Pieces of glass or other transparent materials used for magnification or increased visual acuity.
Lenses designed to be worn on the front surface of the eyeball. (UMDNS, 1999)
The sensory discrimination of a pattern shape or outline.
The tendency to perceive an incomplete pattern or object as complete or whole. This includes the Gestalt Law of Closure.
Soft, supple contact lenses made of plastic polymers which interact readily with water molecules. Many types are available, including continuous and extended-wear versions, which are gas-permeable and easily sterilized.
Artificial implanted lenses.
The portion of the crystalline lens surrounding the nucleus and bound anteriorly by the epithelium and posteriorly by the capsule. It contains lens fibers and amorphous, intercellular substance.
The thin noncellular outer covering of the CRYSTALLINE LENS composed mainly of COLLAGEN TYPE IV and GLYCOSAMINOGLYCANS. It is secreted by the embryonic anterior and posterior epithelium. The embryonic posterior epithelium later disappears.
An illusion of vision usually affecting spatial relations.
The core of the crystalline lens, surrounded by the cortex.
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)
A heterogeneous family of water-soluble structural proteins found in cells of the vertebrate lens. The presence of these proteins accounts for the transparency of the lens. The family is composed of four major groups, alpha, beta, gamma, and delta, and several minor groups, which are classed on the basis of size, charge, immunological properties, and vertebrate source. Alpha, beta, and delta crystallins occur in avian and reptilian lenses, while alpha, beta, and gamma crystallins occur in all other lenses.
Hydrophilic contact lenses worn for an extended period or permanently.
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.
Incomplete rupture of the zonule with the displaced lens remaining behind the pupil. In dislocation, or complete rupture, the lens is displaced forward into the anterior chamber or backward into the vitreous body. When congenital, this condition is known as ECTOPIA LENTIS.
Sterile solutions used to clean and disinfect contact lenses.
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.
Mental process to visually perceive a critical number of facts (the pattern), such as characters, shapes, displays, or designs.
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.
Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light flashes or visual patterns are used to elicit brain activity.
Awareness of oneself in relation to time, place and person.
The misinterpretation of a real external, sensory experience.
The minimum amount of stimulus energy necessary to elicit a sensory response.
Differential response to different stimuli.
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)
Area of the OCCIPITAL LOBE concerned with the processing of visual information relayed via VISUAL PATHWAYS.
The normal decreasing elasticity of the crystalline lens that leads to loss of accommodation.
A perceptual phenomenon used by Gestalt psychologists to demonstrate that events in one part of the perceptual field may affect perception in another part.
Refraction of LIGHT effected by the media of the EYE.
A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.
The real or apparent movement of objects through the visual field.
Methods developed to aid in the interpretation of ultrasound, radiographic images, etc., for diagnosis of disease.
The interference of one perceptual stimulus with another causing a decrease or lessening in perceptual effectiveness.
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.
A dimension of auditory sensation varying with cycles per second of the sound stimulus.
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.
In INFORMATION RETRIEVAL, machine-sensing or identification of visible patterns (shapes, forms, and configurations). (Harrod's Librarians' Glossary, 7th ed)
The process of generating three-dimensional images by electronic, photographic, or other methods. For example, three-dimensional images can be generated by assembling multiple tomographic images with the aid of a computer, while photographic 3-D images (HOLOGRAPHY) can be made by exposing film to the interference pattern created when two laser light sources shine on an object.
A system which emphasizes that experience and behavior contain basic patterns and relationships which cannot be reduced to simpler components; that is, the whole is greater than the sum of its parts.
The posterior aspect of the casing that surrounds the natural CRYSTALLINE LENS.
Signals for an action; that specific portion of a perceptual field or pattern of stimuli to which a subject has learned to respond.
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 technique of inputting two-dimensional images into a computer and then enhancing or analyzing the imagery into a form that is more useful to the human observer.
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.
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 ability to respond to segments of the perceptual experience rather than to the whole.
