| Helmholtz theory of colour vision | A theory that there are three colour-perceiving elements in the retina: red, green, and blue. Perception of other colours arises from the combined stimulation of these elements; deficiency or absence of any one of these elements results in inability to perceive that colour and a misperception of any other colour of which it forms a part. Synonym: Helmholtz theory of colour vision. (05 Mar 2000) |
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| Hering's theory of colour vision | That there are three opponent visual processes: blue-yellow, red-green, and white-black. (05 Mar 2000) |
| scotopic vision | Vision when the eye is dark-adapted. See: dark adaptation, dark-adapted eye. Synonym: night vision, rod vision, scotopia, twilight vision. (05 Mar 2000) |
| stereoscopic vision | The single perception of a slightly different image from each eye. Synonym: stereopsis. (05 Mar 2000) |
| night vision | Vision when the eye is dark-adapted. See: dark adaptation, dark-adapted eye. Synonym: night vision, rod vision, scotopia, twilight vision. (05 Mar 2000) |
| subjective vision | Visual impressions that arise centrally and do not originate with ocular stimuli. (05 Mar 2000) |
| direct vision | Vision stimulated by an object imaged on the fovea centralis. Synonym: direct vision. (05 Mar 2000) |
| direct vision spectroscope | <instrument> A spectroscope consisting of a single tube containing a series of prisms; one end of the tube is placed in as close contact as possible with the substance to be examined while the observer places his eye at the opposite end; it can be used to make a spectroscopic examination of the blood in vivo, as in the ear lobe or web of the thumb. (05 Mar 2000) |
| double vision | <ophthalmology, symptom> The perception of two images of a single object. Synonym: ambiopia, double vision, binocular polyopia. (18 Nov 1997) |
| duplicity theory of vision | That the cones of the retina function in bright light and the rods function in dim light. (05 Mar 2000) |
| indirect vision | Vision resulting from retinal stimulation beyond the macula. Synonym: indirect vision. (05 Mar 2000) |
| organ of vision | The eye and its adnexa. Synonym: organum visus, organ of vision. (05 Mar 2000) |
| oscillating vision | The subjective sensation of oscillation of objects viewed. Synonym: oscillating vision. Origin: L. Oscillo, to swing, + G. Opsis, vision (05 Mar 2000) |
| tinted vision | A condition in which objects appear to be abnormally coloured or tinged with colour; designated according to the colour seen: xanthopsia, yellow vision; erythropsia, red vision; chloropsia, green vision; cyanopsia, blue vision. Synonym: chromatic vision, coloured vision, tinted vision. Compare: dyschromatopsia. Origin: chromato-+ G. Opsis, vision (05 Mar 2000) |
| triple vision | Visual defect in which three images of the same object are seen. Synonym: triple vision. Origin: G. Triploos, triple, + opsis, sight (05 Mar 2000) |