting system which includes the lacrimal glands, eyelid margins, conjunctival sac, and the tear drainage system.Diagnostic Techniques, Ophthalmological: Methods and procedures for the diagnosis of diseases of the eye or of vision disorders.Diplopia: A visual symptom in which a single object is perceived by the visual cortex as two objects rather than one. Disorders associated with this condition include REFRACTIVE ERRORS; STRABISMUS; OCULOMOTOR NERVE DISEASES; TROCHLEAR NERVE DISEASES; ABDUCENS NERVE DISEASES; and diseases of the BRAIN STEM and OCCIPITAL LOBE.Keratitis, Dendritic: A form of herpetic keratitis characterized by the formation of small vesicles which break down and coalesce to form recurring dendritic ulcers, characteristically irregular, linear, branching, and ending in knoblike extremities. (Dictionary of Visual Science, 3d ed)Iritis: Inflammation of the iris characterized by circumcorneal injection, aqueous flare, keratotic precipitates, and constricted and sluggish pupil along with discoloration of the iris.Uveitis, Anterior: Inflammation of the anterior uvea comprising the iris, angle structures, and the ciliary body. Manifestations of this disorder include ciliary injection, exudation into the anterior chamber, iris changes, and adhesions between the iris and lens (posterior synechiae). Intraocular pressure may be increased or reduced.Orthopedic Procedures: Procedures used to treat and correct deformities, diseases, and injuries to the MUSCULOSKELETAL SYSTEM, its articulations, and associated structures.Arthrodesis: The surgical fixation of a joint by a procedure designed to accomplish fusion of the joint surfaces by promoting the proliferation of bone cells. (Dorland, 28th ed)Nitrogen: An element with the atomic symbol N, atomic number 7, and atomic weight [14.00643; 14.00728]. Nitrogen exists as a diatomic gas and makes up about 78% of the earth's atmosphere by volume. It is a constituent of proteins and nucleic acids and found in all living cells.Cervical Atlas: The first cervical vertebra.Autotrophic Processes: The processes by which organisms use simple inorganic substances such as gaseous or dissolved carbon dioxide and inorganic nitrogen as nutrient sources. Contrasts with heterotrophic processes which make use of organic materials as the nutrient supply source. Autotrophs can be either chemoautotrophs (or chemolithotrophs), largely ARCHAEA and BACTERIA, which also use simple inorganic substances for their metabolic energy reguirements; or photoautotrophs (or photolithotrophs), such as PLANTS and CYANOBACTERIA, which derive their energy from light. Depending on environmental conditions some organisms can switch between different nutritional modes (autotrophy; HETEROTROPHY; chemotrophy; or PHOTOTROPHY) to utilize different sources to meet their nutrient and energy requirements.Retinal Vessels: The blood vessels which supply and drain the RETINA.Eyelid DiseasesMicroscopy, 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.Keratoconjunctivitis: Simultaneous inflammation of the cornea and conjunctiva.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.Orbit: Bony cavity that holds the eyeball and its associated tissues and appendages.Cervical Vertebrae: The first seven VERTEBRAE of the SPINAL COLUMN, which correspond to the VERTEBRAE of the NECK.Fibula: The bone of the lower leg lateral to and smaller than the tibia. In proportion to its length, it is the most slender of the long bones.Freeze Substitution: A modification of the freeze-drying method in which the ice within the frozen tissue is replaced by alcohol or other solvent at a very low temperature.Hip Prosthesis: Replacement for a hip joint.Scaphoid Bone: The bone which is located most lateral in the proximal row of CARPAL BONES.Volar Plate: A thick, fibrocartilaginous ligament at the metacarpophalageal joint.Microphthalmos: Congenital or developmental anomaly in which the eyeballs are abnormally small.Prospective Studies: Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.Tibia: The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the FIBULA laterally, the TALUS distally, and the FEMUR proximally.Staining and Labeling: The marking of biological material with a dye or other reagent for the purpose of identifying and quantitating components of tissues, cells or their extracts.Eye Foreign Bodies: Inanimate objects that become enclosed in the eye.Ophthalmic Artery: Artery originating from the internal carotid artery and distributing to the eye, orbit and adjacent facial structures.Preservatives, Pharmaceutical: Substances added to pharmaceutical preparations to protect them from chemical change or microbial action. They include ANTI-BACTERIAL AGENTS and antioxidants.Joint Instability: Lack of stability of a joint or joint prosthesis. Factors involved are intra-articular disease and integrity of extra-articular structures such as joint capsule, ligaments, and muscles.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)Conjunctivitis, Allergic: Conjunctivitis due to hypersensitivity to various allergens.