The ability to detect sharp boundaries (stimuli) and to detect slight changes in luminance at regions without distinct contours. Psychophysical measurements of this visual function are used to evaluate visual acuity and to detect eye disease.
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.
A series of tests used to assess various functions of the eyes.
Relatively bright light, or the dazzling sensation of relatively bright light, which produces unpleasantness or discomfort, or which interferes with optimal VISION, OCULAR. (Cline et al., Dictionary of Visual Science, 4th ed)
The minimum amount of stimulus energy necessary to elicit a sensory response.
A nonspecific term referring to impaired vision. Major subcategories include stimulus deprivation-induced amblyopia and toxic amblyopia. Stimulus deprivation-induced amblyopia is a developmental disorder of the visual cortex. A discrepancy between visual information received by the visual cortex from each eye results in abnormal cortical development. STRABISMUS and REFRACTIVE ERRORS may cause this condition. Toxic amblyopia is a disorder of the OPTIC NERVE which is associated with ALCOHOLISM, tobacco SMOKING, and other toxins and as an adverse effect of the use of some medications.
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).
The science dealing with the correlation of the physical characteristics of a stimulus, e.g., frequency or intensity, with the response to the stimulus, in order to assess the psychologic factors involved in the relationship.
Function of the human eye that is used in dim illumination (scotopic intensities) or at nighttime. Scotopic vision is performed by RETINAL ROD PHOTORECEPTORS with high sensitivity to light and peak absorption wavelength at 507 nm near the blue end of the spectrum.
Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)
The process in which light signals are transformed by the PHOTORECEPTOR CELLS into electrical signals which can then be transmitted to the brain.
Mental processing of chromatic signals (COLOR VISION) from the eye by the VISUAL CORTEX where they are converted into symbolic representations. Color perception involves numerous neurons, and is influenced not only by the distribution of wavelengths from the viewed object, but also by its background color and brightness contrast at its boundary.
Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light flashes or visual patterns are used to elicit brain activity.
Defects of color vision are mainly hereditary traits but can be secondary to acquired or developmental abnormalities in the CONES (RETINA). Severity of hereditary defects of color vision depends on the degree of mutation of the ROD OPSINS genes (on X CHROMOSOME and CHROMOSOME 3) that code the photopigments for red, green and blue.
The total area or space visible in a person's peripheral vision with the eye looking straightforward.
Mental process to visually perceive a critical number of facts (the pattern), such as characters, shapes, displays, or designs.
The awareness of the spatial properties of objects; includes physical space.
The point or frequency at which all flicker of an intermittent light stimulus disappears.
Set of cell bodies and nerve fibers conducting impulses from the eyes to the cerebral cortex. It includes the RETINA; OPTIC NERVE; optic tract; and geniculocalcarine tract.
The electric response evoked in the cerebral cortex by visual stimulation or stimulation of the visual pathways.
The sensory discrimination of a pattern shape or outline.
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)
The study and treatment of defects in binocular vision resulting from defects in the optic musculature or of faulty visual habits. It involves a technique of eye exercises designed to correct the visual axes of eyes not properly coordinated for binocular vision.
The adjustment of the eye to variations in the intensity of light. Light adaptation is the adjustment of the eye when the light threshold is increased; DARK ADAPTATION when the light is greatly reduced. (From Cline et al., Dictionary of Visual Science, 4th ed)
The aperture in the iris through which light passes.
The blending of separate images seen by each eye into one composite image.
Type of vision test used to determine COLOR VISION DEFECTS.
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.
Function of the human eye that is used in bright illumination or in daylight (at photopic intensities). Photopic vision is performed by the three types of RETINAL CONE PHOTORECEPTORS with varied peak absorption wavelengths in the color spectrum (from violet to red, 400 - 700 nm).
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)
Artificial implanted lenses.
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)
Vision considered to be inferior to normal vision as represented by accepted standards of acuity, field of vision, or motility. Low vision generally refers to visual disorders that are caused by diseases that cannot be corrected by refraction (e.g., MACULAR DEGENERATION; RETINITIS PIGMENTOSA; DIABETIC RETINOPATHY, etc.).
Differential response to different stimuli.
Part of the DIENCEPHALON inferior to the caudal end of the dorsal THALAMUS. Includes the lateral geniculate body which relays visual impulses from the OPTIC TRACT to the calcarine cortex, and the medial geniculate body which relays auditory impulses from the lateral lemniscus to the AUDITORY CORTEX.
Method of measuring and mapping the scope of vision, from central to peripheral of each eye.
A specialized field of physics and engineering involved in studying the behavior and properties of light and the technology of analyzing, generating, transmitting, and manipulating ELECTROMAGNETIC RADIATION in the visible, infrared, and ultraviolet range.
The selecting and organizing of visual stimuli based on the individual's past experience.
Normal nystagmus produced by looking at objects moving across the field of vision.
A pair of ophthalmic lenses in a frame or mounting which is supported by the nose and ears. The purpose is to aid or improve vision. It does not include goggles or nonprescription sun glasses for which EYE PROTECTIVE DEVICES is available.
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.
A surgical procedure to correct MYOPIA by CORNEAL STROMA subtraction. It involves the use of a microkeratome to make a lamellar dissection of the CORNEA creating a flap with intact CORNEAL EPITHELIUM. After the flap is lifted, the underlying midstroma is reshaped with an EXCIMER LASER and the flap is returned to its original position.
Cognitive disorders characterized by an impaired ability to perceive the nature of objects or concepts through use of the sense organs. These include spatial neglect syndromes, where an individual does not attend to visual, auditory, or sensory stimuli presented from one side of the body.
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.
Adjustment of the eyes under conditions of low light. The sensitivity of the eye to light is increased during dark adaptation.
Inflammation of the optic nerve. Commonly associated conditions include autoimmune disorders such as MULTIPLE SCLEROSIS, infections, and granulomatous diseases. Clinical features include retro-orbital pain that is aggravated by eye movement, loss of color vision, and contrast sensitivity that may progress to severe visual loss, an afferent pupillary defect (Marcus-Gunn pupil), and in some instances optic disc hyperemia and swelling. Inflammation may occur in the portion of the nerve within the globe (neuropapillitis or anterior optic neuritis) or the portion behind the globe (retrobulbar neuritis or posterior optic neuritis).
Awareness of oneself in relation to time, place and person.
The illumination of an environment and the arrangement of lights to achieve an effect or optimal visibility. Its application is in domestic or in public settings and in medical and non-medical environments.
Refraction of LIGHT effected by the media of the EYE.
A species of the genus MACACA which inhabits Malaya, Sumatra, and Borneo. It is one of the most arboreal species of Macaca. The tail is short and untwisted.
Deviations from the average or standard indices of refraction of the eye through its dioptric or refractive apparatus.
Images seen by one eye.
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)
The real or apparent movement of objects through the visual field.
Area of the OCCIPITAL LOBE concerned with the processing of visual information relayed via VISUAL PATHWAYS.
Photosensitive afferent neurons located primarily within the FOVEA CENTRALIS of the MACULA LUTEA. There are three major types of cone cells (red, blue, and green) whose photopigments have different spectral sensitivity curves. Retinal cone cells operate in daylight vision (at photopic intensities) providing color recognition and central visual acuity.
Processes and properties of the EYE as a whole or of any of its parts.
That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.
Degenerative changes in the RETINA usually of older adults which results in a loss of vision in the center of the visual field (the MACULA LUTEA) because of damage to the retina. It occurs in dry and wet forms.
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)
A cognitive disorder characterized by an impaired ability to comprehend written and printed words or phrases despite intact vision. This condition may be developmental or acquired. Developmental dyslexia is marked by reading achievement that falls substantially below that expected given the individual's chronological age, measured intelligence, and age-appropriate education. The disturbance in reading significantly interferes with academic achievement or with activities of daily living that require reading skills. (From DSM-IV)
Persons with loss of vision such that there is an impact on activities of daily living.
Perception of three-dimensionality.
Application of tests and examinations to identify visual defects or vision disorders occurring in specific populations, as in school children, the elderly, etc. It is differentiated from VISION TESTS, which are given to evaluate/measure individual visual performance not related to a specific population.
A condition of an inequality of refractive power of the two eyes.
The positioning and accommodation of eyes that allows the image to be brought into place on the FOVEA CENTRALIS of each eye.
The absence or restriction of the usual external sensory stimuli to which the individual responds.
The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.
Glaucoma in which the angle of the anterior chamber is open and the trabecular meshwork does not encroach on the base of the iris.
A long-acting injectable antipsychotic agent used for chronic schizophrenia.
Measurement of the various properties of light.
Unequal curvature of the refractive surfaces of the eye. Thus a point source of light cannot be brought to a point focus on the retina but is spread over a more or less diffuse area. This results from the radius of curvature in one plane being longer or shorter than the radius at right angles to it. (Dorland, 27th ed)
The function of the eye that is used in the intermediate level of illumination (mesopic intensities) where both the RETINAL ROD PHOTORECEPTORS and the RETINAL CONE PHOTORECEPTORS are active in processing light input simultaneously.
Lenses designed to be worn on the front surface of the eyeball. (UMDNS, 1999)
The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)
An alternative to REFRACTIVE SURGICAL PROCEDURES. A therapeutic procedure for correcting REFRACTIVE ERRORS. It involves wearing CONTACT LENSES designed to force corrective changes to the curvature of the CORNEA that remain after the lenses are removed. The effect is temporary but is maintained by wearing the therapeutic lenses daily, usually during sleep.
Continuation of visual impression after cessation of stimuli causing the original image.
The study of the physiological basis of human and animal behavior.
Conditions which produce injury or dysfunction of the second cranial or optic nerve, which is generally considered a component of the central nervous system. Damage to optic nerve fibers may occur at or near their origin in the retina, at the optic disk, or in the nerve, optic chiasm, optic tract, or lateral geniculate nuclei. Clinical manifestations may include decreased visual acuity and contrast sensitivity, impaired color vision, and an afferent pupillary defect.
Theoretical representations that simulate psychological processes and/or social processes. These include the use of mathematical equations, computers, and other electronic equipment.
The use of an aberrometer to measure eye tissue imperfections or abnormalities based on the way light passes through the eye which affects the ability of the eye to focus properly.
The removal of a cataractous CRYSTALLINE LENS from the eye.
The sensory interpretation of the dimensions of objects.
Neurons of the innermost layer of the retina, the internal plexiform layer. They are of variable sizes and shapes, and their axons project via the OPTIC NERVE to the brain. A small subset of these cells act as photoreceptors with projections to the SUPRACHIASMATIC NUCLEUS, the center for regulating CIRCADIAN RHYTHM.
Argon. A noble gas with the atomic symbol Ar, atomic number 18, and atomic weight 39.948. It is used in fluorescent tubes and wherever an inert atmosphere is desired and nitrogen cannot be used.
The effect of environmental or physiological factors on the driver and driving ability. Included are driving fatigue, and the effect of drugs, disease, and physical disabilities on driving.
The visually perceived property of objects created by absorption or reflection of specific wavelengths of light.
An exudate between the RETINA and CHOROID from various sources including the vitreous cavity, SUBARACHNOID SPACE, or abnormal vessels.
The system of all phenomena in space and time; the totality of physical reality. It is both a scientific and philosophic concept appearing in all historic eras. (Webster 2d; Dr. James H. Cassedy, NLM History of Medicine Division)
The normal decreasing elasticity of the crystalline lens that leads to loss of accommodation.
The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.
Surgical procedures employed to correct REFRACTIVE ERRORS such as MYOPIA; HYPEROPIA; or ASTIGMATISM. These may involve altering the curvature of the CORNEA; removal or replacement of the CRYSTALLINE LENS; or modification of the SCLERA to change the axial length of the eye.
Recording of electric potentials in the retina after stimulation by light.
Elements of limited time intervals, contributing to particular results or situations.
Disease of the RETINA as a complication of DIABETES MELLITUS. It is characterized by the progressive microvascular complications, such as ANEURYSM, interretinal EDEMA, and intraocular PATHOLOGIC NEOVASCULARIZATION.
The interference of one perceptual stimulus with another causing a decrease or lessening in perceptual effectiveness.
A family of nonmetallic, generally electronegative, elements that form group 17 (formerly group VIIa) of the periodic table.
Absence of the crystalline lens resulting from cataract extraction.
Focusing on certain aspects of current experience to the exclusion of others. It is the act of heeding or taking notice or concentrating.
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)
Devices for examining the interior of the eye, permitting the clear visualization of the structures of the eye at any depth. (UMDNS, 1999)
The administration of substances into the eye with a hypodermic syringe.
Insertion of an artificial lens to replace the natural CRYSTALLINE LENS after CATARACT EXTRACTION or to supplement the natural lens which is left in place.
Lack of correspondence between the way a stimulus is commonly perceived and the way an individual perceives it under given conditions.
A type of refractive surgery of the CORNEA to correct MYOPIA and ASTIGMATISM. An EXCIMER LASER is used directly on the surface of the EYE to remove some of the CORNEAL EPITHELIUM thus reshaping the anterior curvature of the cornea.
The smallest difference which can be discriminated between two stimuli or one which is barely above the threshold.
The act of knowing or the recognition of a distance by recollective thought, or by means of a sensory process which is under the influence of set and of prior experience.
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.
Diseases affecting the eye.
The time from the onset of a stimulus until a response is observed.
A genus, commonly called budgerigars, in the family PSITTACIDAE. In the United States they are considered one of the five species of PARAKEETS.
Presence of an intraocular lens after cataract extraction.
Visualization of a vascular system after intravenous injection of a fluorescein solution. The images may be photographed or televised. It is used especially in studying the retinal and uveal vasculature.
Agents causing contraction of the pupil of the eye. Some sources use the term miotics only for the parasympathomimetics but any drug used to induce miosis is included here.
A procedure to surgically correct REFRACTIVE ERRORS by cutting radial slits into the CORNEA to change its refractive properties.
A syndrome characterized by marked limitation of abduction of the eye, variable limitation of adduction and retraction of the globe, and narrowing of the palpebral fissure on attempted adduction. The condition is caused by aberrant innervation of the lateral rectus by fibers of the OCULOMOTOR NERVE.
Hereditary, progressive degeneration of the neuroepithelium of the retina characterized by night blindness and progressive contraction of the visual field.
Theoretical representations that simulate the behavior or activity of the neurological system, processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.
An optical source that emits photons in a coherent beam. Light Amplification by Stimulated Emission of Radiation (LASER) is brought about using devices that transform light of varying frequencies into a single intense, nearly nondivergent beam of monochromatic radiation. Lasers operate in the infrared, visible, ultraviolet, or X-ray regions of the spectrum.
Assessment of psychological variables by the application of mathematical procedures.
A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.
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.
A form of ocular misalignment characterized by an excessive convergence of the visual axes, resulting in a "cross-eye" appearance. An example of this condition occurs when paralysis of the lateral rectus muscle causes an abnormal inward deviation of one eye on attempted gaze.
A condition in which the intraocular pressure is elevated above normal and which may lead to glaucoma.
Signals for an action; that specific portion of a perceptual field or pattern of stimuli to which a subject has learned to respond.
An imaging method using LASERS that is used for mapping subsurface structure. When a reflective site in the sample is at the same optical path length (coherence) as the reference mirror, the detector observes interference fringes.
Performance of an act one or more times, with a view to its fixation or improvement; any performance of an act or behavior that leads to learning.
A noninflammatory, usually bilateral protrusion of the cornea, the apex being displaced downward and nasally. It occurs most commonly in females at about puberty. The cause is unknown but hereditary factors may play a role. The -conus refers to the cone shape of the corneal protrusion. (From Dorland, 27th ed)
An analogue of GAMMA-AMINOBUTYRIC ACID. It is an irreversible inhibitor of 4-AMINOBUTYRATE TRANSAMINASE, the enzyme responsible for the catabolism of GAMMA-AMINOBUTYRIC ACID. (From Martindale The Extra Pharmacopoeia, 31st ed)
An oval area in the retina, 3 to 5 mm in diameter, usually located temporal to the posterior pole of the eye and slightly below the level of the optic disk. It is characterized by the presence of a yellow pigment diffusely permeating the inner layers, contains the fovea centralis in its center, and provides the best phototropic visual acuity. It is devoid of retinal blood vessels, except in its periphery, and receives nourishment from the choriocapillaris of the choroid. (From Cline et al., Dictionary of Visual Science, 4th ed)
The pressure of the fluids in the eye.
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.
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)
The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.
Voluntary or reflex-controlled movements of the eye.
Age as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or the effect of a circumstance. It is used with human or animal concepts but should be differentiated from AGING, a physiological process, and TIME FACTORS which refers only to the passage of time.
Fluid accumulation in the outer layer of the MACULA LUTEA that results from intraocular or systemic insults. It may develop in a diffuse pattern where the macula appears thickened or it may acquire the characteristic petaloid appearance referred to as cystoid macular edema. Although macular edema may be associated with various underlying conditions, it is most commonly seen following intraocular surgery, venous occlusive disease, DIABETIC RETINOPATHY, and posterior segment inflammatory disease. (From Survey of Ophthalmology 2004; 49(5) 470-90)
The 2nd cranial nerve which conveys visual information from the RETINA to the brain. The nerve carries the axons of the RETINAL GANGLION CELLS which sort at the OPTIC CHIASM and continue via the OPTIC TRACTS to the brain. The largest projection is to the lateral geniculate nuclei; other targets include the SUPERIOR COLLICULI and the SUPRACHIASMATIC NUCLEI. Though known as the second cranial nerve, it is considered part of the CENTRAL NERVOUS SYSTEM.
The continuous sequential physiological and psychological maturing of an individual from birth up to but not including ADOLESCENCE.
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.
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)
Specialized cells that detect and transduce light. They are classified into two types based on their light reception structure, the ciliary photoreceptors and the rhabdomeric photoreceptors with MICROVILLI. Ciliary photoreceptor cells use OPSINS that activate a PHOSPHODIESTERASE phosphodiesterase cascade. Rhabdomeric photoreceptor cells use opsins that activate a PHOSPHOLIPASE C cascade.
The blood vessels which supply and drain the RETINA.
Methods and procedures for the diagnosis of diseases of the eye or of vision disorders.
A genus of the subfamily CERCOPITHECINAE, family CERCOPITHECIDAE, consisting of 16 species inhabiting forests of Africa, Asia, and the islands of Borneo, Philippines, and Celebes.
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)
Psychophysical technique that permits the estimation of the bias of the observer as well as detectability of the signal (i.e., stimulus) in any sensory modality. (From APA, Thesaurus of Psychological Index Terms, 8th ed.)
A species of the genus MACACA inhabiting India, China, and other parts of Asia. The species is used extensively in biomedical research and adapts very well to living with humans.
Studies which start with the identification of persons with a disease of interest and a control (comparison, referent) group without the disease. The relationship of an attribute to the disease is examined by comparing diseased and non-diseased persons with regard to the frequency or levels of the attribute in each group.
The use of green light-producing LASERS to stop bleeding. The green light is selectively absorbed by HEMOGLOBIN, thus triggering BLOOD COAGULATION.
A pathological process consisting of the formation of new blood vessels in the CHOROID.
The diversion of RADIATION (thermal, electromagnetic, or nuclear) from its original path as a result of interactions or collisions with atoms, molecules, or larger particles in the atmosphere or other media. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
The coordination of a sensory or ideational (cognitive) process and a motor activity.
Application of computer programs designed to assist the physician in solving a diagnostic problem.
Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.
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.
The period following a surgical operation.

