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Blindness is the lack of vision, or a loss of vision that cannot be corrected with glasses or contact lenses. Blindness may be partial, with very limited vision, or complete, with no perception of light. People with vision worse than 20/200, or a field of vision of less than 20 degrees in the better eye, are considered legally blind in most states in the U.S.
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Total blindness is the inability to tell light from dark, or the total inability to see. Visual impairment or low vision is a severe reduction in vision that can ' t be corrected with standard glasses or contact lenses and reduces a person ' s ability to function at certain or all tasks.
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A corneal ulcer is a non-penetrating erosion or open sore in the outer layer of the cornea, the transparent area at the front of the eyeball. See also corneal injury .
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The cornea, the clear front part of the eye through which light passes, is subject to many infections and to A close-up view of an ulcer on cornea. ( Custom Medical Stock Photo .
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