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.Burns, ChemicalOculomotor Nerve: The 3d cranial nerve. The oculomotor nerve sends motor fibers to the levator muscles of the eyelid and to the superior rectus, inferior rectus, and inferior oblique muscles of the eye. It also sends parasympathetic efferents (via the ciliary ganglion) to the muscles controlling pupillary constriction and accommodation. The motor fibers originate in the oculomotor nuclei of the midbrain.Sacrum: Five fused VERTEBRAE forming a triangle-shaped structure at the back of the PELVIS. It articulates superiorly with the LUMBAR VERTEBRAE, inferiorly with the COCCYX, and anteriorly with the ILIUM of the PELVIS. The sacrum strengthens and stabilizes the PELVIS.Histocytological Preparation Techniques: Methods of preparing cells or tissues for examination and study of their origin, structure, function, or pathology. The methods include preservation, fixation, sectioning, staining, replica, or other technique to allow for viewing using a microscope.Eye Enucleation: The surgical removal of the eyeball leaving the eye muscles and remaining orbital contents intact.Visual Field Tests: Method of measuring and mapping the scope of vision, from central to peripheral of each eye.Visual Cortex: Area of the OCCIPITAL LOBE concerned with the processing of visual information relayed via VISUAL PATHWAYS.Photosynthesis: The synthesis by organisms of organic chemical compounds, especially carbohydrates, from carbon dioxide using energy obtained from light rather than from the oxidation of chemical compounds. Photosynthesis comprises two separate processes: the light reactions and the dark reactions. In higher plants; GREEN ALGAE; and CYANOBACTERIA; NADPH and ATP formed by the light reactions drive the dark reactions which result in the fixation of carbon dioxide. (from Oxford Dictionary of Biochemistry and Molecular Biology, 2001)Conjunctivitis, Viral: Inflammation, often mild, of the conjunctiva caused by a variety of viral agents. Conjunctival involvement may be part of a systemic infection.
Appendix EMV13 Fusion Maldevelopment Nystagmus Syndrome Adducting Eye Fixation Ocular Motor System Model ... MV10 Infantile Nystagmus Syndrome (Pseudo Pendular with Foveating Saccades) 1/2-Speed Ocular Motor System Model Ramp and Step- ... MV7 Infantile Nystagmus Syndrome (Pseudo Pendular with Foveating Saccades) 1/2-Speed from Ocular Motor System Model and Patient ... MV9 Infantile Nystagmus Syndrome (Pseudo Pendular with Foveating Saccades) 1/2-Speed Pulse Responses Ocular Motor System Model ...
Count-rate analysis from clinical scans in PET with LSO detectors.19847469 - An exploration of ocular fixation in parkinson's disease, multiple system atrophy and p.... 20014189 - Endocarditis ...
Ocular findings in Norwegian patients with ataxia-telangiectasia: a 5 year prospective cohort study - Riise - 2007 - Acta...4). The evaluation of ocular fixation for 5 years is shown in Table 2. Normal fixation was lost in all patients over the age of ... Ocular fixation was unstable, with small intruding saccades and tendency to ocular flutter and sometimes nystagmus beats (Fig. ... Ocular motility was analysed for ocular fixation, smooth pursuit movements, saccades and optokinetic nystagmus. The findings ... Table 2. Ocular fixation / Smooth pursuit movements / Saccades in ten Norwegian patients with AT for five consecutive years. ( ...
Distributions of within-word landing positions for word | Open-iWe found that the average fraction of mislocated fixations ranges from about 10% to more than 30% depending on word length. ... We found that the average fraction of mislocated fixations ranges from about 10% to more than 30% depending on word length. ... Here we propose a new procedure for the self-consistent estimation of the likelihood of mislocated fixations in normal reading ... Here we propose a new procedure for the self-consistent estimation of the likelihood of mislocated fixations in normal reading ...
Patent US6373961 - Eye controllable screen pointer - Google PatentsMethod and apparatus for determining ocular gaze point of regard and fixation duration. ... Method and apparatus for using generic software applications by means of ocular control and suitable methods of interaction. ... Method and apparatus for controlling the operation of an operating system and application programs by ocular control. ...
metabolism in muscle and nervesSpontaneous ocular movements, fixation, pursuit; visual function •Respiration and circulation •Appetite •Seizures Clinical/ ...
Hypnosis Facts - Comedy Stage Hypnotist... "protracted ocular fixation". Remember the movies where a hypnotist would swing a watch hung from a chain in front of his ...
Persistent ocular tremors appear to be associated with Parkinson's diseasePersistent ocular tremors that prevent eye stability during fixation appear to be common among patients with Parkinson disease ... Persistent ocular tremors that prevent eye stability during fixation appear to be common among patients with Parkinson disease ... "All patients with PD exhibited persistent ocular tremor that prevented stability during fixation," the authors conclude. "The ... Persistent ocular tremors appear to be associated with Parkinson's disease. April 9, 2012 ...
Full text of "Diseases Of The Nose Throat And Ear"... while paralysis of the ocular muscles leads to fixation of the eyeball. The thrombosis spreads from one cavernous sinus to the ...