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)
A class of crystallins that provides refractive power and translucency to the lens (LENS, CRYSTALLINE) in VERTEBRATES. Beta-crystallins are similar in structure to GAMMA-CRYSTALLINS in that they both contain Greek key motifs. Beta-crystallins exist as oligomers formed from acidic (BETA-CRYSTALLIN A CHAIN) and basic (BETA-CRYSTALLIN B CHAIN) subunits.
The removal of a cataractous CRYSTALLINE LENS from the eye.
Improvement of the quality of a picture by various techniques, including computer processing, digital filtering, echocardiographic techniques, light and ultrastructural MICROSCOPY, fluorescence spectrometry and microscopy, scintigraphy, and in vitro image processing at the molecular level.
Perception of three-dimensionality.
Absence of crystalline lens totally or partially from field of vision, from any cause except after cataract extraction. Aphakia is mainly congenital or as result of LENS DISLOCATION AND SUBLUXATION.
The blending of separate images seen by each eye into one composite image.
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.
A subclass of crystallins that provides the majority of refractive power and translucency to the lens (LENS, CRYSTALLINE) in VERTEBRATES. Alpha-crystallins also act as molecular chaperones that bind to denatured proteins, keep them in solution and thereby maintain the translucency of the lens. The proteins exist as large oligomers that are formed from ALPHA-CRYSTALLIN A CHAIN and ALPHA-CRYSTALLIN B CHAIN subunits.
Computer systems or networks designed to provide radiographic interpretive information.
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.
A plant genus of the FABACEAE family known for the seeds used as food.
The anterior aspect of the casing that surrounds the natural CRYSTALLINE LENS.
The total area or space visible in a person's peripheral vision with the eye looking straightforward.
The selecting and organizing of visual stimuli based on the individual's past experience.
Sound that expresses emotion through rhythm, melody, and harmony.
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)
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.
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.
A broad family of synthetic organosiloxane polymers containing a repeating silicon-oxygen backbone with organic side groups attached via carbon-silicon bonds. Depending on their structure, they are classified as liquids, gels, and elastomers. (From Merck Index, 12th ed)
Computer-assisted mathematical calculations of beam angles, intensities of radiation, and duration of irradiation in radiotherapy.
Measurement of blood flow based on induction at one point of the circulation of a known change in the intravascular heat content of flowing blood and detection of the resultant change in temperature at a point downstream.
The difference between two images on the retina when looking at a visual stimulus. This occurs since the two retinas do not have the same view of the stimulus because of the location of our eyes. Thus the left eye does not get exactly the same view as the right eye.
A procedure for removal of the crystalline lens in cataract surgery in which an anterior capsulectomy is performed by means of a needle inserted through a small incision at the temporal limbus, allowing the lens contents to fall through the dilated pupil into the anterior chamber where they are broken up by the use of ultrasound and aspirated out of the eye through the incision. (Cline, et al., Dictionary of Visual Science, 4th ed & In Focus 1993;1(1):1)
A subclass of crystallins found in the lens (LENS, CRYSTALLINE) in BIRDS and REPTILES. They are inactive forms of the enzyme argininosuccinate lyase.
The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.
The awareness of the spatial properties of objects; includes physical space.
The failure by the observer to measure or identify a phenomenon accurately, which results in an error. Sources for this may be due to the observer's missing an abnormality, or to faulty technique resulting in incorrect test measurement, or to misinterpretation of the data. Two varieties are inter-observer variation (the amount observers vary from one another when reporting on the same material) and intra-observer variation (the amount one observer varies between observations when reporting more than once on the same material).
Cells that line the inner and outer surfaces of the body by forming cellular layers (EPITHELIUM) or masses. Epithelial cells lining the SKIN; the MOUTH; the NOSE; and the ANAL CANAL derive from ectoderm; those lining the RESPIRATORY SYSTEM and the DIGESTIVE SYSTEM derive from endoderm; others (CARDIOVASCULAR SYSTEM and LYMPHATIC SYSTEM) derive from mesoderm. Epithelial cells can be classified mainly by cell shape and function into squamous, glandular and transitional epithelial cells.
