ablepsia

enUS

blindness

[blīnd´nes] lack or loss of ability to see (see vision). Legally, blindness is defined as less than 20/200 vision in the better eye with glasses (vision of 20/200 is the ability to see at 20 feet only what the normal eye can see at 200 feet). A person with 20° or less vision (pinhole vision) is also legally blind. In 2002, the number of people classified as legally blind in the United States was estimated at 10 million; millions more had severe visual impairments. The five leading causes of impaired vision and blindness in the United States are age-related macular degeneration, cataract, glaucoma, retinopathy" >diabetic retinopathy, and atrophy of the optic nerve" >optic nerve. Besides health care problems, issues related to employment, independent living, and literacy should all be considered when caring for patients who are blind. The American Foundation for the Blind is a resource center for information related to visual problems. They can be contacted by calling 1-800-232-5463 or consulting their web site at http://www.afb.org.blue blindness (blue-yellow blindness) popular names for imperfect perception of blue and yellow tints; see tritanopia and tetartanopia.color blindness color vision deficiency.complete color blindness vision" >monochromatic vision.day blindness hemeralopia.green blindness imperfect perception of green tints; see deuteranopia and protanopia.legal blindness that defined by law, usually, maximal visual acuity in the better eye after correction of 20/200 with a total diameter of the visual field in that eye of 20°.night blindness see night blindness.object blindness (psychic blindness) visual agnosia.red blindness popular name for protanopia.red-green blindness (red-green color blindness) popular names for any imperfect perception of red and green tints, including all the most common types of color vision deficiency. See deuteranomaly, deuteranopia, protanomaly, and protanopia.snow blindness dimness of vision, usually temporary, due to the glare of the sun upon snow.total color blindness vision" >monochromatic vision.yellow blindness popular name for tritanopia.

blindness

1. Inability to see. 2. Absence or severe loss of vision so as to be unable to perform any work for which eyesight is essential. The World Health Organization (WHO) defines blindness as the best corrected visual acuity of 3/60 (20/400) or less, in the better eye. Syn. ablepsia; ablepsy; amaurosis.
blue blindness See tritanopia.
colour blindness Sometimes this term is incorrectly used to cover all forms of colour vision deficiency, however mild or severe. See achromatopsia; defective colour vision; deuteranopia; monochromat; protanopia; tritanopia.
congenital stationary night blindness Night blindness (nyctalopia) inherited as either autosomal dominant with non-progressive nyctalopia but normal daylight visual acuity and visual fields and presumed to be due to a defect in neural transmission between the rods and the bipolars in the retina, or autosomal recessive or X-linked with congenital nyctalopia, myopia, nystagmus and reduced visual acuity. See Oguchi's disease; fundus albipunctatus; hemeralopia; retinitis pigmentosa.
cortical blindness Loss of vision due to lesions in the areas of both occipital lobes of the brain associated with visual functions. It may result from trauma or from a vascular disease (e.g. a circulatory occlusion caused by a stroke). A lesion in one occipital lobe may result in homonymous hemianopia, often with macular sparing.
day blindness See hemeralopia.
eclipse blindness Partial or complete loss of central vision due to a foveal lesion caused by fixating the sun without adequate eye protection. This condition is caused mainly by the infrared radiations from the sun. See actinic.
flash blindness See actinic keratoconjunctivitis.
green blindness See deuteranopia.
hysterical blindness Blindness associated with an emotional shock, which occurs without a physical or organic cause. The patient has normal blink and pupillary responses and the fundus appears normal. A placebo therapy and/or psychological counselling may be required.
legal blindness The definition varies from country to country. In the UK it is equal to either 3/60 (20/400) or worse; or 6/60 (20/200) or worse, with markedly restricted fields.
motion blindness A very rare condition in which a patient is unable to process information about motion, although other visual functions are unimpaired. This is believed to be the result of damage to the middle temporal cortex (V5). See visual association areas.
night blindness See hemeralopia.
perceptual blindness See agnosia.
red blindness See protanopia.
river blindness See onchocerciasis.
snow blindness See actinic keratoconjunctivitis.
word blindness See alexia.

