Someone called you blind, how should you answer him?

That depends on what it is. If it's your own fault, don't take it seriously, because some people really don't have high literacy now, and they can't force it. Let it go if you can. Everything can't be smooth. It is inevitable that you will meet unreasonable people.

If it's bickering, you can give it back to him. You are blind, aren't you? Can't you see my eyes are fine?

In short, don't make things worse. Roll with the punches, roll with the punches. Generosity is not easy, but it can save a lot of trouble.

Unless the other party is really cruel, it is impossible to be cowardly.

Anyway, it depends. Put it down if you can, and fight back if you can't stand it.