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).
The visually perceived property of objects created by absorption or reflection of specific wavelengths of light.
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 measurement of curvature and shape of the anterior surface of the cornea using techniques such as keratometry, keratoscopy, photokeratoscopy, profile photography, computer-assisted image processing and videokeratography. This measurement is often applied in the fitting of contact lenses and in diagnosing corneal diseases or corneal changes including keratoconus, which occur after keratotomy and keratoplasty.
Tomography using x-ray transmission and a computer algorithm to reconstruct the image.
A disease of the eye in which the eyelashes abnormally turn inwards toward the eyeball producing constant irritation caused by motion of the lids.
Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.
Continuation of visual impression after cessation of stimuli causing the original image.
Theoretical representations that simulate psychological processes and/or social processes. These include the use of mathematical equations, computers, and other electronic equipment.
Method of making images on a sensitized surface by exposure to light or other radiant energy.
Deviations from the average or standard indices of refraction of the eye through its dioptric or refractive apparatus.
Lack of correspondence between the way a stimulus is commonly perceived and the way an individual perceives it under given conditions.
Elements of limited time intervals, contributing to particular results or situations.
The positioning and accommodation of eyes that allows the image to be brought into place on the FOVEA CENTRALIS of each eye.
Computer-assisted interpretation and analysis of various mathematical functions related to a particular problem.
Measurement of ocular tension (INTRAOCULAR PRESSURE) with a tonometer. (Cline, et al., Dictionary of Visual Science, 4th ed)
Lenses, generally made of plastic or silicone, that are implanted into the eye in front of the natural EYE LENS, by the IRIS, to improve VISION, OCULAR. These intraocular lenses are used to supplement the natural lens instead of replacing it.
Presence of an intraocular lens after cataract extraction.
Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.
Three-dimensional representation to show anatomic structures. Models may be used in place of intact animals or organisms for teaching, practice, and study.
Digital image data sets, consisting of complete, anatomically detailed, three-dimensional representations of the normal male and female human bodies.
The acoustic aspects of speech in terms of frequency, intensity, and time.
Global conflict primarily fought on European continent, that occurred between 1914 and 1918.
Electronic hearing devices typically used for patients with normal outer and middle ear function, but defective inner ear function. In the COCHLEA, the hair cells (HAIR CELLS, VESTIBULAR) may be absent or damaged but there are residual nerve fibers. The device electrically stimulates the COCHLEAR NERVE to create sound sensation.
That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.
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 use of statistical and mathematical methods to analyze biological observations and phenomena.
A class of porins that allow the passage of WATER and other small molecules across CELL MEMBRANES.
Computer-based representation of physical systems and phenomena such as chemical processes.
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.
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.
Each of the upper and lower folds of SKIN which cover the EYE when closed.
Making measurements by the use of stereoscopic photographs.
The rhythmical expansion and contraction of an ARTERY produced by waves of pressure caused by the ejection of BLOOD from the left ventricle of the HEART as it contracts.
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.
Absence of the crystalline lens resulting from cataract extraction.
Resistance and recovery from distortion of shape.
Theory and development of COMPUTER SYSTEMS which perform tasks that normally require human intelligence. Such tasks may include speech recognition, LEARNING; VISUAL PERCEPTION; MATHEMATICAL COMPUTING; reasoning, PROBLEM SOLVING, DECISION-MAKING, and translation of language.
The basic subunit of beta-crystallins.
Computer-assisted processing of electric, ultrasonic, or electronic signals to interpret function and activity.
Methods of creating machines and devices.
The graphic registration of the frequency and intensity of sounds, such as speech, infant crying, and animal vocalizations.
The absence or restriction of the usual external sensory stimuli to which the individual responds.
A condition of an inequality of refractive power of the two eyes.
