vision /vi·sion/ (vizh´un)
double vision.
Patient discussion about double vision.
1. the sense by which objects in the external environment are perceived by means of the light they give off or reflect.
2. the act of seeing.
3. an apparition; a subjective sensation of seeing not elicited by actual visual stimuli.
4. visual acuity.
achromatic vision monochromatic vision.
anomalous trichromatic vision defective color vision in which a person has all three cone pigments but one is deficient or anomalous but not absent.
binocular vision the use of both eyes together without diplopia.
central vision that produced by stimuli impinging directly on the macula retinae.
chromatic vision color v.
color vision
1. perception of the different colors making up the spectrum of visible light.
2. chromatopsia.
day vision visual perception in the daylight or under conditions of bright illumination.
dichromatic vision defective color vision in which one of the three cone pigments is missing; the two types are protanopia and deuteranopia.
direct vision central v.
double vision diplopia.
indirect vision peripheral v.
low vision impairment of vision such that there is significant visual handicap but also significant usable residual vision.
monochromatic vision complete color blindness; inability to discriminate hues, all colors of the spectrum appearing as neutral grays with varying shades of light and dark.
monocular vision vision with one eye.
multiple vision polyopia.
night vision visual perception in the darkness of night or under conditions of reduced illumination.
oscillating vision oscillopsia.
peripheral vision that produced by stimuli falling on areas of the retina distant from the macula.
solid vision , stereoscopic vision perception of the relief of objects or of their depth; vision in which objects are perceived as having three dimensions.
trichromatic vision
1. any ability to distinguish the three primary colors of light and mixtures of them.
2. normal color vision.
tunnel vision
1. that in which the visual field is severely constricted.
2. in psychiatry, restriction of psychological or emotional perception to a limited range.
| double vision n. A disorder of vision in which a single object appears double. Also called diplopia. |
double vision.
See diplopia.
vision
the faculty of seeing; sight.
The basic components of vision are the eye itself, the visual center in the brain, and the optic nerve, which connects the two. Abnormalities of vision in animals can only be inferred by an assessment of the animal's response to a variety of visual stimuli. The commonly used tests of vision are the menace reflex test, the watching of a moving object and the obstacle test. These can all be performed in subdued light as a test for night blindness.
achromatic vision
vision characterized by lack of color vision.
aphakic vision
vision after lens removal.
binocular vision
the use of both eyes together, without diplopia.
central vision
that produced by stimulation of receptors in the fovea centralis.
day vision
visual perception in the daylight or under conditions of bright illumination.
double vision
diplopia.
half vision
hemianopia.
monocular vision
vision with one eye.
night vision
visual perception in the darkness of night or under conditions of reduced illumination.
panoramic vision
360° vision conferred on grazing herbivora by the lateral placement of their eyes.
peripheral vision
that produced by stimulation of receptors in the retina outside the macula lutea.
photopic vision
vision in bright illumination.
scotopic vision
vision in low illumination.
vision test
see visual acuity test.
diplopia
The condition in which a single object is seen as two rather than one. This is usually due to images not stimulating corresponding retinal areas. Other causes are given below. Syn. double vision (colloquial). See differential prismatic effect; haplopia; myasthenia gravis; retinal corresponding points; polyopia; multiple sclerosis; strabismus; diplopia test; triplopia.
binocular diplopia Diplopia in which one image is seen by one eye and the other image is seen by the other eye.
crossed diplopia See heteronymous diplopia.
heteronymous diplopia Binocular diplopia in which the image received by the right eye appears to the left and that received by the left eye appears to the right. In this condition the images are formed on the temporal retina. Syn. crossed diplopia.
homonymous diplopia Binocular diplopia in which the image received by the right eye appears to the right and that received by the left eye appears to the left. In this condition, the images are formed on the nasal retina. Syn. uncrossed diplopia.
incongruous diplopia Diplopia present in individuals with abnormal retinal correspondence in which the relative positions of the two images differ from what would be expected on the basis of normal retinal correspondence. Example: an exotrope experiencing homonymous diplopia instead of heteronymous diplopia. Syn. paradoxical diplopia. See abnormal retinal correspondence.