单词	ablepsia
释义	ablepsia enUS ablepsia, ablepsy a lack or loss of sight. — ableptical, adj.See also: Blindness EncyclopediaSeeblindness ablepsia enUS blindness [blīnd´nes] lack or loss of ability to see (see vision). Legally, blindness is defined as less than 20/200 vision in the better eye with glasses (vision of 20/200 is the ability to see at 20 feet only what the normal eye can see at 200 feet). A person with 20° or less vision (pinhole vision) is also legally blind. In 2002, the number of people classified as legally blind in the United States was estimated at 10 million; millions more had severe visual impairments. The five leading causes of impaired vision and blindness in the United States are age-related macular degeneration, cataract, glaucoma, retinopathy" >diabetic retinopathy, and atrophy of the optic nerve" >optic nerve. Besides health care problems, issues related to employment, independent living, and literacy should all be considered when caring for patients who are blind. The American Foundation for the Blind is a resource center for information related to visual problems. They can be contacted by calling 1-800-232-5463 or consulting their web site at http://www.afb.org.blue blindness (blue-yellow blindness) popular names for imperfect perception of blue and yellow tints; see tritanopia and tetartanopia.color blindness color vision deficiency.complete color blindness vision" >monochromatic vision.day blindness hemeralopia.green blindness imperfect perception of green tints; see deuteranopia and protanopia.legal blindness that defined by law, usually, maximal visual acuity in the better eye after correction of 20/200 with a total diameter of the visual field in that eye of 20°.night blindness see night blindness.object blindness (psychic blindness) visual agnosia.red blindness popular name for protanopia.red-green blindness (red-green color blindness) popular names for any imperfect perception of red and green tints, including all the most common types of color vision deficiency. See deuteranomaly, deuteranopia, protanomaly, and protanopia.snow blindness dimness of vision, usually temporary, due to the glare of the sun upon snow.total color blindness vision" >monochromatic vision.yellow blindness popular name for tritanopia. blindness 1. Inability to see. 2. Absence or severe loss of vision so as to be unable to perform any work for which eyesight is essential. The World Health Organization (WHO) defines blindness as the best corrected visual acuity of 3/60 (20/400) or less, in the better eye. Syn. ablepsia; ablepsy; amaurosis. blue blindness See tritanopia. colour blindness Sometimes this term is incorrectly used to cover all forms of colour vision deficiency, however mild or severe. See achromatopsia; defective colour vision; deuteranopia; monochromat; protanopia; tritanopia. congenital stationary night blindness Night blindness (nyctalopia) inherited as either autosomal dominant with non-progressive nyctalopia but normal daylight visual acuity and visual fields and presumed to be due to a defect in neural transmission between the rods and the bipolars in the retina, or autosomal recessive or X-linked with congenital nyctalopia, myopia, nystagmus and reduced visual acuity. See Oguchi's disease; fundus albipunctatus; hemeralopia; retinitis pigmentosa. cortical blindness Loss of vision due to lesions in the areas of both occipital lobes of the brain associated with visual functions. It may result from trauma or from a vascular disease (e.g. a circulatory occlusion caused by a stroke). A lesion in one occipital lobe may result in homonymous hemianopia, often with macular sparing. day blindness See hemeralopia. eclipse blindness Partial or complete loss of central vision due to a foveal lesion caused by fixating the sun without adequate eye protection. This condition is caused mainly by the infrared radiations from the sun. See actinic. flash blindness See actinic keratoconjunctivitis. green blindness See deuteranopia. hysterical blindness Blindness associated with an emotional shock, which occurs without a physical or organic cause. The patient has normal blink and pupillary responses and the fundus appears normal. A placebo therapy and/or psychological counselling may be required. legal blindness The definition varies from country to country. In the UK it is equal to either 3/60 (20/400) or worse; or 6/60 (20/200) or worse, with markedly restricted fields. motion blindness A very rare condition in which a patient is unable to process information about motion, although other visual functions are unimpaired. This is believed to be the result of damage to the middle temporal cortex (V5). See visual association areas. night blindness See hemeralopia. perceptual blindness See agnosia. red blindness See protanopia. river blindness See onchocerciasis. snow blindness See actinic keratoconjunctivitis. word blindness See alexia.
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ablepsia

ablepsia, ablepsy

ablepsia

blindness

blindness