Theoretical representations that simulate the behavior or activity of systems, processes, or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.
Images seen by one eye.
Polymers of silicone that are formed by crosslinking and treatment with amorphous silica to increase strength. They have properties similar to vulcanized natural rubber, in that they stretch under tension, retract rapidly, and fully recover to their original dimensions upon release. They are used in the encapsulation of surgical membranes and implants.
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.
The most anterior portion of the uveal layer, separating the anterior chamber from the posterior. It consists of two layers - the stroma and the pigmented epithelium. Color of the iris depends on the amount of melanin in the stroma on reflection from the pigmented epithelium.
The process of pictorial communication, between human and computers, in which the computer input and output have the form of charts, drawings, or other appropriate pictorial representation.
The making of a continuous circular tear in the anterior capsule during cataract surgery in order to allow expression or phacoemulsification of the nucleus of the lens. (Dorland, 28th ed)
Computer systems or programs used in accurate computations for providing radiation dosage treatment to patients.
Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.
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)
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
The process in which light signals are transformed by the PHOTORECEPTOR CELLS into electrical signals which can then be transmitted to the brain.
Methods and procedures for the diagnosis of diseases of the eye or of vision disorders.
Inflammation of the cornea.
The functional superiority and preferential use of one eye over the other. The term is usually applied to superiority in sighting (VISUAL PERCEPTION) or motor task but not difference in VISUAL ACUITY or dysfunction of one of the eyes. Ocular dominance can be modified by visual input and NEUROTROPHIC FACTORS.
The electric response evoked in the cerebral cortex by visual stimulation or stimulation of the visual pathways.
The fitting and adjusting of artificial parts of the body. (From Stedman's, 26th ed)
Patterns (real or mathematical) which look similar at different scales, for example the network of airways in the lung which shows similar branching patterns at progressively higher magnifications. Natural fractals are self-similar across a finite range of scales while mathematical fractals are the same across an infinite range. Many natural, including biological, structures are fractal (or fractal-like). Fractals are related to "chaos" (see NONLINEAR DYNAMICS) in that chaotic processes can produce fractal structures in nature, and appropriate representations of chaotic processes usually reveal self-similarity over time.
An excessive amount of fluid in the cornea due to damage of the epithelium or endothelium causing decreased visual acuity.
A series of tests used to assess various functions of the eyes.
Processes and properties of the EYE as a whole or of any of its parts.
One or more layers of EPITHELIAL CELLS, supported by the basal lamina, which covers the inner or outer surfaces of the body.
Procedures for correcting HEARING DISORDERS.
The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.
Devices or objects in various imaging techniques used to visualize or enhance visualization by simulating conditions encountered in the procedure. Phantoms are used very often in procedures employing or measuring x-irradiation or radioactive material to evaluate performance. Phantoms often have properties similar to human tissue. Water demonstrates absorbing properties similar to normal tissue, hence water-filled phantoms are used to map radiation levels. Phantoms are used also as teaching aids to simulate real conditions with x-ray or ultrasonic machines. (From Iturralde, Dictionary and Handbook of Nuclear Medicine and Clinical Imaging, 1990)
A type of scanning probe microscopy in which a probe systematically rides across the surface of a sample being scanned in a raster pattern. The vertical position is recorded as a spring attached to the probe rises and falls in response to peaks and valleys on the surface. These deflections produce a topographic map of the sample.
Maf proto-oncogene protein is the major cellular homolog of the V-MAF ONCOGENE PROTEIN. It was the first of the mammalian MAF TRANSCRIPTION FACTORS identified, and it is induced in activated T-LYMPHOCYTES and regulates GENETIC TRANSCRIPTION of INTERLEUKIN-4. c-maf is frequently translocated to an immunoglobulin locus in MULTIPLE MYELOMA.
A family of transcription factors that control EMBRYONIC DEVELOPMENT within a variety of cell lineages. They are characterized by a highly conserved paired DNA-binding domain that was first identified in DROSOPHILA segmentation genes.
