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.
The positioning and accommodation of eyes that allows the image to be brought into place on the FOVEA CENTRALIS of each eye.
The use of metallic devices inserted into or through bone to hold a fracture in a set position and alignment while it heals.
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.
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.
A condition in which the intraocular pressure is elevated above normal and which may lead to glaucoma.
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.
Specialized devices used in ORTHOPEDIC SURGERY to repair bone fractures.
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.
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 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.
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.
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.
The use of nails that are inserted into bone cavities in order to keep fractured bones together.
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 of LIGHT effected by the media of the EYE.
Devices which are used in the treatment of orthopedic injuries and diseases.
Measurement of ocular tension (INTRAOCULAR PRESSURE) with a tonometer. (Cline, et al., Dictionary of Visual Science, 4th ed)
Processes and properties of the EYE as a whole or of any of its parts.
Tumors or cancer of the EYE.
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.
Voluntary or reflex-controlled movements of the eye.
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.
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)
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)
Rods of bone, metal, or other material used for fixation of the fragments or ends of fractured bones.
Damage or trauma inflicted to the eye by external means. The concept includes both surface injuries and intraocular injuries.
The physiological restoration of bone tissue and function after a fracture. It includes BONY CALLUS formation and normal replacement of bone tissue.
The pressure of the fluids in the eye.
An abrupt voluntary shift in ocular fixation from one point to another, as occurs in reading.
Tuberculous infection of the eye, primarily the iris, ciliary body, and choroid.
The fluid secreted by the lacrimal glands. This fluid moistens the CONJUNCTIVA and CORNEA.
Sterile solutions that are intended for instillation into the eye. It does not include solutions for cleaning eyeglasses or CONTACT LENS SOLUTIONS.
A fracture in which the bone is splintered or crushed. (Dorland, 27th ed)
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.
Mild to severe infections of the eye and its adjacent structures (adnexa) by adult or larval protozoan or metazoan parasites.
The process in which light signals are transformed by the PHOTORECEPTOR CELLS into electrical signals which can then be transmitted to the brain.
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.
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)
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.
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)
Abnormally low intraocular pressure often related to chronic inflammation (uveitis).
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)
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)
The turning inward of the lines of sight toward each other.
Fractures of the femur.
An enzyme system that catalyzes the fixing of nitrogen in soil bacteria and blue-green algae (CYANOBACTERIA). EC
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)
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.
The front third of the eyeball that includes the structures between the front surface of the cornea and the front of the VITREOUS BODY.
Diseases of the cornea.
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 in which the break in bone is not accompanied by an external wound.
The blending of separate images seen by each eye into one composite image.
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.
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.
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)
Congenital absence of or defects in structures of the eye; may also be hereditary.
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.
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. A very hard, gray, toxic, and nearly infusible metal element, atomic number 76, atomic weight 190.2, symbol Os. (From Dorland, 28th ed)
Breaks in bones.
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)
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)
The thin, highly vascular membrane covering most of the posterior of the eye between the RETINA and SCLERA.
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.
Methods of preparing tissue for examination and study of the origin, structure, function, or pathology.
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)
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)
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.
The cycle by which the element carbon is exchanged between organic matter and the earth's physical environment.
Application of pharmaceutically active agents on the tissues of the EYE.
Each of the upper and lower folds of SKIN which cover the EYE when closed.
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.
Deviations from the average or standard indices of refraction of the eye through its dioptric or refractive apparatus.
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.
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.
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.
Methods and procedures for recording EYE MOVEMENTS.
The total area or space visible in a person's peripheral vision with the eye looking straightforward.
Elements of limited time intervals, contributing to particular results or situations.
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 in which there is an external wound communicating with the break of the bone.
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.
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.
Surgery performed on the eye or any of its parts.
Stratified squamous epithelium that covers the outer surface of the CORNEA. It is smooth and contains many free nerve endings.
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.
Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light flashes or visual patterns are used to elicit brain activity.
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.
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.
The plan and delineation of prostheses in general or a specific prosthesis.
Glaucoma in which the angle of the anterior chamber is open and the trabecular meshwork does not encroach on the base of the iris.
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.
Inflammation of the cornea.
Bones that constitute each half of the pelvic girdle in VERTEBRATES, formed by fusion of the ILIUM; ISCHIUM; and PUBIC BONE.
The surgical cutting of a bone. (Dorland, 28th ed)
Migration of a foreign body from its original location to some other location in the body.
The joint involving the CERVICAL ATLAS and axis bones.
The grafting of bone from a donor site to a recipient site.
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)
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).
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.
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.
A bone on the ventral side of the shoulder girdle, which in humans is commonly called the collar bone.
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.
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.
Inflammation of the eyelids.
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)
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).
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)
Techniques for securing together the edges of a wound, with loops of thread or similar materials (SUTURES).
Malfunction of implantation shunts, valves, etc., and prosthesis loosening, migration, and breaking.
Images seen by one eye.
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.
The properties, processes, and behavior of biological systems under the action of mechanical forces.
Injuries to the wrist or the wrist joint.
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.
Fractures of the proximal humerus, including the head, anatomic and surgical necks, and tuberosities.
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.
A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.
Fractures of the articular surface of a bone.
A dead body, usually a human body.
The aperture in the iris through which light passes.
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.
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)
A repeat operation for the same condition in the same patient due to disease progression or recurrence, or as followup to failed previous surgery.
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)
Broken bones in the vertebral column.
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.
Congenital anomaly in which some of the structures of the eye are absent due to incomplete fusion of the fetal intraocular fissure during gestation.
Materials used in closing a surgical or traumatic wound. (From Dorland, 28th ed)
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.
Tumors or cancer of the CONJUNCTIVA.
The absence or restriction of the usual external sensory stimuli to which the individual responds.
The longest and largest bone of the skeleton, it is situated between the hip and the knee.
The toothlike process on the upper surface of the axis, which articulates with the CERVICAL ATLAS above.
Examination of the interior of the eye with an ophthalmoscope.
A partial or complete return to the normal or proper physiologic activity of an organ or part following disease or trauma.
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)
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)
Disorder occurring in the central or peripheral area of the cornea. The usual degree of transparency becomes relatively opaque.
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)
The selecting and organizing of visual stimuli based on the individual's past experience.
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)
Eye movements that are slow, continuous, and conjugate and occur when a fixed object is moved slowly.
Injury to any part of the eye by extreme heat, chemical agents, or ultraviolet radiation.
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.
The tear-forming and tear-conducting system which includes the lacrimal glands, eyelid margins, conjunctival sac, and the tear drainage system.
Methods and procedures for the diagnosis of diseases of the eye or of vision disorders.
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.
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)
Inflammation of the iris characterized by circumcorneal injection, aqueous flare, keratotic precipitates, and constricted and sluggish pupil along with discoloration of the iris.
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.
Procedures used to treat and correct deformities, diseases, and injuries to the MUSCULOSKELETAL SYSTEM, its articulations, and associated structures.
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)
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.
The first cervical vertebra.
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.
The blood vessels which supply and drain the RETINA.
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.
Simultaneous inflammation of the cornea and conjunctiva.
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.
Bony cavity that holds the eyeball and its associated tissues and appendages.
The first seven VERTEBRAE of the SPINAL COLUMN, which correspond to the VERTEBRAE of the NECK.
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.
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.
Replacement for a hip joint.
The bone which is located most lateral in the proximal row of CARPAL BONES.
A thick, fibrocartilaginous ligament at the metacarpophalageal joint.
Congenital or developmental anomaly in which the eyeballs are abnormally small.
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.
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.
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.
Inanimate objects that become enclosed in the eye.
Artery originating from the internal carotid artery and distributing to the eye, orbit and adjacent facial structures.
Substances added to pharmaceutical preparations to protect them from chemical change or microbial action. They include ANTI-BACTERIAL AGENTS and antioxidants.
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.
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 due to hypersensitivity to various allergens.
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.
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.
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.
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.
The surgical removal of the eyeball leaving the eye muscles and remaining orbital contents intact.
Method of measuring and mapping the scope of vision, from central to peripheral of each eye.
Area of the OCCIPITAL LOBE concerned with the processing of visual information relayed via VISUAL PATHWAYS.
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)
Inflammation, often mild, of the conjunctiva caused by a variety of viral agents. Conjunctival involvement may be part of a systemic infection.
Fractures of the lower jaw.

MST neuronal responses to heading direction during pursuit eye movements. (1/2420)

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)

Eye movement deficits following ibotenic acid lesions of the nucleus prepositus hypoglossi in monkeys II. Pursuit, vestibular, and optokinetic responses. (2/2420)

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)

Optimality of position commands to horizontal eye muscles: A test of the minimum-norm rule. (3/2420)

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)

Short-latency vergence eye movements induced by radial optic flow in humans: dependence on ambient vergence level. (4/2420)

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)

Motor cortical encoding of serial order in a context-recall task. (5/2420)

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)

Action of the brain stem saccade generator during horizontal gaze shifts. I. Discharge patterns of omnidirectional pause neurons. (6/2420)

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)

Optical imaging of functional domains in the cortex of the awake and behaving monkey. (7/2420)

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)

Three-dimensional eye-head coordination during gaze saccades in the primate. (8/2420)

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)

