monocular diplopia

Also found in: Dictionary, Thesaurus, Legal, Financial, Encyclopedia.

mo·noc·u·lar di·plo·pi·a

a double image or an extra ghost image produced in one eye, almost always by an aberration of the ocular media; for example, a corneal or lenticular irregularity, an uncorrected astigmatism or an irregularity of the vitreous or the retina. If a similar process occurs in both eyes (bilateral monocular diplopia), that is, the doubling is still present with either eye covered, the patient may still only see two images; seeing multiple images (polyopia) is rare.

mo·noc·u·lar di·plo·pi·a

(mon-ok'yū-lăr dip-lō'pē-ă)
A double image or an extra ghost image produced in one eye.

vision (V) 

1. The appreciation of differences in the external world, such as form, colour, position, etc. resulting from the stimulation of the retina by light.
2. See unaided visual acuity.
achromatic vision See achromatopsia.
alternating vision See contact lens.
ambient vision Vision mediated primarily by the peripheral retina and involved in spatial orientation and recognition of motion. See focal vision.
anomalous trichromatic vision See anomalous trichromatism.
binocular vision  (BV) Condition in which both eyes contribute towards producing a percept which may or may not be fused into a single impression. See sensory fusion; monoblepsia; critical period; bar reading test; FRIEND test; hole in the hand test; Worth's four dot test; Worth's classification of binocular vision; binocular vision single zone of clear.
binocular single vision See single binocular vision.
blue vision See chromatopsia.
blurred vision Vision characterized by poor visual acuity or in which the edges of objects are indistinct. It may be due to uncorrected or poorly corrected ametropia or presbyopia, anomalies of the ocular media (e.g. cataract, corneal opacity, haemorrhage in the vitreous), amblyopia, excess lacrimation, spasm of accommodation, optic neuritis, angle-closure glaucoma, diabetes, multiple sclerosis, migraine, etc.
central vision Vision of objects formed on the foveola or the macula. See sensory fusion.
chromatic vision See colour vision.
colour vision  (CV) Vision in which the colour sense is experienced. Syn. chromatic vision. See Hering's of colour vision theory; Young-Helmholtz theory.
daylight vision See photopic vision.
defective colour vision See defective colour vision.
deuteranomalous vision See deuteranomaly.
dichromatic vision See dichromatism.
distance vision  (DV) Vision of objects situated either at infinity or more usually at some 5 or 6 m. See Snellen chart; near vision.
diurnal vision See photopic vision.
double v . See diplopia.
eccentric v . See eccentric fixation; peripheral vision.
entoptic v . See entoptic image.
extrafoveal vision See peripheral vision.
field of vision See visual field.
focal vision Vision mediated by, primarily, the macular area of the retina and involved in the examination and identification of objects. See ambient vision.
green v . See chromatopsia.
gun barrel v . See tunnel vision.
haploscopic vision Vision as obtained by looking in a haploscope.
indirect vision See peripheral vision.
industrial vision The branch of optometry concerned with vision and perception by the individual at work, the evaluation of visual performance in a given occupation, the prescribing of protective ocular devices and the determination of the optimum environment (e.g. illumination) to accomplish a visual task efficiently.
intermediate vision Vision of objects situated beyond 40 cm from the eye but closer than, say, 1.5 m. See distance vision; near vision.
island of vision A description of the visual field as a three-dimensional hill surrounded by a sea of darkness. Stimuli that fall within the island can be seen, whereas stimuli that fall outside the island cannot be seen. The height of the island represents the sensitivity of the eye, with the highest acuity at the top of the hill corresponding to foveal vision and declining progressively towards the periphery (when the eye is light-adapted). See visual field.
low vision Vision impairment even after correction by conventional lenses, resulting from either congenital anomalies or ocular diseases such as cataract, glaucoma, age-related macular degeneration, pathological myopia, trachoma, onchocerciasis, etc. The correction and rehabilitation of patients with low vision is achieved by special aids called low vision aids (LVA) such as a telescopic lens, and appropriate counselling (e.g. about illumination and reading distance). The criteria that the health authorities normally use to classify a person as having partial sight take into consideration not only the corrected visual acuity but also the extent of visual field loss (generally less than 20º). Syn. partial sight; subnormal vision.The World Health Organization (WHO) defines low vision as visual acuity less than 6/8 (20/60) and equal to or better than 3/60 (10/200) in the better eye with best correction. See low vision aids; blindness; bracketing; Bailey-Lovie chart; contrast sensitivity chart; clipover; deaf-blind; halogen lamp; cross-cylinder lens; telescopic lens; apparent magnification; relative distance magnification; relative size magnification; magnifier; Kestenbaum's rule; magnifying spectacles; pinhole spectacles; galilean telescope; Pepper test; typoscope; eccentric viewing.
mesopic vision Vision at intermediate levels between photopic and scotopic vision, and corresponding to luminances ranging from about 10−3 to 10 cd/m2. Syn. twilight vision.
monochromatic vision Synonym of monochro-matism. See monochromat.
monocular vision Vision of one eye only.
multiple vision See polyopia.
near vision  (NV) Vision of objects situated 25-50 cm from either the eye, or more commonly the spectacle plane. See Jaeger test types; distance vision.
night vision; nocturnal vision See scotopic vision.
panoramic vision Vision of some animals whose eyes are located laterally so that the two visual fields overlap only slightly or are adjacent, thus providing vision over a much larger region of the environment than if the two lines of sight were aimed in the same direction.
peripheral vision Vision resulting from stimulation of the retina outside the fovea or macula. Syn. eccentric vision; extrafoveal vision; indirect vision. See sensory fusion; central vision.
photopic vision Vision at high levels of luminance (above 10 cd/m2) and resulting from the functioning of the cones. Syn. daylight vision; diurnal vision. See duplicity theory; differential threshold.
protanomalous vision See protanomaly.
red vision See chromatopsia.
vision science The scientific study of how the visual system contributes to an understanding of the environment by processing and interpreting the light stimulation to the eye. Various disciplines contribute to vision science including anatomy, biology, optics, physiology and psychology.
scotopic vision Vision at low levels of luminance, below about 10−3 cd/m2 and resulting from the functioning of the rods. Syn. night vision; nocturnal vision; scotopia. See duplicity theory.
vision screener An instrument used to measure various visual functions rapidly and inexpensively. There are various models, but most are modified stereoscopes with an internally illuminated set of targets and an optical system or variable target positioning to simulate either a near or far testing distance. Most of these instruments measure visual acuity, heterophoria, fusion, stereopsis, colour vision and visual field. See photorefraction.
simultaneous vision See contact lens.
single binocular vision (SBV) Condition in which both eyes contribute towards producing a single fused percept. See sensory fusion.
spatial vision See depth perception.
stereoscopic vision See stereopsis.
subnormal vision See low vision.
telescopic vision See tunnel vision.
vision therapy; vision training See visual training.
tritanomalous vision See tritanomaly.
tunnel vision Vision limited to the central part of the visual field as though one were looking through a hollow tube. It may be a symptom of hysteria, malingering, the final stage of either open-angle glaucoma or retinitis pigmentosa, etc. Syn. gun barrel vision; telescopic vision. See hysterical amblyopia; visual expander field.
twilight vision See mesopic vision.
Worth's classification of binocular vision For the purpose of visual rehabilitation, binocular vision is often classified into three grades: (1) simultaneous binocular vision (first-degree fusion or superimposition); (2) fusion (sensory fusion or second-degree fusion or flat fusion); (3) stereopsis (third-degree fusion). See sensory fusion; superimposition.
yellow vision See xanthopsia.