Why and how is soft copy reading possible in clinical practice? (1/2967)

The properties of the human visual system (HVS) relevant to the diagnostic process are described after a brief introduction on the general problems and advantages of using soft copy for primary radiology interpretations. At various spatial and temporal frequencies the contrast sensitivity defines the spatial resolution of the eye-brain system and the sensitivity to flicker. The adaptation to the displayed radiological scene and the ambient illumination determine the dynamic range for the operation of the HVS. Although image display devices are determined mainly by state-of-the-art technology, analysis of the HVS may suggest technical characteristics for electronic displays that will help to optimize the display to the operation of the HVS. These include display size, spatial resolution, contrast resolution, luminance range, and noise, from which further consequences for the technical components of a monitor follow. It is emphasized that routine monitor quality control must be available in clinical practice. These image quality measures must be simple enough to be applied as part of the daily routine. These test instructions might also serve as elements of technical acceptance and constancy tests.  (+info)

Impairment in preattentive visual processing in patients with Parkinson's disease. (2/2967)

We explored the possibility of whether preattentive visual processing is impaired in Parkinson's disease. With this aim, visual discrimination thresholds for orientation texture stimuli were determined in two separate measurement sessions in 16 patients with idiopathic Parkinson's disease. The results were compared with those of 16 control subjects age-matched and 16 young healthy volunteers. Discrimination thresholds were measured in a four-alternative spatial forced-choice paradigm, in which subjects judged the location of a target embedded in a background of distractors. Four different stimulus configurations were employed: (i) a group of vertical targets among horizontal distractors ('vertical line targets'); (ii) targets with varying levels of orientation difference on a background of spatially filtered vertically oriented noise ('Gaussian filtered noise'); (iii) one 'L' among 43 '+' signs ('texton'), all of which assess preattentive visual processing; and (iv) control condition, of one 'L' among 43 'T' distractors ('non-texton' search target), which reflects attentive visual processing. In two of the preattentive tasks (filtered noise and texton), patients with Parkinson's disease required significantly greater orientation differences and longer stimulus durations, respectively. In contrast, their performance in the vertical line target and non-texton search target was comparable to that of the matched control subjects. These differences were more pronounced in the first compared with the second session. Duration of illness and age within the patient group correlated significantly with test performance. In all conditions tested, the young control subjects performed significantly better than the more elderly control group, further indicating an effect of age on this form of visual processing. The results suggest that, in addition to the well documented impairment in retinal processing, idiopathic Parkinson's disease is associated with a deficit in preattentive cortical visual processing.  (+info)

Accurate memory for colour but not pattern contrast in chicks. (3/2967)

The visual displays of animals and plants often look dramatic and colourful to us, but what information do they convey to their intended, non-human, audience [1] [2]? One possibility is that stimulus values are judged accurately - so, for example, a female might choose a suitor if he displays a specific colour [3]. Alternatively, as for human advertising, displays may attract attention without giving information, perhaps by exploiting innate preferences for bright colours or symmetry [2] [4] [5]. To address this issue experimentally, we investigated chicks' memories of visual patterns. Food was placed in patterned paper containers which, like seed pods or insect prey, must be manipulated to extract food and their patterns learnt. To establish what was learnt, birds were tested on familiar stimuli and on alternative stimuli of differing colour or contrast. For colour, birds selected the trained stimulus; for contrast, they preferred high contrast patterns over the familiar. These differing responses to colour and contrast show how separate components of display patterns could serve different roles, with colour being judged accurately whereas pattern contrast attracts attention.  (+info)

Characteristics of discrepancies between self-reported visual function and measured reading speed. Salisbury Eye Evaluation Project Team. (4/2967)

PURPOSE: Visual impairment is a risk factor for morbidity in the elderly and is often screened for by self-report. This study evaluates whether there are subsets for whom there is a discrepancy between self-reported and measured function. METHODS: The prevalence of a discrepancy between self-reported difficulty reading a newspaper and measured reading speed was determined in 2520 community-based men and women, aged 65 to 84 years, and the discrepant group characterized by polychotomous regression. RESULTS: Of subjects who reported minimal difficulty reading a newspaper, 10.8% (227/2107) read newsprint-sized text (0.21 degrees) more slowly than 80 words/min, a level previously shown to be necessary for sustained reading. Poor visual acuity, presence of psychiatric symptoms, and less satisfaction with vision were associated with being in the group that read slowly and reported difficulty with reading. Better cognition, better visual acuity, more years of education, white race, and fewer psychiatric symptoms were associated with being in the group that read more quickly and reported minimal difficulty. When reading the text size at which subjects read their fastest, only 2.6% of those with minimal difficulty remained discrepant. These individuals were more likely to have less education, be male, be African American, and have poorer cognitive status than those who did not remain discrepant. CONCLUSIONS: A subset of the elderly population have a substantial discrepancy between self-reported reading difficulty and measured reading speed. In some, this discrepancy may be based on underlying expectations and experiences, and in others it may represent a transition from no visual impairment to visual impairment.  (+info)

Perceived visual ability for independent mobility in persons with retinitis pigmentosa. (5/2967)

PURPOSE: To determine the distribution of perceived ability for independent mobility in people who are at various stages of retinitis pigmentosa (RP). METHODS: A questionnaire was developed to ask subjects to rate how difficult they found each of 35 mobility situations if they had no assistance. The scale was 1 (no difficulty) to 5 (extreme difficulty). In each of 127 subjects, the Rasch analysis, a latent trait analysis, was used to convert the ordinal difficulty ratings into interval measures of perceived visual ability for independent mobility. RESULTS: Content validity of the questionnaire was shown by good separation indexes (4.55 and 8.0) and high reliability scores (0.96 and 0.98) for the person and the item parameters. Construct validity was shown with model fit statistics. Criterion validity of the questionnaire was shown by good discrimination among mobility-related behavior such as "limit independent travel," "always ask for accompaniment," "use a mobility aid," and "have a fear of falling." The mobility situation shown to require the least visual ability was "moving about in the home"; the situation requiring the most was "walking at night." Bivariate regression analysis determined that for every decade of disease progression, perceived visual ability for mobility decreased by approximately 0.5 logit, which was slightly less than 10% of the total range in the study sample. A linear combination of the visual function measures, log minimum angle of resolution, log contrast sensitivity, and log retinal area accounted for 57% of the variability in the person measure. CONCLUSIONS: The patient-based assessment, developed to determine difficulty across a range of mobility situations, is a valid way to measure perceived ability for independent mobility. This latent trait varies systematically with the progression of RP and with visual function measures.  (+info)

Cone signal contributions to electroretinograms [correction of electrograms] in dichromats and trichromats. (6/2967)

PURPOSE: To find out how the different cone types contribute to the electroretinogram (ERG) by quantifying the contribution of the signal pathways originating in the long (L-) and the middle (M-) wavelength-sensitive cones to the total ERG response amplitude and phase. METHODS: ERG response amplitudes and phases were measured to cone-isolating stimuli and to different combinations of L- and M-cone modulation. Conditions were chosen to exclude any contribution of the short wavelength-sensitive (S-) cones. The sensitivity of the ERG to the L and the M cones was defined as the cone contrast gain. RESULTS: In the present paper, a model is provided that describes the ERG contrast gains and ERG thresholds in dichromats and color normal trichromats. For the X-chromosome-linked dichromats, the contrast gains of only one cone type (either the L or the M cones) sufficed to describe the ERG thresholds for all stimulus conditions. Data suggest that the M-cone contrast gains of protanopes are larger than the L-cone contrast gains of deuteranopes. The response thresholds of the trichromats are modeled by assuming a vector summation of signals originating in the L and the M cones. Their L- and M-cone contrast gains are close to a linear interpolation of the data obtained from the dichromats. Nearly all trichromats had larger L- than M-cone contrast gains. Data from a large population of trichromats were examined to study the individual variations in cone weightings and in the phases of the cone pathway responses. CONCLUSIONS: The data strongly suggest that the missing cone type in dichromats is replaced by the remaining cone type. The mean L-cone to M-cone weighting ratio in trichromats was found to be approximately 4:1. But there is a substantial interindividual variability between trichromats. The response phases of the L- and the M-cone pathways can be reliably quantified using the response phases to the cone-isolating stimuli or using a vector addition of L- and M-cone signals.  (+info)

Selective color constancy deficits after circumscribed unilateral brain lesions. (7/2967)

The color of an object, when part of a complex scene, is determined not only by its spectral reflectance but also by the colors of all other objects in the scene (von Helmholtz, 1886; Ives, 1912; Land, 1959). By taking global color information into account, the visual system is able to maintain constancy of the color appearance of the object, despite large variations in the light incident on the retina arising from changes in the spectral content of the illuminating light (Hurlbert, 1998; Maloney, 1999). The neural basis of this color constancy is, however, poorly understood. Although there seems to be a prominent role for retinal, cone-specific adaptation mechanisms (von Kries, 1902; Poppel, 1986; Foster and Nascimento, 1994), the contribution of cortical mechanisms to color constancy is still unclear (Land et al., 1983; D'Zmura and Lennie, 1986). We examined the color perception of 27 patients with defined unilateral lesions mainly located in the parieto-temporo-occipital and fronto-parieto-temporal cortex. With a battery of clinical and specially designed color vision tests we tried to detect and differentiate between possible deficits in central color processing. Our results show that color constancy can be selectively impaired after circumscribed unilateral lesions in parieto-temporal cortex of the left or right hemisphere. Five of 27 patients exhibited significant deficits in a color constancy task, but all of the 5 performed well in color discrimination or higher-level visual tasks, such as the association of colors with familiar objects. These results indicate that the computations underlying color constancy are mediated by specialized cortical circuitry, which is independent of the neural substrate for color discrimination and for assigning colors to objects.  (+info)

