cone of light


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cone

 [kōn]
1. a solid figure or body having a circular base and tapering to a point.
2. one of the conelike structures which, with the rods, form the light-sensitive elements of the retina; the cones make possible the perception of color. See also eye and vision. Called also retinal cone.
3. in radiology, a conical or open-ended cylindrical structure formerly used as an aid in centering the radiation beam and as a guide to source-to-film distance. Cones were commonly attached to the x-ray tube prior to the use of the collimator.
4. in root canal therapy, a solid substance with a tapered form, usually made of gutta-percha or silver, fashioned to conform to the shape of a root canal.
ether cone a cone-shaped device used over the face in administration of ether for anesthesia.
gutta-percha cone in root canal therapy, a plastic radiopaque cone made from gutta-percha and other ingredients, available in standard sizes according to the dimensions of root canal reamers and files; used to fill and seal the canal along with sealer cements. Called also gutta-percha point.
cone of light the triangular reflection of light seen on the tympanic membrane.
pressure cone the area of compression exerted by a mass in the brain, as in transtentorial herniation.
retinal cone cone (def. 2).
silver cone silver point.

light re·flex

1. Synonym(s): pupillary reflex
2. a red glow reflected from the fundus of the eye when a light is cast on the retina, as in retinoscopy; Synonym(s): eye reflex, fundus reflex
3. a triangular area at the anterior inferior part of the tympanic membrane, extending from the umbo to the periphery, where there is seen a reflection of light. Synonym(s): cone of light, Politzer luminous cone, pyramid of light, red reflex, Wilde triangle

cone of light,

1 a triangular reflection observed during an ear examination when the light of an otoscope is focused on the image of the malleus.
2 the group of light rays entering the pupil of the eye and forming an image on the retina.

red re·flex

(red rē'fleks)
Term describing reflection of light from retina in healthy eyes; abnormality in ocular media, refractive state, or retina can cause this reflex to be abnormal.
Synonym(s): cone of light, light reflex (3) , pyramid of light.

cone

1. a solid figure or body having a circular base and tapering to a point, especially one of the conelike structures of the retina, which, with the retinal rods, form the light-sensitive elements of the retina. The cones make possible the perception of color.
2. in radiology, a conical or open-ended cylindrical structure used as an aid in producing high detail x-rays.
3. surgical cone.

cone cells (1)
the commonest, if not the sole, photoreceptors in the central area of the retina, where the function of acute vision is located. See also cone (1) above.
cone down
in radiology, to restrict the x-ray beam. See also collimation.
cone dysplasia (1)
progressive dysplasia of retinal cones in Alaskan malamute dogs; causes impaired day vision from an early age. The rods are normal.
ether cone
a cone-shaped device used over the face in administration of ether for anesthesia.
cone flower
cone of light
the triangular reflection of light seen on the tympanic membrane.
pressure cone
the area of compression exerted by a mass in the brain, as in transtentorial herniation.
retinal c's
see cone (1) above.
cone shellfish
see conus.
References in periodicals archive ?
Linazasoro's cone of light makes a dignified and appropriate heart for the scholarly powerhouse of the university.
While our tests did reveal that the spotlight has a slightly more concentrated overall illumination pattern, the cone of light emerging from the bulb, measured at diameters of equal brightness, is only 12 percent smaller than that of the floodlight.
To understand this you need to know that NA is a measure of the angle of the cone of light entering the objective.
Consider, for example, an etalon placed between a telescope's objective and eyepiece, where the angle of the cone of light passing through it varies with the objective's f/ratio.
Numerical aperture (NA) is the collection angle or cone of light that an objective can accept from an object point; it is strongly influenced by the refractive index of the medium between the specimen and the objective lens.
One person put their hand into this sharp cone of light, and as the hand went in, the other people made sounds - a higher- or lower-pitched sound in response to what the hand was doing.
Optical basics Numerical aperture (NA) is the collection angle or cone of light that an objective can accept from an object point; it is strongly influenced by the refractive index of the medium between the specimen and the objective lens.
Its index of refraction is not uniform but increases away from the long axis, making it very convenient for generating a divergent cone of light.
The larger the numerical aperture, the larger the cone of light the fiber handles.
As all the telescope-making books explain, offsetting the diagonal enables it to send a full cone of light to the eyepiece.