Aids for people who are blind or visually impaired

Publication Type: Book Chapter
Publication: Cooper, RA, Ohnabe H, Hobson D, (Eds.) An Introduction to Rehabilitation Engineering, Taylor & Francis, New York, p.287-313 (2007)

Learn the approximate size of the visually impaired population Understand the different types and dimensions of visual impairment and their different impacts on visual task performance Learn about the basic methods of vision assessment Understand the problems caused by dual sensory loss Gain knowledge about the history of what has been done in this field Gain knowledge of the different approaches to medical and surgical function restoration Learn how universal design concepts apply to blind and visually impaired persons Understand the different approaches to assistive technology for way-finding Understand the problems and options for reading and graphics access Understand the barriers (and potential solutions) to computers, Internet, and telecommunications access faced by this population Understand the employment and daily living problems and solutions for blind and visually impaired persons The causes and demographics of blindness vary greatly in different parts of the world. In most industrialized countries, approximately 0.4% of the population is called “legally blind” for the purposes of qualifying for government assistance. With variations by country, this definition means best corrected acuity of 20/200 or worse (i.e., onetenth of “normal” visual resolution) or a visual field restricted to 20 or less. In the US, this definition includes approximately 1 million people; 3.5 to 5 million have low vision, usually defined as best corrected visual acuity less than 20/70; and almost 14 million have some visual impairment that hampers performance and enjoyment of everyday activities. About 200,000 to 300,000 have no useful vision at all. For our purposes, the term “blind” is restricted to this group, and “low vision” or “visually impaired” is used for those with partial vision. Although most people with low vision are in the older age groups, the totally blind population is more evenly distributed.

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