field
[fēld] 1. an area or open space, as an operative field or visual field.
2. a range of specialization in knowledge, study, or occupation.
3. in embryology, the developing region within a range of modifying factors.
auditory field the space or range within which stimuli will be perceived as sound.
disturbed energy field a nursing diagnosis defined as a disruption of the flow of energy surrounding a person's being that results in disharmony of the body, mind, and/or spirit.
energy field the flow of energy surrounding a person.
high-power field the area of a slide visible under the high magnification system of a microscope.
individuation field a region in which an organizer influences adjacent tissue to become a part of a total embryo.
inverted Y field in
radiation therapy, such as for
malignant lymphoma, a circumscribed area of irradiation below the diaphragm, covering the spleen, extending down the midline, and branching inferiorly to form tails across the inguinal areas.
low-power field the area of a slide visible under the low magnification system of a microscope.
magnetic field that portion of space about a
magnet in which its action is perceptible.
morphogenetic field an embryonic region out of which definite structures normally develop.
operating field (
operative field) an isolated area where surgery is performed; it must be kept sterile by aseptic techniques (see
surgical asepsis). Called also
surgical field.
sterile field an
operative field that is properly sterile according to
surgical asepsis. It includes having all furniture and equipment covered with sterile drapes and all personnel being properly attired.
visual field (F) (vf) the area within which stimuli will produce the sensation of sight with the eye in a straight-ahead position.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
field
(feld) 1. An open expanse of land.
2. A discipline or an area of study.
3. A region of space in which a given force operates or a given condition exists.
4. A place of natural conditions, as opposed to a controlled environment, such as a laboratory or a hospital.
auditory field
The spatial region in which a given person can hear sounds.
cortical field
A segment of the cerebral cortex that carries out a given function. For example, the front of the parietal lobe -- the postcentral gyrus -- can be called a primary somatosensory field, and the parietal cortex farther back can be called an association field.
dry field
A colloquial term for a bloodless surgical field in which the surgeon's vision is not obscured.
electric field
The region in space in which the attractive or repulsive effects of a given electric charge have an effect.
electromagnetic field
Abbreviation: EMF
The region in space in which the photons produced by moving electric charges have an effect. EMFs can be produced by power lines, radio waves, and microwaves. The energy produced in an EMF increases as the frequency of the photons increases, and EMFs produced by very high frequency photons (e.g., xrays and gamma rays) are sufficiently energetic to induce cancer.
eye field
Any region of the cortex concerned with sensation from or movement of an eye.
field of fixation
The widest limits of vision in all directions within which the eyes can fixate.
field of Forel
One the layers of axons -- many originating in the globus pallidus -- that form the lower (inferior) border of the thalamus in the brain. Together, the axons and neighboring neuronss are called the subthalamic reticular nucleus.
Synonym: Forel's field, prerubral field free field
A space in which there are no surfaces that reflect specific frequencies of sound.
gradient-induced electric field
An electric field that may surround an object placed in a rapidly changing magnetic environment, such as one generated by a magnetic resonance imaging device.
gravitational field
The region in space in which the attractive effects of a given mass have an effect.
hand field
Any region of the cortex concerned with sensation from or movement of a hand.
heart field
The region of the embryo destined to produce the heart.
high-power field
The portion of an object seen when the high-magnification lenses of a microscope are used.
hippocampal field
Any of the three contiguous, but histologically distinguishable, sheets of cells that form the cortex of the hippocampus; the fields are usually called CA1, CA2, and CA3.
low-power field
The portion of an object seen when the low-magnification lenses of a microscope are used.
lung field
The region in the body containing a lung. Often, 'lung field' refers to the section of a medical image (e.g., chest xray) that shows a lung.
magnetic field
The space permeated by the magnetic lines of force surrounding a permanent magnet or coil of wire carrying electric current.
prerubral field
Field of Forel.
pulsing electromagnetic field
Abbreviation: PEMF
An alternating electrical current used to produce an electromagnetic field. This may induce healing when applied to a fractured bone. The field is applied noninvasively to the affected limb. It may be moderately helpful in treating bony nonunion. See:
diathermyreceptive field
A description of the effective stimuli of a given neuron. For sensory receptor neurons, the receptive field is the type of effective stimulation (e.g., light, sound, mechanical pressure) and the range of sensitive locations (e.g., center of visual field, left auditory field, tip of right thumb).
sterile field
A body surface, along with surrounding drapes or towels, within which an operation may safely take place without introducing potentially hazardous microorganisms into a patient.
Patient care
The field is prepared by meticulously washing and scrubbing the patient on whom an operation will be performed with disinfectant solution. Sterile drapes and towels are placed over the patient to cover any unprepared skin or clothing with sterilized fabric. All surgical instruments that enter the operative theatre are cleansed according to decontamination and sterilization practices. Finally, all surgical personnel scrub for prescribed time periods with disinfectants before entering the operating room. They must wear sterile gloves, gowns, masks and shoe covers and replace these if any of them contact nonprepared items during surgery.
surgical field
The area in which an operation is performed. This field is prepared and covered to maintain sterility during operations.
useful field of view
Abbreviation: UFOV
A test of visual attention that measures the space in which an individual can receive information rapidly from two separate sources. It is a strong predictor of accidents in older drivers. Training can expand the useful field of view and increase the visual processing speed of an elderly person.
field of vision
Visual field.


