I think jobs with computers are, in many ways, more forgiving to those with bad eyesight than other jobs. I have bad vision (just enough so I can't drive) but thanks to Gtk / Compiz, I can arbitrarily change the font size to be as big as I like it, and Orca and other screenreaders would help if I were completely blind. However, if I were a scientist or a taxicab driver or at a factory or throwing darts for a living, I'd be much worse off because I couldn't make those accommodations.