The Question and Answer section for Blindness is a great resource to ask questions, find answers, and discuss the novel.
The doctor's wife is the only character in the entire novel who does not lose their sight. This phenomenon remains unexplained in the novel. Unable to leave her husband to be interned, she lies to the doctors and claims to be...
I don't know what every character represents but hopefully this helps a little,
I don't believe we're ever given a time frame, but we can infer the story takes place during modern times, or possibly at a time in the not so distant furture.