TY - CONF. T1 - Ocular fixation and saccades in motor neurone disease: markers of frontal lobe dysfunction?. AU - Donaghy, C.. AU - Pinnock, R.. AU - Abrahams, S.. AU - Cardwell, C.. AU - Hardiman, O.. AU - Patterson, V.. AU - McGivern, R. C.. AU - Gibson, J. M.. PY - 2008/6. Y1 - 2008/6. M3 - Abstract. SP - 50. EP - 50. T2 - Meeting of the European Epidemiological Society. Y2 - 1 June 2008. ER - ...
Purpose : While microsaccades during fixation are highly correlated in both eyes, the literature is less coherent regarding drifts (Otero-Millan et al, 2014). If drifts show uncorrelated components, the positions of the images of a fixated target on the retina are no longer (mirror)-symmetrical. Symmetrical corrective microsaccades should then no longer be optimal for both eyes. To better understand this question, we studied interocular correlations in ocular drifts. Methods : We built a high resolution binocular eye tracker with two USB3 infrared monochrome cameras having 640x480 pixel resolution and 320 Hz sampling rate (TheImagingSource, Model DMK33UX174). Both inputs were merged into one video buffer to synchronize binocular tracking, cutting the sampling rate down to 160 Hz. We developed software to precisely track both pupil centers and first Purkinje image centers generated by a field of IR LEDs (angular noise level ,2 arcmin). After an automated self-calibration procedure, fixational eye ...
Fixation changes in glaucoma are generally overlooked, as they are not strikingly evident as in macular diseases. Fundus perimetry might give additional insights into this aspect, along with traditional perimetric measures. In this work we propose a novel method to quantify glaucomatous changes in fixation features as detected by fundus perimetry and relate them to the extent of glaucomatous damage. We retrospectively analysed fixation data from 320 people (200 normal subjects and 120 with glaucoma) from the Preferred Retinal Locus (PRL) detection of a Compass perimeter. Fixation stability was measured as Bivariate Contour Ellipse Area (BCEA), and using two novel metrics: (1) Mean Euclidean Distance (MED) from the Preferred Retinal Locus, and (2) Sequential Euclidean Distance (SED) of sequential fixation locations. These measures were designed to capture the spread of fixation points, and the frequency of position changes during fixation, respectively. In the age corrected analysis, SED was
A more fruitful way to uncover a useful function for microsaccades would be to choose tasks in which shifts of attention between small details (small enough to fit within the central half degree of the retina) would be expected to be crucial. Winterson and Collewijn (1976) measured eye movements of naïve subjects who were asked to aim and shoot a rifle (no bullets) or thread a needle. During the interval of about 2-4 seconds when they performed these tasks, microsaccade rate was never greater than their baseline rate during steady fixation (2/s) and in fact dropped to about 0.5/s during the final portions of the trials. Bridgeman and Palca (1980) obtained a similar result in a comparable task that required a high acuity visual judgment without a directly related motor activity. Specifically, subjects had to judge whether the tip of a moving horizontally oriented thread would have ended above or below the tip of a stationary, vertical needle. Like Winterson and Collewijn (1976), Bridgeman ...
Fixation is a common characteristic in the behavior of an autistic child. The child may be fixated on a book, a picture, a person, maps, music, numbers, or a movie. Whatever the fixation, the high functioning autistic child will become a resident expert on the subject. They will memorize and will be able to regurgitate […]
One further possibility is that childrens unstable fixation and their lower sensitivities are both symptoms of some more global immaturity, such as a general lack of attentiveness. This could be assessed in future by adding explicit catch trials to the test protocol in order to assess childrens false-negative (lapse) rates and false-positive rates (trigger errors).39 Previous work by Tschopp and colleagues40 has shown that lapse rates measured in this manner are strong predictors of childrens thresholds on standard automated perimetry; and on this basis, it seems plausible that such lapses may also explain some or all of childrens deficits in MP. A second/additional possibility is that childrens reduced sensitivities were a direct consequence of their reduced fixation stability. Substantial reductions in visual sensitivity are known to occur during eye movements,41,42 and children made more and larger eye movements than adults (e.g., due to searching behaviors, physiological nystagmus, or ...
Monkeys were trained to perform the DPX task (a validated AX-CPT variant) similar to tasks used to measure deficits in executive control in patients (Jones et al., 2010) (see Fig. 1). Each trial a sequence of two dot patterns was presented (a cue followed by a probe; see Fig. 1C) separated by a delay. At the start of each trial, monkeys directed their gaze at the fixation cross presented at the center of the display for a period of 0.5 s. They were required to maintain gaze fixated within 3.3° of the central fixation target throughout the trial (if eye position moved outside this window, the trial aborted). After the initial fixation period, the cue (orange dots) was presented for 1 s, followed by a 1 s delay period, after which the probe (white dots) was presented for 0.5 s (see Fig. 1A). The intertrial interval (from the offset of the probe to the onset of the following cue, including the 0.5 s fixation period) was 1.86 s. Total trial length, from the onset of the cue of one trial to the ...
In Experiment 2, we addressed this third component. We studied the prediction power of a very simple gaze map and offered insights toward building more predictive gaze-augmented saliency models. We discovered that four challenges need to be addressed before making a general model: (a) How to adjust the parameters of the cone? Some parameters that constrain a gaze map include width of the cone, angular uncertainty, and effective length from the center to focus energy (attentional span). Ideally, one would want to only bias the object(s) that the actor is looking at in the scene. If one modulates everything along the cone, then background unattended objects falling on the cone will be modulated as well (which is not efficient). In Experiment 2, we employed a uniform map. The results of Experiment 3 can be used to calibrate this simple map. For example, a better than uniformly distributing activation would emphasize more at the center line (bisector angle) of the cone and decay it using a Gaussian ...
To determine how subjects allocate gaze to plan their route through the obstacles, we developed the following two measures: spatial gaze distance and spatial-temporal gaze distance. For both measures, we used the positions of the obstacle and the end gates to divide the path into eight segments (S1-S8; see Fig. 2A). Each segment is the same length, expect for the first one (S1) because of the subjects start position and the last one (S8) that represents the end region of the path; these unequal segment lengths are accounted for in the calculation of each of the two gaze distance measures. The anterior-posterior position of the subjects chest marker determines which segment they are located in. For both measures, we determined which segment(s) subjects fixated relative to their location for the first five segments they walked through. We excluded the last three segments because the subjects have walked past the fourth obstacle by this point and gaze begins to deviate from the walking path and ...
Research focusing on perceptual-cognitive skill in sport is abundant. However, the existing qualitative syntheses of this research lack the quantitative detail necessary to determine the magnitude of differences between groups of varying levels of skills, thereby limiting the theoretical and practical contribution of this body of literature. We present a meta-analytic review focusing on perceptual-cognitive skill in sport (N = 42 studies, 388 effect sizes) with the primary aim of quantifying expertise differences. Effects were calculated for a variety of dependent measures (i.e., response accuracy, response time, number of visual fixations, visual fixation duration, and quiet eye period) using point-biserial correlation. Results indicated that experts are better than nonexperts in picking up perceptual cues, as revealed by measures of response accuracy and response time. Systematic differences in visual search behaviors were also observed, with experts using fewer fixations of longer duration, ...
Introducing an eye-gaze device to an individual who is non - verbal can open up a world of possibility for them; it can allow them to communicate, engage with games and play as well as allowing them to access and control their environment. When working with children who have the potential to use eye gaze, it can be difficult to find fun and motivating ways to encourage them to engage with the device. Introducing communication-based programs too early can be too demanding and may ultimately lead to failure using the device. Smartbox Technologies have developed a program called Look to Learn and describe it as a motivating and fun way to get started with eye gaze technology. Every activity has been developed in consultation with teachers and therapists to improve access and choice-making skills. The software consists of 40 specially created activities that easily allows therapists, families and teachers develop basic eye-gaze interaction with the child. A companion workbook is also available from ...
A unique package of 18 carefully graded activities designed to assess and teach attention and looking skills, simple access skills and understanding of eye gaze. These fun and meaningful activities can be used with all children on their first steps with eye gaze. They provide a progression of skills from experiential a
Amidst the mania of self-driving, did you dismiss the role of eye-gaze tracking and driver monitoring systems (DMS) in cars?. ...
Sitting by the window,I lay my gaze on the vain clusters of clouds gathered together as if to celebrate the pain in my heart. Does this pa ...
Task transparency in learning by demonstration : gaze, pointing, and dialog. . Biblioteca virtual para leer y descargar libros, documentos, trabajos y tesis universitarias en PDF. Material universiario, documentación y tareas realizadas por universitarios en nuestra biblioteca. Para descargar gratis y para leer online.
Her gaze trained on the door that Nikki had just exited, she didnt notice the man sitting next to her until he spoke. Im surprised you didnt go with them. She tore her gaze from the door to look at hi
Read 962 frequently asked questions about DressLily, with answers from previous customers and DressLily staff, or ask your own question.
Écrins National Park, nature reserve located in the départements of Hautes-Alpes and Isère, southeastern France. The park, which was created in 1973, occupies 226,694 acres (91,740 hectares) and is the second largest national park in France. It encompasses the Alpine peaks of Barre des Écrins
There was a lot of past effort to figure out what fixational eye movements contribute to our vision, adds lead author Ziad Hafed, Ph.D., Sloan-Swartz Fellow in the Systems Neurobiology Laboratory, but nobody had looked at the neural mechanism that generates these movements. Without such knowledge, one could only go so far in evaluating microsaccades significance and why they actually exist. Wondering whether the command center responsible for generating fixational eye movements resides within the same brain structure that is in charge of initiating and directing large voluntary eye movements, Hafed decided to measure neural activity in the superior colliculus before and during microsaccades. He not only discovered that the superior colliculus is an integral part of the neural mechanism that controls microsaccades, but he also found that individual neurons in the superior colliculus are highly specific about which particular microsaccade directions and amplitudes they command-whether they be, ...
DOI /s z Clustering of Gaze During Dynamic Scene Viewing is Predicted by Motion Parag K. Mital Tim J. Smith Robin L. Hill John M. Henderson Received: 23 April 2010 / Accepted: 5 October
In a companion paper, we reported that the goldfish oculomotor neural integrator could be trained to instability or leak by rotating the visual surround with a velocity proportional to +/- horizontal eye position, respectively. Here we analyze changes in the firing rate behavior of neurons in area I in the caudal brainstem, a central component of the oculomotor neural integrator. Persistent firing could be detuned to instability and leak, respectively, along with fixation behavior. Prolonged training could reduce the time constant of persistent firing of some cells by more than an order of magnitude, to |1 s. Normal visual feedback gradually retuned persistent firing of integrator neurons toward stability, along with fixation behavior. In animals with unstable fixations, approximately half of the eye position-related cells had upward or unstable firing rate drift. In animals with leaky fixations, two-thirds of the eye position-related cells showed leaky firing drift. The remaining eye position-related
TY - JOUR. T1 - Decreased fixation stability of the preferred retinal location in juvenile macular degeneration. AU - Bethlehem, R.A.. AU - Dumoulin, S.O.. AU - Dalmaijer, E.S.. AU - Smit, M.. AU - Berendschot, T.T.. AU - Nijboer, T.C.. AU - van der Stigchel, S.. PY - 2014/6/17. Y1 - 2014/6/17. N2 - Macular degeneration is the main cause for diminished visual acuity in the elderly. The juvenile form of macular degeneration has equally detrimental consequences on foveal vision. To compensate for loss of foveal vision most patients with macular degeneration adopt an eccentric preferred retinal location that takes over tasks normally performed by the healthy fovea. It is unclear however, whether the preferred retinal locus also develops properties typical for foveal vision. Here, we investigated whether the fixation characteristics of the preferred retinal locus resemble those of the healthy fovea. For this purpose, we used the fixation-offset paradigm and tracked eye-position using a high spatial ...
TY - JOUR. T1 - Eye movement patterns in solving scientific graph problems. AU - Yen, Miao Hsuan. AU - Lee, Chieh Ning. AU - Yang, Yu Chun. PY - 2012/7/13. Y1 - 2012/7/13. N2 - Eye movement patterns of science- and non-science students in solving scientific graph problems were compared. Experts (science-students) tended to spend more time, compared to novices, to comprehend the questions during the first run / inspection. Concerning the main graph region, both the True and False subregions (corresponding to correct and wrong answer choices, respectively) were inspected carefully during the first run. Significant differences were observed in the second run, in which the False region was fixated longer when participants made wrong responses.. AB - Eye movement patterns of science- and non-science students in solving scientific graph problems were compared. Experts (science-students) tended to spend more time, compared to novices, to comprehend the questions during the first run / inspection. ...
Purpose: To investigate whether glaucoma produces measurable changes in eye movements.. Methods: Fifteen glaucoma patients with asymmetric vision loss (difference in mean deviation [MD] , 6 dB between eyes) were asked to monocularly view 120 images of natural scenes, presented sequentially on a computer monitor. Each image was viewed twice-once each with the better and worse eye. Patients eye movements were recorded with an Eyelink 1000 eye-tracker. Eye-movement parameters were computed and compared within participants (better eye versus worse eye). These parameters included a novel measure: saccadic reversal rate (SRR), as well as more traditional metrics such as saccade amplitude, fixation counts, fixation duration, and spread of fixation locations (bivariate contour ellipse area [BCEA]). In addition, the associations of these parameters with clinical measures of vision were investigated.. Results: In the worse eye, saccade ...