The front third of the eyeball that includes the structures between the front surface of the cornea and the front of the VITREOUS BODY.
The fluid secreted by the lacrimal glands. This fluid moistens the CONJUNCTIVA and CORNEA.
Posterior portion of the CEREBRAL HEMISPHERES responsible for processing visual sensory information. It is located posterior to the parieto-occipital sulcus and extends to the preoccipital notch.
A giant elastic protein of molecular mass ranging from 2,993 kDa (cardiac), 3,300 kDa (psoas), to 3,700 kDa (soleus) having a kinase domain. The amino- terminal is involved in a Z line binding, and the carboxy-terminal region is bound to the myosin filament with an overlap between the counter-connectin filaments at the M line.
Voluntary or reflex-controlled movements of the eye.
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.
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 perceived attribute of a sound which corresponds to the physical attribute of intensity.
The transparent, semigelatinous substance that fills the cavity behind the CRYSTALLINE LENS of the EYE and in front of the RETINA. It is contained in a thin hyaloid membrane and forms about four fifths of the optic globe.
One of the alpha crystallin subunits. In addition to being expressed in the lens (LENS, CRYSTALLINE), alpha-crystallin B chain has been found in a variety of tissues such as HEART; BRAIN; MUSCLE; and KIDNEY. Accumulation of the protein in the brain is associated with NEURODEGENERATIVE DISEASES such as CREUTZFELDT-JAKOB SYNDROME and ALEXANDER DISEASE.
The continuous measurement of physiological processes, blood pressure, heart rate, renal output, reflexes, respiration, etc., in a patient or experimental animal; includes pharmacologic monitoring, the measurement of administered drugs or their metabolites in the blood, tissues, or urine.
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)
Congenital or developmental anomaly in which the eyeballs are abnormally small.
Microscopy in which the object is examined directly by an electron beam scanning the specimen point-by-point. The image is constructed by detecting the products of specimen interactions that are projected above the plane of the sample, such as backscattered electrons. Although SCANNING TRANSMISSION ELECTRON MICROSCOPY also scans the specimen point by point with the electron beam, the image is constructed by detecting the electrons, or their interaction products that are transmitted through the sample plane, so that is a form of TRANSMISSION ELECTRON MICROSCOPY.
Controlled operation of an apparatus, process, or system by mechanical or electronic devices that take the place of human organs of observation, effort, and decision. (From Webster's Collegiate Dictionary, 1993)
The volume of BLOOD passing through the HEART per unit of time. It is usually expressed as liters (volume) per minute so as not to be confused with STROKE VOLUME (volume per beat).
A family of Urodela consisting of 15 living genera and about 42 species and occurring in North America, Europe, Asia, and North Africa.
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.)
Imaging techniques used to colocalize sites of brain functions or physiological activity with brain structures.
A group of homologous proteins which form the intermembrane channels of GAP JUNCTIONS. The connexins are the products of an identified gene family which has both highly conserved and highly divergent regions. The variety contributes to the wide range of functional properties of gap junctions.
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)
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.
Physical motion, i.e., a change in position of a body or subject as a result of an external force. It is distinguished from MOVEMENT, a process resulting from biological activity.
Imaging methods that result in sharp images of objects located on a chosen plane and blurred images located above or below the plane.
A ring of tissue extending from the scleral spur to the ora serrata of the RETINA. It consists of the uveal portion and the epithelial portion. The ciliary muscle is in the uveal portion and the ciliary processes are in the epithelial portion.
A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.
The acidic subunit of beta-crystallins.
The pressure of the fluids in the eye.
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.
Analysis based on the mathematical function first formulated by Jean-Baptiste-Joseph Fourier in 1807. The function, known as the Fourier transform, describes the sinusoidal pattern of any fluctuating pattern in the physical world in terms of its amplitude and its phase. It has broad applications in biomedicine, e.g., analysis of the x-ray crystallography data pivotal in identifying the double helical nature of DNA and in analysis of other molecules, including viruses, and the modified back-projection algorithm universally used in computerized tomography imaging, etc. (From Segen, The Dictionary of Modern Medicine, 1992)
Examination of the interior of the eye with an ophthalmoscope.
