How do you ask a blind person if they need help?

Observe, Approach, Ask, Assist.

It’s important to understand that the blind and visually impaired are incredibly capable and often fully independent. So, don’t assume that just because they are blind that they need help.  Instead:

1.  Observe: make sure they really do need help before you;
2.  Approach: if you suspect someone may need a hand, walk up, greet them and identify yourself.
3.  Ask: “Hi my name is John, can I help you with that?” The person will accept your offer or tell you if they don’t require assistance.
4.  Assist: listen to the reply and assist as required.