Study EEG under a variety of conditions to explore relaxation and brain rhythmsthe software can filter and display each rhythm separately: alpha, beta, delta, and theta. Study alpha rhythms in the occipital lobe, reaction times, and hemispheric asymmetry. Use the system to demonstrate changes in the parasympathetic and sympathetic nervous system. Add EOG (occipital signal) to study eye movement, saccades, tracking, angular displacement, or ocular fixations. Use the stimulator to study evoked responseauditory, visual, or somatosensory. Record reaction time and measure nerve conduction velocity. The system samples quickly enough to easily record spontaneous nerve activity from small animals and insects. ...
Human visual perception almost completely relies on the fact that the eyes are able to fixate points within a visual scene. But the term fixation may easily be misunderstood. We never fixate perfectly and we can count ourselfes lucky in this regard, since small eye movements during fixation clearly mediate perception. Fixational eye movements prevent the visual world from fading. My research focusses mainly on microsaccades, small flicks of the eye during intended fixation. For some decades, there was reasonable doubt in the purpose of these small movements. Over the last ten years, however, neurophysiological findings and improved eye-movement-recording techniques pushed the topic over the surface again and doubts diminished in the light of new evidence. If youre interested, take a look at my fairly exhaustive review on that topic in Vision Research.. During my PhD I studied what microsaccades tell us about the workings of the oculomotor system and had a few key insights. In one series of ...
TY - JOUR. T1 - Reversible inactivation of pSTS suppresses social gaze following in the macaque (Macaca mulatta). AU - Roy, Arani. AU - Shepherd, Stephen V.. AU - Platt, Michael L.. PY - 2014/2. Y1 - 2014/2. N2 - Humans and other primates shift their attention to follow the gaze of others [gaze following (GF)]. This behavior is a foundational component of joint attention, which is severely disrupted in neurodevelopmental disorders such as autism and schizophrenia. Both cortical and subcortical pathways have been implicated in GF, but their contributions remain largely untested. While the proposed subcortical pathway hinges crucially on the amygdala, the cortical pathway is thought to require perceptual processing by a region in the posterior superior temporal sulcus (pSTS). To determine whether pSTS is necessary for typical GF behavior, we engaged rhesus macaques in a reward discrimination task confounded by leftward- and rightward-facing social distractors following saline or muscimol ...
The fundamental role of the visual system is to guide behavior in natural environments. In order to optimize information transmission many animals have evolved a non-homogeneous retina and serially sample visual scenes by saccadic eye movements. Such eye movements, however, introduce high-speed retinal motion and decouple external and internal reference frames. Until now, these processes have only been studied with unnatural stimuli, eye movement behavior, and tasks. These experiments confound retinotopic and geotopic coordinate systems and may probe a non-representative functional range. Here we develop a real-time gaze-contingent display with precise spatio-temporal control over high-definition natural movies. In an active condition, human observers freely watched nature documentaries and indicated the location of periodic narrow-band contrast increments relative to their gaze position. In a passive condition under central fixation, the same retinal input was replayed to each observer by ...
Alteration of a fixation or peripheral stimulus displayed on a computer-driven display allows a human subject to maintain extended visual fixation upon the resulting dynamic stimulus. The fixation is presented upon the display and the stimulus is altered to allow resensitization of the subjects retina, thereby allowing prolonged visual fixation upon the resulting dynamic target. A dynamic stimulus may utilize a frequency doubling illusion.
At intersections and especially at uncontrolled intersections it is a good idea to make sure that you have made eye contact with other drivers. Brief eye contact helps communicate your and the other drivers intent, whether they are aware of you or not, and helps to avoid collisions in the intersection or, at a minimum, who is pulling out first.. Longer eye contact often indicates something else altogether.. The system I propose, then, is one that promotes unambiguous eye contact communication between drivers and does so by exaggerating the drivers gaze direction using simple external gaze direction indicators.. The gaze direction of the driver is established using existing gaze detection and tracking technology housed inside the car and slightly above the line of sight of the driver at the top of the windshield. The gaze data is then processed and output as absolute rotation coordinates for the mechanically manipulated gaze direction indicators or annuciators. In a manner similar to Waldo ...
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What to do. You can use the slower/faster buttons to change speed. Disappearance persists down to surprisingly low speeds. You can use the smaller / larger buttons to change size. Disappearance persists up to surprisingly large sizes.. You change the colour of the rotating crosses, the dots and the background. The dots disappear into whatever colour the background has.. The grating on/off button allows to observe the filling-in process more closely: when the grid is visible, it continues through the vanishing yellow dots. The defaults button at the top restores the standard settings.. Comment. Steady fixation favours disappearance, blinks or gaze shifts induce reappearance. All in all reminiscent of the Troxler effect, but stronger and more resistant to residual eye movements.. An interesting fact was mentioned by Pete in the guestbook: If you stare at one of the yellow dots, even the center (green) dot will seem to change to yellow. Yes, I agree, and quite unexpected.. In Feb 2008, John ...
This study analyzed how an unexpected, transient, passive movement of the head during saccades that were initiated while the head was fixed, affects the trajectory of saccades. We showed that the accuracy of the saccade was not altered by the head perturbation. A system based on separate eye and head controllers would not maintain accuracy, because the eye controller would have no way to assess the amount of the gaze trajectory that had been affected by a perturbation with a VOR gain ,1. Thus, our results imply that the brain combines the action of the VOR (whatever its gain) and a feedback mechanism for gaze. We also showed that the saccade trajectory is affected more by the perturbation for larger saccade amplitudes, and when the onset of the head perturbation was close to the onset of the saccade. Finally, we showed that the modulation of the saccade trajectory was insensitive to the latency of the saccade with respect to the target presentation.. In our experiment, we created a passive ...
Active exploration of the visual world depends on sequential shifts of gaze that bring prioritized regions of a scene into central vision. The efficiency of this system is commonly attributed to a mechanism of inhibition of return (IOR) that discourages re-examination of previously-visited locations. Such a process is fundamental to computational models of attentional selection and paralleled by neurophysiological observations of inhibition of target-related activity in visuomotor areas. However, studies examining eye movements in naturalistic visual scenes appear to contradict the hypothesis that IOR promotes exploration. Instead, these reports reveal a surprisingly strong tendency to shift gaze back to the previously fixated location, suggesting that refixations might even be facilitated under natural conditions. Here we resolve this apparent contradiction, based on a probabilistic analysis of gaze patterns recorded during both free-viewing and search of naturalistic scenes. By simulating saccadic
A vertebral fixation device includes a fixation main body, two fixation rods and a rotatable clamping block. The fixation main body is made up of a fixation base having a fixation hole. Located respectively at both ends of the fixation base is a fixation block having an arcuate surface capable of holding one of the two fixation rods in conjunction with one of two arcuate recesses of the rotatable clamping block. The rotatable clamping block is provided at the bottom thereof with a retaining projection engageable securely with the fixation hole of the fixation main body.
Eye and head tracking of an oscillating visual flow was studied in 1-, 2-, and 3-month-old infants using EOG and an opto-electronic system. A pronounced decrease in phaselag of gaze velocity was observed over this age period, from 170 to 70 msec, but gain changed only marginally. Latency of the onse …
Lucid dream science has come a long way in the last few decides, culminating in recent research using brainwave, bloodflow and eye movement data.
Prevue: Aiming for the fine balance between being straightforward and having a comprehensive result, our Prevue Job-Fit report has one standardized format. Along with the customizable benchmarks and the shared core assessment, by using the same report format, youll be able to compare your candidates to different job positions that may be a better fit, or use it in succession planning for future job growth.. Our report is divided into several parts. Youll find a Prevue Results Graph comparing the candidates assessment results to the job-fit profile you have customized for the role. The suitability score in the report comes from a formula that analyzes the areas where the candidate has landed (or not landed) on the benchmark - meaning the higher the score, the better match they are with the job.. We complement these findings by providing you an interview guide that targets areas off the benchmark. These suggested questions are designed to probe at how this may affect the candidates performance ...
To determine whether chip components are properly mounted on a printed circuit board, two sets of slit light beams for projecting slit line images in mutually perpendicular directions are alternately made incident thereon diagonally from above. Edges of the mounted chip components produce discontinuities in the projected slit beam image patterns such that the positions, sizes, orientations, etc. of individual mounted components can be calculated from image data obtained from viewing positions above the circuit board by a camera or the like. Since it can be easily ascertained how the slit line image pattern should appear if proper components are properly mounted, an analysis of the calculated data can indicate whether the chip components are properly mounted on the tested printed circuit board.
Find the right height and most comfortable viewing position for your monitor with a PC monitor stand. Proper ergonomic monitor stand elevation helps reduce neck and eye strain.
A comprehensive evaluation of the patients visual motor systems ability to track and change visual fixation, maintain and accurately change focus, and to maintain the efficient use of two eyes functioning together. Problems in these areas may contribute to inefficient reading and a poor attention span.. ...
Technical preview functionality is supported for evaluation purposes but is unwarranted and is not production-ready. Informatica recommends that you use in non-production environments only. Informatica intends to include the preview functionality in an upcoming release for production use, but might choose not to in accordance with changing market or technical circumstances. For more information, contact Informatica Global Customer Support ...
If you are a high school junior or senior just getting started with the college search, visiting us during this event is a great option to get an introductory look at Luther. Make sure to bring your parents, since we have activities for them, too.. The registration deadline for the October 17 Preview Day is Tuesday, October 15.. Preview Day Schedule. ...
Learn the difference between Lightrooms previews, smart previews and other caches, so you can select the right ones to optimize Lightrooms performance.
Guddan Tumse Na Ho Payega 18 June 2019 Preview: Akshat finally expresses his feelings to Guddan - Guddan Tumse Na Ho Payega 18June 2019 Preview: Akshat writes a letter to Guddan expressing his feelings for her. Watch Tonights episode for more updates
We offer a great selection of fixation tools for paediatric vision testing including medical pen torches, Lang cubes and Kay Picture fixation sticks.
Reading back at several of my previous posts, I realized that I sounded more like a version of myself rather than my whole self. It was like I had amplified parts of myself and excluded other parts. Yeah...I dont want to do that. I want to find out more about who I am, who I want to be, and project that out into the world. When I look at the past ten years, I realize that the times when things seemed to fall into place were those times when I was being the most authentic. But like when you are a kid and finally master a task, only to screw it up when you holler at your mom to have her come watch...I think that once I realized that the Universe had cast its gaze on me I have always immediately tripped over myself and face planted on the sidewalk ...
The ZB MED preprint Viewer preVIEW includes all COVID-19, corona, SARS-CoV-2 related preprints from medRxiv, bioRxiv, arXiv, and ChemRxiv.
The ZB MED preprint Viewer preVIEW includes all COVID-19, corona, SARS-CoV-2 related preprints from medRxiv, bioRxiv, arXiv, and ChemRxiv.
Fixational eye movements comprise of fast microsaccades alternating with slow inter-saccadic drifts. These physiologic eye movements play an important role in visual perception. Amblyopic patients are known to have fixation instability, particularly of the amblyopic eye. We examined eye movement abnormalities that contribute to this instability. We found that fixation stability is affected by the presence of fusion maldevelopment nystagmus (FMN). However, some amblyopes can have nystagmus without nasally directed slow phases and reversal in direction of the quick phase on ocular occlusion, features seen in FMN. In patients without nystagmus, we found increased amplitude of fixational saccades and inter-saccadic drifts. We categorized amblyopia patients by type (anisometropic, strabismic, or mixed) and eye movement waveform (no nystagmus, nystagmus without FMN, and FMN). We found specific fast and slow eye movement abnormalities of the fellow and amblyopic eye during fellow, amblyopic and both ...
Facial expression and gaze direction play an important role in social communication. Previous research has demonstrated the perception of anger is enhanced by direct gaze, whereas it is unclear whether perception of fear is enhanced by averted gaze. In addition, previous research has shown the anxiety affects the processing of facial expression and gaze direction, but hasnt measured or controlled for depression. As a result, firm conclusions cannot be made regarding the impact of individual differences in anxiety and depression on perceptions of face expressions and gaze direction. The current study attempted to reexamine the effect of the anxiety level on the processing of facial expressions and gaze direction by matching participants on depression scores. A reliable psychophysical index of the range of eye gaze angles judged as being directed at oneself (the Cone of Direct Gaze: CoDG) was used as the dependent variable in this study. Participants were stratified into high/low trait anxiety groups and
Reflex eye movements occur during linear head movements to maintain ocular fixation on visual targets. Some theoretical considerations and experimental findings are presented in this chapter to support a compensatory role for the LVOR. The discussion is limited to primates since their visual-vestibular interactions and target fixation are improved by binocular foveate vision and depth perception. It is concluded that three LVORS - the horizontal response to IA motion, the vertical response to DV motion, and both the horizontal and vertical responses to 5 Hz NO motion - show characteristics consistent with the kinematics of ideal compensatory eye movements that help maintain stable
