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You've been told the truth. According to the entry on blindness in the Yahoo! Health Encyclopedia, anyone with vision worse than 20/200 that cannot be improved with corrective lenses is considered legally blind. In addition, people with a visual field of less than 20 degrees diameter (10 degrees radius) are also considered legally blind. The American Optometric Association states that a person with 20/20 vision can clearly identify a row of 9mm letters from 20 feet. A legally blind person with vision of 20/200 has to be as close as 20 feet to identify objects that people
with normal vision can spot from 200 feet. So a legally blind person needs a distance of two feet to spot the letters on a standard eye chart that is 20 feet away. Legal blindness is very common in older people because eyesight tends to worsen with time and age. Approximately 135 out of every 1,000 people over the age of 65 are considered legally blind. About 1.3 million Americans fall into this category. Only about 10% of legally blind people read Braille, and a much smaller percentage use white canes or guide dogs. In the United States, the leading causes of blindness are accidents, diabetes,
glaucoma, and macular degeneration. Worldwide, the leading cause is vitamin A deficiency, which is entirely preventable. Between 100 and 140 million children are vitamin A deficient, and up to a half million of them go blind every year.
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