Most recent papers with the keyword cycloversion | Read by QxMDInstability of ocular torsion during fixation: cyclovergence is more stable than cycloversion. ... www.readbyqxmd.com/read/8160416/instability-of-ocular-torsion-during-fixation-cyclovergence-is-more-stable-than-cycloversion ... Assessment of ocular counterroll during head tilt using binocular video oculography.. Hermann D Schworm, Jan Ygge, Tony Pansell ... This study therefore examines the variation of torsion during a smooth asymmetric vergence task in which a fixation target was ...
R J Krauzlisocular fixation*visual fields*cues*neurons*visual pathways*reaction time*neural pathways*attention*visual perception* ... We found that eye movements significantly promoted perceptual coherence compared to fixation. These results indicate that eye ...
Mike Rinckocular fixation*memory disorders*diagnostic and statistical manual of mental disorders*major depressive disorder*psychomotor ...
William H Swansonocular fixation*tomography*theoretical models*algorithms*eye movements*predictive value of tests*false negative reactions ... ocular adaptation*lighting*crystalline lens*pupil*color perception*neurological models*glaucoma*retinal ganglion cells*vision ... Structure and function in patients with glaucomatous defects near fixation. Asifa Shafi. Graduate Center for Vision Research, ... Structure and function in patients with glaucomatous defects near fixation. Asifa Shafi. Graduate Center for Vision Research, ...
N D Schiffocular fixation*computer simulation*language. N D Schiff. Summary. Affiliation: Cornell University ...
Howard A Rowleyocular fixation*x ray computed tomography*hydrocephalus*color perception*cerebral angiography*thrombolytic therapy*choice ... Three-dimensional high-resolution magnetic resonance imaging of ocular and orbital malignancies. Sharon McCaffery. Department ...
Ataxia-Telangiectasia in Ophthalmology Clinical Presentation: History, Physical, CausesNystagmus may reduce distance visual acuity and impair fixation. The vestibulo-ocular movements are preserved, but there is a ... Ocular findings in Norwegian patients with ataxia-telangiectasia: a 5 year prospective cohort study. Acta Ophthalmol Scand. ... Eventually, the ocular telangiectasia becomes generalized and simulates a conjunctivitis. * Oculomotor abnormalities appear ... Ocular manifestations of ataxia-telangiectasia. Am J Ophthalmol. 2002 Dec. 134(6):891-6. [Medline]. ...
Pakistan Journal of OphthalmologyPost-Keratoplasty Glaucoma in Secondary Trans-Scleral Fixation of Posterior Chamber Intra-Ocular Lens Implant ...
Functional Assessment of Head-Eye Coordination During Vehicl... : Optometry and Vision ScienceVisual impairment, resulting from ocular abnormalities or brain lesions, can significantly ... Vergence Errors: Some Hitherto Unreported Aspects of Fixation Disparity. * Influence of Ocular Gaze and Head Position on 4 m ... Forced Vergence Fixation Disparity Curves in Presbyopia. * Convergence Insufficiency, Fixation Disparity, and Control Systems ... This ocular torsion was of similar magnitude to that produced by the gravity-sensing otoliths during a 45° head tilt with ...
Cancer therapy that boosts immune system ready for wider testingPersistent ocular tremors that prevent eye stability during fixation appear to be common among patients with Parkinson disease ... Persistent ocular tremors appear to be associated with Parkinson's disease. April 9, 2012 ...
NIOSHTIC-2 Publications Search - 00168704 - Ocular discomfort and other symptoms of eyestrain at low levels of illumination.... was reviewed and discussed with emphasis on fixation, convergence and control of the size of the pupil. Prescription glasses ... Ocular discomfort and other symptoms of eyestrain at low levels of illumination.. ... was reviewed and discussed with emphasis on fixation, convergence and control of the size of the pupil. Prescription glasses ...
Patente US20110087148 - Ocular implant with stiffness qualities, methods of implantation and system - Google PatentesDescribed is an ocular implant including an elongate member having an internal lumen forming a flow pathway, at least one ... spur and the ciliary body in the region of the iris root portion of the ciliary body can provide for additional fixation to ... Delivery system for ocular implant. US9241832. 18 Abr 2013. 26 Ene 2016. Transcend Medical, Inc.. Delivery system for ocular ... Apparatus and Method for Ocular Treatment. US20090036819 *. 6 Oct 2008. 5 Feb 2009. Glaukos Corporation. Drug eluting ocular ...
Myopia progression control using bifocal contact lenses - ALLER THOMAS A.Measuring fixation disparity comprises determining an amount of actual crossing of the patient's eyes. Fixation disparity ... Ocular growth associated with myopia progression may further be reduced with the bifocal contact lens prescription. Hence, the ... Measuring fixation disparity comprises determining an amount of actual crossing of the patient's eyes. Fixation disparity ... eso fixation disparity, or eso associated phoria; measuring an amount of fixation disparity; and prescribing a bifocal contact ...