Abstract: BACKGROUND: The broad autism phenotype includes subclinical autistic characteristics found to have a higher prevalence in unaffected family members of individuals with autism. These characteristics primarily affect the social aspects of language, communication, and human interaction. The current research focuses on possible neurobehavioral characteristics associated with the broad autism phenotype. METHODS: We used a face-processing task associated with atypical patterns of gaze fixation and brain function in autism while collecting brain functional magnetic resonance imaging (fMRI) and eye tracking in unaffected siblings of individuals with autism. RESULTS: We found robust differences in gaze fixation and brain function in response to images of human faces in unaffected siblings compared with typically developing control individuals. The siblings gaze fixations and brain activation patterns during the face processing task were similar to that of the autism group and showed decreased ...
To do: Fixate your gaze on the red dot, while paying attention to the solid grey circle (called an artificial scotoma. After a few seconds of steady fixation, the solid circle will fill in with the surrounding dynamic noise. Eye movements or blinks will cause the grey circle to reappear.. To notice: After the dynamic noise disappears (in 20 seconds), a powerful texture after-image takes the place originally occupied by the solid grey circle. This after-image may be dynamic: the so-called Twinkle effect (Ramachandran and Gregory, 1991) or static (Spillmann and Kurtenbach, 1992).. Dynamic filling-in occurs when eye movements are lacking or reduced. Our laboratory has showed that microsaccades (small involuntary eye movements that occur when we attempt to fixate) counteract visual fading and filling-in during visual fixation (Troncoso, Macknik and Martinez-Conde, 2008).. ...
This thesis is about our peripheral vision. Peripheral vision is poor compared to central vision, due to both neural and optical factors. The optical factors include astigmatism, defocus and higher order aberrations consisting mainly of coma. Neurally, the density of ganglion cells decreases towards the periphery, which limits the sampling density. The questions that this thesis attempts to answer are how much and under which circumstances correction of optical errors can improve peripheral vision. For this, an adaptive optics system has been constructed with a wavefront sensor and a deformable mirror working in closed loop to perform real-time correction of optical errors. To investigate vision, psychophysical routines utilizing Bayesian methods have been evaluated and modified for peripheral vision to handle the presence of aliasing, fixation instability and rapid fatigue.. We found that correcting both refractive errors and higher order aberrations improved peripheral low-contrast resolution ...
Even if all external circumstances are kept equal, the oculomotor system shows intra-individual variability over time, affecting measures such as microsaccade rate, blink rate, pupil size, and gaze position. Recently, some of these measures have been associated with ADHD on a between-subject level. However, it remains unclear to what extent these measures constitute stable individual traits. In the current study, we investigate the intra-individual reliability of these oculomotor features. Combining results over three experiments (,100 healthy participants), we found evidence for intra-individual reliability over different time points (repeatability) as well as over different conditions (generalization). Furthermore, we correlated oculomotor variability with self-assessed ADHD tendencies, mind wandering, and impulsivity, and found evidence against such correlations. As such, the oculomotor system shows reliable intra-individual reliability, but its use for distinguishing self-assessed individual ...
A fundamental task performed by many visual systems is to distinguish apparent motion caused by eye movements from real motion occurring within the environment. During saccadic eye movements, this task is achieved by inhibitory signals of central and retinal origin that suppress the output of motion-detecting neurons. To investigate the retinally-generated component of this suppression, we used a computational model of a locust looming-detecting pathway that experiences saccadic suppression. This model received input from the camera of a mobile robot that performed simple saccade-like movements, allowing the models response to simplified real stimuli to be tested. Retinally-generated saccadic suppression resulted from two inhibitory mechanisms within the looming-detectors input architecture. One mechanism fed inhibition forward through the network, inhibiting the looming-detectors initial response to movement. The second spread inhibition laterally within the network, suppressing the ...
Prolonged Eye Gaze (usually for a few seconds or more), coupled with a breath focus with multiple members of an audience, one person at a time, is one of the primary ways for speakers to access the state of Relational Presence with their audience, forming the cornerstone of Speaking Circles practice.. More generally in human behavior, eye gaze is critical for processing social signals. We use eye gaze, including focused eye contact and inspection of facial expression, to predict anothers intention and mental state.1 Infants begin to use eye gaze socially at around four months of age. An infants eye contact with their caregiver may influence the development of typical social gaze behaviors1 and also directly reflect the infants attachment and comfort with their mother.2 The amount of eye contact between a mother and her newborn may also correlate with her sensitivity or capacity for attunement.3 Shared eye gaze thus underlies and is formative in the development of social ...
Local scene meaning was represented by meaning maps (Henderson & Hayes, 2017). Meaning maps capture the spatial distribution of semantic features in scenes. To generate meaning maps, each scene photograph was decomposed into a series of highly overlapping, tiled circular patches at fine and course spatial scales (Figure 2). The two scales and numbers of patches were chosen based on simulations showing that ground-truth visual properties of scenes can be recovered from them (Henderson & Hayes, 2017). Patches were rated by workers on Amazon Mechanical Turk (MTurk). MTurk workers each rated a randomly selected subset of individually presented patches taken from the set of scenes to be rated. MTurk workers were recruited from the United States, had a hit approval rate of 99% and 500 hits approved, were only allowed to participate in the study once, and were paid $0.50 cents per assignment. All workers provided informed consent. Each worker rated 300 random patches. Workers were instructed to assess ...
ORCID: 0000-0002-8579-8546 and Rayner, Keith (2011) Linguistic and cognitive influences on eye movements during reading. In: The Oxford Handbook of Eye Movements. Oxford Library of Psychology . Oxford University Press, pp. 751-766. ISBN 978-0-19-953978-9 (Unpublished) Full text not available from this repository.. Official URL: ...
Why does the painting appear to move at all? The phenomenon is known as illusory motion, and most scientists attribute it to a flaw in our visual cortex. But according to the Arizona researchers new study, the motion is actually a result of microsaccades - unconscious eye movements that occur spontaneously whenever we focus our eyes. The researchers arrived at their conclusion after mounting tiny infared cameras on a helmet and tracking the eyeballs of people confronted with Enigma. Oddly, microsaccade rates increased right before the motion began and all but disappeared before the painting went still. The illusions real, it seems, but in a twist that Alan Watts and Carlos Castaneda anticipated, its an illusion that lies within us all. ...
In the background of evolution, gaze following is one of the oldest manifestations of leadership. Three-month-old babies, for example, already follow the eye movements of their parents. Psychologists at VU University Amsterdam ...
Severely slowed saccades in ,I,spinocerebellar ataxia,/I, have previously been shown to be at least partially closed-loop in nature: their long duration means that they can be modified in-flight in response to intrasaccadic target movements. In this study, a woman with these pathologically slowed saccades could modify them in-flight in response to target movements, even when saccadic suppression of displacement prevented conscious awareness of those movements. Thus saccadic suppression of displacement is not complete, in that it provides perceptual information that is sub-threshold to consciousness but which can still be effectively utilised by the oculomotor system. ...
In the present apparatus 1, a tomogram is acquired. Hereinafter, the photographing operation of the present apparatus will be described. The examiner instructs the subject to gaze at the fixation target of the fixation target projection unit 300, and then, while viewing the anterior segment observation image taken by the camera for anterior segment observation not shown on the monitor 75 The alignment operation is performed using the operation unit 76 (for example, a joystick (not shown)) so that the measurement optical axis comes to the pupil center of the eye to be examined.. The control unit 70 acquires interference signals of at least two frames different in time at the same position. For example, the control unit 70 controls the drive of the light scanner 108 to scan the measurement light on the fundus. For example, measurement light is scanned in the x direction along a first scan line S1 shown in FIG. Note that scanning the measurement light in the x direction is called B-scan. ...
This study examined performance measures and eye movements associated with complex arithmetic strategies in young and older adults. Participants added pairs of three-digit numbers using two different strategies, under choice and no-choice conditions. Older adults made more errors but were not significantly slower than young adults, and response times and errors showed no interaction between age and the number of carries. Older adults chose strategies less adaptively than young adults. Eye movements were consistent with use of required strategies on no-choice trials and reported strategies on choice trials. Eye movement data also suggested that young adults more successfully distinguished between strategies. Implications of these findings for understanding aging effects in complex arithmetic are discussed ...
This paper introduces an approach to use eye movement data in the context of program comprehension studies. The central aspect is the development of coding schemes, which reflect cognitive processes behind the observable visual behavior of programmers. For this purpose, we discuss to first use a quantitative approach to find those episodes in the eye movements that yield the most potential for analysis. Subsequently, qualitative methods can be used on this subset.. ...
Researchers at Washington University in St. Louis have shown that a simple visual technique called subtle gaze direction, in which gentle visual cues are
Coordinating the movements of different body parts is a challenging process for the central nervous system because of several problems. Four of these main difficulties are: first, moving one part can
Information foraging connects optimal foraging theory in ecology with how humans search for information. The theory suggests that, following an information scent, the information seeker must optimize the tradeoff between exploration by repeated steps in the search space vs. exploitation, using the resources encountered. We conjecture that this tradeoff characterizes how a user deals with uncertainty and its two aspects, risk and ambiguity in economic theory. Risk is related to the perceived quality of the actually visited patch of information, and can be reduced by exploiting and understanding the patch to a better extent. Ambiguity, on the other hand, is the opportunity cost of having higher quality patches elsewhere in the search space. The aforementioned tradeoff depends on many attributes, including traits of the user: at the two extreme ends of the spectrum, analytic and wholistic searchers employ entirely different strategies. The former type focuses on exploitation first, interspersed with bouts
What is the current CAP recommendation for initial fixation of CJD tissue - phenol formalin or just plain 10% NBF? What is the reference? The information that I have recommends phenol formalin, but when I recently asked a question regarding this, it seems many people use only 10% NBF. Thanks in advance for any info. Laurie Colbert ...
Entropy-based measures are an important tool to study human gaze behavior under various conditions. Measures, such as the gaze transition entropy, are used to quantify the predictability of transitions between consecutive fixations. However, these measures do not account for temporal dependencies beyond interactions of order one. Therefore, we propose a novel approach to quantifying predictability in scanpath data by estimating the active information storage (AIS), which allows to account for temporal dependencies spanning multiple fixations. AIS is calculated as the mutual information between the past state of a process and its next value. It is thus able to measures how much information a sequence of past fixations provides about the next. Applying this approach to scanpath data recorded during a visual search task revealed significant temporal dependencies beyond interactions of order one and allowed to differentiate between induced observer states based on estimated AIS values. ...
This medical exhibit fetures the progression of a right lower leg injury. It depicts the initial condition of the fracture, the initial fixation with an external fixator, the internal fixation, and the subsequent condition.
abstract = {Observers show a marked tendency to fixate the center of the screen when viewing scenes on computer monitors. This is often assumed to arise because image features tend to be biased toward the center of natural images and fixations are correlated with image features. A common alternative explanation is that experiments typically use a central pre-trial fixation marker, and observers tend to make small amplitude saccades. In the present study, the central bias was explored by dividing images post hoc according to biases in their image feature distributions. Central biases could not be explained by motor biases for making small saccades and were found irrespective of the distribution of image features. When the scene appeared, the initial response was to orient to the center of the screen. Following this, fixation distributions did not vary with image feature distributions when freely viewing scenes. When searching the scenes, fixation distributions shifted slightly toward the ...
A phosphorescent ophthalmic instrument for fixating a patients eye during an ophthalmic procedure. The instrument includes a fixation structure attachable to the patients eye, at least a portion of the fixation ring being made from a phosphorescent material. This material, visible to the physician after exposure to incident visible light when substantially all room (and operating) lights are turned off, enables the physician to visualize the location of the fixation ring in a dark operating environment.
ICD-9 code 379.57 for Deficiencies of saccadic eye movements is a medical classification as listed by WHO under the range - DISORDERS OF THE EYE AND A
We present an approach to measure and model the parameters of human point-of-gaze (PoG) in 3D space. Our model considers the following three parameters: position of the gaze in 3D space, volume encompassed by the gaze and time for the gaze to arrive on the desired target. Extracting the 3D gaze position from binocular gaze data is hindered by three problems. The first problem is the lack of convergence - due to micro saccadic movements the optical lines of both eyes rarely intersect at a point in space. The second problem is resolution - the combination of short observation distance and limited comfort disparity zone typical for a mobile 3D display does not allow the depth of the gaze position to be reliably extracted. The third problem is measurement noise - due to the limited display size, the noise range is close to the range of properly measured data. We have developed a methodology which allows us to suppress most of the measurement noise. This allows us to estimate the typical time which ...
Example query formulation session from the eye-tracking study described in our CIKM 2014 paper An Eye-tracking Study of User Interactions with Query Auto Completion.. ...
