I'm legally blind , you wouldn't know it by looking at me and I only carry a cane some of the time . I don't tell anyone until I see there might be some sort of job conflict .

Personally, I walk in with a cane. But the thing I struggle with is if I should mention my disability during the phone interview, or at some point before the in-person interview. Surprising the interviewer doesn't feel like a good idea, but on the other hand, disclosing early feels like it puts me at an enormous disadvantage.

I'm blind now, but back when I worked I would simply mention my disability in my resume. I had 10% of sight with normal contrast perception and field of view, which didn't affect my ability to code, and employers were often more interested in my work history and my ability to crack the coding interviews than in my eyesight.

EDIT: I should also mention that I never had to carry a cane because the only problem I had with my eyesight was the distance: I had to get closer to objects or signs in order to see or read them; I also had to get a lot closer to the screen than normal people, but didn't need magnifiers, negative colors, larger mouse cursors, or improved contrast in order to use a computer.

Thank you for asking this and I'm curious about the replies. My wife is legally blind and has had jobs not get back to her because she mentioned that she uses a magnifier or might need a zoomed in computer setup to work. She has worked as a barista successfully but only because her friend hooked her up.

If you're in the US, the Job Accommodation Network can help you decide when to bring it up. It's funded by the Department of Labor. "JAN provides free, confidential technical assistance about job accommodations and the Americans with Disabilities Act (ADA)"
http://askjan.org/indiv/index.htm
800)526-7234 (Voice)
(877)781-9403 (TTY)