Medical Information Search (Adaptation, Psychological)GLP-2 enhances gastrointestinal function and plays an important role in nutrient homeostasis.Fixation, Ocular: The positioning ... An abrupt voluntary shift in ocular fixation from one point to another, as occurs in reading.Cultural Characteristics: Those ... They mediate the sense of hearing.Mice, Inbred C57BLOcular Physiological Phenomena: Processes and properties of the EYE as a ... Ocular: The adjustment of the eye to variations in the intensity of light. Light adaptation is the adjustment of the eye when ...
The Afferent Visual Pathway: Designing a Structural-Functional Paradigm of Multiple SclerosisIn the modern ocular imaging era, OCT has allowed us to acquire high-resolution, noninvasive imaging of retinal architecture ( ... At the binocular fixation point, an image is projected onto anatomically corresponding retinal locations . Objects in front ... A. J. Green, S. McQuaid, S. L. Hauser, I. V. Allen, and R. Lyness, "Ocular pathology in multiple sclerosis: retinal atrophy and ... Monocular inputs to the cortex are arranged in ocular dominance columns. Because our two eyes have different views of visual ...
ARTICLES | Journal of Applied PhysiologyBusettiniC, Miles FA, Schwarz U, and Carl J. Human ocular responses to translation of the observer and of the scene: dependence ... In contrast, subjects typically maintained fixation on a target directly ahead during treadmill locomotion studies (18, 30, 31 ... MooreST, Clement G, Dai M, Raphan T, Solomon D, and Cohen B. Ocular and perceptual responses to linear acceleration in ... PaigeGD, Barnes GR, Telford L, and Seidman SH. Influence of sensorimotor context on the linear vestibulo-ocular reflex. In: New ...
Diazotroph: Diazotrophs are bacteria and archaea that fix atmospheric nitrogen gas into a more usable form such as ammonia.LevobetaxololGuiding Eyes for the Blind: Yorktown Heights, New YorkHerbert screw: The Herbert screw (invented by Timothy Herbert) is a variable pitch cannulated screw typically made from titanium for its stainless properties as the screw is normally intended to remain in the patient indefinitely. It became generally available in 1978.Fixative (drawing): In drawing, a fixative is a liquid, similar to varnish, which is usually sprayed over a finished piece of artwork, usually a dry media artwork, to better preserve it and prevent smudging.Ocular dominance: Ocular dominance, sometimes called eye preference or eyedness, is the tendency to prefer visual input from one eye to the other. It is somewhat analogous to the laterality of right- or left-handedness; however, the side of the dominant eye and the dominant hand do not always match.Intramedullary rodOcular albinismHarrington Meeting HouseImbert-Fick law: The Imbert-Fick "law" was invented by Hans Goldmann (1899–1991) to give his newly marketed tonometer (with the help of the Haag-Streit Company) a quasi-scientific basis; it is mentioned in the ophthalmic and optometric literature, but not in any books of physics. According to Goldmann,Goldmann H.Intraocular lymphoma: Intraocular lymphoma is a rare malignant form of eye cancer. Intraocular lymphoma may affect the eye secondarily from a metastasis from a non-ocular tumor or may arise within the eye primarily (primary intraocular lymphoma, PIOL).Kirschner wireConjugate gaze palsyEye injuryIntraocular pressureSaccade: A saccade ( , French for jerk) is quick, simultaneous movement of both eyes between two phases of fixation in the same direction.Cassin, B.AlachrymaArtificial tearsRobert BrobergLogMAR 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.Diffuse unilateral subacute neuroretinitis: Diffuse unilateral subacute neuroretinitis (DUSN) is a rare condition that occurs in otherwise healthy, often young patients and is due to the presence of a subretinal nematode.ConjunctivochalasisLigneous 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.FormaldehydeNonunion: Nonunion is permanent failure of healing following a broken bone.Convergence of measures: In mathematics, more specifically measure theory, there are various notions of the convergence of measures. For an intuitive general sense of what is meant by convergence in measure, consider a sequence of measures μn on a space, sharing a common collection of measurable sets.Femoral fractureVanadium nitrogenaseAqueous humour: The aqueous humour is a transparent, gelatinous fluid similar to plasma, but containing low protein concentrations. It is secreted from the ciliary epithelium, a structure supporting the lens.Vitreous membrane: The vitreous membrane (or hyaloid membrane or vitreous cortex) is a layer of collagen separating the vitreous humour from the rest of the eye. At least two parts have been identified anatomically.Anterior segment mesenchymal dysgenesis: Anterior segment dysgenesis (ASD) is a failure of the normal development of the tissues of the anterior segment of the eye. It leads to anomalies in the structure of the mature anterior segment, associated with an increased risk of glaucoma and corneal opacity.Supracondylar humerus fractureBullous