The properties, processes, and behavior of biological systems under the action of mechanical forces.
Combination or superimposition of two images for demonstrating differences between them (e.g., radiograph with contrast vs. one without, radionuclide images using different radionuclides, radiograph vs. radionuclide image) and in the preparation of audiovisual materials (e.g., offsetting identical images, coloring of vessels in angiograms).
Infection of the cornea by an ameboid protozoan which may cause corneal ulceration leading to blindness.
Loss of epithelial tissue from the surface of the cornea due to progressive erosion and necrosis of the tissue; usually caused by bacterial, fungal, or viral infection.
Diseases of the cornea.
Fractures of the zygoma.
The ability to differentiate tones.
Computed tomography modalities which use a cone or pyramid-shaped beam of radiation.
The developmental entity of a fertilized chicken egg (ZYGOTE). The developmental process begins about 24 h before the egg is laid at the BLASTODISC, a small whitish spot on the surface of the EGG YOLK. After 21 days of incubation, the embryo is fully developed before hatching.
A form of fluorescent antibody technique commonly used to detect serum antibodies and immune complexes in tissues and microorganisms in specimens from patients with infectious diseases. The technique involves formation of an antigen-antibody complex which is labeled with fluorescein-conjugated anti-immunoglobulin antibody. (From Bennington, Saunders Dictionary & Encyclopedia of Laboratory Medicine and Technology, 1984)
Procedure of producing an imprint or negative likeness of the teeth and/or edentulous areas. Impressions are made in plastic material which becomes hardened or set while in contact with the tissue. They are later filled with plaster of Paris or artificial stone to produce a facsimile of the oral structures present. Impressions may be made of a full complement of teeth, of areas where some teeth have been removed, or in a mouth from which all teeth have been extracted. (Illustrated Dictionary of Dentistry, 1982)
The process whereby an utterance is decoded into a representation in terms of linguistic units (sequences of phonetic segments which combine to form lexical and grammatical morphemes).
Plastic surgery performed, usually by excision of skin, for the elimination of wrinkles from the skin.
An enzyme that catalyzes reversibly the oxidation of an aldose to an alditol. It possesses broad specificity for many aldoses. EC
A light microscopic technique in which only a small spot is illuminated and observed at a time. An image is constructed through point-by-point scanning of the field in this manner. Light sources may be conventional or laser, and fluorescence or transmitted observations are possible.
Organs which might be damaged during exposure to a toxin or to some form of therapy. It most frequently refers to healthy organs located in the radiation field during radiation therapy.
The analysis of a critical number of sensory stimuli or facts (the pattern) by physiological processes such as vision (PATTERN RECOGNITION, VISUAL), touch, or hearing.
Detachment of the corpus vitreum (VITREOUS BODY) from its normal attachments, especially the retina, due to shrinkage from degenerative or inflammatory conditions, trauma, myopia, or senility.
The time from the onset of a stimulus until a response is observed.
A technique for maintenance or growth of animal organs in vitro. It refers to three-dimensional cultures of undisaggregated tissue retaining some or all of the histological features of the tissue in vivo. (Freshney, Culture of Animal Cells, 3d ed, p1)
Improvement in the quality of an x-ray image by use of an intensifying screen, tube, or filter and by optimum exposure techniques. Digital processing methods are often employed.
A network of cross-linked hydrophilic macromolecules used in biomedical applications.
For older people with normal color vision, the crystalline lens may become slightly yellow due to cataracts, which moves the ... the image sensor equivalent A-weighting and equal-loudness contour, related sound concepts Charles A. Poynton (2003). Digital ...