First paragraph: Among all of the non-verbal social signals which humans use, eye-gaze is arguably the most important in terms of conveying something about the current contents of the gazers inner world. This is because people tend to look at things which are relevant to their immediate ongoing behaviour - things they are about to act upon, things in which they are interested or things about which they are thinking or talking. Once we come to understand that gazing at something brings about an inner experience of the gazed-at object, and that other people experience something similar when their eyes point towards the same object, then perceiving anothers gaze and following their line of regard to the gazed at object actually brings about a meeting of minds; at one level, both people will share a similar visual experience of one aspect of the world. This kind of joint or shared attention is considered by some to be an important milestone in developing the full range of mental state concepts ...
In the masked edge condition, the target presentation was identical with that under normal conditions, except that it was preceded and succeeded for 12 ms by a no-offset vernier target, i.e., a pair of vertically aligned lines, which appeared and moved just like the offset lines during the remainder of the target presentation. In this masked edge condition, there was thus no offset during the relatively undisturbed beginning and ending of the target presentation; the subject therefore had to make the discrimination while the pattern was moving and flanked by something moving ...
While the inbox is the first thing a subscriber sees, its often the last thing considered when creating an email. Every inbox shows the sender (or from) name and subject line for an email. Many also display some preview text. And optimizing preview text is one of the most effective ways to increase open rates-sometimes up to 45%. In this post, well cover what preview text is, how to use it, and where its supported.
The browser you are using is no longer supported on this site. It is highly recommended that you use the latest versions of a supported browser in order to receive an optimal viewing experience. The following browsers are supported: Chrome, Edge (v80 and later), Firefox and Safari. ...
The browser you are using is no longer supported on this site. It is highly recommended that you use the latest versions of a supported browser in order to receive an optimal viewing experience. The following browsers are supported: Chrome, Edge (v80 and later), Firefox and Safari. ...
The browser you are using is no longer supported on this site. It is highly recommended that you use the latest versions of a supported browser in order to receive an optimal viewing experience. The following browsers are supported: Chrome, Edge (v80 and later), Firefox and Safari. ...
The browser you are using is no longer supported on this site. It is highly recommended that you use the latest versions of a supported browser in order to receive an optimal viewing experience. The following browsers are supported: Chrome, Edge (v80 and later), Firefox and Safari. ...
The browser you are using is no longer supported on this site. It is highly recommended that you use the latest versions of a supported browser in order to receive an optimal viewing experience. The following browsers are supported: Chrome, Edge (v80 and later), Firefox and Safari. ...
The browser you are using is no longer supported on this site. It is highly recommended that you use the latest versions of a supported browser in order to receive an optimal viewing experience. The following browsers are supported: Chrome, Edge (v80 and later), Firefox and Safari. ...
The browser you are using is no longer supported on this site. It is highly recommended that you use the latest versions of a supported browser in order to receive an optimal viewing experience. The following browsers are supported: Chrome, Edge (v80 and later), Firefox and Safari. ...
While the human eye can be remarkably accurate, it isn't perfect and all of us have a blind spot. Learn why you have a blind spot and how to detect it.
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When sending message with enter key and insertion point is not at the end of the message, it will create a line break there.. Also there seems to be a bunch of emojis that dont show correctly in the app which might already be a known issue but just in case. Not sure if the emoji pack I linked was incompete or some in-app problems. Some telegram emojis seems to use two emojis as their source like this one: In sailorgram it show as four emojis: man, woman and two boys.. The size of image preview could be smaller as I recieved a screenshot of a phone screen and the preview was almost as large as my own screen. Also if recieved or sent a picture in landscape mode its preview is larger than in vertical mode and if changed to vertical after that the preview picture stays as large as in landscape mode and will go out of boundaries of the message area. The preview size is fixed if swipe out of the chat and come back.. Another issue is that if the app is open but ...
Ive found an interesting text that I would like to share. Ive edited it and placed it here in a more normal reading structure, but if you want to experience t
Tobi Dynavox The eye gaze is a technology that synthesizes with your eye movements and allows you to type words with your eyes. It is a very useful tool if
KOAMs Tawnya Bach and Michael Hayslip preview the five new movies opening in 4-state theaters this weekend: Tawnya also presents her box office Top 5 predictions. Tawnyas Top 5 Predictions: 1...
Now that Ive spent some more time with Windows 10 Technical Preview 2 for Phones. I have some more observations about how Windows Phone will improve.
Fixation (visual) Ocular tremor Saccade Darwin, R. W.; Darwin, E. (1786). "New Experiments on the Ocular Spectra of Light and ... They typically occur during prolonged visual fixation (of at least several seconds), not only in humans, but also in animals ... Current research in visual neuroscience and psychophysics is investigating how microsaccades relate to fixation correction, ... Movements of the Eyes (Pion, London, 1988). Guerrasio, Lorenzo (2011). Subcortical Control of Visual Fixation. Dissertation, ...
Ocular dysmetria also makes it difficult to maintain fixation on a stationary object. Hemispheric cerebellar syndromes cause ... Intention tremor Ocular dysmetria "dysmetria - definition of dysmetria in the Medical dictionary - by the Free Online Medical ... Midline cerebellar syndromes can cause ocular dysmetria, a condition in which the eyes can not track an object properly and ... A person with saccadic dysmetria will constantly produce abnormal eye movements including microsaccades, ocular flutter, and ...
Complete re-epithelialization on the ocular surface with no symptom is achieved in 3 weeks. Results show that fibrin glue ... fixation is easy, reliable and efficient with the corneal surface. Because fibrin fulfills the mechanical aspects of neuronal ...
The nerve dysfunction induces esotropia, a convergent squint on distance fixation. On near fixation the affected individual may ... Thus, the toxin works both therapeutically, by helping to reduce symptoms and enhancing the prospects for fuller ocular ... 3. Cross fixation which develops in the presence of infantile esotropia or nystagmus blockage syndrome and results in habitual ... In such cases recession of the medial rectus of the affected eye is accompanied by recession and/or posterior fixation ( ...
The influence on ocular fixations on the McGurk effect". Perception and Psychophysics. 65 (4): 533-567. doi:10.3758/bf03194582 ...
Ocular stability is maintained by three different ocular motor systems The fixation system The visuo-vestibular stabilizing ... The fixation system and its deficit In the fixation system, the ocular motor noise that comes from microsaccades, microtremors ... A deficit in this fixation system results in ocular instability that mainly leads to acquired pendular nystagmus and saccadic ... The vestibulo-ocular reflex deficit (especially when bilateral) and a deficit of vestibulo-ocular reflex inhibition can result ...
He postulated that "protracted ocular fixation" fatigued certain parts of the brain and caused a trance - a "nervous sleep" or ... to a physiological process resulting from prolonged attention to a bright moving object or similar object of fixation. ...
Ocular tissueEdit. Bullous keratopathy that is characterized by corneal stromal edema related to cell loss and endothelial ... Results show that fibrin glue fixation is easy, reliable and efficient with the corneal surface.[45] ... Chawla B, Tandon R (2008). "Sutureless amniotic membrane fixation with fibrin glue in symptomatic bullous keratopathy with poor ... Complete re-epithelialization on the ocular surface with no symptom is achieved in 3 weeks. ...
Scharioth and Pavilidis in 2006 reported the scleral tuck and intrascleral haptic fixation of a posterior chamber Intra ocular ... Maggi and Maggi in 1997 were the first to report sutureless scleral fixation of a special IOL. Gabor ... Topical lubricants are prescribed according to the ocular surface changes. Preservative free lubricants are initiated in ...
... of an object at fixation. Polyopia occurs when both eyes are open, or when one eye is open, during fixation on a stimulus. ... In addition, motor visual function should be assessed through examination of pupillary reactions, ocular motility, optokinetic ... Known cases of polyopia provide evidence that, in relation to the stimulus at fixation, multiple images can appear at a ... However, Bender's theory does not account for recent studies in which fixation did not change and no eye movements were ...
When the head translates, for example during walking, the visual fixation point is maintained by rotating gaze direction in the ... The vestibulo-ocular reflex is one of the fastest reflexes in the human body.[citation needed] During head-free pursuit of ... The vestibulo-ocular reflex (VOR) is a reflex acting to stabilize gaze during head movement, with eye movement due to ... The vestibulo-ocular reflex is driven by signals arising from the vestibular system of the inner ear. The semicircular canals ...
The size of the deviation: slight, small, moderate or large Speed to take up fixation: if the eye takes up fixation fast it ... The two primary types of ocular deviations are the tropia and the phoria. A tropia is a misalignment of the two eyes when a ... cc RET holds fixation RE(T)' holds fixation Hirschberg test Lancaster red-green test Strabismus Ansons, A.M; Davis, H (2014). ... and to see whether their fixation is steady, central and maintained. Assessing the patient's fixation is especially important ...
... just because they are very near the starting fixation and have a reasonable contrast). The following fixations jump from face ... It can also be noted that there are different types of eye movements: fixational eye movements (microsaccades, ocular drift, ... Fixations are comparably static points where the eye rests. However, the eye is never completely still, but gaze position will ... The resulting perception is also known as eyesight, sight, or vision (adjectival form: visual, optical, or ocular). The various ...
In a person with normal ocular alignment the light reflex lies slightly nasal from the center of the cornea (approximately 11 ... and will be symmetrical in an individual with normal fixation. For an abnormal result, based on where the light lands on the ... The Krimsky test is essentially the Hirschberg test, but with prisms employed to quantitate deviation of ocular misalignment by ...
For near fixation, the patient should hold an accommodative target (fixation stick) at 33 cm, ensuring it is in line with their ... doi:10.1016/j.ajo.2007.09.012 Campos, E.C., & von Noorden, G.K. (2006). Binocular vision and ocular motility (6th ed.) (p.177) ... Note: It is important to ensure the patient maintains good fixation, by continuing to look at the near fixation stick. 4. As ... For example, near fixation stick Distance target. For example, most commonly a Snellen chart is utilised, however the LogMAR ...
... and an accommodative fixation target such as a letter on a fixation stick for near, or a Snellen Chart letter for distance. The ... or loss of control of ocular misalignments. Motor anomalies can be managed in various ways, however, in order to commence ... convergence by asking patient to report when blur is appreciated progress of a patient undergoing management for ocular ... Diagnosis and Management of Ocular Motility Disorders [John Wiley & Sons]. Retrieved from ...
... ocular MeSH G11.697.716.260.253 - fixation, ocular MeSH G11.697.716.260.378 - nystagmus, physiologic MeSH G11.697.716.260. ... ocular MeSH G11.697.716.154 - adaptation, ocular MeSH G11.697.716.154.371 - dark adaptation MeSH G11.697.716.182 - blinking ... ocular MeSH G11.697.677.330 - evoked potentials, visual MeSH G11.697.677.340 - eye color MeSH G11.697.677.360 - figural ... ocular MeSH G11.697.677.911 - vision MeSH G11.697.677.911.500 - phosphenes MeSH G11.697.677.911.700 - vision, binocular MeSH ...
... ocular fixation and saccadic movements Difficulties opening the eyelids This can have particular relevance when driving. People ... Gitchel GT, Wetzel PA, Baron MS (2012). "Pervasive ocular tremor in patients with Parkinson disease". Arch Neurol. 69 (8): 1011 ... eye surface Alteration in the tear film Visual hallucinations Decreased eye convergence Blepharospasm Abnormalities in ocular ...
Binasal occlusion can be used to discourage cross-fixation. However, the management of cross-fixation congenital esotropia ... Infantile esotropia is an ocular condition of early onset in which one or either eye turns inward. It is a specific sub-type of ... Cross-fixation congenital esotropia, also called Cianci's syndrome is a particular type of large-angle infantile esotropia ... Initial alternation of the squint present with crossed fixation, i.e. the affected individual uses the left eye to look right ...
In 1956 he published The microscope in ocular surgery [7] and The continuous edge to edge suture in full thickness grafts [8]; ... pneumatic fixation rings, applanation tonometers, and applanation lenses to measure the diameter of the resection made with the ... Oftal.Optom Vol 5 p 179 [34] 19- A new operating microscope for ocular surgery. 1967; Amer J, Ophthal 63, 90 Nª1 [35] 20- ... In 1967 he published A new operating microscope for ocular surgery [17] describing a microscope developed jointly with his ...
... is a condition of binocular fixation in which the lines of vision meet at the object toward which they are directed ... and considered as a normal condition of balance of the ocular muscles of the two eyes. The condition opposite of Orthophoria, ...
These problems may directly affect the extra-ocular muscles themselves, and may also result from conditions affecting the nerve ... Cross fixation involves the use of the right eye to look to the left and the left eye to look to the right; a visual pattern ... However, others will eventually require extra-ocular muscle surgery to resolve their problems. Congenital esotropia, or ... It is, however, associated with other ocular dysfunctions including oblique muscle over-actions, Dissociated Vertical Deviation ...
In fact, upper eyelid retraction is the most common ocular sign of Graves' orbitopathy. This finding is associated with lid lag ... a widened palpebral fissure during fixation (Dalrymple's sign) and an incapacity of closing the eyelids completely ( ... Lid-lengthening surgeries can be done on upper and lower eyelid to correct the patient's appearance and the ocular surface ... Graves' ophthalmopathy is diagnosed clinically by the presenting ocular signs and symptoms, but positive tests for antibodies ( ...
Vestibulo-ocular reflex can be tested using a video recorded head impulse test or vHIT. In this test, SCA1 typically has normal ... while the absence of a square wave pattern during fixation reduces the likelihood of SCA3. One possible system for the ... Certain patterns in ocular motor disorders, detectable with video-oculography, appear to typify certain SCA types. While SCA1 ... Luis L, Costa J, Muñoz E, de Carvalho M, Carmona S, Schneider E, Gordon CR, Valls-Solé J (July 2016). "Vestibulo-ocular reflex ...