keratopathyIris dilator muscleBinocular vision: Binocular vision is vision in which creatures having two eyes use them together. The word binocular comes from two Latin roots, bini for double, and oculus for eye.Ciliary body: The ciliary body is a part of the eye that includes the ciliary muscle, which controls the shape of the lens, and the ciliary epithelium, which produces the aqueous humor. The ciliary body is part of the uvea, the layer of tissue that delivers oxygen and nutrients to the eye tissues.Retinal regeneration: Retinal regeneration deals with restoring retinal function to vertebrates so impaired.Charles D. Phelps: Charles Dexter Phelps (September 16, 1937 – September 13, 1985) was a prominent American medical doctor, professor, and researcher in the field of ophthalmology. The clinical studies he oversaw contributed to significant advances in the scientific understanding and surgical and pharmacological treatment of glaucoma.Osmium tetroxideChalkstick fracture: Chalkstick fractures are fractures, typically of long bones, in which the fracture is transverse to the long axis of the bone, like a broken stick of chalk. A healthy long bone typically breaks like a hard woody stick as the collagen in the matrix adds remarkable flexibility to the mineral and the energy can run up and down the growth rings of bone.StrabismusInterbody fusion cage: An interbody fusion cage (colloquially known as a "spine cage") is a prosthesis used in spinal fusion procedures to maintain foraminal height and decompression. They are cylindrical or square-shaped devices, and usually threaded.Inferior rectus muscle: The inferior rectus muscle is a muscle in the orbit.Saal Greenstein syndrome: Saal Greenstein syndrome is a very rare autosomal recessive genetic disorder characterized by stunted growth, short limbs, microcephaly, and an anomalous cleavage of the anterior chamber of the eye. The disorder is similar to Robinow syndrome except for anterior chamber anomalies and, in one case, hydrocephalus.Spasm 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.Carbon fixation: Carbon fixation or сarbon assimilation refers to the conversion process of inorganic carbon (carbon dioxide) to organic compounds by living organisms. The most prominent example is photosynthesis, although chemosynthesis is another form of carbon fixation that can take place in the absence of sunlight.Fowkes hypothesis: The Fowkes hypothesis (after F. M.PhenylacetyleneHay–Wells syndromeJoint dislocationAutorefractor: 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.Symbiosis Center of Health Care: Symbiosis Center of Health Care (SCHC) is an organization under Symbiosis Society which takes care of health of symbiosis family be it student or staff.http://www.Lens Controller: A Lens Controller is device that controls motorized photographic lens functions such as zoom, focus, and iris or aperture.Kruegle, Herman (2007).Meridian (perimetry, visual field): Meridian (plural: "meridians") is used in perimetry and in specifying visual fields. According to IPS Perimetry Standards 1978 (2002): "Perimetry is the measurement of [an observer's] visual functions ...Temporal analysis of products: Temporal Analysis of Products (TAP), (TAP-2), (TAP-3) is an experimental technique for studyingCicatricial pemphigoidOptimax: Optimax is a UK-based laser eye treatment specialist which has 38 locations nationwide. Optimax was established as one of the first private clinics to offer laser eye surgery.Purtscher's retinopathy: Purtscher's retinopathy is a disease where part of the eye (retina) is damaged. Usually associated with severe head injuries, it may also occur with other types of trauma, such as long bone fractures, or with several non-traumatic systemic diseases.Chorioretinitis: Chorioretinitis is an inflammation of the choroid (thin pigmented vascular coat of the eye) and retina of the eye. It is a form of posterior uveitis.New Zealand rabbit
(1/2420) MST neuronal responses to heading direction during pursuit eye movements.
As you move through the environment, you see a radial pattern of visual motion with a focus of expansion (FOE) that indicates your heading direction. When self-movement is combined with smooth pursuit eye movements, the turning of the eye distorts the retinal image of the FOE but somehow you still can perceive heading. We studied neurons in the medial superior temporal area (MST) of monkey visual cortex, recording responses to FOE stimuli presented during fixation and smooth pursuit eye movements. Almost all neurons showed significant changes in their FOE selective responses during pursuit eye movements. However, the vector average of all the neuronal responses indicated the direction of the FOE during both fixation and pursuit. Furthermore, the amplitude of the net vector increased with increasing FOE eccentricity. We conclude that neuronal population encoding in MST might contribute to pursuit-tolerant heading perception. (+info)
(2/2420) Eye movement deficits following ibotenic acid lesions of the nucleus prepositus hypoglossi in monkeys II. Pursuit, vestibular, and optokinetic responses.
