You don't have to be totally blind to see losing your vision affects more than the eyes.
According to the National Institutes of Health (NIH), in the United State alone:
More than 20.4 million adults suffer from cataracts
1.7 million suffer from advanced Age-related Macular Degeneration (AMG)
7.3 million suffer from intermediate AMG
2.2 million suffer from glaucoma
Don't forget about the more than 4 million other adult Americans who suffer from some degree of blindness due to …