Geometric representation of the mechanisms underlying human curvature detection. (8/2967)

Combined manipulation of blur, line length and contrast reveal two distinct processes involved in curvature detection. When line length is small relative to blur, thresholds are almost directly proportional to blur and independent of line length. When line length is large relative to blur thresholds are directly proportional to line length and independent of blur. The aspect ratio (line length/blur) of curved contours represents a scale-invariant metric which forms the decisive factor in determining curvature performance.  (+info)

We found rhythmic oscillations in visual contrast sensitivity time locked to the execution of a voluntary reaching action. Three aspects appear particularly relevant. First, the oscillations emerge a long time before the action onset. Second, the action was not visually guided, all visual information being completely irrelevant for motor planning and execution. Third, oscillations were found for targets presented in both the left and right visual hemifields. The present results strongly suggest an automatic nonspecific coupling between early motor planning and early visual processing, possibly mediated by transient synchronization of motor and visual neuronal activities.. The observed rhythmicity in visual contrast sensitivity is the likely behavioral signature of oscillatory activity in visual areas within the theta band. Previous studies have established a firm relationship between the probability of perceiving a near-threshold visual stimulus and the prestimulus phase of ongoing cortical ...
Mars Letter Contrast Sensitivity Test. Identifying functional losses in low contrast perception (often associated with glare sensitivity). Buy online.
Objectives: To determine whether blurred vision caused by exposure to triethylamine (TEA) can be detected by the measurement of contrast sensitivity. Methods: 41 cold box core makers of three foundries and 82 control workers were examined. A detailed ocular and medical history was obtained from the subjects. The contrast sensitivity of the core makers was measured on Monday and Friday of the same week both before and immediately after work and also on a third day, when air samples of TEA were collected. Contrast sensitivity and visual acuity were measured by optotype figures at full contrast, 2.5% contrast, and 0.6% contrast. The changes in contrast sensitivity were used for the analysis. The results of binocular vision and the results of the dominant eye were analysed. Urine specimens for the analysis of TEA were collected on every occasion when contrast sensitivity was measured. Results: 78% of the core makers had had symptoms of blurred vision, and31% had had trouble driving or working. The ...
Purpose: : To evaluate human achromatic spatial contrast sensitivity (CSF) with transient visual evoked cortical potential (tVECP). To compare electrophysiological and psychophysical measurements. Methods: : Six healthy subjects (21 ± 2 years-old) were monocularly tested. The stimuli were black and white horizontal sinusoidal gratings, 40 cd/m2 mean luminance, presented in a 5º circular patch. Six spatial frequencies were used: 0.4, 0.8, 2, 4, 8, and 10 cycles per degree (cpd), in 1 Hz squarewave reversal mode. Electrophysiological contrast thresholds were estimated by linear regressions fitted to data point representing P100 tVECP amplitude as a function of log contrast, extrapolated to zero amplitude. Psychophysics measurements were performed in the same spatial frequencies plus 1 and 6 cpd, using identical spatio-temporal configuration as used in tVECP experiments (dynamic presentation) and using stationary stimuli (static presentation). Psychophysical contrast sensitivity was obtained ...
Contrast sensitivity function is decreased in many disease entities notably: cataract, age related macular degeneration and glaucoma. It is also lowered in individuals that undergo kerato-refractive surgery procedures. Traditional contrast sensitivity tests printed on charts are limited in the fact that a certain working distance is needed and are prone to degradation due to use. The electronic M&S Smart System contrast sensitivity testing unit provides the flexibility to use at variable distance and provides better resolution capabilities especially at lower contrast due to the visual display system. The purpose of the study was to evaluate the short-term repeatability and use of Landolt C contrast sensitivity function test in ocular healthy and in individuals with decreased visual function.. ...
Contrast discrimination is an important type of information for establishing image quality metrics based on human vision. We used a dual-masking paradigm to study how contrast discrimination can be influenced by the presence of adjacent stimuli. In a dual masking paradigm, the observers task is to detect a target superimposed on a pedestal in the presence of flankers. The flankers (1) reduce the target threshold at zero pedestal contrast; (2) reduce the size of pedestal facilitation at low pedestal contrasts; and (3) shift the TvC (Target threshold vs. pedestal contrast) function horizontally to the left on a log-log plot at high pedestal contrasts. The horizontal shift at high pedestal contrasts suggests that the flanker effect is a multiplicative factor that cannot be explained by previous models of contrast discrimination. We extended a divisive inhibition model of contrast discrimination by implementing the flanker effect as a multiplicative sensitivity modulation factor that account for ...
The observed shift in the contrast gain function is consistent with previous measures of spatial vision loss with age. For instance, Sloane, Owsley, and Jackson (1988) measured contrast sensitivity for young and old observers with spatial frequencies ranging from 0.5 to 8 c/deg and luminance levels ranging from mesopic to photopic. At a low temporal frequency, the slope of the sensitivity function (inverse of the threshold function) spanning the range of luminance was steeper for older than younger observers at spatial frequencies below 4 c/deg. This means that older observers required more contrast at low luminance levels to detect a sine-wave grating than their younger counterparts. This pattern of contrast sensitivity loss is consistent with a reduction in the contrast gain slope of the underlying mechanism at low spatial frequencies. In addition, suprathreshold measures of spatial vision performance also support a reduction in contrast gain within one (or both) of the pathways. Losses in ...
The observed shift in the contrast gain function is consistent with previous measures of spatial vision loss with age. For instance, Sloane, Owsley, and Jackson (1988) measured contrast sensitivity for young and old observers with spatial frequencies ranging from 0.5 to 8 c/deg and luminance levels ranging from mesopic to photopic. At a low temporal frequency, the slope of the sensitivity function (inverse of the threshold function) spanning the range of luminance was steeper for older than younger observers at spatial frequencies below 4 c/deg. This means that older observers required more contrast at low luminance levels to detect a sine-wave grating than their younger counterparts. This pattern of contrast sensitivity loss is consistent with a reduction in the contrast gain slope of the underlying mechanism at low spatial frequencies. In addition, suprathreshold measures of spatial vision performance also support a reduction in contrast gain within one (or both) of the pathways. Losses in ...
TY - JOUR. T1 - Rhythmic modulation of visual contrast discrimination triggered by action. AU - Benedetto, Alessandro. AU - Spinelli, Donatella. AU - Morrone, M. Concetta. PY - 2016/5/25. Y1 - 2016/5/25. N2 - Recent evidence suggests that ongoing brain oscillations may be instrumental in binding and integrating multisensory signals. In this experiment, we investigated the temporal dynamics of visual-motor integration processes. We show that action modulates sensitivity to visual contrast discrimination in a rhythmic fashion at frequencies of about 5 Hz (in the theta range), for up to 1 s after execution of action. To understand the origin of the oscillations, we measured oscillations in contrast sensitivity at different levels of luminance, which is known to affect the endogenous brain rhythms, boosting the power of alpha-frequencies. We found that the frequency of oscillation in sensitivity increased at low luminance, probably reflecting the shift in mean endogenous brain rhythm towards higher ...
This study aimed to explore the neural development status of the visual system of children (around 8 years old) using contrast sensitivity. We achieved this by eliminating the influence of higher order aberrations (HOAs) with adaptive optics correction. We measured HOAs, modulation transfer functions (MTFs) and contrast sensitivity functions (CSFs) of six children and five adults with both corrected and uncorrected HOAs. We found that when HOAs were corrected, children and adults both showed improvements in MTF and CSF. However, the CSF of children was still lower than the adult level, indicating the difference in contrast sensitivity between groups cannot be explained by differences in optical factors. Further study showed that the difference between the groups also could not be explained by differences in non-visual factors. With these results we concluded that the neural systems underlying vision in children of around 8 years old are still immature in contrast sensitivity.
Human contrast sensitivity to visual patterns vs. model predictions.a, Probability distribution of the 512 possible 3×3 1-bit pixel patterns (grey histogram).
Rabin Contrast Sensitivity (CS) Test. Contrast sensitivity test comparable to the Small Letter Contrast Test. Buy online from Precision Vision!
To evaluate the effects on contrast sensitivity (CS) measurements of intravitreal bevacizumab injections associated with standard metabolic control in eyes
With the increasing rise of toxicity, and the increasing awareness of this huge problem, we need to have ways of determining which patients are likely to b
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Contrast response functions (CRFs) for the VEP were obtained with a Discrete Fourier Transform (DFT) technique employing swept contrast gratings. VEP CRFs in infants were found to have a form similar to those observed in adults, being linear functions of log contrast over a range of near-threshold c …
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Neural activity during repeated presentations of a sensory stimulus exhibits considerable trial-by-trial variability. Previous studies have reported that trial-by-trial neural variability is reduced (quenched) by the presentation of a stimulus. However, the functional significance and behavioral relevance of variability quenching, and the potential physiological mechanisms that may drive it have rarely been studied. Here we recorded neural activity with EEG as subjects performed a two-interval forced-choice contrast discrimination task. Trial-by-trial neural variability was quenched by approximately 40% after the presentation of the stimulus, relative to the variability apparent before stimulus presentation, yet there were large differences in the magnitude of variability quenching across subjects. Individual magnitudes of quenching predicted individual discrimination capabilities such that subjects who exhibited larger quenching had smaller contrast discrimination thresholds and steeper ...
Purpose. To distinguish among three explanations of the in sensitivity to low frequency gratings, i. e., the low frequency cut in contrast sensitivity curves. Methods. We manipulated sensitivity to low frequencies by presenting gratings while simultanously increasing or decreasing mean luminance. The test gratings ranged from 0.25 to 18 c/deg, subtended 2.3, 4.5 or 9.1 deg, always had a mean luminance of 38 cd/m2, and were surrounded by a dark field. Contrast sensitivity was measured by forced choice between two 100 msec intervals separated by 500 msec. Between stimulus presentations the gratings were replaced by uniform fields of 0.1, 38, or 76 cd/m2. Both the contrast and luminance changed abruptly. Results. When the luminance was constant at 38 cd/m2 both between and during stimulus presentation, sensitivity to these abruptly presented gratings showed an attenuation at low frequencies, but the attenuation was not as great as is observed with gratings presented and removed gradually, as has ...
04.02.2019 ► Spatial resolution is a key property of eyes when it comes to understanding how animals perceive visual signals. In the current paper (J. Vision), Matteo Santon et al. describe the contrast sensitivity function of a small, benthic marine triplefin fish, using an optokinetic reflex approach. Compared to other fish, the authors conclude that such reflex seems to be adapted to process low spatial frequency information from stimuli in the peripheral visual field and show that small marine fish can feature excellent contrast sensitivity at optimal spatial frequency. ...
A multiresolution-analysis-based local contrast transform is proposed to enhance local structures in x-ray images. The local contrast is defined as a ratio of the local intensity variation to the local mean. With wavelet multiresolution decomposition, the detail coefficients and approximation coefficients are interpreted, respectively, as local variations and local averages in virtue of the localization property of wavelet transform. Based on the local contrast transform, an algorithm is developed to modify coefficients before wavelet synthesis. An across-scale local contrast is obtained when the scale associated with the local variation is different from that of the local mean. The nonlinearity and local adaptiveness properties of local contrast transform result in structural enhancement in local dark regions in the reconstructed images. We applied this technique to deboned poultry inspection using x-ray images. Because of its high x-ray absorption, a foreign inclusion appears as a ...
Measuring eyesight for drivers involves several different important categories of vision. A positive result of Visual Acuity Screening is that it ensures that signs and other critical markings in the roadway environment (lane markings) would be adequately legible to most drivers. Thus a minimum level to driving in Ireland, with 2 functioning eyes, is 6/12 for Group 1 applicants (A1, A, B,EB, M or W) and 6/7.5 for Group 2 applicants (C1, C, EC1, EC, D1, D, ED1, ED), trucks, buses etc Contrast sensitivity refers to the amount of contrast a person needs in order to detect or identify an object or pattern in varying light levels. Think of trying to read the eye chart through a fog. A fog that is getting more and more dense. A person who has poor contrast sensitivity requires a higher contrast to see objects or patterns from a person who has good contrast sensitivity i.e. they need a more stark black on white difference. Impairment of contrast sensitivity can result from a number of different eye and ...
TY - CHAP. T1 - Fixation, contrast sensitivity and childrens reading. AU - Cornelissen, P. PY - 1993. Y1 - 1993. M3 - Chapter. SN - 0-444-89949-9. VL - 3. T3 - Studies In Visual Information Processing. SP - 139. EP - 162. BT - Facets of dyslexia and its remediation. ER - ...
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Nodes with grey background indicate a prediction accuracy for the nodes greater than 0.6. Isolated nodes do not have connections due to the structure difference
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Test for quick measurement of low contrast visual acuity at 25%, 10%, 5%, 2.5%, and 1.25% contrast by measuring the distance where the symbols are seen. 10M symbols correspond to visual acuity 0.10 at 1 m, 0.05 at 0.5 m and 0.3 at 3 m. VA values are thus easy to calculate. Test includes a ...
Samuel Achilefu, PhD, the Michel M. Ter-Pogossian Professor of Radiology, has been elected as a fellow to the Royal Society of Chemistry and to The Optical Society.. ...
We assessed the accuracy of contrast-defined shape detection of stimuli of constant aspect ratio, namely, circular bandpass stimuli whose radii were sinusoidally varied about a mean radius. Performance for these contrast-defined shapes, which we show is determined by the global rather than the local attributes of the stimulus, is 2-8 times worse than that for their luminance-defined counterparts, suggesting separate processing limitations. By spatially and orientationally filtering the two-dimensional fractal-noise carriers of which these stimuli were composed, we determined whether there are specific rules concerning the spatial and orientational input to shape detectors from mechanisms sensitive to the carrier structure. The results suggest that second-order circularity detectors receive mixed input from spatial-frequency-tuned and orientationally tuned cells.. © 2001 Optical Society of America. Full Article , PDF Article ...