The eyes are moved by a combination of neural commands that code eye velocity and eye position. The eye position signal is supposed to be derived from velocity-coded command signals by mathematical integration via a single oculomotor neural integrator. For horizontal eye movements, the neural integrator is thought to reside in the rostral nucleus prepositus hypoglossi (nph) and project directly to the abducens nuclei. In a previous study, permanent, serial ibotenic acid lesions of the nph in three rhesus macaques compromised the neural integrator for fixation but saccades were not affected. In the present study, to determine further whether the nph is the neural substrate for a single oculomotor neural integrator, the effects of those lesions on smooth pursuit, the vestibulo-ocular reflex (VOR), vestibular nystagmus (VN), and optokinetic nystagmus (OKN) are documented. The lesions were correlated with long-lasting deficits in eye movements, indicated most clearly by the animals' inability to maintain steady gaze in the dark. However, smooth pursuit and sinusoidal VOR in the dark, like the saccades in the previous study, were affected minimally. The gain of horizontal smooth pursuit (eye movement/target movement) decreased slightly (<25%) and phase lead increased slightly for all frequencies (0.3-1.0 Hz, +/-10 degrees target tracking), most noticeably for higher frequencies (0.8-0.7 and approximately 20 degrees for 1.0-Hz tracking). Vertical smooth pursuit was not affected significantly. Surprisingly, horizontal sinusoidal VOR gain and phase also were not affected significantly. Lesions had complex effects on both VN and OKN. The plateau of per- and postrotatory VN was shortened substantially ( approximately 50%), whereas the initial response and the time constant of decay decreased slightly. The initial OKN response also decreased slightly, and the charging phase was prolonged transiently then recovered to below normal levels like the VN time constant. Maximum steady-state, slow eye velocity of OKN decreased progressively by approximately 30% over the course of the lesions. These results support the previous conclusion that the oculomotor neural integrator is not a single neural entity and that the mathematical integrative function for different oculomotor subsystems is most likely distributed among a number of nuclei. They also show that the nph apparently is not involved in integrating smooth pursuit signals and that lesions of the nph can fractionate the VOR and nystagmic responses to adequate stimuli. (+info)
(3/2420) Optimality of position commands to horizontal eye muscles: A test of the minimum-norm rule.
Six muscles control the position of the eye, which has three degrees of freedom. Daunicht proposed an optimization rule for solving this redundancy problem, whereby small changes in eye position are maintained by the minimum possible change in motor commands to the eye (the minimum-norm rule). The present study sought to test this proposal for the simplified one-dimensional case of small changes in conjugate eye position in the horizontal plane. Assuming such changes involve only the horizontal recti, Daunicht's hypothesis predicts reciprocal innervation with the size of the change in command matched to the strength of the recipient muscle at every starting position of the eye. If the motor command to a muscle is interpreted as the summed firing rate of its oculomotor neuron (OMN) pool, the minimum-norm prediction can be tested by comparing OMN firing rates with forces in the horizontal recti. The comparison showed 1) for the OMN firing rates given by Van Gisbergen and Van Opstal and the muscle forces given by Robinson, there was good agreement between the minimum-norm prediction and experimental observation over about a +/-30 degrees range of eye positions. This fit was robust with respect to variations in muscle stiffness and in methods of calculating muscle innervation. 2) Other data sets gave different estimates for the range of eye-positions within which the minimum-norm prediction held. The main sources of variation appeared to be disagreement about the proportion of OMNs with very low firing-rate thresholds (i.e., less than approximately 35 degrees in the OFF direction) and uncertainty about eye-muscle behavior for extreme (>30 degrees ) positions of the eye. 3) For all data sets, the range of eye positions over which the minimum-norm rule applied was determined by the pattern of motor-unit recruitment inferred for those data. It corresponded to the range of eye positions over which the size principle of recruitment was obeyed by both agonist and antagonist muscles. It is argued that the current best estimate of the oculomotor range over which minimum-norm control could be used for conjugate horizontal eye position is approximately +/-30 degrees. The uncertainty associated with this estimate would be reduced by obtaining unbiased samples of OMN firing rates. Minimum-norm control may result from reduction of the image movement produced by noise in OMN firing rates. (+info)
(4/2420) Short-latency vergence eye movements induced by radial optic flow in humans: dependence on ambient vergence level.
Radial patterns of optic flow, such as those experienced by moving observers who look in the direction of heading, evoke vergence eye movements at short latency. We have investigated the dependence of these responses on the ambient vergence level. Human subjects faced a large tangent screen onto which two identical random-dot patterns were back-projected. A system of crossed polarizers ensured that each eye saw only one of the patterns, with mirror galvanometers to control the horizontal positions of the images and hence the vergence angle between the two eyes. After converging the subject's eyes at one of several distances ranging from 16.7 cm to infinity, both patterns were replaced with new ones (using a system of shutters and two additional projectors) so as to simulate the radial flow associated with a sudden 4% change in viewing distance with the focus of expansion/contraction imaged in or very near both foveas. Radial-flow steps induced transient vergence at latencies of 80-100 ms, expansions causing increases in convergence and contractions the converse. Based on the change in vergence 90-140 ms after the onset of the steps, responses were proportional to the preexisting vergence angle (and hence would be expected to be inversely proportional to viewing distance under normal conditions). We suggest that this property assists the observer who wants to fixate ahead while passing through a visually cluttered area (e.g., a forest) and so wants to avoid making vergence responses to the optic flow created by the nearby objects in the periphery. (+info)
(5/2420) Motor cortical encoding of serial order in a context-recall task.
