How long after getting hit in the eye does it take to turn blue?

Seconds to hours: By blue you probably mean the skin around the eye gets black and blue. That is from ruptured blood vessels under the skin. It can happen instantly or up to 24hrs later. When we do eyelid surgery sometimes patient notice a black and blue eyes the next day. The eye itself turn red if directly hit. You must have an eye exam to rule out damage to your eye.