monocular diplopia Diplopia seen by one eye only. It is usually caused by irregular refraction in one eye (e.g. in early cataracts, corneal opacity) or by dicoria or polycoria. It may be induced by placing a biprism in front of one eye. See ghost image; luxation of the lens.
paradoxical diplopia See incongruous diplopia.
pathological diplopia Any diplopia due to an eye disease (e.g. proptosis), an anomaly of binocular vision (e.g. strabismus), a variation in the refractive index of the media of the eye (e.g. cataract), a subluxation of the crystalline lens, or to a general disease (e.g. multiple sclerosis, myasthenia gravis). See exophthalmos; luxation of the lens.
physiological diplopia Normal phenomenon which occurs in binocular vision for non-fixated objects whose images fall on disparate retinal points. It is easily demonstrated to persons with normal binocular vision: fixate binocularly a distant object and place a pencil vertically some 25 cm in front of your nose. You should see two rather blurred pencils. The observation of physiological diplopia has been found to be useful in the management of eso or exo deviations, suppression, abnormal retinal correspondence, etc. (Fig. D4). See Brock string; retinal disparity.
diplopia test See diplopia test.
uncrossed diplopia See homonymous diplopia.
binocular diplopia Diplopia in which one image is seen by one eye and the other image is seen by the other eye.
crossed diplopia See heteronymous diplopia.
heteronymous diplopia Binocular diplopia in which the image received by the right eye appears to the left and that received by the left eye appears to the right. In this condition the images are formed on the temporal retina. Syn. crossed diplopia.
homonymous diplopia Binocular diplopia in which the image received by the right eye appears to the right and that received by the left eye appears to the left. In this condition, the images are formed on the nasal retina. Syn. uncrossed diplopia.
incongruous diplopia Diplopia present in individuals with abnormal retinal correspondence in which the relative positions of the two images differ from what would be expected on the basis of normal retinal correspondence. Example: an exotrope experiencing homonymous diplopia instead of heteronymous diplopia. Syn. paradoxical diplopia. See abnormal retinal correspondence.
monocular diplopia Diplopia seen by one eye only. It is usually caused by irregular refraction in one eye (e.g. in early cataracts, corneal opacity) or by dicoria or polycoria. It may be induced by placing a biprism in front of one eye. See ghost image; luxation of the lens.
paradoxical diplopia See incongruous diplopia.
pathological diplopia Any diplopia due to an eye disease (e.g. proptosis), an anomaly of binocular vision (e.g. strabismus), a variation in the refractive index of the media of the eye (e.g. cataract), a subluxation of the crystalline lens, or to a general disease (e.g. multiple sclerosis, myasthenia gravis). See exophthalmos; luxation of the lens.
physiological diplopia Normal phenomenon which occurs in binocular vision for non-fixated objects whose images fall on disparate retinal points. It is easily demonstrated to persons with normal binocular vision: fixate binocularly a distant object and place a pencil vertically some 25 cm in front of your nose. You should see two rather blurred pencils. The observation of physiological diplopia has been found to be useful in the management of eso or exo deviations, suppression, abnormal retinal correspondence, etc. (Fig. D4). See Brock string; retinal disparity.
diplopia test See diplopia test.
uncrossed diplopia See homonymous diplopia.
)
Fig. D4 Physiological diplopia. The subject fixates a distant object A
Patient discussion about double vision.
Q. what is the cause for double vision
A. Double vision, or diplopia, as it's called, may be due to many conditions, including disorders of the muscles of the eye (extra-ocular muscles) and the nerves controlling them, disorders of the eye ball (enlarged eyeball as in Graves' ), and sometimes disorders of vision.
Diplopia may manifest important conditions, so consulting a doctor (e.g. neurologist or ophthalmologist) may be wise.
You may read more here:
www.nlm.nih.gov/medlineplus/ency/article/003029.htm
Read more or ask a question about double visionDiplopia may manifest important conditions, so consulting a doctor (e.g. neurologist or ophthalmologist) may be wise.
You may read more here:
www.nlm.nih.gov/medlineplus/ency/article/003029.htm
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