The neural encoding of serial order was studied in the motor cortex of monkeys performing a context-recall memory scanning task. Up to five visual stimuli were presented successively on a circle (list presentation phase), and then one of them (test stimulus) changed color; the monkeys had to make a single motor response toward the stimulus that immediately followed the test stimulus in the list. Correct performance in this task depends on memorization of the serial order of the stimuli during their presentation. It was found that changes in neural activity during the list presentation phase reflected the serial order of the stimuli; the effect on cell activity of the serial order of stimuli during their presentation was at least as strong as the effect of motor direction on cell activity during the execution of the motor response. This establishes the serial order of stimuli in a motor task as an important determinant of motor cortical activity during stimulus presentation and in the absence of changes in peripheral motor events, in contrast to the commonly held view of the motor cortex as just an "upper motor neuron." (+info)
(6/2420) Action of the brain stem saccade generator during horizontal gaze shifts. I. Discharge patterns of omnidirectional pause neurons.
Omnidirectional pause neurons (OPNs) pause for the duration of a saccade in all directions because they are part of the neural mechanism that controls saccade duration. In the natural situation, however, large saccades are accompanied by head movements to produce rapid gaze shifts. To determine whether OPNs are part of the mechanism that controls the whole gaze shift rather than the eye saccade alone, we monitored the activity of 44 OPNs that paused for rightward and leftward gaze shifts but otherwise discharged at relatively constant average rates. Pause duration was well correlated with the duration of either eye or gaze movement but poorly correlated with the duration of head movement. The time of pause onset was aligned tightly with the onset of either eye or gaze movement but only loosely aligned with the onset of head movement. These data suggest that the OPN pause does not encode the duration of head movement. Further, the end of the OPN pause was often better aligned with the end of the eye movement than with the end of the gaze movement for individual gaze shifts. For most gaze shifts, the eye component ended with an immediate counterrotation owing to the vestibuloocular reflex (VOR), and gaze ended at variable times thereafter. In those gaze shifts where eye counterrotation was delayed, the end of the pause also was delayed. Taken together, these data suggest that the end of the pause influences the onset of eye counterrotation, not the end of the gaze shift. We suggest that OPN neurons act to control only that portion of the gaze movement that is commanded by the eye burst generator. This command is expressed by driving the saccadic eye movement directly and also by suppressing VOR eye counterrotation. Because gaze end is less well correlated with pause end and often occurs well after counterrotation onset, we conclude that elements of the burst generator typically are not active till gaze end, and that gaze end is determined by another mechanism independent of the OPNs. (+info)
(7/2420) Optical imaging of functional domains in the cortex of the awake and behaving monkey.
As demonstrated by anatomical and physiological studies, the cerebral cortex consists of groups of cortical modules, each comprising populations of neurons with similar functional properties. This functional modularity exists in both sensory and association neocortices. However, the role of such cortical modules in perceptual and cognitive behavior is unknown. To aid in the examination of this issue we have applied the high spatial resolution optical imaging methodology to the study of awake, behaving animals. In this paper, we report the optical imaging of orientation domains and blob structures, approximately 100-200 micrometer in size, in visual cortex of the awake and behaving monkey. By overcoming the spatial limitations of other existing imaging methods, optical imaging will permit the study of a wide variety of cortical functions at the columnar level, including motor and cognitive functions traditionally studied with positron-emission tomography or functional MRI techniques. (+info)
(8/2420) Three-dimensional eye-head coordination during gaze saccades in the primate.