The contours in the ACT run NW-SE. At the Canberra GPO is about −440, at Scriviner Dam −510, at Lake Tuggeranong Dam −600, and ... It is coarsely crystalline and pale in comparison to other granites.[citation needed] Muscovite occurs in unweathered rock. ... There is a limestone lens north of Uriarra Crossing. The outcrop goes from Mountain Creek Road in the west to the Murrumbidgee ... The contours run North east. Each year it shifts 2.2 minutes to the east. Magnetic field in all three components is measured ...
... structure of boron-rich metal borides Crystal structure prediction Crystal system Crystal twinning Crystalline Crystalline ... Ceiling level Celestial spheres Celor lens Centauro event Center-of-momentum frame Center for Integrated Plasma Studies Center ... Gaussian Contemporary Physics Contiguity Continuity equation Continuous wave Continuum mechanics Contorsion tensor Contour line ... Collective excitations Collider Collider Detector at Fermilab Colligative properties Collimated light Collimating lens ...
In a typical system, illumination is provided by a diffuse source set at the focal plane of a collimating lens. A focusing lens ... one cannot tell the difference between contour lines indicating a peak versus contour lines indicating a trough. To resolve the ... Two optical resonators constructed from crystalline sapphire, controlling the frequencies of two lasers, were set at right ... A convex spherical mirror is positioned so that its center of curvature coincides with the focus of the lens being tested. The ...
The cornea and lens act together as a compound lens to project an inverted image onto the retina. The retina consists of a ... V2 serves much the same function as V1, however, it also handles illusory contours, determining depth by comparing left and ... The armored shell of the chiton Acanthopleura granulata is also covered with hundreds of aragonite crystalline eyes, named ... The eye's lens becomes too inflexible to accommodate to normal reading distance, focus tending to remain fixed at long distance ...
In PED, the probe size is limited by the lens aberrations and sample thickness. With a typical value for spherical aberration, ... Put simply, in a crystalline solid, the probability of interaction between an electron and ion in the lattice depends strongly ... This includes a reduction in thickness fringes, bend contours, and strain fields. While these features can often provide useful ... Because many dynamical contrast effects are highly sensitive to the orientation of the crystalline sample with respect to the ...
These devices, known as pilot beams or pilot lasers (if a laser is used) help guide the adjustments made to the lens of the ... The aim is to form sharp relief images with steep first relief and contoured shoulder supported edges to give a high-standard ... Pores in the surface expose natural grains and crystalline "stubs" which, when heated very quickly, can separate a microscopic ... At the point of engraving, the laser beam is focused through a lens at the engraving surface, allowing very precise and ...
ISBN 0-691-00659-8. Maddison, Angus (2007), Contours of the World Economy, 1-2030 AD: Essays in Macro-Economic History, p. 55, ... Because Rome was located on a volcanic peninsula, with sand which contained suitable crystalline grains, the concrete which the ... American Ceramic Society, Kingery, W. D., & Lense, E. (1985). Ancient technology to modern science. Ceramics and civilization, ...
It then passes through the pupil (controlled by the iris) and is further refracted by the lens. The cornea and lens act ... V2 serves much the same function as V1, however, it also handles illusory contours, determining depth by comparing left and ... The armored shell of the chiton Acanthopleura granulata is also covered with hundreds of aragonite crystalline eyes, named ... Together the cornea and lens refract light into a small image and shine it on the retina. The retina transduces this image into ...
... which is caused by the eye's crystalline lens losing elasticity, progressively reducing the ability of the lens to accommodate ... Skull temples: bend down behind the ears, follow the contour of the skull and rest evenly against the skull Library temples: ... Corrective lenses can be produced in many different shapes from a circular lens called a lens blank. Lens blanks are cut to fit ... "BluTech Lenses - Technology, The story behind BluTech Lenses". BluTech Lenses. Vimont, Celia (27 April 2017). "Are Computer ...
