Kadanshi: You're in luck. Cause you can't really wear contacts while boxing anyways. Ha! I too am near sighted (pretty badly actually). So long as we're not boxing in California (where apparently a boxer, by law, must have 20/20 vision!?!!?) we're fine to fight. It does make some things more difficult, but you can definitely still fight. The one thing I really had to work on was not squinting, or offering any sign to my opponent that I couldn't see so well.

Steven is right, too. Slip, duck, and weave. Staying close works, but so long as you have decent depth perception you should be capable of working on the outside, as well. It all depends on how comfortable you are with your eye-sight (or lack there of). To strengthen my eyes, or just become more accustomed, i try to not wear my contacts or my glasses for several hours a day. While you might not be able to see any clearer, your ability to discern shadows/blurs will improve a great deal. It's gotten to the point where I can see my opponents tells, despite not seeing them with any real clarity. It all has to do with seeing patterns of movement and other easily discernable things like posture/hand position.

Good luck!