how to limit vision when walking into a certain area?

say my player walks into a certain invisible brick, how could I make it so that his vision is limited while inside it?

edit: I got a good answer but I guess I should've been more specific, think of it as fog.

if you mean make everything dark, you will have to:

1. turn off all lighting in that area so it’s pitch black, locally or on the server you can decide
2. add a light source inside of the character, locally. then it will seem like they can only see a certain distance and the light from other players won’t affect them.