| Bjerrum screen | A flat, usually black surface used to measure the central 30 degrees of the field of vision. Synonym: Bjerrum screen. (05 Mar 2000) |
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| Bjerrum, Jannik | <person> Danish ophthalmologist, 1851-1926. See: Bjerrum's scotoma, Bjerrum screen, Bjerrum's sign. (05 Mar 2000) |
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| Bjerrum's scotoma | A comet-shaped scotoma, occurring in glaucoma, attached at the temporal end to the blind spot or separated from it by a narrow gap; the defect widens as it extends above and nasally curves around the fixation spot, and then extends downward to end exactly at the nasal horizontal meridian. Synonym: Bjerrum's sign, sickle scotoma. (05 Mar 2000) |
| Bjerrum's sign | A comet-shaped scotoma, occurring in glaucoma, attached at the temporal end to the blind spot or separated from it by a narrow gap; the defect widens as it extends above and nasally curves around the fixation spot, and then extends downward to end exactly at the nasal horizontal meridian. Synonym: Bjerrum's sign, sickle scotoma. (05 Mar 2000) |
| bar screen | A screen made of parallel bars set 3/4" to 2" apart used to filter out large objects. (05 Dec 1998) |
| rare-earth screen | An intensifying screen made of a rare-earth oxide phosphor, more efficient than calcium tungstate, especially at the higher kilovoltages used in modern radiography. (05 Mar 2000) |
| vestibular screen | A screen made of acrylic resin that covers the labial or buccal surfaces of one or both dental arches; used to treat oral habits and to stimulate tooth movement by using perioral muscle force. (05 Mar 2000) |
| Hess screen | A screen used in the measurement of ocular deviation. (05 Mar 2000) |
| screen | 1. To provide with a shelter or means of concealment; to separate or cut off from inconvience, injury, or danger; to shelter; to protect; to protect by hiding; to conceal; as, fruits screened from cold winds by a forest or hill. "They were encouraged and screened by some who were in high comands." (Macaulay) 2. To pass, as coal, gravel, ashes, etc, through a screen in order to separate the coarse from the fine, or the worthless from the valuable; to sift. 3. To examine a group of objects methodically, to separate them into groups or to select one or more for some purpose. As (a), To inspect the qualifications of candidates for a job, to select one or more to be hired. (b) (Biochem, Med) To test a large number of samples, in order to find those having specific desirable properties; as, to screen plant extracts for anticancer agents. Origin: Screened; Screening. 1. Anything that separates or cuts off inconvience, injury, or danger; that which shelters or conceals from view; a shield or protection; as, a fire screen. "Your leavy screens throw down." (Shak) "Some ambitious men seem as screens to princes in matters of danger and envy." (Bacon) 2. A dwarf wall or partition carried up to a certain height for separation and protection, as in a church, to separate the aisle from the choir, or the like. 3. A surface, as that afforded by a curtain, sheet, wall, etc, upon which an image, as a picture, is thrown by a magic lantern, solar microscope, etc. 4. A long, coarse riddle or sieve, sometimes a revolving perforated cylinder, used to separate the coarser from the finer parts, as of coal, sand, gravel, and the like. 5. A netting, usu. Of metal, contained in a frame, used mostly in windows or doors to allow in fresh air while excluding insects. Screen door, a door of which half or more is composed of a screen. Screen window, a screen fitted for insertion into a window frame. 6. The surface of an electronic device, as a television set or computer monitor, on which a visible image is formed. The screen is frequently the surface of a cathode-ray tube containing phosphors excited by the electron beam, but other methods for causing an image to appear on the screen are also used, as in flat-panel displays. 7. The motion-picture industry; motion pictures. "A star of stage and screen." Origin: OE. Scren, OF. Escrein, escran, F. Ecran, of uncertain origin; cf. G. Schirm a screen, OHG. Scrim, scern a protection, shield, or G. Schragen a trestle, a stack of wood, or G. Schranne a railing. Source: Websters Dictionary (01 Mar 1998) |
| screen defense | The use of falsified or incomplete memories or affects to cover repressed but associated memories and affects. (05 Mar 2000) |
| screen-film contact | The closeness and uniformity with which the X-ray film in a cassette lies against the screen. Image resolution is dependent on this closeness and uniformity of contact. (05 Mar 2000) |
| screen memory | In psychoanalysis, a consciously tolerable memory that unwittingly serves as a cover for another associated memory which would be emotionally painful if recalled. (05 Mar 2000) |
| specimen screen | <microscopy> A disk of fine screen, usually 200-mesh stainless steel, copper, or nickel, which supports the replica or specimen support film for observation in the microscope. (05 Aug 1998) |
| strep screen | A quick test for strep throat that is performed off a standard throat swab. Results can be obtained within a hour in most cases. (27 Sep 1997) |
| intensifying screen | A screen used in radiography. (05 Mar 2000) |
| tangent screen | A flat, usually black surface used to measure the central 30 degrees of the field of vision. Synonym: Bjerrum screen. (05 Mar 2000) |