Principal Investigator:KAJITA Etsuko, Project Period (FY):1997 - 1998, Research Category:Grant-in-Aid for Scientific Research (C), Section:一般, Research Field:Nursing
TY - JOUR. T1 - Differential impact of exogenous and endogenous attention on the contrast sensitivity function across eccentricity. AU - Jigo, Michael. AU - Carrasco, Marisa. N1 - Funding Information: We thank Antoine Barbot, Rachel Denison, Antonio Fern?ndez, David Heeger, Michael Landy, and Jonathan Winawer for their helpful comments, as well as Maya Mosley for assistance in data collection. Funded by National Institutes of Health R01-EY019693 and NEI R21-EY026185 to MC. Publisher Copyright: © 2020 Association for Research in Vision and Ophthalmology Inc. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.. PY - 2020. Y1 - 2020. N2 - Both exogenous and endogenous covert spatial attention enhance contrast sensitivity, a fundamental measure of visual function that depends substantially on the spatial frequency and eccentricity of a stimulus. Whether and how each type of attention systematically improves contrast sensitivity across spatial frequency and eccentricity are fundamental to ...
The goal of this study was to predict visual acuity (VA) and contrast sensitivity function (CSF)with tissue redness grading after pterygium surgery. A total of 67 primary pterygium participants were selected from patients who visited an ophthalmology clinic. We developed a semi-automated computer program to measure the pterygium fibrovascular redness from digital pterygium images. The final outcome of this software is a continuous scale grading of 1 (minimum redness) to 3 (maximum redness). The region of interest (ROI)was selected manually using the software. Reliability was determined by repeat grading of all 67 images, and its association with CSF and VA was examined. The mean and standard deviation of redness of the pterygium fibrovascular images was 1.88 ± 0.55. Intra-grader and inter-grader reliability estimates were high with intraclass correlation ranging from 0.97 to 0.98. The new grading was positively associated with CSF (p , 0.01) and VA (p , 0.01). The redness grading was able to ...
TY - JOUR. T1 - Reply to J. H. Verbaken. T2 - Contrast sensitivity function as a screening test. AU - Legge, Gordon E.. AU - Rubin, Gary S.. PY - 1987/4. Y1 - 1987/4. UR - UR - U2 - 10.1097/00006324-198704000-00012. DO - 10.1097/00006324-198704000-00012. M3 - Article. AN - SCOPUS:84939109685. VL - 64. SP - 293. EP - 295. JO - American Journal of Optometry and Physiological Optics. JF - American Journal of Optometry and Physiological Optics. SN - 1040-5488. IS - 4. ER - ...
Fingerprint Dive into the research topics of Visual function of a patient with advanced adrenoleukodystrophy: Comparison of luminance and color contrast sensitivities. Together they form a unique fingerprint. ...
Purpose: AMD is one of the leading causes of vision loss globally. Since color vision impairment is often one of the first symptoms of retinal disease, earlier AMD detection may be possible using color vision screenings. This potential detection could result in earlier treatment and decreased progression of the disease before irreversible damage to sight occurs.. Methods: Patients from the Illinois Eye Institute and Chicago Eye Institute were asked to perform the King Devick Variable Color Contrast Sensitivity(VCCSC) iPad test monocularly at their best corrected near visual acuity with black, red, blue, green, and yellow letters at various contrast levels (100%,75%,50%, and 25%). Identification accuracy (out of 5 letters) was recorded as both color and contrast changed.. Results: Data was analyzed using SPSS v21. All values are presented as means±SEM. The control group (n=35) age 50-79 years (46% male, 54% female). The non-exudative (NE) AMD(n=26) age 60-82 years (67% male, 33% female). A ...
At the recent ESCRS meeting in London, Dr David Evans participated as a faculty member in a course about contrast sensitivity (CS). Dr Gregory Pamel was the Course Director. During the course, Dr Evans covered the scientific basis of testing contrast sensitivity with sine-wave gratings and how it compares to standard visual acuity as a measure for real-world vision. Dr Pamel provided detailed information about the clinical significance of contrast sensitivity testing for cataract documentation, evaluation of refractive surgery outcomes and the use of CS testing to aid in evaluating the need for and results of re-treatments after initial refractive surgery. He also provided the most recent CS findings for new methods of presbyopia correction, including FDA trial data from ReVision Optics and AcuFocus. Dr Pamel then shared his thoughts about the importance of preserving patient quality of vision when correcting presbyopia and how CS testing is an important metric to determine the best outcomes. ...
The perception of speed is influenced by visual contrast. In primary visual cortex (V1), an early stage in the visual perception pathway, the neural tuning to speed is directly related to the neural tuning to temporal frequency of stimulus changes. The influence of contrast on speed perception can be caused by the joint dependency of neural responses in V1 on temporal frequency and contrast. Here, we investigated how tuning to contrast and temporal frequency in V1 of anesthetized mice are related. We found that temporal frequency tuning is contrast-dependent. V1 was more responsive at lower temporal frequencies than the dLGN, consistent with previous work at high contrast. The temporal frequency tuning moves toward higher temporal frequencies with increasing contrast. The low half-maximum temporal frequency does not change with contrast. The Heeger divisive normalization equation provides a good fit to many response characteristics in V1, but does not fit the dependency of temporal frequency and
TY - JOUR. T1 - Reaction time to motion onset of luminance and chromatic gratings is determined by perceived speed. AU - Burr, David C.. AU - Fiorentini, Adriana. AU - Morrone, Concetta. PY - 1998/12. Y1 - 1998/12. N2 - We measured reaction times for detecting motion onset for sinusoidal gratings whose contrast was modulated in either luminance or chromaticity, for various drift rates and contrasts. In general, reaction times to chromatic gratings were slower than to luminance gratings of matched cone contrast, but the difference in response depended critically on both contrast and speed. At high image speeds there was virtually no difference, whereas at low speeds, the difference was pronounced, especially at low contrasts. At high image speeds there was little dependence of reaction times on contrast (for either luminance or colour), whereas at low speeds the dependence was greater, particularly for chromatic stimuli. This pattern of results is reminiscent of those found for apparent speed of ...
Far contrast sensitivity (ie, the ability to detect slight changes in luminance before they become indistinguishable) was assessed binocularly with the participants best spectacle correction at a distance of 3 m using the Vector Vision CSV 1000 illuminated box (one site) and the Vision Contrast Test System (other site). Contrast sensitivity was assessed at spatial frequencies of 1.5, 3, 6, 12, and 18 cycles per degree (cpd). For CSV 1000, contrast sensitivity was not measured at spatial frequency 1.5 cpd because there was no option for this frequency. Raw scores were transformed to logMar (logarithm of the minimum angle of resolution) units. A higher numeric value represents better contrast sensitivity ...
PubMed Central Canada (PMC Canada) provides free access to a stable and permanent online digital archive of full-text, peer-reviewed health and life sciences research publications. It builds on PubMed Central (PMC), the U.S. National Institutes of Health (NIH) free digital archive of biomedical and life sciences journal literature and is a member of the broader PMC International (PMCI) network of e-repositories.
The CSF represents the reciprocal of the minimum contrast required to detect sinusoidal gratings that vary in spatial frequency (the number of cycles per degree of visual angle, cpd). As shown in the top panel of figure 3, scotopic CSFs were found to be low pass for all age groups. Statistically significant age related declines in contrast sensitivities were found for spatial frequencies at or below 1.2 cpd. This greater loss in contrast sensitivity at low spatial frequencies is quite different from photopic contrast sensitivity changes with age in which the decline in sensitivity is only at higher spatial frequencies for luminance varying stimuli.26,27 An analysis of these results in terms of optical factors could be rejected, while the results are consistent with age related changes in scotopic neural pathways.. The bottom panel of figure 3 shows the highest spatial frequency (the CSF cut-off frequency) that can be detected under scotopic conditions as a function of age. The axis on the ...
Laser in situ keratomileusis (LASIK) surgery has been performed worldwide since 1990. Historically, LASIK has been reported to decrease contrast sensitivity post operatively and patients have been advised to take the day off of work and potentially the day after LASIK. More recently, utilizing advanced laser technology for optimized corneal ablation and creation of the flap has the potential for improved LASIK surgery results and improved recovery time. Visual recovery and management of immediate post operative visual acuity is important for patient satisfaction ...
A new contrast sensitivity system was built with an iPAD connected to a 24 TFT-screen TFT monitor with a HDMI cable. The monitor was calibrated with a colorimeter. An image, showing incrementing spatial frequency along the x-axis and decreasing contrast along the Y-axis, was generated with custom software that allowed imaging on the the iPAD or the TFT monitor. While watching the image on the TFT monitor at 5 m, the subject was asked to draw a line in between contrast perceived and no contrast perceived. The line drawn by the subject was shown on the screen in use after the end of the tracking. The contrast perceived at each spatial frequency was stored in a data file. Totally, 20 subjects with visual acuity 1.0 and no known eye pathology were randomized on 2 groups with 6 males and 4 males to be measured for contrast sensitivity on both eyes with Vistech 6500 chart or UCST, depending on group belonging. Spectral contrast sensitivity was recorded for each eye and the time consumed for ...
PURPOSE: Loss of neuroretinal structure and function, ascribed to a HIV-associated Neuroretinal Disorder (HIV-NRD), in the absence of ocular opportunistic infections, has been reported in HIV-infected individuals treated with combination antiretroviral therapy (cART). Whether HIV-infected individuals with prolonged well-suppressed infection remain at risk for HIV-NRD, is unknown. METHODS: Ninety-two HIV-infected men with suppressed viremia on cART for at least 12 months (HIV+) and 63 HIV-uninfected, highly comparable, male controls (HIV-), aged at least 45 years, underwent functional measurements of spatial (Pelli Robson contrast sensitivity [PR CS]) and temporal contrast sensitivity (TCS) and straylight, as well as spectral-domain optical coherence tomography analysis measured total and individual retinal layer thickness ...
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Existing pixel-based just noticeable distortion (JND) models only take into account luminance adaptation and texture masking (TM). Similarly, existing discrete cosine transform (DCT) based models do not take into account foveal vision effects and do not estimate TM efficiently. As human visual system (HVS) is not sensitive to distortion below the JND threshold, estimation of the perceptual visibility threshold is widely used in digital and video processing applications. The authors propose a comprehensive and efficient pixel-based JND model incorporating all major factors which contribute to the JND estimation. The evaluation of contrast masking (CM) is done by distinguishing the edge and TM with respect to the entropy masking properties of the HVS. Similarly, the foveal vision effects are also taken into account for the comprehensive estimation of contrast sensitivity function (CSF). Hence, the proposed pixel-based JND model incorporates the spatio-temporal CSF, foveal vision effects, influence ...
Background: Amblyopic observers present abnormal spatial interactions between a low-contrast sinusoidal target and high-contrast collinear flankers. It has been demonstrated that perceptual learning (PL) can modulate these low-level lateral interacti
Purpose: To investigate whether a small angle glare test in a clinical setting can produce and detect a significant decrease in contrast sensitivity with age in normal young and elderly eyes. Methods: Contrast sensitivity (CS), with and without glare, was measured in 20 subjects. The subjects were all fully corrected. CS was measured using the Freiburg Visual Acuity & Contrast Test (FrACT) software running on a Macintosh imac (CRT). In our set-up the software uses a 4AFC-method, and the test distance was 4 meters. Glare was induced by a Fostec DCR® II light source with a randomised fiberoptical bundle mirrored into the centre of a Landolt C test target. Full test symmetry was accomplished by using this glare set-up. The test target and the glare source subtended an angle of about 1.3° and 0.2° respectively, yielding a 0.5° glare angle. The target mean luminance was 61 cd/m2 and the illuminance at the eye was 15 lux with glare. Results: We measured 20 subjects (20 to 59 yrs) with no known ...
It oversees the development of new device technologies such as sources and detectors as components, active elements such as modulators/switches, integration of optical components to perform various functions, development of active optical system/subsystem technologies including hardware, propagation considerations, and beam manipulation techniques.
The Optical Society of Americas news and policy section contains information designed to keep reporters, OSA members and the public informed of happenings at OSA, in government programs and in the optics community.
Ive heard about this a while ago, but now its statistically proven. Shooting Games can increase/help a players vision. It has to do with Contrast Sensitivity, apparently shooting games (Like Call of Duty 4 or Halo 3) increase and exercise your Contrast Sensitivity. What is contrast sensitivity? It is your ability to notice tiny changes…
Contrast Downloads. MSU Smart Brightness & Contrast - Free high-qualitybrightness & contr plugin for VirtualDub. CrispyPix - Brighten and sharpen images, zoom, adjust contrast...all from inside Microsoft Internet Explorer. Right-click on the image and you get an easy-to-use interface. Buy it now, or download a free trial
We present a spatial frequency domain multiplexing method for extending the imaging depth range of a SDOCT system without any expensive device. This method uses two reference arms with different round-trip optical delay to probe different depth regions within the sample. Two galvo scanners with different pivot-offset distances in the reference arms are used for spatial frequency modulation and multiplexing. While simultaneously driving the galvo scanners in the reference arms and the sample arm, the spatial spectrum of the acquired two-dimensional OCT spectral interferogram corresponding to the shallow and deep depth of the sample will be shifted to the different frequency bands in the spatial frequency domain. After data filtering, image reconstruction and fusion the spatial frequency multiplexing SDOCT system can provide an approximately 1.9 fold increase in the effective ranging depth compared with that of a conventional single-reference-arm full-range SDOCT system ...
Computational modeling is a useful method for generating hypotheses about the contributions of impaired neurobiological mechanisms, and their interactions, to psychopathology. Modeling is being increasingly used to further our understanding of schizophrenia, but to date, it has not been applied to questions regarding the common perceptual disturbances in the disorder. In this article, we model aspects of low-level visual processing and demonstrate how this can lead to testable hypotheses about both the nature of visual abnormalities in schizophrenia and the relationships between the mechanisms underlying these disturbances and psychotic symptoms. Using a model that incorporates retinal, lateral geniculate nucleus (LGN), and V1 activity, as well as gain control in the LGN, homeostatic adaptation in V1, lateral excitation and inhibition in V1, and self-organization of synaptic weights based on Hebbian learning and divisive normalization, we show that (a) prior data indicating ...