... the extra-ocular muscles adjust the vergence angle between the two visual axes so that the fixation target X is projected in ... fixation The reading fixation disparity reaches a minimum at a certain moment in time during the fixation The reading fixation ... the objective fixation disparity can be measured with eye trackers in the moments of fixation. This reading fixation disparity ... A patient may or may not have fixation disparity and a patient may have a different fixation disparity at distance than near. ...
4. Adler, F. H. M., Fliegelman, Maurice (AB) (1934). "Influence of Fixation on the Visual Acuity." Archives of Ophthalmology 12 ... 1993). "Ocular microtremor measurement system: design and performance." Med Biol Eng Comput 31(3): 205-12. 2. Coakley, D. and J ... Ocular microtremor (OMT) is a constant, physiological, high frequency (peak 80 Hz), low amplitude (estimated circa 150-2500 nm ... He proposed that the frequency of the ocular microtremors might also explain why there is a threshold at half that rate (~43Hz ...
Usually, these implants are covered with a material that permits fixation of the extraocular recti muscles, such as donor ... A few ocular prostheses today are made of cryolite glass. A variant of the ocular prosthesis is a very thin hard shell known as ... Makers of ocular prosthetics are known as ocularists. An ocular prosthesis does not provide vision; this would be a visual ... having an artificial eye Fabricating Ocular Prostheses History of Artificial Eyes Ocular Prosthetics Eyeform Opticians Ocular ...
Ocular drifts occur incessantly during intersaccadic fixation. Although the frequency of ocular drifts is usually lower than ... Fixation or visual fixation is the maintaining of the visual gaze on a single location. An animal can exhibit visual fixation ... The term "fixation" can either be used to refer to the point in time and space of focus or the act of fixating. Fixation, in ... Ocular drifts were first found to be caused by an instability of the ocular motor system.[citation needed] However, more recent ...
On each fixation and in real time, parafoveal text is magnified to equalize its perceptual impact with that of concurrent ... has revealed some of the ocular and psychological mechanisms involved in the visual system. The gaze-contingent techniques aim ... McConkie, G.W; Rayner, K (1975). "The span of the effective stimulus during a fixation in reading". Perception & Psychophysics ... McConkie, G.W; Rayner, K (1975). "The span of the effective stimulus during a fixation in reading". Perception & Psychophysics ...
As part of the NASDA Life Science Cell Culture Kit, this experiment used six petri-dish-like Plant Fixation Chambers (PFCs). ... while some were tested to estimate how space flight affected the gain of the otolith-ocular reflex and measure the otolith ...
In contrast, fixation disparity is a very small deviation of the pointing directions of the eyes that is present while ... Ocular ischemic syndrome / Central retinal vein occlusion. *Central retinal artery occlusion. *Branch retinal artery occlusion ... In order to understand how heterophoria occurs, we must understand of how the eye can maintain proper fixation with non aligned ...
Extra-oral prostheses are further divided into hemifacial, auricular (ear), nasal, orbital and ocular. Intra-oral prostheses ... passive devices are very useful in bimanual tasks that require fixation or support of an object, or for gesticulation in social ...
These data suggest the near fixation of the dark allele in the region. The expected time to fixation of this recessive allele ... Ocular melanosis. *Melanosis. References[edit]. *^ Morales, E. (1995). The Guinea Pig : Healing, Food, and Ritual in the Andes ... "Near fixation of melanism in leopards of the Malay Peninsula". Journal of Zoology. 282 (3): 201-206. doi:10.1111/j.1469- ... polymorphism in 11 of 37 felid species and reaches high population frequency in some cases but never achieves complete fixation ...
After completion of surgery, the patient is transferred to the post anesthesia care unit and closely monitored. When the patient is judged to have recovered from the anesthesia, he/she is either transferred to a surgical ward elsewhere in the hospital or discharged home. During the post-operative period, the patient's general function is assessed, the outcome of the procedure is assessed, and the surgical site is checked for signs of infection. There are several risk factors associated with postoperative complications, such as immune deficiency and obesity. Obesity has long been considered a risk factor for adverse post-surgical outcomes. It has been linked to many disorders such as obesity hypoventilation syndrome, atelectasis and pulmonary embolism, adverse cardiovascular effects, and wound healing complications.[11] If removable skin closures are used, they are removed after 7 to 10 days post-operatively, or after healing of the incision is well under way. It is not uncommon for surgical ...
This indicates that the lack of vision is neurological rather than ocular. It specifically indicates that the occipital cortex ... A lack of visual fixation and tracking [4]. *Denial of visual loss (Anton-Babinski syndrome) ... and delayed visual maturation-must be distinguished from ocular visual impairment in terms of their different causes and ... is that the pupils of individuals with cortical blindness will respond to light whereas those of individuals with ocular visual ...
During fixation, neurons near the front edge - the foveal zone - are tonically active. During smooth pursuit, neurons a small ... Pierrot-Deseilligny, C; Müri RM; Ploner CJ; Gaymard B; Rivaud-Péchoux S (2003). "Cortical control of ocular saccades in humans ... In primates, eye movements can be divided into several types: fixation, in which the eyes are directed toward a motionless ... This portion of the SC contains many "fixation" neurons that fire continually while the eyes remain fixed in a constant ...
Furthermore, individual V1 neurons in humans and animals with binocular vision have ocular dominance, namely tuning to one of ... above the point of fixation), more recent work indicates that this area is more extensive than previously appreciated, and like ... ocular dominance and orientation. However, this model cannot accommodate the color, spatial frequency and many other features ...
Wolfgang H. Vogel, Andreas Berke (2009). "Brief History of Vision and Ocular Medicine". Kugler Publications. p.97. ISBN 90-6299 ... Some say that the fixation or obsession with correction of the area could be a sub-disorder such as anorexia or muscle ...
... cognitive load from ocular parameters through simulation and in-flight studies". Journal of Eye Movement Research. 12. doi: ... number of gaze fixations , 500 milliseconds. *saccade speed. *pupillary hippus[24]. Individual differences in processing ... ocular parameters[47] and so on. In aviation there are numerous simulation studies on analysing pilots' distraction and ... "Cognitive load estimation using ocular parameters in automotive". Transportation Engineering. 2: 100008. doi:10.1016/j.treng. ...
... and ocular affections such as ptosis and nystagmus, as well as psychological effects such as apathy, akinesia, lethargy, timing ... "fixation of certain patterns of relationship among various groups of cells" and that this resulted in obsessions, delusions and ...
Pine, Keith R.; Sloan, Brian H.; Jacobs, Robert J. (2015). Clinical Ocular Prosthetics. Springer. ISBN 9783319190570. .. ... passive devices are very useful in bimanual tasks that require fixation or support of an object, or for gesticulation in social ... Extra-oral prostheses are further divided into hemifacial, auricular (ear), nasal, orbital and ocular. Intra-oral prostheses ...
"Resorbable bone fixation alloys, forming, and post-fabrication treatments". Materials Science and Engineering: C. 70 (1): 870- ... ocular prosthesis, and injectable filler.[1][2][3] ...
Fixation (visual). *Optical coherence tomography (OCT). References[edit]. *^ Myron Yanoff; Jay S. Duker (6 November 2013). ... Ocular immune system. *Optical coherence tomography. *Eye care professional. *Eye disease. *Refractive error ...
... ocular Colobomata unilobar lung heart defect Colobomatous microphthalmia heart disease hearing Colobomatous microphthalmia ... absent tibia Cleft palate lateral synechia syndrome Cleft palate short stature vertebral anomalies Cleft palate stapes fixation ... craniosynostosis maternal hyperthyroiditis Congenital cystic adenomatoid malformation Congenital cystic eye multiple ocular and ...
The rear half of the eye was placed in an alum solution to enable fixation of the bleached rhodopsin, which resulted in a ... the Fourth Doctor applies the theory with some of the ocular tissue of the alien Wirrn to project not just still images, but ...
Some say that the fixation or obsession with correction of the area could be a sub-disorder such as anorexia or muscle ... "Brief History of Vision and Ocular Medicine". Kugler Publications. p.97. ISBN 90-6299-220-X P. Santoni-Rugiu, A History of ...
Ocular: narrowed eye slits, almond shaped eyes, epicanthal folds (extra eyelid tissue), epibulbar dermoids (benign tumors of ... "Nasal reconstruction with full-thickness cranial bone grafts and rigid internal skeleton fixation through a coronal incision". ... However, in FND this suppression is prevented in the midline by the increased inter-ocular distance. This causes the so-called ...
The results after MISS regarding postoperative ocular alignment are widely described in the so far still limited literature on ... D. S. Mojon: Minimally invasive strabismus surgery for rectus muscle posterior fixation. In: Ophthalmologica. 223(2), 2009, S. ...
Certain ocular diseases can come from sexually transmitted diseases such as herpes and genital warts. If contact between the ... measured from the fixation point, i.e., the point at which one's gaze is directed) varies by facial anatomy, but is typically ... The distance between the VDU and keyboard should be kept as short as possible to minimize evaporation from the ocular surface ... Rolando, M; Zierhut, M (March 2001). "The ocular surface and tear film and their dysfunction in dry eye disease". Survey of ...
There are different critical periods within specific systems, e.g. visual system has different critical periods for ocular ... such as visual fixation, grasping, symbol use and working memory. However, these skills continue to develop well after the ...
To initially relieve double vision (diplopia) caused by an extra-ocular muscle palsy, an eye care professional may recommend ... Georgievski Z, Koklanis K, Leone J (2008). "Fixation behaviour in the treatment of amblyopia using atropine". Clinical and ...
... diplopia is induced which is the driving force for the eyes to change fixation and therefore re-gain bifoveal fixation meaning ... ISSN 1040-5488 Pavan-Langston, D. (2008). Manual of ocular diagnosis and therapy. Philadelphia: Wolters Kluwer Health/ ... Eccentric fixation is less common but nonetheless a possible reason as to why a patient may fail the 4 PRT. Anisometropia in a ... Eccentric fixation utilises an abnormal retinal correspondence point and not the fovea, no movement under the prism is seen ...
Throughout the tristate area, complex ocular injuries are referred to NYEE's Eye Trauma Service. NYEE provides medical care for ... In the Management of Amblyopia with Eccentric Fixation". American Journal of Ophthalmology. 48 (4): 490-502. doi:10.1016/0002- ... Research includes adaptive optics cellular imaging, functional and metabolic imaging, glaucoma, neuro-ophthalmology ocular ... Specialized services include cataract surgery, corneal and refractive surgery, glaucoma, neuro-ophthalmology, ocular immunology ...
... to affix the amniotic membrane in severe ocular surface disease lesi ... The MCBS method also leads to rapid reconstruction of the ocular surface and provides a surface conducive to further procedures ... In all cases, stable adherence of the amniotic membrane was maintained until the epithelialization of the ocular surface was ... During follow-up, all patients acquired a smooth and acceptable ocular surface without any persistent epithelial defect, ...
Reversible inactivation of macaque dorsomedial frontal cortex: effects on saccades and fixations.  Sommer, MA; Tehovnik, EJ ( ... The macaque frontal eye field (FEF) is involved in the generation of saccadic eye movements and fixations. To better understand ...
Ocular Accommodation, Convergence, and Fixation Disparity A Manual of Clinical Analysis. Ocular Accommodation, Convergence, and ... Goss, David A. is the author of Ocular Accommodation, Convergence, and Fixation Disparity A Manual of Clinical Analysis with ...
Ocular Motor Kinematics: The Law of the Fixation Planes You will receive an email whenever this article is corrected, updated, ... RS Jampel; Ocular Motor Kinematics: The Law of the Fixation Planes . Invest. Ophthalmol. Vis. Sci. 2002;43(13):2648. ... The Law of the Fixation Planes: The function of extraocular muscles is to maintain the FPs of the two eyes coplanar in all ... Abstract: : Purpose: To present the results of experiments in oculomotor kinematics and evidence for the Law of the Fixation ...
Ocular fixation and saccades in motor neurone disease: markers of frontal lobe dysfunction?. 2008. Abstract from Meeting of the ... Ocular fixation and saccades in motor neurone disease: markers of frontal lobe dysfunction? / Donaghy, C.; Pinnock, R.; ... Donaghy, C, Pinnock, R, Abrahams, S, Cardwell, C, Hardiman, O, Patterson, V, McGivern, RC & Gibson, JM 2008, Ocular fixation ... title = "Ocular fixation and saccades in motor neurone disease: markers of frontal lobe dysfunction?", ...
Impaired Visual Fixation Suppression Of The Vestibulo-Ocular Reflex (VOR). Video of Fixsupp 2 fi01 No Audio. ... In particular when the patient turns the head to the left, there is a prominent impairment of visual fixation suppression of ... In particular when the patient turns the head to the left, there is a prominent impairment of visual fixation suppression of ...
Effect of aging on ocular fixation and microsaccades during optic flow Angelo Arleo; Marcia Bécu; Guillaume Tatur; Alix de ... This study assessed ocular fixation statistics and microsaccade characteristics under no-flow (control) as well as radial and ... Effect of aging on ocular fixation and microsaccades during optic flow You will receive an email whenever this article is ... Moreover, tangential optic flow significantly affected the ocular fixation drift slope, and it amplified the extent of drift ...
IMPORTANT: If you are concerned about your eyes and require an urgent consultation, DO NOT use this form. Please call one of our clinics during office hours or contact your nearest emergency department.. ...
... quality and stability of ocular fixation, and the bottom-up and top-down influences that affect fixation behaviour. ... The concept of ocular fixation must be understood in relative, rather than absolute terms. This is both because there is no ... 1. The quality of ocular fixation: how well do we keep our eyes still?. Human eyes never stop moving, despite our subjective ... To measure the quality of ocular fixation, one must be able to establish how often, and to what extent, eye motion intrudes ...
... and a fixation light beam (24). A fixation light spot in the vicinity of the fovea (30) and the fovea are imaged by means of a ... camera (40). This makes it possible to check whether the patient has reliably fixated the fixation light source (22). In ... Ocular microcirculation examination and treatment apparatus. US6238385. Jun 2, 1998. May 29, 2001. Nidek Co., Ltd.. Laser ... a fixation light source for emitting a fixation light beam at a visible wavelength, the fixation light beam provided for visual ...
Fixation, Ocular* * Humans * Male * Middle Aged * Orientation * Pattern Recognition, Visual* * Reaction Time ...
Diminished gaze fixation is one of the core features of autism and has been proposed to be associated with abnormalities in the ... Fixation, Ocular / physiology* * Functional Laterality / physiology * Humans * Image Processing, Computer-Assisted / methods ... Gaze fixation and the neural circuitry of face processing in autism Nat Neurosci. 2005 Apr;8(4):519-26. doi: 10.1038/nn1421. ... Diminished gaze fixation is one of the core features of autism and has been proposed to be associated with abnormalities in the ...