VISUAL FIELD
visual field
The area within which objects may be seen when the eye is fixed.
Synonym: field of vision See: illustration; perimetryMedical Dictionary, © 2009 Farlex and Partners
field
A limited area.
binocular visual field An approximately circular zone of radius about 60º centred on the point of fixation (slightly larger in the lower part of the field) in which an object stimulates both retinas simultaneously. Beyond that area on each side, the visual field is monocular.
See visual field.
field of excursion See field of fixation.
field of fixation The area in space over which an eye can fixate when the head remains stationary. The field of fixation is smaller than the field of vision. It extends to approximately 47º temporally, 45º nasally, 43º upward and 50º downward.
Syn. field of excursion; motor field.
See apparent field of view;
real field of view;
visual field.
field glasses See binoculars.
keyhole visual field A term used to describe a visual field defect in which there is a bilateral homonymous hemianopia with macular sparing. An occipital lobe lesion sparing the posterior tips of the occipital lobe usually causes this lesion.
field lens See eyepiece.
motor field See field of fixation.
receptive field The retinal area within which a light stimulus can produce a potential difference in a single cell. Retinal ganglion receptive fields are circular, often with a response different in the centre than in the periphery (also referred to as on-centre/off-centre or centre/surround organization). Ganglion cell receptive fields are very small in the macular region and large in the periphery of the retina. Receptive fields also exist in the lateral geniculate bodies where they are similar to those of the retina. In the visual cortex they have various shapes and sizes and may only respond to either a vertical bar or a black dot moving in a given direction and at a given speed, etc. Receptive fields reflect the interaction between excitation and inhibition between neighbouring neurons. The term can also describe the region of space that induces these neural responses (Fig. F2).
See complex cell;
hypercomplex cell;
simple cell;
lateral inhibition;
summation.
field stop See diaphragm.
surrounding field That area of the field of view surrounding any object.
field of view The extent of an object plane seen through an optical instrument.
field of view, apparent Angle subtended by the exit port of a sighting instrument or an empty frame aperture at the centre of the entrance pupil of the eye.
Syn. apparent peripheral field of view.
Note: when referring to the apparent field of fixation, the reference point is the centre of rotation of the eye.
Syn. apparent macular field of view (Fig. F3).
See field of fixation.
field of view, real Angle subtended by the effective diameter of a lens at the point conjugate with the centre of the entrance pupil of the eye.
Syn. real peripheral field of view; true field of view.
Note: when referring to the real field of fixation, the reference point is the centre of rotation of the eye.
Syn. real macular field of view (Fig. F3).
See jack-in-the-box phenomenon.
field of vision See visual field.
visual field (VF) The extent of space in which objects are visible to an eye in a given position. The extent of the visual field tends to diminish with age. The visual field can be measured either monocularly or binocularly. In the horizontal plane meridian the visual field extends to nearly 190º with both eyes open, the area seen binocularly, that is the region where both eyes can see the simulus is about 120º, and the area seen by one eye only is about 154º.
Syn. field of vision.
See binocular visual field;
kinetic perimetry;
static perimetry;
confrontation test;
island of vision.
visual field expander An optical system designed to enlarge the field of vision. The most common types are
reverse telescopes (e.g. looking through the objective of a galilean telescope), which minify objects being viewed but present more information by means of the enlarged visual field. They are usually of low power because of the reduction in visual acuity induced by the minification of the image. Prisms can also be used to expand the visual field. These systems are used mainly to improve mobility in patients with glaucoma and retinitis pigmentosa who have constricted visual fields or tunnel vision.


Fig. F2 Typical responses from receptive fields of retinal ganglion cells to a spot of light shone on the area indicated by the bars in each type of receptive field. 'on'-centre cells respond best when stimulated in the central part of the field. 'off'-centre cells respond best when stimulated in the surround of the field


Fig. F3 Apparent and real field of view seen through A, a converging lens, and B, a diverging lens, placed in a diaphragm. The apparent field of view is decreased by the converging lens and increased by the diverging lens (E, centre of the entrance pupil; E′, its image formed by the lens)
Table F2 Average extent of the normal visual field (in degrees) of one eye of a young adult looking in the straight-ahead position, and measured with a white target subtending 1.0º under normal room illumination |
temporally | 94º |
down and temporally | 88º |
down | 70º |
down and nasally | 54º |
nasally | 60º |
up and nasally | 56º |
up | 54º |
up and temporally | 64º |
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann
Patient discussion about field
Q. is there like a big break through in the field of autism therapy and approaching?
A. there is a large amount of research on Autism. Social, neurological, psychiatric etc. today because of new imagine equipment there is better understanding of how our brain works (there are much more to be revealed but still). And there are breakthroughs all the time. You can get updated about research on the subject in this site:
http://www.autism-society.org/site/PageServer?pagename=research_home
Q. My mother works in the medical field. I don’t want to discuss with my parents.I would appreciate your answer. I have some of the symptoms of ADHD for the past recent months. I am aware of the symptoms and now I feel the symptoms in me. People only notice these things as funny little quirks but this affects me severely. My mother works in the medical field. I don’t want to discuss with my parents. I would appreciate your answer.
A. You are not making use of your mother’s help at the right time. I shall suggest you to discuss your problem with your mom. She can offer you the right support and guidance. I doubt whether she possess experience in the area of your problem. But it is wise to discuss this to your parents. This may also be the reason for you having developed the symptoms of ADHD (not being social). Feel free to discuss with your parents.
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