Disclosed herein are systems and methods for calibrating a continuous analyte sensor, such as a continuous glucose sensor. One such system utilizes one or more electrodes to measure an additional analyte. Such measurements may provide a baseline or sensitivity measurement for use in calibrating the sensor. Furthermore, baseline and/or sensitivity measurements may be used to trigger events such as digital filtering of data or suspending display of data.
We used a cross-modal dual task to examine how changing visual-task demands influenced auditory processing, namely auditory thresholds for amplitude- and frequency-modulated sounds. Observers had to attend to two consecutive intervals of sounds and report which interval contained the auditory stimulus that was modulated in amplitude (Experiment 1) or frequency (Experiment 2). During auditory-stimulus presentation, observers simultaneously attended to a rapid sequential visual presentation-two consecutive intervals of streams of visual letters-and had to report which interval contained a particular color (low load, demanding less attentional resources) or, in separate blocks of trials, which interval contained more of a target letter (high load, demanding more attentional resources). We hypothesized that if attention is a shared resource across vision and audition, an easier visual task should free up more attentional resources for auditory processing on an unrelated task, hence improving auditory
Mean age of LCG (48 eyes) was significantly higher(29.26±5.00vs26.45±3.74,P=0.006). F/M ratio was comparable in two groups and 2.7 in total. Post-op CDVA was comparable in two groups(1.22±0.23vs1.25±0.44,P = 0.7). Post-op UDVA was higher in HCG(1.31±0.37vs1.15±0.23,P =0.001). Pre-op mean manifest SE was more myopic in LCG(-4.41±2.02vs-3.28±1.41,P = 0.001) while post-op SE were comparable. Mean post-op photopic and mesopic contrast sensitivities were better in HCG; however mean improvement of contrast sensitivities were higher in LCG. Pre-op mean Defocus and Pentafoil aberrations were higher in LCG. After the operation they became comparable ...
Small changes in contrast sensitivity after LASIK can be documented using a dedicated computer program displaying optotypes on a monitor. Contrast sensitivity is impaired at 1 and 3 months, while complete recovery is observed after 6 months. This course is partly concealed if the spectacle refraction is not taken into account ...
A red background is used for men whose data has not yet been fully analyzed. His position on the tree is not yet final, and will in general be downstream of the current position. He may not be positive for all the SNPs/INDELs in the block he descends from.. Men whose NGS data have been fully analyzed are indicated with a grey background color.. Those men with a grey background and a pink bar to their left have been finalized, but havent gone through as much scrutinity as earlier kits have. In particular, no search has been made for recurrent SNPs or other unusual mutations. For the vast majority of kits, this has no effect at all, but I will review them as necessary in the future.. ...
A red background is used for men whose data has not yet been fully analyzed. His position on the tree is not yet final, and will in general be downstream of the current position. He may not be positive for all the SNPs/INDELs in the block he descends from.. Men whose NGS data have been fully analyzed are indicated with a grey background color.. Those men with a grey background and a pink bar to their left have been finalized, but havent gone through as much scrutinity as earlier kits have. In particular, no search has been made for recurrent SNPs or other unusual mutations. For the vast majority of kits, this has no effect at all, but I will review them as necessary in the future.. ...
Development of Population since 1875 within the Current Boundaries (Blue Line: Population; Dotted Line: Comparison to Population Development of Brandenburg state; Grey Background: Time of Nazi rule; Red Background: Time of Communist rule) Development of Population since 1875 within the Current Boundaries (Blue Line: Population; Dotted Line: Comparison to Population Development of Brandenburg state; Grey Background: Time of Nazi rule; Red Background: Time of Communist rule) Recent Population Development (Blue Line) and Forecasts Recent Population Development (Blue Line) and Forecasts Detailed data sources are to be found in the Wikimedia Commons
the Accessibility Menu suits Explorer 10 and higher, Opera and Chrome. With browsers like Safari and Firefox on Mac computers, activating keyboard navigation is necessary, and is done on the browsers settings menu. Pressing on the TAB key will activate the navigation options for the website. At the front page of the website the following options will appear: Accessibility Statement - open the websites accessibility statement text. Skip to content - begin navigation from the main area of content on the page (this option skips the navigation options at the top) Skip to menu - begin navigation from the main site menu. Skip to search - moves the browser to the search box (assuming that the site has a search box). Skip to cart - moves the browser to the shopping cart (assuming that the site has a cart). Activate high contrast - Changes the sites colors in order to suit the vision of colorblind or blind individuals. ...
the Accessibility Menu suits Explorer 10 and higher, Opera and Chrome. With browsers like Safari and Firefox on Mac computers, activating keyboard navigation is necessary, and is done on the browsers settings menu. Pressing on the TAB key will activate the navigation options for the website. At the front page of the website the following options will appear: Accessibility Statement - open the websites accessibility statement text. Skip to content - begin navigation from the main area of content on the page (this option skips the navigation options at the top) Skip to menu - begin navigation from the main site menu. Skip to search - moves the browser to the search box (assuming that the site has a search box). Skip to cart - moves the browser to the shopping cart (assuming that the site has a cart). Activate high contrast - Changes the sites colors in order to suit the vision of colorblind or blind individuals. ...
We know that adults contrast sensitivity and spatial resolution are better along the horizontal than vertical meridian -a.k.a. horizontal vertical anisotropy (HVA)- and better in the lower than upper vertical meridian -a.k.a. vertical meridian asymmetry (VMA; Carrasco et al., Spatial Vision 2000, JOV 2002). We also know that for adults the speed of information accrual follows the same pattern, i.e. it is faster along the horizontal meridian and slowest at the North locations (Carrasco et al., VSS 2002). In this study, we investigated the developmental course of these asymmetries with children ages 5-12, by using stimuli of different levels of familiarity, such as shapes, letters and numbers. We used a 4AFC character identification task to determine the presence and extent of the HVA and VMA. Each trial consisted of a central fixation point followed by a 1 stimulus, presented for 50 ms. The stimulus appeared at one of 10 possible eccentricities, ranging from 4 to 13 , along each of the 8 ...
An apparatus is disclosed for making unchirped holographic diffraction gratings that are formed from curved lines in a thin film. The gratings so made focus as well as reflect light that is confined to the film incorporating the grating. SU BACKGROUND OF THE INVENTION Gratings have been incorporated in integrated optics devices for several purposes, including the fabrication of distributed feedback lasers, light-wave couplers, and band-rejection filters. Integrated-optics gratings known to the prior art were composed at straight lines, and therefore could not focus the light being processed. Gratings that combine focusing and diffraction were known to be desirable, but the prior art was unable to produce them. The closest prior art that has come to our attention is a method and apparatus for producing curved-line holographic gratings that have unequally spaced, or chirped, lines (U.S. Pat. No. 3,578,845, issued on May 18, 1971 to K. E. Brooks et al). This reference teaches the production of gratings
This test uses a series of cards depicting cartoon faces of different contrast levels. The contrast sensitivity assessment ... It is especially vital to assess a child's contrast sensitivity at a young age in order to determine the distance and accuracy ... such as contrast sensitivity, visual field, color vision, visual adaptation, motion perception, and ocular function and ... Contrast sensitivity. Retrieved from Official website ( ...
... which is the ratio of binocular contrast sensitivity to the contrast sensitivity of the better eye. B S R = C S b i n o c u l a ... Contrast sensitivity. Visual acuity. A practical measure of binocularity is the binocular summation ratio BSR, ... By combining the information received in each eye, binocular summation can improve visual acuity, contrast sensitivity, flicker ... Schrödinger (1926) put forth an equation for binocular brightness and contrast combination where each monocular input is ...
"Contrast sensitivity" (PDF). LEA-Test Ltd. Retrieved 21 July 2018. Physiologic Optics: Dioptrics of the Eye, Functions of the ... This produces a contrast of about 1% with the illumination of surrounding cones. The mechanism of detection is the ability to ... In low light (i.e., scotopic vision), cones do not have sufficient sensitivity and vision is subserved by rods. Spatial ... Under optimal conditions of good illumination, high contrast, and long line segments, the limit to vernier acuity is about 8 ...
A person's contrast sensitivity function is contrast sensitivity as a function of spatial frequency. Normally, peak contrast ... Contrast sensitivity is the reciprocal of the smallest contrast for which a person can see a sine-wave grating. ... Reducing the contrast of an image reduces the visibility of these high spatial frequencies because contrast sensitivity for ... At higher spatial frequencies, comprising finer and finer lines, contrast sensitivity decreases, until at about forty cycles ...
Contrast sensitivity may be affected. The change in the refractive index of the cornea may result in subtle refractive shifts, ...
Contrast sensitivity may be diminished. There could be an abnormal electroretinogram or visual evoked potentials. Neuron- ...
2 Visual Acuity, Contrast Sensitivity". University of Utah. Retrieved 19 July 2009. (CS1 errors: external links, Articles with ... Barghout, Lauren (2014). Vision: How Global Perceptual Context Changes Local Contrast Processing (Ph.D. Dissertation 2003). ...
Contrast sensitivity is the inverse of the smallest contrast that can be detected; a contrast sensitivity of 100 means that the ... A contrast sensitivity function describes an animal's ability to detect the contrast of grating patterns of different spatial ... Birds have comparably lower contrast sensitivity than mammals. Humans have been shown to detect contrasts as low as 0.5-1% ... Spatial luminance contrast sensitivity tests of macaque and human observers". Vision Research. 14 (1): 75-81. doi:10.1016/0042- ...
Do you have a low-contrast sensitivity? For example, do they have trouble seeing a grey car at dusk, a black car at night, or a ...
... and the sensitivity to contrast in sine wave stimuli is characterized by the contrast sensitivity function. Contrast ... Skottun, Bernt C.; Skoyles, John R. (2007). "Contrast sensitivity and magnocellular functioning in schizophrenia". Vision ... "Spatio-temporal luminance contrast sensitivity and visual backward masking in schizophrenia". Experimental Brain Research. 156 ... "The effect of peripheral visual motion on focal contrast sensitivity in positive-and negative-symptom schizophrenia". ...
ISBN 0-471-97440-4. Peter G. J. Barten (1999). Contrast Sensitivity of the Human Eye and Its Effects on Image Quality. SPIE ... A database of camera spectral sensitivity is created and its space analyzed. For X-ray films, the spectral sensitivity is ... incorporating the spectral sensitivity. When the sensor system is linear, its spectral sensitivity and spectral responsivity ... Spectral sensitivity is the relative efficiency of detection, of light or other signal, as a function of the frequency or ...
"Luminance Contrast". Hwang, Alex D; Peli, Eli (14 February 2016). "Positive and negative polarity contrast sensitivity ... brightness contrast, lightness contrast, color contrast, simultaneous contrast, successive contrast, etc.). Contrast in physics ... The contrast between two full-screen patterns (full-screen contrast) always is a successive contrast.[citation needed] contrast ... 1 means no contrast. The contrast can also be specified by the contrast modulation (or Michelson contrast), CM, defined as: C M ...
Norcia and Tyler have used the technique to document the development of visual acuity and contrast sensitivity through the ... Norcia A. M.; Tyler C. W.; Allen D. (1986). "Electrophysiological assessment of contrast sensitivity in human infants". ... The resulting plot of stimulus luminance versus wavelength is a plot of the spectral sensitivity of the visual system. Sensory ...
Niemeyer, James E.; Paradiso, Michael A. (2017-02-01). "Contrast sensitivity, V1 neural activity, and natural vision". Journal ... The fading of the lilac circles is due to a loss of sensitivity to that stimulus and the adaptation to the new stimulus. To ... Visual adaptation is the temporary change in sensitivity or perception when exposed to a new or intense stimulus, and the ... The aftereffects of exposure to a visual stimulus or pattern causes loss of sensitivity to that pattern and induces stimulus ...
Most older adult humans lose photopic spatial contrast sensitivity. Adults in their 70s require about three times more contrast ... "Aging and Neural Spatial Contrast Sensitivity: Photopic Vision". Vision Research. 33 (7): 939-949. doi:10.1016/0042-6989(93) ... Their sensitivity ranges overlap to provide vision throughout the visible spectrum. The maximum efficacy is 683 lm/W at a ... Candela Cone cell Contrast (vision) Mesopic vision Night vision Purkinje effect Photometry (optics) Photosensitive ganglion ...
The NHK measured contrast sensitivity for the Rec. 2020 color space using Barten's equation which had previously been used to ...
Colored transparent insert discs to increase the contrast sensitivity. Semi-transparent occluder to block the non-aiming eye ... In contrast to most other eye glasses, shooting glasses usually only have one lens that corrects the ametropia of the dominant ...
It was a stark contrast to his own heightened sensitivity. During this time in prison he began experiencing the epileptic ...
C. Enroth-Cugell; J. G. Robson (1966). "The Contrast Sensitivity of Retinal Ganglion Cells of the Cat". Journal of Physiology. ... A major drawback to application of the algorithm is an inherent reduction in overall image contrast produced by the operation. ... Marr and Hildreth recommend the ratio of 1.6 because of design considerations balancing bandwidth and sensitivity. The url for ...
These improvement theories include the improvement of visual contrast sensitivity. Other developments include the ability to ...
Enroth-Cugell C, Robson JG (December 1966). "The contrast sensitivity of retinal ganglion cells of the cat". The Journal of ...
... may rarely cause a reduction in best night-time acuity due to the impairment of contrast sensitivity function (CSF) which is ... "Laser in situ keratomileusis for myopia and the contrast sensitivity function". Journal of Cataract and Refractive Surgery. 30 ... Contrast vision may also be greatly reduced. Rods contain a receptor-protein called rhodopsin. When light falls on rhodopsin, ...
Recordings of S potentials at the axon terminals of RGCs in the LGN suggest that there is high contrast sensitivity in the ... opposed by low contrast sensitivity in cells found in the parvocellular layer. Both old and new world primates have been used ... Due to this contrast information, these cells are good at detecting changes in luminance, and thus provide useful information ... Parasol ganglion cells have high light/dark contrast detection, and are more sensitive at low spatial frequencies than high ...