... therapy includes a particular combination of a photosensitizer and light source for a photodynamic therapy used to treat ocular ... Bone fixation system. July, 2006. Sweeney. 20070060939. Expandable and retractable cannula. March, 2007. Lancial et al. ... A treatment for ocular disease as recited in claim 11 wherein the light source includes a laser. 15. A treatment for ocular ... A treatment for ocular disease as recited in claim 16 wherein the light source includes a laser. 20. A treatment for ocular ...
The present invention relates to a method and apparatus for treating ocular tissue. ... Fracture Fixation Apparatus. December, 2009. Yamazaki et al.. Primary Examiner:. HUPCZEY, JR, RONALD JAMES ...
An integrated rigid fixation orbital expander has a coupling tunnel, an injection port, and a substantially spherically shaped ... Total ocular replacement apparatus with muscle attachment sites. US5330529 *. Feb 17, 1993. Jul 19, 1994. Cepela Mark A. ... The integrated rigid fixation orbital expander 10 is inserted within the muscle cone and coupled to a multi-hole plate 50, such ... The integrated rigid fixation orbital expander 10 according to one aspect of the invention is shown in FIGS. 1-4. As shown in ...
The fixation is presented upon the display and the stimulus is altered to allow resensitization of the subjects retina, ... thereby allowing prolonged visual fixation upon the resulting dynamic target. A dynamic stimulus may utilize a frequency ... Alteration of a fixation or peripheral stimulus displayed on a computer-driven display allows a human subject to maintain ... extended visual fixation upon the resulting dynamic stimulus. ... Automated ocular perimetry, particularly kinetic perimetry. ...
Ocular Alignment. *Visual Fixation. *Light Touch. *Saccadic Eye Movement. *Convergence. *Visual Spatial Inattention ...
do not have abnormal fixation. *IOP greater than 36 mm Hg. *significant retinal disease ... Safety and Efficacy Study of BETAXON 0.5% and AZOPT 1.0% in Pediatric Patients With Glaucoma or Ocular Hypertension. The safety ... Glaucoma Ocular Hypertension Drug: BETAXON (levobetaxolol HCl) Drug: AZOPT (brinzolamide) Phase 3 ... Ocular Hypertension. Vascular Diseases. Cardiovascular Diseases. Eye Diseases. Brinzolamide. Carbonic Anhydrase Inhibitors. ...
... ocular hypertension in 2 eyes. No cases of postoperative cystoid macular edema (CME), vitreous hemorrhage (VH), IOL dislocation ... The 27-gauge needle-guided intrascleral IOL fixation technique with built-in 8-0 absorbable sutures is easy to perform with ... Eyes from 14 patients who underwent 27-gauge needle-guided intrascleral IOL fixation with built-in 8-0 absorbable sutures were ... fixation with fewer anterior segment manipulations in eyes lacking sufficient capsular support. ...
Fixation, Ocular*. Humans. Middle Aged. Reference Values. Vision, Ocular*. From MEDLINE®/PubMed®, a database of the U.S. ... Next Document: Fixation duress in the pathogenesis of upper eyelid retraction in thyroid orbitopathy. A prospective.... ...
Fixation, Ocular. Habituation, Psychophysiologic. Humans. Infant. Knowledge*. Learning*. Male. Mental Recall. Orientation*. ...
Fixation and Following. *Ocular Alignment (Screen for Strabismus). *Corneal Light Reflex (Hirschberg Test) ...
Browse miscellaneous ophthalmic videos depicting management of ocular trauma, IOFB, removal of parasites and worms, and surgery ... Keratoplasty and Cataract Removal in a Patient With Severe Iatrogenic Ocular Surface Disease. A. John Kanellopoulos, MD ... Iridodialysis and Intrascleral Haptic Fixation. Ashvin Agarwal, MD. ... Keratoplasty and Cataract Removal in a Patient With Severe Iatrogenic Ocular Surface Disease. A. John Kanellopoulos, MD ...
... and various ocular conditions. Evaluation of fixation and alignment can identify amblyopia or strabismus. Red reflex ... Visual acuity measurement and external ocular examination are performed to recognize refractive error, childhood glaucoma, ... examination is used to diagnose retinoblastoma, childhood cataracts, and other ocular abnormalities. ... Ocular fixation should be evaluated routinely. Children as young as six weeks should have some response to an examiners face. ...
... the ocular structures are placed in a global coordinate system based on ocular imaging. In some embodiments, the ocular ... inside the global coordinate system lead to direction of an automated positioning system that is directed based on the ocular ... In some embodiments, inflammatory ocular disorders are treated, specifically macular degeneration. In some embodiments, ... Ocular fixation and stabilization device for ophthalmic surgical applications. US6888919. 2 Nov 2001. 3 May 2005. Varian ...
A method and system for performing an ocular irradiation procedure on a patients eye is disclosed. The system includes a head ... Ocular fixation and stabilization device for ophthalmic surgical applications. US6865253 *. 18 Sep 2001. 8 Mar 2005. Brainlab ... Ocular fixation and stabilization device for ophthalmic surgical applications. US7027557 *. 13 May 2004. 11 Abr 2006. Jorge ... As used herein "ocular disease" refers to a disease of the eye, including, but not limited to tumors, ocular degeneration, such ...
At all times during recording, attempts were made to pacify the child and obtain their attention to the fixation screen at 1 ... ocular abnormalities (eye disease), head position, null or neutral zone characteristics, and other ocular motor disease. In ... Ocular motor recording protocol. The infant was seated in a comfortable position in a parent or caretakers lap. The infrared ... Ocular motor recordings can provide a prediction of the potential best corrected visual acuity. Such a measure is the nystagmus ...
Just got my MRI back as a followup to neck pains after a anterior internal fixation c6-7 3 yrs ago. New report sates : ... 2018 General Information on Dry Eyes-Now known as Ocular Surface Disorder ... Just got my MRI back as a followup to neck pains after a anterior internal fixation c6-7 3 yrs ago. New report sates : ...
Excessive blinking may indicate ocular surface disease in children. * Ocular Surgery News U.S. Edition, January 10. Ken K. ... Small-gauge vitreoretinal instrumentation can be used for scleral fixation of IOLs. ... Ocular Surgery News U.S. Edition, September 10. Alex Mammen, MD. * A major factor in optimizing cataract surgery outcomes is ... Ocular Surgery News U.S. Edition, April 10. Julia Polat, MD. * Trabeculectomy and tube shunt implantation are the most ...
  • Reversible inactivation of macaque dorsomedial frontal cortex: effects on saccades and fixations. (
  • Ocular fixation and saccades in motor neurone disease: markers of frontal lobe dysfunction? (
  • Visual fixations correspond to moments of "useful vision", unlike saccades during which we are blind. (
  • A diminutive version of classical saccades-the rapid eye movements that change the line of sight from one fixation target to the next-microsaccades or fixational saccades are small-magnitude saccades produced during the attempt to fixate one's gaze on a target [ 4 - 6 ]. (
  • Ordinarily, a saccade is generated when underlying activity in the oculomotor circuit is robust enough to inhibit pontine omnipause neurons (OPNs), which gate the saccadic system by firing spikes at a tonic rate during fixation and becoming quiescent during saccades ( Keller, 1974 ). (
  • Head movements didn't contribute to these findings, nor did saccades, blinks, or other eye movements change the ocular tremor. (
  • The fixation problems in Parkinson's somewhat resembled the involuntary rapid eye movements of pendular nystagmus (fast, uncontrollable eye movements), but with greater complexity and smaller magnitude of movement not reset by saccades, suggesting it is an ocular tremor rather than pendular nystagmus, the researchers argued. (
  • showing more fixations and frequent saccades of small amplitude. (
  • Adaptive plasticity in the naso-occipital linear vestibulo-ocular reflex. (
  • Canal-otolith interactions in the squirrel monkey vestibulo-ocular reflex and the influence of fixation distance. (
  • Influence of sensorimotor context on the linear vestibulo-ocular reflex. (
  • When the head is turned to the right, the vestibulo-ocular reflex moves the eyes to maintain visual fixation. (
  • They typically occur during prolonged visual fixation (of at least several seconds), not only in humans, but also in animals with foveal vision (primates, cats, dogs etc. (
  • Similarly, Alpert reported the normal humans had a fixation index between 60 and 70 (Alpert, 1974). (
  • Intrascleral reverse pocket approach of transconjunctival transscleral sulcus fixation of intraocular lens in eyes with ocular trauma. (
  • To report a modified surgical technique for intrascleral intraocular lens (IOL) fixation with fewer anterior segment manipulations in eyes lacking sufficient capsular support. (
  • Pathological changes of any factor may cause abnormal flow of AH and elevate intraocular pressure, which may lead to ocular hypertension (OHT). (
  • Transconjunctival Sutureless Intrascleral Fixation of Secondary Intraocular Lenses in Patients with Uveitis. (
  • We report a case of late breakage of a 9-0 polypropylene transscleral suture used for fixation of a dislocated capsular bag-intraocular lens-modified capsular tension ring complex in a 52-year-old woman with Marfan syndrome. (
  • Lack of zonular support, lenticular dysgenesis, and aphakia are common issues in anterior segment surgery that require intraocular lens (IOL) fixation. (
  • Polypropylene suture is approved for ophthalmic use and for intraocular implant fixation. (
  • 20 eyes of 15 patients with no ocular conditions other than cataract had implantation of posterior chamber intraocular lens (AcrySof. (
  • Vision screening begins with a review of family and personal vision history to identify risk factors requiring referral, including premature birth, Down syndrome, cerebral palsy, and a family history of strabismus, amblyopia, retinoblastoma, childhood glaucoma, childhood cataracts, or ocular or genetic systemic disease. (
  • Evaluation of fixation and alignment can identify amblyopia or strabismus. (
  • Ocular alignment should be assessed during vision screening in children to identify strabismus and amblyopia. (
  • The ocular motor systems of patients with INS and no strabismus (with or without associated sensory deficits) are otherwise normal, showing normal smooth pursuit, saccadic, and vestibulo-ocular systems. (
  • Current research in visual neuroscience and psychophysics is investigating how microsaccades relate to fixation correction, memory, control of binocular fixation disparity and attentional shifts. (
  • Normal binocular single vision occurs with bifoveal fixation and normal retinal correspondence in everyday sight. (
  • Normal binocular single vision results due to the presence of bifoveal fixation and normal retinal correspondence and vice versa. (
  • The purpose of this study was to determine whether a new binocular RBS (BRBS) instrument can detect simultaneous fixation of both eyes. (
  • Goss, David A. is the author of 'Ocular Accommodation, Convergence, and Fixation Disparity A Manual of Clinical Analysis' with ISBN 9780409903065 and ISBN 040990306X. (
  • Convergence insufficiency (CI) is a common disorder of ocular alignment among both children and adults. (
  • CI is diagnosed on the findings of a remote near point of convergence and decreased fusional convergence at near fixation. (
  • Convergence insufficiency is one of few forms of ocular misalignment that is relatively common in both children and adults. (
  • Sustained fixation induced changes in phoria and convergence peak velocity. (
  • Two different sustained fixations (1° and 16° convergent rotation along the subject's midline) were used to study whether phoria had an influence on the peak velocity of convergence responses located at two initial vergence positions (1° or 'far' steps and 12° or 'near' steps). (
  • As a result of sustained fixation, phoria was adapted and the peak velocity of the near and far convergence steps was modified. (
  • This article demonstrates a novel technique using modified continuous blanket suture (MCBS) to affix the amniotic membrane in severe ocular surface disease lesions. (
  • 2. A treatment for ocular disease as recited in claim 1 wherein the photosensitizer is Talaporfin Sodium. (
  • 3. A treatment for ocular disease as recited in claim 1 wherein the light source includes at least one light emitting diode. (
  • 4. A treatment for ocular disease as recited in claim 1 wherein the light source includes a laser. (
  • 5. A treatment for ocular disease as recited in claim 1 wherein the spot size of the light for treatment is within the range of 200 microns-6000 microns. (
  • 11 Numerous reports on the ocular motor behaviour in human albinos, patients with retinal disease, and visual deprivation amblyopia have shown INS to be the predominant ocular oscillation. (
  • Research has demonstrated that patients with Parkinson's disease exhibit persistent ocular tremors that prevent stability during fixation 2 . (
  • Through oculomotor testing, the RightEye Vision System is designed to identify these ocular tremors, which may not only help doctors to diagnose the disease but may also help detect the disease at an earlier stage since ocular tremors are often detectable well before other commonly recognized symptoms of the disease surface. (
  • Note also that this study suggests that precise measurement of ocular tremor with specialized techniques may be a very sensitive diagnostic tool early in the course of Parkinson Disease. (
  • By comparison, the same fixation instability was seen in just two of 60 age-matched controls, one of whom apparently had presymptomatic Parkinson's disease based on symptoms that developed over 2 years of follow up, the group reported online in the Archives of Neurology . (
  • Fixation instability did not correlate with duration or severity of disease or dopa-equivalent dosing either. (
  • The fact that this behavior was universally observed in every tested patient with Parkinson's disease, including unmedicated patients, suggests that ocular tremor is a function of the disease process and not induced by medication," Baron's group wrote. (
  • However, the Parkinson's disease patients did differ compared with the 60 age-matched controls recruited from among patients' family and friends, among whom just 3.3% showed similar oscillatory fixation instability. (
  • Seoul KPro was originally designed for use in severe ocular surface disease in Asians. (
  • In particular when the patient turns the head to the left, there is a prominent impairment of visual fixation suppression of the VOR, mild-to-moderate when the head is turned to the right. (
  • The diagnosis of impaired fixation suppression is made by observing the effect of asking the subject to fix his eyes upon a clearly visible target, upon any ongoing nystagmus.The most commonly used test procedure is one described by Albert (1974). (
  • Fixation suppression can also be calculated from rotatory chair tests by having the subject track a chair fixed laser projected on a wall. (
  • There is evidence that there are multiple systems that participate in fixation suppression. (
  • Smooth pursuit can be used to suppress nystagmus, and some investigators have suggested that fixation suppression is redundant with the pursuit test. (
  • Similarly, fixation suppression is probably affected by the many other variables which affect pursuit. (
  • This seems reasonable, although it would seem unrealistic to rely on fixation suppression alone to differentiate between these two entities. (
  • Based on many years of ENG lab experience, the author feels that fixation suppression of caloric responses adds very little to the diagnostic value of the test. (
  • Fixation suppression of rotatory chair responses, which is actually a different quantity -- eye velocity/chair velocity, is often valuable. (
  • Alpert JN, (1974) Failure of fixation suppression: a pathologic effect of vision on caloric nystagmus. (
  • The variability of fixation suppression of caloric-induced nystagmus. (
  • This article describes the proper procedure for administering the fixation suppression test and analyzing the results. (
  • The most common protocol for testing fixation suppression is based on the procedure described by Alpert (1974). (
  • During the fixation suppression test, the light can be turned on for visual fixation. (
  • This will ensure that the nystagmus intensity just before fixation is still strong enough to produce a valid test of fixation suppression while at the same time, preserving the peak of caloric responses. (
