What is your vision?

Could you be more specific? That's a very vague question.

Do you mean, what is your vision of where you will be in five years? Ten years?

Do you mean, what is your vision of where you will be in five years? ten years?

See, I thought they were asking if the OP requires glasses, contacts, if his vision is 20/20.

That just goes to show that being very clear about your question, really helps us provide an answer that's appropriate. :)

You asked this under Interviews, so I would take the approach of vision for the company.
"My vision for Mega World Conglomerate is to help us adapt to the ever changing times of a global economy, as we cut expenses, find new markets and resources, and study the cultures and business approaches of each part of this very small world."

I said 'we' so it sounds like you already work there. I added a little human element. It's mostly dry and boring, so jazz it up a bit and make it more specific for your line of work and the company you are applying to.