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Visual impairment

16 二月, 2015 - 12:51
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Students with visual impairments have difficulty seeing even with corrective lenses. Most commonly the difficulty has to do with refraction (the ability to focus), but some students may also experience a limited field of view (called tunnel vision) orbe overly sensitive to light in general. As with hearing loss, labels for visual impairment depend somewhat on the extent and nature of the problem. Legal blindness means that the person has significant tunnel vision or else visual acuity (sharpness of vision) of 20/200 or less, which means that he or she must be 20 feet away from an object that a person with normal eyesight can see at 200 feet. Low vision means that a person has some vision usable for reading, but often needs a special optical device such as a magnifying lens for doing so. As with hearing loss, the milder the impairment, the more likely that a student with a vision problem will spend some or even all the time in a regular class.