The purpose of this investigation was to describe the neural constraints on three-dimensional (3-D) orientations of the eye in space (Es), head in space (Hs), and eye in head (Eh) during visual fixations in the monkey and the control strategies used to implement these constraints during head-free gaze saccades. Dual scleral search coil signals were used to compute 3-D orientation quaternions, two-dimensional (2-D) direction vectors, and 3-D angular velocity vectors for both the eye and head in three monkeys during the following visual tasks: radial to/from center, repetitive horizontal, nonrepetitive oblique, random (wide 2-D range), and random with pin-hole goggles. Although 2-D gaze direction (of Es) was controlled more tightly than the contributing 2-D Hs and Eh components, the torsional standard deviation of Es was greater (mean 3.55 degrees ) than Hs (3.10 degrees ), which in turn was greater than Eh (1.87 degrees ) during random fixations. Thus the 3-D Es range appeared to be the byproduct of Hs and Eh constraints, resulting in a pseudoplanar Es range that was twisted (in orthogonal coordinates) like the zero torsion range of Fick coordinates. The Hs fixation range was similarly Fick-like, whereas the Eh fixation range was quasiplanar. The latter Eh range was maintained through exquisite saccade/slow phase coordination, i.e., during each head movement, multiple anticipatory saccades drove the eye torsionally out of the planar range such that subsequent slow phases drove the eye back toward the fixation range. The Fick-like Hs constraint was maintained by the following strategies: first, during purely vertical/horizontal movements, the head rotated about constantly oriented axes that closely resembled physical Fick gimbals, i.e., about head-fixed horizontal axes and space-fixed vertical axes, respectively (although in 1 animal, the latter constraint was relaxed during repetitive horizontal movements, allowing for trajectory optimization). However, during large oblique movements, head orientation made transient but dramatic departures from the zero-torsion Fick surface, taking the shortest path between two torsionally eccentric fixation points on the surface. Moreover, in the pin-hole goggle task, the head-orientation range flattened significantly, suggesting a task-dependent default strategy similar to Listing's law. These and previous observations suggest two quasi-independent brain stem circuits: an oculomotor 2-D to 3-D transformation that coordinates anticipatory saccades with slow phases to uphold Listing's law, and a flexible "Fick operator" that selects head motor error; both nested within a dynamic gaze feedback loop. (+info)
- Three-dimensional eye movements were measured simultaneously with both systems during fixation, saccades, optokinetic stimulation, and vestibular stimulation. (readbyqxmd.com)
- The vestibulo-ocular movements are preserved, but there is a poor ability to initiate saccades. (medscape.com)
- All children over the age of 4 years had abnormal saccade movements, a form of ocular motor apraxia. (wiley.com)
- During reading, we generate saccadic eye movements to move words into the center of the visual field for word processing.Our approach is based on iterative computation of the proportions of several types of oculomotor errors, the underlying probabilities for word-targeting, and corrected distributions of landing positions.These results show that fixation probabilities are strongly affected by oculomotor errors. (nih.gov)
- The major finding of the present study was that using modern eye movement tracking, oscillatory fixation instability was universally seen in a large cohort of 112 patients with PD," the authors write. (medicalxpress.com)
- The authors found that all 112 patients with PD showed persistent ocular instability while fixating on a target, compared with only two of the 60 control patients. (medicalxpress.com)
- Visual impairment, resulting from ocular abnormalities or brain lesions, can significantly affect driving performance. (lww.com)
- However, due to systematic and random errors in the oculomotor system, distributions of within-word landing positions are rather broad and show overlapping tails, which suggests that a fraction of fixations is mislocated and falls on words to the left or right of the selected target word. (nih.gov)
- These results show that fixation probabilities are strongly affected by oculomotor errors. (nih.gov)
- Persistent ocular tremors that prevent eye stability during fixation appear to be common among patients with Parkinson disease (PD) suggesting that precise oculomotor testing could provide an early physiological biomarker for diagnosing PD, according to a report published Online First by Archives of Neurology . (medicalxpress.com)
- The authors compared oculomotor function between 112 patients with Parkinson disease and 60 age-matched controls during fixation and while tracking a randomly displaced target on a PC monitor. (medicalxpress.com)
- The fact that this behavior was universally observed in every tested patient with PD, including unmedicated patients, suggests that ocular tremor is a function of the disease process and not induced by medication. (medicalxpress.com)
- Nystagmus may reduce distance visual acuity and impair fixation. (medscape.com)
- One of the most complex visual tasks when driving was exiting a multistory car park, which involved the scanning of hundreds of parked vehicles with an average fixation time of approximately 100 ms. The vertical vestibulo-ocular reflex was also found to make a significant contribution to the maintenance of dynamic visual acuity even while driving on paved surfaces. (lww.com)
- 10 Visual pathology is unlikely to be a major contributing factor to the increased fatality rate for the younger (age range, 15-24 years) group of drivers, but recent open-road studies have identified a more limited pattern of gaze fixations in novice drivers as compared with those with more experience. (lww.com)
- The diagnosis of AT can be supported at preschool age by the onset of ocular motor apraxia and conjunctival telangiectasias. (wiley.com)
- Ataxia telangiectasia (AT) is a rare autosomal recessive disorder characterized by early onset progressive cerebellar ataxia, oculocutaneous telangiectasias, ocular motor apraxia, dysartria and immunodeficiency. (wiley.com)
- To document the cyclovertical ocular motor mechanism used for vertical fusion in healthy subjects, and to explore whether vertical vergence training in healthy individuals can produce objectively confirmed vertical deviations that change with head tilt, revealing a basic mechanism that can produce a pattern of misalignment in an otherwise normal ocular motor system that is similar to superior oblique muscle paresis (SOP). (readbyqxmd.com)
- All patients with PD exhibited persistent ocular tremor that prevented stability during fixation," the authors conclude. (medicalxpress.com)
- To assess relations between perimetric sensitivity and neuroretinal rim area using high-resolution perimetric mapping in patients with glaucomatous defects within 10° of fixation. (labome.org)
- We found that the average fraction of mislocated fixations ranges from about 10% to more than 30% depending on word length. (nih.gov)
- Comparison of fixation positions between -15 degrees and +15 degrees showed that horizontal and vertical eye position signals of the two systems were highly correlated (R2 = 0. (readbyqxmd.com)