The eye changes focus by shifting the position of the entire lens with respect to the retina, instead of reshaping the lens as ... The deimatic display (a rapid change to black and white with dark 'eyespots' and contour, and spreading of the body and fins) ... They reflect light using plates of crystalline chemochromes made from guanine. When illuminated, they reflect iridescent colors ... Leucophores, usually located deeper in the skin than iridophores, are also structural reflectors using crystalline purines, ...
... because the microwave heating denatures proteins in the crystalline lens of the eye (in the same way that heat turns egg whites ... they do not travel as ground waves which follow the contour of the Earth, or reflect off the ionosphere (skywaves). Although at ... lens antenna, slot antenna, and phased array. The ability of short waves to quickly heat materials and cook food had been ... using quasioptical components such as prisms and lenses made of paraffin, sulfur and pitch and wire diffraction gratings, to ...
Since the beam out of the end of the fiber diverges rapidly, lenses are used to create a suitable spot size on the workpiece at ... usually resulting in a brittle cold solder joint with a crystalline appearance. ... and non-metallic fillers for contouring. ...
Contour and down feathers are generally identified as the main targets, although in some cases, tail and flight feathers are ... The nictitating membrane also covers the eye and acts as a contact lens in many aquatic birds. With the exception of pigeons ... without which the crystalline structure would be too brittle to keep its form; the organic matrix is thought to have a role in ... pennaceous feather Also, contour feather. A type of feather present in most modern birds and in some other species of ...
ISBN 978-90-04-11123-3. Maddison, Angus (2007), Contours of the World Economy, 1-2030 AD: Essays in Macro-Economic History, p. ... Because Rome was located on a volcanic peninsula, with sand which contained suitable crystalline grains, the concrete which the ... for a course on the history of technology through a Thomas Kuhn-ian lens. Concept of Civilization Events. From Jaroslaw Kessler ...
Crystalline. lattice, 4 2D. Vona & Rus, (Dartmouth). 1999. I-Cube. lattice, 3D. Unsal, (CMU). 1999. ... Bionic contact lens. *Head-mounted display. *Head-up display. *Optical head-mounted display ...
... photodetectors (QDPs) can be fabricated either via solution-processing,[74] or from conventional single-crystalline ... Bionic contact lens. *Head-mounted display. *Head-up display. *Optical head-mounted display ... it is known that liquid crystalline structures of wild-type viruses (Fd, M13, and TMV) are adjustable by controlling the ... semiconductors.[75] Conventional single-crystalline semiconductor QDPs are precluded from integration with flexible organic ...
For older people with normal color vision, the crystalline lens may become slightly yellow due to cataracts, which moves the ... the image sensor equivalent A-weighting and equal-loudness contour, related sound concepts Charles A. Poynton (2003). Digital ...
The contours in the ACT run NW-SE. At the Canberra GPO is about −440, at Scriviner Dam −510, at Lake Tuggeranong Dam −600, and ... It is coarsely crystalline and pale in comparison to other granites.[citation needed] Muscovite occurs in unweathered rock. ... There is a limestone lens north of Uriarra Crossing. The outcrop goes from Mountain Creek Road in the west to the Murrumbidgee ... The contours run North east. Each year it shifts 2.2 minutes to the east. Magnetic field in all three components is measured ...
In addition, the crystalline lens is futilely attempting to focus on the blurred contours, which results in the throbbing ...
Professional Soft Flat Blush Foudation Liquid Makeup Brush Head Contour Cosmetic posted by subsed ... Womens Laser Cut Round Metal Mirror Lens Sunglasses A102 posted by avaloncraven ...
Cataracts of the eye can be defined as any opacity of the crystalline lens in which congenital cataract is especially important ... This contour of the optic cup progresses until it is quite noticeable in stage 16, small grooves can also be seen above and ... Abnormal Lens Development. Overview of Normal Lens Development As stated above, the lens originates from the ectoderm on top of ... The lens pit then detatches after deepening further and becomes the lens vesicle. From here the cells of the lens differentiate ...