  • The common protocol requires testing fixation suppression for at least one right-beating and one left-beating caloric response. (
  • However, for valid comparison of fixation suppression for different nystagmus directions, the intensity of the nystagmus just before fixation should be approximately the same for two irrigations. (
  • If the patient keeps his or her eyes closed or avoids looking directly at the target, the fixation test is probably invalid and the tracings should not be misidentified as failure of fixation suppression. (
  • The most common method for analyzing the fixation suppression test is to compare the nystagmus intensity after fixation with the nystagmus intensity before fixation (ANSI, 1999). (
  • Red reflex examination is used to diagnose retinoblastoma, childhood cataracts, and other ocular abnormalities. (
  • OKN testing can also be used to identify subtle ocular motor abnormalities (eg, incomplete internuclear ophthalmoplegia). (
  • To investigate the prevalence of ocular abnormalities suggestive of glaucoma damage in systemic sclerosis (SSc). (
  • Ocular abnormalities suggesting glaucomatous neuropathy without ocular hypertension were dramatically more prevalent in patients with SSc. (
  • We prospectively compared the prevalence of ocular abnormalities associated with glaucoma in a group of patients with SSc compared with control subjects with osteoarthritis (OA). (
  • The visual line rotates within the FP.The oblique muscles share a common axis that is fixed in the FP at an angle of about 39 degs with the sagittal head planes.The vertical recti share a common axis that is fixed in the fixation plane at an angle of about 67 degs with the sagittal head planes. (
  • Yet, the study of ocular instability has a long history-starting with Jurin's 1738 observation [ 1 ] that the 'trembling of the eye' is unremitting-but it has proceeded in spurts and starts, and it is only in recent years that it has become a mainstay of oculomotor and visual neuroscience. (
  • It is perhaps owing to uneven research progress in this field that such terms as visual 'fixation' or 'fixational eye movements', have come to exist, given that there is no such thing as gaze fixation. (
  • They occur at a rate of one to two per second during sustained fixation attempts [ 9 ], and at a rate of approximately 0.5 per second during the brief fixations that occur while freely viewing a visual scene [ 10 ]. (
  • Alteration of a fixation or peripheral stimulus displayed on a computer-driven display allows a human subject to maintain extended visual fixation upon the resulting dynamic stimulus. (
  • The fixation is presented upon the display and the stimulus is altered to allow resensitization of the subject's retina, thereby allowing prolonged visual fixation upon the resulting dynamic target. (
  • Visual acuity measurement and external ocular examination are performed to recognize refractive error, childhood glaucoma, and various ocular conditions. (
  • Influence of Fixation on the Visual Acuity. (
  • Fixation (visual) Ocular tremor Saccade Darwin, R. W. (
  • Ocular dominance can be modified by visual input and NEUROTROPHIC FACTORS. (
  • Articulate the description of ocular motor skill impairment, visual field loss, visual spatial inattention and midline syndrome. (
  • Demonstrate competent assessment of ocular motor skills, visual field loss, visual spatial inattention and midline syndrome. (
  • Prescribe treatment interventions for ocular motor skills, visual field loss, visual spatial inattention and midline syndrome. (
  • Influence of age, spatial memory, and ocular fixation on localization of auditory, visual, and bimodal targets by human subjects. (
  • One of the key features of vestibular nystagmus is that in normal individuals, the nystagmus intensity is strongly reduced by visual fixation. (
  • In VNG, the fixation test can be done by removing the cover of the goggles and again asking the patient to look at a visual target. (
  • The best time to initiate visual fixation is shortly after the caloric response has reached its peak and the nystagmus intensity is beginning to decline. (
  • The tracings should be marked at the onset of fixation after making sure that the patient is actually attempting to fixate on a small visual target. (
  • The examiner can sometimes recognize this by observing the patient's eyes during visual fixation. (
  • When the head is turned to the right, the eyes move with it, breaking visual fixation, and a refixation saccade is seen as the eyes dart back to the examiner's face. (
  • Visual function was assessed at term equivalent age (TEA) using a prevalidated battery evaluating ocular spontaneous motility, ability to fix and follow a target, reaction to color, stripes discrimination and visual attention at distance. (
  • Through comprehensive modeling, age, visual axis indices, visual acuity, and contrast sensitivity were found to be the main factors significantly associated with dynamic ocular globe cyclotorsions during single-step TransPRK. (
  • Observation of the triplet siblings demonstrates normal ocular appearance and visual fixation behavior in both. (
  • The ocular examination consists of the external examination, pupil examination, red reflex testing to assess ocular media, the examination of the ocular fundus by using ophthalmoscopy, and an assessment of visual function. (
  • What does visual fixation do? (
  • and (iii) ocular motor behavior in the visual search tasks is similar for dyslexic children and for typical readers, except for the disconjugacy during and after the saccade: dyslexic children are impaired in comparison to typical children. (
  • The atypical eye movement's patterns observed in dyslexic children suggest a deficiency in the visual attentional processing as well as an impairment of the ocular motor saccade and vergence systems interaction. (
  • Models of eye guidance in reading rely on the concept of the perceptual span-the amount of information perceived during a single eye fixation, which is considered to be a consequence of visual and attentional constraints. (
  • In the current study, we first measured complete visual and vestibular tuning curves from single neurons in FEFsem and MSTd while the animals varied static fixation positions under a passive viewing task. (
  • Brain dysfunction must explain the abnormal visual responses, as abnormal ocular structures, abnormal eye movements, and refractive error do not. (
  • It is now widely accepted that "cortical blindness" is not an appropriate diagnostic term for children with early, acquired visual impairment due to non-ocular causes. (
  • In some embodiments, inflammatory ocular disorders are treated, specifically macular degeneration. (
  • Ocular motility disorders secondary to sinus surgery. (
  • Other ocular disorders included age-related macular degeneration in 17 percent and glaucoma in 8 percent of patients. (
  • A diagnosis of functional diplopia should not be entertained based simply on the absence of gross ocular misalignment, because sometimes very subtle misalignment of the ocular axes, which are difficult to elucidate at the bedside, may require more sensitive tests. (
  • On the other hand, one should not be surprised to see gross ocular misalignment without diplopia as brain plasticity usually takes over if diplopia is longstanding and the image from one eye is suppressed. (
  • Postoperative complications included postoperative hypotony in 3 eyes, ocular hypertension in 2 eyes. (
  • We focus on the variations of IPE stiffness in a rat ocular hypertension (OHT) model, so as to prepare for exploring the mechanism of duration of OHT. (
  • Patients admitted to hospital for an organ failure, patients with a history of ocular hypertension or presenting a cataract were excluded. (
  • Many authors extol the advantages of knotless Z-suturing fixation of the distal suture(4) and, for the proximal end, sliding knots, cow-hitch, or other modifications. (
  • Ocular microtremor (OMT) is a constant, physiological, high frequency (peak 80 Hz), low amplitude (estimated circa 150-2500 nm (1)) eye tremor. (
  • Currently, intrascleral fixation of posterior chamber IOL implantation is widely performed because of its safety, efficacy, and stability. (
  • 27 infants with involuntary ocular oscillations typical of INS are included in this analysis. (
  • Involuntary ocular oscillations have been classified in many ways, resulting in some confusion and disagreement among clinicians, physiologists, psychologists, and bioengineers. (
  • Medicated and unmedicated patients didn't differ in fundamental frequency, magnitude of the oscillations, or in fixation instability as measured by root mean square velocity while fixing the gaze on a target. (
  • a ) Fixational eye movements recorded during a 2 s fixation. (
  • More recent studies are less common for ocular microtremor than for other fixational eye movements. (
  • The macaque frontal eye field (FEF) is involved in the generation of saccadic eye movements and fixations. (
  • Square wave jerks are brief, conjugate, random movements away from the target that interrupt stable fixations, according to the authors. (
  • Ocular microtremor can potentially help in the difficult diagnosis of brainstem death, as well as monitoring patients while under anaesthesia (3). (
  • Just got my MRI back as a followup to neck pains after a anterior internal fixation c6-7 3 yrs ago. (
  • Breakage occurred despite use of a cow-hitch technique for external and internal fixation. (
  • 10. Eccentric Fixation Selective Bibliography, 1967-1971 , (ed 2). (
  • Peripheral vestibular nystagmus is usually well suppressed by fixation. (
  • Because in ENG, caloric nystagmus is usually recorded with eyes closed, fixation can be induced by simply asking the patient to open his or her eyes and to look at a target straight ahead. (
  • 1 Ocular vasospasm is thought to induce optic nerve head damage, and this phenomenon was recently shown to contribute to the pathogenesis of glaucoma. (
  • This study assessed ocular fixation statistics and microsaccade characteristics under no-flow (control) as well as radial and tangential optic flow conditions in 51 subjects (21 - 80 y/o). (
  • All optic flow conditions reduced the fixation area to a similar extent in all age groups. (
  • Moreover, tangential optic flow significantly affected the ocular fixation drift slope, and it amplified the extent of drift significantly more in aged compared to young subjects. (
  • Although, whenever possible, optic capture is optimal, when the bag cannot be employed, intra- and transscleral implant fixation as well as iris fixation techniques are available. (
  • The fiber connector chambers enable quick fixation of the fiber optic laser light source, the company says. (
  • A photodynamic therapy includes a particular combination of a photosensitizer and light source for a photodynamic therapy used to treat ocular diseases. (
  • This is the first time a surgical technology developed in Asia was introduced in Keratoprostheses and Artificial Corneas, and shows that Seoul KProis widely recognized as the textbook approach to ocular surface diseases. (
  • In some embodiments, the ocular structures are. (
  • In some embodiments, the ocular structures are placed in a global coordinate system based on ocular imaging. (
  • In some embodiments, the ocular structures inside the global coordinate system lead to direction of an automated positioning system that is directed based on the ocular structures within the coordinate system. (
  • External examination of the ocular structures consists of a penlight evaluation of the eyelids, conjunctiva, sclera, cornea, and iris. (
  • It is characterized by an exophoria at near fixation and reports of horizontal diplopia and eye strain with prolonged reading. (
  • As expected, ocular dominance histograms showed a monocular bias compared with normal animals, but many cells could still be driven via both eyes. (
  • Binocularity (the percentage of measurements with bilateral fixation) was determined from the BRBS output. (
  • We also discuss the accuracy, quality and stability of ocular fixation, and the bottom-up and top-down influences that affect fixation behaviour. (
  • The 27-gauge needle-guided intrascleral IOL fixation technique with built-in 8-0 absorbable sutures is easy to perform with fewer anterior chamber manipulations and achieves both anatomical and optical stability. (
  • Altogether, this group had persistent problems with fixation stability. (
  • The Law of the Fixation Planes: The function of extraocular muscles is to maintain the FPs of the two eyes coplanar in all stable head positions and in all gaze directions. (
  • A method and system for performing an ocular irradiation procedure on a patient's eye is disclosed. (
  • A light source (10) produces fixation light and procedure light. (
  • A scanning device (16) deflects the fixation light to produce a fixation pattern (P) of the fixation light on the eye, and deflects the procedure light to produce a procedure pattern (S) of the procedure light on the eye. (
  • A controller (12) controls the scanning device such that the fixation and procedure patterns move relative to each other, and/or the fixation pattern dynamically changes. (
  • During follow-up, all patients acquired a smooth and acceptable ocular surface without any persistent epithelial defect, infection or ulceration. (
  • A fixation light spot in the vicinity of the fovea (30) and the fovea are imaged by means of a camera (40). (
  • These findings demonstrate that DS creates an environment on the ocular surface that stimulates the production of Th17-inducing cytokines by corneal and conjunctival epithelia that promote Th17 differentiation through a dendritic cell-mediated pathway. (
  • The most widely used treatments for BK are ethylenediaminetetraacetic acid (EDTA) chelation and superficial keratectomy, which remove calcium deposits, restore the corneal surface, and improve ocular comfort [ 3 - 5 ]. (
  • Overall, neuronal responses were not affected by switches in ocular fixation. (
  • The unremitting 'trembling of the eye' that occurs even during gaze fixation was first noted by Jurin in 1738. (
  • In 1794, Erasmus Darwin documented that gaze fixation produces perceptual fading, a phenomenon rediscovered in 1804 by Ignaz Paul Vital Troxler. (
  • A second population of neurons was suppressed by social gaze cues, possibly subserving task demands by maintaining fixation on the observed face. (
  • 1993). "Ocular microtremor measurement system: design and performance. (
  • Additionally, the devices have scratch-resistant insulated ocular objectives and distal saphir-windows that prevent internal glass corrosion. (
  • In all cases, stable adherence of the amniotic membrane was maintained until the epithelialization of the ocular surface was completed. (
  • Amniotic membrane transplantation (AMT) has been widely used for ocular surface reconstruction as it facilitates epithelialization while suppressing ocular surface inflammation, neovascularization, and scarring of the stroma [ 13 - 17 ]. (
  • However, 63% of the Parkinson's patients had fixation instability that moved their focus enough on occasion to reach the 0.5° threshold thought to create problems with vision. (
  • For individual patients, the frequency of these ocular tremors appeared stable, never varying by more than 1 Hz, though the amplitude fluctuated in a regular pattern. (
  • The MCBS method also leads to rapid reconstruction of the ocular surface and provides a surface conducive to further procedures, such as autolimbal and allolimbal transplantation and keratoplasty. (
  • Consequently, all membranes remain intact until the ocular surface completely re-epithelializes. (
  • For several years, Chris was a senior lecturer and researcher in the School of Optometry & Vision Sciences at Cardiff University where, as Co-Director of the Contact Lens & Anterior Eye Research Unit (CLAER) she established her research interests examining the ocular surface and the tear film, hand hygiene, and evidence-based practice, alongside her clinical work. (
  • 1. The quality of ocular fixation: how well do we keep our eyes still? (
  • Eyes from 14 patients who underwent 27-gauge needle-guided intrascleral IOL fixation with built-in 8-0 absorbable sutures were studied. (
  • The fixation index is the ratio of nystagmus peak slow-phase velocity with fixation to nystagmus intensity with fixation removed (e.g. complete darkness or eyes closed). (