field (fēld)
field
field,
field,
Patient discussion about fielded.
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 may be perceived as sound.
individuation field a region in which an organizer influences adjacent tissue to become a part of a total embryo.
morphogenetic field an embryonic region out of which definite structures normally develop.
visual field (F) (vf) the area within which stimuli will produce the sensation of sight with the eye in a straight-ahead position.
field
Etymology: AS, feld
1 a defined space, area, or distance. The field of vision represents the total area that can be seen with one fixed eye. The binocular field is the area that can be seen with both eyes.
2 an area within a computer record where a specified type of data is stored.
field,
n three-dimensional zone in which an array of forces interact in tangible, recognizable ways.
field,
n an area, region, or space.
field block,
n See block, field.
field, operating,
n the area immediately surrounding and directly involved in a treatment procedure (e.g., all the teeth included in a rubber dam application for the restoration of a single tooth or portions thereof).
field, radiation,
n the region in which radiant energy is being propagated.
field
1. an area or open space, such 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.
field beans
see phaseolus.
field experiments
experiments conducted on large groups of animals in conditions thought to be average for the particular type of commercial operation.
field fever
leptospirosis.
field fungi
fungi that attack plants that grow in the field. See also storage fungi.
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.
low-power field
the area of a slide visible under the low magnification system of a microscope.
morphogenetic field
an embryonic region out of which definite structures normally develop.
field nettle
see stachys arvensis.
field pea
pisumsativum.
field penny-cress
see thlaspi arvense.
field poppy
see papaverrhoeas.
sequential field trial
a trial to which additional segments are added as results are obtained in original segments, e.g. concentrating efforts on aspects of the work which appear to be promising.
field trial
see field experiments (above).
visual field
the area within which stimuli will produce the sensation of sight with the eye in a straight-ahead position.
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.
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 |
Patient discussion about fielded.
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
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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