grapho-, graph-, -graph, -graphy, -grapher, -graphia
(Greek: to scratch; to write, to record, to draw, to describe; that which is written or described)
As indicated at the bottom of this page, there is a significantly large number of graphic word-entry groups in this unit. Such an extensive listing is provided to show how important the grapho- element is to the English language.
2. An instrument consisting of an electron tube in which an accelerated beam of electrons produces images on a fine-grain photographic emulsion.
An image produced with this tool.
2. The use of image tubes to form intensified electron images of astronomical objects and record them directly on film or film-plates
Electrodes are placed on the skin around the eye and the individual is subjected to a variety of stimuli so that the quality of eye movements can be determined.
2. A method of assessing and recording eye movements by measuring the electric activity of the extraocular muscles.
3. The registering of eye movements in spontaneous and induced nystagmus, using either a bioelectric or a photoelectric technique.
The bioelectric method records the changes in electrical potential produced by movements of the eye in the plane of two electrodes placed on either side of the eye or, if vertical nystagmus is to be measured, then the two electrodes are positioned above and below the eye.
Its important clinical application is the testing of vestibular function or the sense of balance and spatial orientation.
2. A sensitive electrical test for detection of retinal pigment epithelium dysfunction.
3. The study and interpretation of electroencephalograms made by moving the eyes a constant distance between two fixed points.
4. The recording and interpretation of the voltages which go with eye movements.
Eye-position voltages from electrodes placed on the skin near the eye are amplified and applied to a strip-chart recorder.
A computer records and displays the pattern of the pulses generated by contact of the tongue with the electrodes.
It uses electrostatic charges, dry ink (toner) and light to produce images on paper.
Examples are processes employing selenium-coated drums or zinc-oxide-coated paper.
2. A kind of photography using electric rather than chemical processes to transfer an image onto paper, as in xerography.
3. An electrostatic image-forming process in which light, X-rays, or gamma rays form an electrostatic image on a photoconductive, insulating medium.
The charged image areas attract and hold a fine powder called a toner, and the powder image is then transferred to paper or fused there by heat.
Electrophotography now includes both xerography and xeroradiography.
An electrode placed on a plastic contact lens is used to pick up voltage from the surface of the eyeball.2. A test in which the electrical potentials generated by the retina of the eye are measured when the retina is stimulated by light.
The instrument used to do such electroretinography is known as an electroretinograph and the resultant recording is called an electroretinogram.
In an ERG, an electrode is placed on the cornea at the front of the eye. The electrode measures the electrical response of the rods and cones, and the visual cells in the retina at the back of the eye.
An ERG (electroretinograph) may be useful in the evaluation of hereditary and acquired disorders of the retina.
A normal ERG shows the appropriate responses with increased light intensity. An abnormal ERG is found in conditions; such as, arteriosclerosis of the retina, detachment of the retina, and temporal arteritis with eye involvement.