Talk directly to the person, determine what he or she wants, and how best to deliver it by consulting with the person. This may sound very simple, and it is. Appropriate interaction is common courtesy and common sense. Do's and don'ts when interacting with people with print disabilities do not question the person's disability.
Disabilities are often invisible.
Such aids give people the freedom to move about independently. Otherwise both you and the person who is vision impaired will feel awkward. Do not direct questions through their companion. Therefore, talk about what is happening. Direct people who are vision impaired to their left and right, not yours.