Spatial luminance contrast sensitivity tests of macaque and human observers", Vision Res. 14: 75-81 (1974). Thorell, L.G., De ... Spatial luminance contrast sensitivity tests of macaque and human observers", Vision Res. 14: 75-81 (1974) De Valois, R.L. & ... That the wavelength discrimination and luminance contrast sensitivity measured in monkeys were very similar to those obtained ... had proposed that the percept of color emerged from spectrally-opponent mechanisms in the visual system that contrasted red vs ...
This contrasted with the left hemisphere's lower level of sensitivity to variations. Although the concept of the left-brain ... In fMRI studies by Koutstaal the level of sensitivity of the right visual cortex with respect to the single exposure of an ... These studies illustrate the role of the left prefrontal cortex in exerting control over one's environment in contrast to the ...
Optical filter systems to increase the contrast sensitivity for the aiming eye. Semi-transparent occluders for the non-aiming ...
The physiognomy and the surface of the sitter's skin are delicately rendered; delicacy and sensitivity contrast with the long, ...
... increases image processing speed and improves sensitivity, contrast and color reproduction." The main differences ...
In contrast, the sensitivity and specificity can be estimated from case-control studies. Suppose the fecal occult blood (FOB) ... The PPV can also be computed from sensitivity, specificity, and the prevalence of the condition: PPV = sensitivity × prevalence ... sensitivity}}\times {\text{prevalence}}}{{\text{sensitivity}}\times {\text{prevalence}}+(1-{\text{specificity}})\times (1-{\ ... Binary classification Sensitivity and specificity False discovery rate Relevance (information retrieval) Receiver-operator ...
Daw, N. W.; Enoch, J. M. (1973). "Contrast sensitivity, westheimer function and stiles-crawford effect in a blue cone ...
20 Hz), which is energy that cannot be heard because it falls below the range of human hearing sensitivity. In contrast, ... Because the auditory system has varying sensitivity to sound as a function of frequency, unprotected noise exposures to mid- to ...
The taller the stack is, the narrower the vertical dispersion will be and the higher the sensitivity will be on-axis. A ... Horizontal line arrays, by contrast, have a very narrow horizontal output pattern and a tall vertical pattern. A row of ...
... with visual contrast provided by staining the normal tissues a mahogany brown with Lugol's iodine. Medical devices used for ... including sensitivity in discussing the topic in Aboriginal communities, embarrassment, anxiety and fear about the procedure. ... stage does not incorporate lymph node involvement in contrast to the TNM staging for most other cancers. For cases treated ...
Second, because of the high-contrast resolution of muography, a small void of less than 0.001% of the entire volume can be ... due to the lack of directional sensitivity in the Geiger counter, imaging was impossible. In a famous experiment in the 1960s, ... Electronic tracking data can be processed almost instantly with an adequate computer processor; in contrast, film muography ...
... lower contrast: for ex. Rodinal/Adonal (1:25 about 10 mins., 1:50 about 20 mins.) or higher contrast: any paper developer 1+4 ... extended red sensitivity). Converted and packaged by Foma orthochromatic film with a clear base spectral sensitivity 380-610 nm ... extended spectral sensitivity from IR to near-UV, to be stored in special black cartridges Discontinued same emulsion as Maco ... strong contrast and low exposure tolerance, fine grain not much subject to grain aliasing in usual resolution scans ...
"Contrasting Patterns of Diterpene Acid Induction by Red Pine and White Spruce to Simulated Bark Beetle Attack, and ... Interspecific Differences in Sensitivity Among Fungal Associates". Journal of Chemical Ecology. 41 (6): 524-532. doi:10.1007/ ...
In contrast, 74% of the questions had no commonality between organizations. Although the idea of fit is similar in many ... Lievens, Filip; Peeters, Helga (January 2008). "Interviewers' Sensitivity to Impression Management Tactics in Structured ... In contrast, if the interviewer perceives the applicant as uncomfortable or anxious discussing the disability, this may either ... whereas, in contrast, anxious or uncomfortable during their interview may view an organization less favorably, causing the ...
Way Jeng of described her performance as energetic, yet innocent and simple, but contrasting to Wendee Lee's voicing ... Theron Martin called her acting of "Pacifica's brattiness and deep sensitivity solidly pegged", although it is different from ... In contrast, Shelkie was desired to be portrayed as very cold and emotionless, which she describes as "cold, but sympathetic." ...
In contrast, however others have argued that Pocahontas's love scene in Act III is where the truest poetry of the piece emerges ... The portrayals of the Indians in the play, from a perspective of racial sensitivity, have been met with mixed reviews by modern ...
In contrast, prices in the US and the UK have recently skyrocketed, then fallen as a result of changes in supply and storage.[ ... Due to the sensitivity of liquefaction facilities to sulfur and mercury elements, the gas being sent to the liquefaction ...
... acetate can be a substitute for the radioactive and toxic uranyl acetate (used as a standard contrasting agent in ... Condensation reaction in the bandpass reaction cell improves sensitivity for uranium, thorium, neodymium and praseodymium ... Despite these published alternatives, uranyl acetate (UAc) is still the standard for EM contrasting. In the periodic table the ... Uranyl acetate has been the standard contrasting agent in transmission electron microscopy (TEM) for decades. However, its use ...
... and details that contrast with the hard-edged, splintery look typically associated with woodcuts. She has generally worked on ... with a sublimation of subject and sensitivity to form." Much of Walters's work in the 1960s focused on expressive black-and- ... to create contrasts between flatness and depth, and realism and imagination. In subject matter, she turned from the ...
This is in contrast to the Japanese experience reported by Sasaki et al., likely reflecting heterogeneity of the disease in ... Oertel WH, Wächter T, Quinn NP, Ulm G, Brandstädter D (April 2003). "Reduced genital sensitivity in female patients with ... Women have also reported reduced genital sensitivity. As the disease progresses one of three groups of symptoms predominates. ...
In contrast, crewed vehicles need additional fuel after a lunar landing to enable a return trip back to Earth for the crew. ... and a seismometer designed with sensitivity high enough to detect the impact of a 5 lb (2.3 kg) meteorite on the opposite side ... In contrast to Soviet lunar exploration triumphs in 1959, success eluded initial U.S. efforts to reach the Moon with the ...
He called those numbers sustainable, contrasting them with low Windows 8 sales which he blamed for a slump in the market. Wong ... praising the improvements in speed and touchpad sensitivity over the CR-48 prototype, as well as the long battery life and the ... By contrast, sales of Apple tablets and laptops to U.S. schools dropped that year to 19 percent, compared with 52 percent in ...
Water is not a homogeneous commodity for several reasons which include sensitivity to location, time of use, form of the water ... Groundwater banking can be compared and contrasted to the use of surface reservoirs. Groundwater banking has many advantages ...
Her sensitivity becomes a phobia towards older corporate mascots, especially the Michelin Man. She wears only black, gray or ... The footage, released freely to a global audience with a lack of time or place indicators, has also been contrasted to Pattern ... She uses her interest in marketing trends and fads, and her psychological sensitivity to logos and advertising, in her work as ... the contrasting of boardroom with street; the impossibility and dire necessity of making art in the face of instant co-optation ...
Tuning of color contrast signals to visual sensitivity maxima of tree shrews by three Bornean highland Nepenthes species. Plant ... montana visual sensitivity maxima in the green and blue wavebands, making it stand out against adjacent parts of the pitcher. ...
In contrast to VCRs, hard-disk based digital video recorders make "time shifting" more convenient and also allow for functions ... this feature detects motion in the total image or a user definable portion of the image and usually provides sensitivity ...
In 2019, Grażyna Kubica-Heller of Jagiellonian University presented a paper Strong authorial 'I' and feminist sensitivity - two ... Presented to the American Anthropological Association in 1957, her report contrasted the differences between the treatment of ... Kubica-Heller, Grażyna (29 August 2019). Strong authorial 'I' and feminist sensitivity - two Polish women-anthropologists ...
Zaleski, Annie (3 June 2014). "Travis' The Man Who paved the way for Coldplay's sensitivity". A.V. Club. Onion Inc. Retrieved 8 ... contrasting with the dark mood surrounding 12 Memories. Travis played at the Coachella Music and Arts Festival on 28 April 2007 ...
Tradem's leftist viewpoints did not set the tone for the publication, and was contrasted by Pencioiu (the latter, although he ... without sensitivity, without imagination, an artist cannot become anything other than, at most, a fecund and passable worker, ... in contrast with Moldavians such as Bacovia, Petică, and Benjamin Fondane. In their view, Demetrescu and his fellow Wallachians ... thus contrasting with Macedonski's post-Parnassian school, as well as with the balladesque literature produced by Ştefan ...
It is contrasted with China, a collectivist country people tend to worry more about the overall well-being of the group and put ... where subordinates tend to build greater sensitivity and cautiousness when communicating with their supervisors. It is a common ... In contrast, employees in high power distance cultures are less likely to be themselves around authority; They are also less ... explanation for this phenomenon is that the rooted perception and acceptance of inequality somehow dampens their sensitivity to ...
This sensitivity has not, however, prevented both Jewish and Muslim works from accusations of destroying archeological evidence ... in contrast to religious entities. The public currently uses the two names interchangeably. During the last generation, ... Due to the extreme political sensitivity of the site, no real archaeological excavations have ever been conducted on the Temple ...
Each has a specific pitch and timbre that has a specific rhythmic role). 8.) Kaleidoscopic range of dramatically contrasting ... through tonal inflection or linguistic sensitivity sound (i.e., making a guitar or turntable "talk" or "speak"). 9.) Fixed melo ... These ideas include: 1.) Rhythmic/metrical contrast or clash (includes significant use of syncopation, unusual metric changes, ... lots of layers or parts in 2-bar phrase or loop a few parts that fill up the aural space through contrasting timbres, using a ...
He has made his own fortune through hard work and good sense, in direct contrast to Sir Walter who has only wasted the money ... and sensitivity of the older type, Wentworth adds the qualities of gallantry, independence, and bravery that come with being a ...
RoHS and other environmental laws are in contrast to historical and contemporary law that seek to address only acute toxicology ... Added moisture sensitivity, all of which may compromise quality and reliability. Potential reliability concerns were addressed ...
By contrast, at a fan gathering in 2008, St. John joked about Todd and Marty bonding during the Carlivati storyline, stating, " ... "We didn't exercise proper sensitivity to the history of the character of Todd. We have re-evaluated and decided not to sell the ... "Todd stalks Nora" The Todd chords heard during the storyline in which he stalks Nora, contrasted by birds chirping in the ... features that contrasted well with the character's "pouty, sensual mouth". The features, which conferred "a charming, boyish ...
In contrast to previous Adventurers League storylines, Ravenloft: Mist Hunters will shift away from a tactical combat focus and ... In 2020, Wizards was criticized by its community for how it deals with issues of cultural sensitivity, especially with the ...
Gary Heiting describes how a contrast sensitivity test can detect vision problems that might not show up on a conventional eye ... Contrast sensitivity testing. Contrast sensitivity testing often isn't included in a routine eye exam. Your eye doctor ... Symptoms of reduced contrast sensitivity. If you have low contrast sensitivity, you may have problems with night driving, ... Contrast sensitivity function (CSF). Detailed contrast sensitivity measurements that include both size (spatial frequency) and ...
Contrast Test (DH CS test), manufactured and marketed by Precision Vision is unique in that it features a simple schematic of a ... A new contrast sensitivity test is on the market, thanks to two New England College of Optometry faculty members. D. Luisa ... The dimmest face that the patient detects provides a measure of their contrast sensitivity. The DH image is offset from the ... "We wanted to design a quick and effective test of contrast sensitivity for the pediatric population that could also be used ...
Contrast Sensitivity Isocontours Of The Central Visual Field. We have a new manuscript out in Nature Scientific Reports, ... Contrast sensitivity isocontours (CSIs) may reduce test variability in SAP by identifying regions of the visual field with ... Contrast Sensitivity Isocontours Of The Central Visual Field.. Authors: Agnes Y. J. Choi, Lisa Nivison-Smith, Jack Phu, Barbara ... found CSI guided analysis detected a significantly greater deviation in sensitivity of AMD eyes from normal compared to a ...
Contrast Sensitivity Testing Charts useful in clinical testing. Helps detect early signs of vision loss from forming cataracts ... Contrast Sensitivity Tests *Peak Contrast Sensitivity. *Low Contrast Letter, Symbol & Reading Charts ...
Shah, K. H., Holland, G. N., Yu, F., Van Natta, M., & Nusinowitz, S. (2006). Contrast Sensitivity and Color Vision in HIV- ... Shah KH, Holland GN, Yu F, Van Natta M, Nusinowitz S. Contrast Sensitivity and Color Vision in HIV-infected Individuals Without ... Contrast Sensitivity and Color Vision in HIV-infected Individuals Without Infectious Retinopathy. In: American journal of ... Contrast Sensitivity and Color Vision in HIV-infected Individuals Without Infectious Retinopathy. / Shah, Kayur H.; Holland, ...
Fourth-root summation of contrast over area in the central visual field: no end in sight spatially inhomogeneous sensitivity is ... Fourth-root summation of contrast over area: no end in sight when spatially inhomogeneous sensitivity is compensated by a ... Meese, T. (Creator), Baldwin, A. (Creator) (22 Sep 2015). Fourth-root summation of contrast over area in the central visual ... field: no end in sight spatially inhomogeneous sensitivity is compensated by a witchs hat. Aston Data Explorer. 10.17036/ ...
Tests used to measure contrast sensitivity include the following:. * Pelli-Robson contrast sensitivity chart. Each letter ... The contrast decreases from one triplet to the next. The log contrast sensitivity varies from 0.00-2.25. ... Contrast sensitivity test. This test measures the ability to perceive slight changes in luminance between regions that are not ... Utility of coronal contrast-enhanced fat-suppressed FLAIR in the evaluation of optic neuropathy and atrophy. Eur J Radiol Open ...
Tests used to measure contrast sensitivity include the following:. * Pelli-Robson contrast sensitivity chart. Each letter ... The contrast decreases from one triplet to the next. The log contrast sensitivity varies from 0.00-2.25. ... Contrast sensitivity test. This test measures the ability to perceive slight changes in luminance between regions that are not ... Utility of coronal contrast-enhanced fat-suppressed FLAIR in the evaluation of optic neuropathy and atrophy. Eur J Radiol Open ...
... testing. Contrast sensitivity testing gauges your ability to see objects in terms of size and contrast. ... Even if you have 20/20 vision, you may have poor contrast sensitivity. Contrast sensitivity testing is important because it ... What is contrast sensitivity?. In standard vision testing, an eye chart is viewed in high contrast conditions, where black ... When you undergo a contrast sensitivity test, you may be shown images such as dots and bars with different contrasting ...
Contrast sensitivity changes across the visual field with age and is often measured clinically with various forms of perimetry ... Contrast Sensitivity on 1/f Noise Is More Greatly Impacted by Older Age for the Fovea Than Parafovea. ... In daily life, the visual scene is more complicated, and therefore, the standard clinical measures of contrast sensitivity may ... Contrast thresholds were measured for a Gabor patch of 6 cycles per degree (sine wave grating masked by a Gaussian envelope of ...
Smooth-pursuit eye movement and directional motion-contrast sensitivity in schizophrenia ... Smooth-pursuit eye movement and directional motion-contrast sensitivity in schizophrenia. You are here *UTAS Home ... Slaghuis, WL and Bowling, AC and French, RL, Smooth-pursuit eye movement and directional motion-contrast sensitivity in ... No significant differences were found between the control and positive-symptom group in directional motion-contrast sensitivity ...
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Contrast sensitivity. / Shapley, Robert (Editor); Lam, Dominic Man-Kit (Editor).. Cambridge : MIT Press, 1993.. Research output ... Shapley, Robert (Editor) ; Lam, Dominic Man-Kit (Editor). / Contrast sensitivity. Cambridge : MIT Press, 1993. ... Shapley R, (ed.), Lam DM-K, (ed.). Contrast sensitivity. Cambridge: MIT Press, 1993. ... Shapley, R., & Lam, D. M-K. (Eds.) (1993). Contrast sensitivity. MIT Press. ...
Comparison of mold exposures, work-related symptoms, and visual contrast sensitivity between employees at a severely water- ... Comparison of mold exposures, work-related symptoms, and visual contrast sensitivity between employees at a severely water- ... Title : Comparison of mold exposures, work-related symptoms, and visual contrast sensitivity between employees at a severely ... and visual contrast sensitivity between employees at a severely water-damaged school and employees at a school without ...
GADELHA, Maria José Nunes et al. Achromatic contrast sensitivity for vertical sine-wave gratings in adolescents and adults. ... The aim of this study was to characterize the contrast sensitivity function (CSF) of adolescents and young adults. Was measured ... Palavras-chave : Visual perception; Contrast sensitivity; Psychophysical method; Linear sine-wave grating; Adolescents and ... These results suggest that the process of development and maturation of the visual perception of contrast interacts differently ...
baseball, contrast, contrast sensitivity, exercise, hockey, multi-object, multiple tracking, new exercise, resources, sight, ... The newest exercise is an enhanced version of the Contrast Sensitivity exercise released in December. What is Contrast Tracking ... The Effects of Contrast Sensitivity on Hitting. Like Teddy KGB, elite hitters are always on the lookout for clues to what the ... Contrast Sensitivity Added to Vizual Edge Training. We have developed a new training exercise that tests your ability to ...
contrast sensitivity. Retinal function, structure changes in proliferative diabetic retinopathy revealed. October 28, 2015. // ... Category: NewsTag: contrast sensitivity, Diabetic retinopathy, optical tomography, retina, retinal function, retinal pigment ... Retinal function was evaluated using a number of tests, including contrast sensitivity, frequency doubling perimetry (FDP) and ...
... contrast sensitivity and color vision. Our different screening cards can be used with a stereoscope, to also test the visual ...
We provide eyeglass consultations for low contrast sensitivity. Schedule an evaluation in Arlington or Mansfield, Texas. ... What is Low Contrast Sensitivity?. Poor contrast sensitivity is easiest to notice while driving at night or in foggy conditions ... Treatments for Contrast Sensitivity Issues in Arlington and Mansfield. This condition can be dangerous. If you have a hard time ... What Causes Low Contrast Sensitivity?. Several conditions can result in this issue. Common causes include:. *Diabetic ...
These contrast sensitivity deficits detected with the quick CSF test would have been missed with the traditional Pelli-Robson ... "Contrast sensitivity function [CSF] testing may be a valuable addition to the standard cataract evaluation to enhance surgical ... A quick test with active learning algorithms may give physicians a novel way to measure contrast sensitivity (CS) when ... The primary outcomes were the area under the log CSF (AULCSF), contrast acuity (CA), and CS thresholds at 1, 1.5, 3, 6, 12, and ...
A more discerning measure of functional vision is contrast sensitivity testing. ... Contrast Sensitivity Testing - Suzanne Corcoran, COE. February 1, 2007. 01-02-2007. MIC Support closed ... A more discerning measure of functional vision is contrast sensitivity testing. New IOLs have rekindled an interest in this ...
Step up to the plate with sharp visual skills like contrast sensitivity and watch your game improve. Sports vision training ...
The CSV-1000E contrast sensitivity chart test face is the most widely used contrast sensitivity test in the world. This test ... Contrast Sensitivity, Distance Charts, Ophthalmic Clinical Research, Pelli Robson chart. Pelli-Robson Contrast Sensitivity ... Pelli-Robson Trans-Illuminated Contrast Sensitivity Chart *Trans-Illuminated Contrast Sensitivity Pelli-Robson Chart SLOAN Peak ... Pelli-Robson Trans-Illuminated Contrast Sensitivity Chart. *Trans-Illuminated Contrast Sensitivity Pelli-Robson Chart SLOAN ...
Step up to the plate with sharp visual skills like contrast sensitivity and watch your game improve. Sports vision training ...
Contrast sensitivity and its determinants in people with diabetes: SN-DREAMS-II, Report No 6 - (Eye 31, 460 (March 2017)). 9 ...
Visual acuity and contrast sensitivity. In: Schachat AP, Sadda SVR, Hinton DR, Wilkinson CP, Wiedemann P, eds. Ryans Retina. ...
Spatial Contrast Sensitivity. Auditory. Pure Tone Audiogram. Screening Test for Auditory Perceptual Disorders. Test of Auditory ...
The contrast sensitivity function of the praying mantis Sphodromantis lineola. .wpfb-left { float: left; width: 300px; } .wpfb- ...
Contrast sensitivity was checked using Cambridge low-contrast grating. Abnormal contrast sensitivity was observed in 27.1% of ... Contrast sensitivity is proposed as a potential screening tool for the early detection of diabetic retinopathy. A cross- ... Abnormal Cambridge low-contrast grating sensitivity results associated with diabetic retinopathy as a potential screening tool ... Mass Screening (‎3)‎Questionnaires (‎2)‎Sensitivity and Specificity (‎2)‎Vaginal Smears (‎2)‎...查看更多发布日期2007 - 2008 (‎6)‎ ...
Each observers contrast sensitivity was measured with the CAT2000 Contrast Sensitivity Accurate Tester (Neitz Instruments Co ... In a strict sense, the contrast sensitivity of the viewers eyes, the modulation transfer function (MTF) of the shooting system ... Japan). Five observers had contrast sensitivities lower than the normative limits. Objective refraction was measured ... probabilities of each object for each observer, except for some observers with low contrast sensitivity. ...
  • CRAG latex agglutination test sensitivity (97.0%-97.8%) and specificity (85.9%-100%) varied between manufacturers. (
  • Probably the most widely used device to test contrast sensitivity is the Pelli Robson contrast sensitivity chart. (
  • Visual function was determined using the Pelli-Robson contrast sensitivity test and the Farnsworth-Munsell 100-Hue color test (FM-100). (
  • Pelli-Robson contrast sensitivity chart. (
  • These contrast sensitivity deficits detected with the quick CSF test would have been missed with the traditional Pelli-Robson contrast testing, he added. (
  • This could be caused by a loss of contrast sensitivity from the surgery. (
  • Most affected patients are asymptomatic, although there may be some loss of contrast sensitivity even in the absence of reduced Snellen visual acuity. (
  • Low contrast sensitivity can be a symptom of certain eye conditions or diseases such as cataracts , glaucoma or diabetic retinopathy . (
  • Contrast sensitivity is proposed as a potential screening tool for the early detection of diabetic retinopathy. (
  • Abnormal contrast sensitivity was observed in 27.1% of eyes with diabetic retinopathy, compared with 9.0% in unaffected eyes, a statistically significant difference. (
  • Contrast sensitivity is a very important measure of visual function, especially in situations of low light, fog or glare, when the contrast between objects and their background often is reduced. (
  • When you undergo a contrast sensitivity test, you may be shown images such as dots and bars with different contrasting backgrounds under varying conditions such as glare. (
  • Experiencing light glare at night may be an indication of low contrast sensitivity . (
  • Poor contrast sensitivity is easiest to notice while driving at night or in foggy conditions where light may reflect and create a glare. (
  • The main aim of this thesis was to evaluate the performance of the contrast sensitivity clock (CSC), a new screening device for measuring contrast sensitivity (CS) and glare. (
  • If the student performs poorly, more attention will be given to issues of lighting, contrast and glare. (
  • A quick test with active learning algorithms may give physicians a novel way to measure contrast sensitivity (CS) when evaluating patients before cataract surgery , according to Augustine Bannerman, an undergraduate research assistant, and Filippos Vingopoulos, MD, both from the Harvard Retinal Imaging Laboratory at Massachusetts Eye and Ear in Boston. (
  • Purpose: To investigate the relationship between abnormal contrast sensitivity and abnormal color vision among human immunodeficiency virus (HIV)-infected individuals who have normal visual acuity and to seek host factors that predict these abnormalities. (
  • Results: The prevalences of abnormal contrast sensitivity and abnormal color vision were 7.0% and 9.9%, respectively. (
  • Conclusions: Abnormal contrast sensitivity and abnormal color vision can occur independently in HIV-infected individuals and can be present in the absence of severe immunosuppression. (
  • Abnormal contrast sensitivity and color vision are present in almost all adults with ON even in the absence of a measurable decrease in visual acuity. (
  • namely, border ownership, contrast preference, binocular stereoscopic information, selectivity for side-of-figure, Gestalt rules, and strength of attentional modulation, as well as the time course during which such properties arise. (
  • It is concluded that monocular and binocular contrast sensitivity deficits define important characteristics of amblyopia and strabismus that are not captured by visual acuity alone and can be measured efficiently using the quick CSF. (
  • We have a new manuscript out in Nature Scientific Reports, Contrast Sensitivity Isocontours Of The Central Visual Field . (
  • Contrast sensitivity isocontours (CSIs) may reduce test variability in SAP by identifying regions of the visual field with statistically similar patterns of change that can be analysed collectively and allow a point (disease)-to-CSI (normal) comparison in disease assessment as opposed to a point (disease)-to-point (normal) comparison. (
  • We have a new publication in IOVS , Pattern Recognition Analysis Reveals Unique Contrast Sensitivity Isocontours Using Static Perimetry Thresholds Across The Visual Field (Direct link here ). (
  • To determine the locus of test locations that exhibit statistically similar age-related decline in sensitivity to light increments and age-corrected contrast sensitivity isocontours (CSIs) across the central visual field (VF). (
  • Our results revealed a strong eccentricity dependence in performance between older and younger adults, highlighting age-related differences in the contrast detection mechanisms between fovea and parafovea for stimuli presented on nonuniform backgrounds. (
  • Tokyo, October 9, 2012 - Hitachi, Ltd. (TSE:6501, "Hitachi") today announced the development of basic technology for a contrast agent *1 to be used with high-sensitivity photo-acoustic imaging, a medical imaging technique suited for the detection of minute tumor growths deep within the body. (
  • The development of a contrast agent which would reach the target tumor and efficiently generate ultrasound signals was an issue which needed to be overcome in achieving high sensitivity detection of tumors. (
  • The contrast agent is basic technology which can contribute to the early detection or treatment of cancer through the combination with bio-markers which selectively bind to specific diseased tissue. (
  • LC-MS provides a combination of detection selectivity and sensitivity, speed of analysis, and robust performance that is well suited to the rapid structural characterization of candidate therapeutic substances and high-throughput screening assessment of pharmacological activity (1-3). (
  • LC-UV determinations lack sufficient selectivity and sensitivity, making detection and quantitation problematic for the newer, more potent low-dose pharmaceuticals. (
  • Sensitivity ranges from 100-32000 for working in a variety of lighting conditions and the sensor's design also integrates a 425-point Fast Hybrid AF system for accurate tracking and detection of subjects. (
  • In contrast, organic scintillator materials have good processability and stability, but due to the low atomic weight of their constituent atoms (hence the limited X-ray absorption), the imaging resolution and detection sensitivity are low. (
  • Detailed contrast sensitivity measurements that include both size (spatial frequency) and contrast are used to plot a person's contrast sensitivity function (CSF). (
  • Contrast sensitivity testing is important because it allows Optometrists to determine how well you function in real-world conditions, where objects may "blend" and become indistinguishable in backgrounds with similar colouring. (
  • Retinal function was evaluated using a number of tests, including contrast sensitivity, frequency doubling perimetry (FDP) and photostress testing. (
  • Contrast sensitivity function [CSF] testing may be a valuable addition to the standard cataract evaluation to enhance surgical decision-making, particularly in patients with subjective visual complaints despite good visual acuity [VA]," Bannerman said. (
  • The aim of this study was to characterize the contrast sensitivity function (CSF) of adolescents and young adults. (
  • Bhowmick B, Gaur D, Rastogi P. Effects of whole body vibration on human contrast sensitivity function. (
  • Evaluation of the precision of contrast sensitivity function assessment on a tablet device. (
  • These CSIs could guide future structure-function and alternate hemifield asymmetry analyses by comparing matched areas of similar sensitivity signatures. (
  • CHICAGO - With modern LASIK, the speed of visual recovery experienced by patients is rapid and contrast sensitivity function (CSF) is improved. (
  • This study aims to determine whether contrast thresholds in older adults are different from younger adults when measured on a 1/f noise background (a nonuniform background whose spatial frequency content is similar to those present in the natural vision environments). (
  • Contrast thresholds were measured for a Gabor patch of 6 cycles per degree (sine wave grating masked by a Gaussian envelope of standard deviation 0.17°) presented on 1/f noise background (root-mean-square contrast, 0.05 and 0.20) that subtended 15° diameter of the central visual field. (
  • Older adults demonstrate increased contrast thresholds compared with younger adults. (
  • Cluster analysis of age-corrected sensitivity thresholds revealed unique CSIs for GI-V, with smaller stimuli having a greater number of unique clusters. (
  • The quick CSF test detected disproportionate significant contrast deficits at 6 cpd in the various metrics evaluated in cataractous eyes and even in those with good VA, the authors noted. (
  • The TCE-exposed group had deficits in the following neurobehavioral tests compared to the non-exposed workers: lower visual contrast sensitivity scores for both eyes at 6 cycles per degree and at 12 cycles per degree for the right eye, a larger postural sway area for the most challenging test condition, and slower completion time in the Grooved Pegboard Test. (
  • [ 1 ] although permanent residual deficits in color vision and contrast and brightness sensitivity are common. (
  • Ophthalmologic examination, including best spectacle-corrected visual acuity (BSCVA), pupil size, ocular dominance, contrast sensitivity under mesopic and photopic conditions, and wavefront analysis, was performed 2 months and 1 and 2 years after surgery. (
  • However, for a patient with large mesopic pupils who does a lot of night driving, there may be a distinct advantage to implanting an aspheric IOL that offsets the cornea's positive spherical aberration, in an effort to maximize contrast sensitivity and minimize night myopia. (
  • A) Prediction of cryptococcal antigen titer based on laser thermal contrast measurement and concept of lateral flow immunochromatographic assay (LFA) thermal contrast measurement in which a laser irradiates the test line in the LFA ( 19 ). (
  • B) Association of measured semiquantitative LFA cryptococcal antigen (CRAG) titer starting at a 1:250 dilution by the predicted CRAG titer based on thermal contrast measurement. (
  • Measurements on the negative portion of the x-axis are beyond the visual range when specimens were diluted 1:250, yet still detectable by thermal contrast. (
  • By coupling a thermal desorption aerosol gas chromatograph (TAG) simultaneously to a flame ionization detector (FID) and an iodide CIMS, we use the individual particle-phase analytes, quantified by the FID, to examine the sensitivity of the CIMS and its variability between isomers of the same elemental formula. (
  • A comparative test regarding each individual stimulation caused by mechanical attrition and thermal probe with clinical test was done (air syringe) in order to verify the presence of sensitivity in three phases: before treatment, after 7 and 14 days. (
  • Studies generally have shown greater contrast sensitivity, particularly in dim light, and better performance on night-driving tests with Tecnis compared with spherical IOLs, and, in some cases, also compared with other aspherics. (
  • In most cases, people with cataracts notice a significant improvement in both visual acuity and contrast sensitivity after cataract surgery. (
  • In standard vision testing, an eye chart is viewed in high contrast conditions, where black letters or numbers of varying sizes are sharply displayed against well-lit, white backgrounds. (
  • FIRST (Fibered Imager foR a Single Telescope) is a post-extreme AO instrument module undergoing commissioning at the Subaru Telescope that enables high-contrast imaging at sub-diffraction limit spatial scales. (
  • This means high detail and texture, even on high-contrast colors. (
  • The radiotracer proved to be a superior, high-contrast imaging diagnostic in patients, visualizing tumors that express low or moderate levels of αvβ3 integrin with high sensitivity. (
  • The addition of the 64Cu label to EBRGD provides persistent, high-contrast diagnostic images in glioblastoma patients. (
  • By supporting your eyes at a cellular level, you can effectively promote visual acuity, contrast sensitivity and reduce the occurrence of age-related eye symptoms like hazy, blurred, or double vision. (
  • At all followup examinations, contrast sensitivity results showed no significant differences between the two aspheric IOLs at all spatial frequencies. (
  • But instead of the letters getting smaller on each successive line, it is the contrast of the letters (relative to the chart background) that decreases with each line. (
  • Pattern recognition analysis was used to cluster test locations across the VF exhibiting equal age-related sensitivity decline (age-related CSIs), and points of equal age-corrected sensitivity (age-corrected CSIs) for GI-V. (
  • CSIs facilitate pooling of sensitivities to reduce the variability of individual test locations. (
  • Visual impairment is defined as significant limitation of visual functions, such as visual acuity, contrast sensitivity, visual field, colour vision, and dark adaptation, resulting from disease, trauma, or congenital or degenerative conditions that can be treated or not (1, 2). (
  • In case of impaired colour vision, decreased contrast or colour sensitivity, patients should consult a retina specialist. (
  • In daily life, the visual scene is more complicated, and therefore, the standard clinical measures of contrast sensitivity may not predict a patient's visual experience in more natural environments. (
  • By testing with several different contrast levels configured together, the patient's contrast sensitivity level is better assessed and records will be more precise. (
  • A contrast sensitivity test measures your ability to distinguish between finer and finer increments of light versus dark (contrast). (
  • 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. (
  • The so-called quick CSF test uses "a Bayesian active learning algorithm that maximizes information extraction over a very large set of possible combinations of contrast and spatial frequency that ultimately creates a curve separating visible from invisible stimuli with great test-related repeatability and testing times of 2 to 5 minutes per eye," Bannerman said. (
  • There was a small but significant test size-dependent sensitivity decline with age, with smaller stimuli declining more rapidly. (
  • Contrast sensitivity was checked using Cambridge low-contrast grating. (
  • Further, it was found that measurement of tumors deep within the body could be achieved with high resolution, something which had hitherto been difficult with conventional contrast agents. (
  • As a result, it is now possible to spend more time in investigating a particular section of a tumor or an entire tumor located deep within the body, opening the way for high resolution measurement of tumors located deep within the body which was hitherto difficult with conventional contrast agents. (
  • We provide a detailed analysis of the sensitivity for different measurement protocols, and we show that our nanoscale velocimetry scheme outperforms current fluorescence based approaches even when diffusion noise is dominant. (
  • For solid lesions, MRI (with contrast or fat suppression) is preferred in areas in close proximity to the bony wall. (
  • Schutte, C & Skeel, RL 2006, ' Visual Contrast Sensitivity and Neuropsychological Performance in a Healthy Elderly Sample ', Journal of Clinical & Experimental Neuropsychology . (
  • Visual contrast sensitivity decreased and chest tightness increased (odds ratio 2.9) with increasing current exposure. (
  • The medical evaluation included a health questionnaire, five neurobehavioral tests (Grooved Pegboard, Postural Sway, Trail Making, Visual Contrast Sensitivity, and Symbol Color Recode), and biological monitoring for TCAA, a metabolite of TCE. (
  • Your eye doctor might perform the test because of a specific visual complaint you have or because he or she suspects you have a condition that is affecting your ability to discern contrast. (
  • Other, more sophisticated devices also may be used to test your contrast sensitivity. (
  • If your eye doctor determines that you need a contrast sensitivity test, it likely will be administered after a standard visual acuity test and before your pupils are dilated . (
  • A new contrast sensitivity test is on the market, thanks to two New England College of Optometry faculty members. (
  • The Mayer-Kran™ Double-Happy™ Contrast Test (DH CS test), manufactured and marketed by Precision Vision is unique in that it features a simple schematic of a smiling face and is available as both a screening version and full set. (
  • The DH contrast test consists of cards printed with progressively lighter versions of the smiling face, ranging from "nearly black" to "very dim. (
  • We wanted to design a quick and effective test of contrast sensitivity for the pediatric population that could also be used with older patients, especially those who might not be able to respond to standard tests. (
  • Dr. Mayer and Dr. Kran developed the test over several years, and have been conducting clinical research regarding the use of DH contrast test with pediatric patients since 2014. (
  • It's important to test both acuity and contrast sensitivity-especially for patients at risk of cerebral visual impairment, whose acuity may not be predictive of contrast sensitivity," Dr. Kran emphasizes. (
  • Clinical Application Of A Novel Contrast Sensitivity Test To A Low Vision Population: The Quick CSF Method. (
  • In the post-operative sensitivity test, the subjects who used the product without desensitizing showed higher levels of sensitivity in different types of teeth, regardless of sex or age. (
  • Poor contrast sensitivity also can increase your risk of a fall if you fail to see that you need to step down from a curb onto similarly colored pavement. (
  • Designed by DG Pelli, JG Robson and A J Wilkins, because they see contrast sensitivity as a realistic assessment of how well the patient sees large faint objects. (
  • The aim of this study was to clinically assess the incidence of negative pulp sensitivity to cold among maxillary canines in infraocclusion submitted to orthodontic traction. (
  • We emphasize that from the teeth evaluated, the premolars showed higher sensitivity index, followed by the canines and incisors. (
  • Along with reduced TMJ functioning the patient presented with some altered cranial nerve findings related to photophobia, contrast sensitivity, and convergence insufficiency. (
  • Fourteen teeth from the experimental group showed lack of pulp sensitivity, whereas only one tooth from the control group showed negative pulp sensitivity. (
  • Tooth sensitivity or known as dentin hypersensitivity is short or transient sharp pain of a rapid onset that arises from exposed dentin layer of one or more teeth subsequent to loss of tooth structure ( enamel layer of the crown or cementum layer of the root). (
  • Areas of exposed dentin at the junction between the crown and the root (cervical area) account for much of the observed tooth sensitivity. (
  • Tooth sensitivity is defined as an experience of pain or discomfort that is sharp, sudden, piercing or excruciating in nature that is felt deep into the nerve endings. (
  • Generally tooth sensitivity is caused by receding gums and enamel damage that leads to dentinal tubules in the dentine layer to be exposed and hence sensitized. (
  • These responses are correlated with the adverse effect of tooth sensitivity, in cases with the peroxide concentration, time, frequency of of vital tooth bleaching. (
  • However, dentin it is sometimes so severe that the treatment is exposure may be a factor in tooth sensitivity as it is discontinued (KUGEL et al. (
  • This shows that sensitivity to local weather conditions varies across the early lifetime of young birds (nestling-fledgling stages) and illustrates the mechanisms by which larger scale (climate) variations influence the body condition of individuals. (
  • This estimate is significantly narrower and a bit lower than the IPCC-estimated 66% probability range for equilibrium climate sensitivity of 2 to 4.5°C for doubled atmospheric CO2, and is illustrated in Figure 1. (
  • For comparison, in their study also using the LGM to constrain climate sensitivity , Hansen and Sato (2011) used a mean surface temperature change of 5°C, consistent with the body of literature (Figure 2). (
  • Since the radiative forcing associated with doubled CO2 is 3.7 Watts per square meter (W/m2), Hansen and Sato's result implies a fast-feedback climate sensitivity of 2.8°C, which is slightly outside the Schmittner et al. (
  • our new temperature reconstruction explains a lot of the difference between our climate sensitivity estimate and previous estimates. (
  • In short, the MARGO data for the ocean show very small temperature change from the ice age to today, and thus lead to the low climate sensitivity, but they disagree with some independent estimates showing larger temperature change. (
  • Furthermore, they lead to an answer that disagrees with many other lines of evidence for climate sensitivity. (
  • First, the performance of Overflow is evaluated by carrying out sensitivity and uncertainty analyses. (
  • Principle-visual pigments bleach when exposed to an intense light source, resulting in a transient state of sensitivity loss and reduced central visual acuity. (
  • The log contrast sensitivity varies from 0.00-2.25. (
  • It is targeted at patients who cannot read or verbalize the letters or numbers on standard contrast sensitivity tests. (
  • In this category you can find all screening tests for the visual functions of the eye such as stereo vision, contrast sensitivity and color vision. (
  • Although the sensitivity of these tests may be high, their use as quantitative tools for assessment of anergy is limited. (
  • This contrast agent uses nano-droplets *2 which repeatedly change to a gaseous state and generate ultrasound pulses when irradiated by a light source. (
  • In comparison to conventional contrast agents, a high ultrasound signal representing almost a tripling of sensitivity was confirmed. (
  • By employing this nano-droplet, a strong ultrasound signal is achieved representing almost a tripling of sensitivity. (
  • With conventional contrast agents, an ultrasound signal is generated only once when the agent changes to a gaseous state. (
  • Assessment of contrast sensitivity will provide information on the degree of loss of the ability to detect materials when they are presented on low contrasting backgrounds. (
  • The following information was recorded on a standard paper collection form: 1) the presence of liver-to-kidney contrast 2) the degree of the brightness of the liver parenchyma, 3) the presence of deep beam attenuation, 4) the presence of echogenic walls in the small intrahepatic vessels, and 5) the definition of the gallbladder walls. (
  • Contrast sensitivity changes across the visual field with age and is often measured clinically with various forms of perimetry on plain backgrounds. (
  • These results suggest that the process of development and maturation of the visual perception of contrast interacts differently with the mechanisms that process spatial frequencies. (
  • Even if you have 20/20 visual acuity , you can have eye or health conditions that may diminish your contrast sensitivity and make you feel that you are not seeing well. (
  • They've had good results identifying reduced contrast sensitivity, even in children with relatively good visual acuity and full visual fields, where it might typically be missed. (
  • The earlier a patient can be accurately evaluated for contrast sensitivity and acuity, the more successful interventional strategies to accommodate their visual impairments can be. (
  • Vibration is a known aeromedical stressor in rotary-winged aircraft and is known to affect visual acuity (VA). In aerospace operational conditions, contrast sensitivity (CS) takes the upper hand over VA for optimal visual performance. (
  • Visual acuity and contrast sensitivity. (
  • Note: The Bayer in Radiology contrast and device products should be used in accordance with the Prescribing Information and Instructions For Use, respectively. (
  • In conclusion, the teeth that had been submitted to orthodontic traction were more likely to lack sensitivity than those that had not been submitted to the same procedure. (
  • The correlation of the data x teeth sensitivity were obtained separately, and tabulated for further comparative analysis. (
  • 2008). and cultural desires for `the perfect smile' and Posttreatment sensitivity is usually related consequently they often elect for invasive treatment to small microscopic enamel defects and subsurface of disease free teeth (THEOBALD et al. (
  • We realized that there was no reliable method to assess young patients who had difficulty seeing low contrast objects," Dr. Mayer says, explaining the motivation behind the test's creation. (
  • However, patients who underwent the Anwar technique showed better contrast sensitivity. (
  • Jay S. Pepose, MD, PhD, clinical professor of ophthalmology at Washington University in St. Louis, understands the desire to give patients the best possible postoperative vision and image contrast. (
  • Gadolinium-based contrast agents (GBCAs) increase the risk for NSF among patients with impaired elimination of the drugs. (
  • Injection of 64Cu-EBRGD to the patients with recurrent glioblastoma showed high accumulation at the tumor with continuously increased tumor-to-background contrast over time. (
  • Note how much contrast this scene has lost compared with the image depicting normal sight. (
  • We did not identify relationships between impaired contrast sensitivity and impaired color vision. (
  • We could not identify significant correlations between either contrast sensitivity or color vision values and the following factors: current or nadir (lowest previous) CD4+ T-lymphocyte count, HIV blood level, and Karnofsky score. (
  • Here at Paragon Eye Associates, we offer comprehensive eye exams to diagnose contrast sensitivity issues accurately. (
  • The real world, however, is full of shades of grey in which those people hampered by poor contrast sensitivity can have serious problems seeing distinct images under certain conditions. (
  • Comparison of visual sensitivity between conditions revealed three mechanisms that the visual system has adapted to compensate for peri-saccadic vision changes. (