Wake by Robert Sawyer

15-year-old Caitlin has been blind from birth. A Japanese scientist tries an experimental procedure on her, inserting a tiny device behind one eye. A larger, external device - Caitlin dubs it an "eyepod" - is intended to decode visual signals to allow her to see, but the results are unexpected... and wonderful. I don't want to give away the plot, so I'll just recommend this book unreservedly. Sawyer has been awarded more than 40 book awards and his novels appeal to the general adult reading public, not just science fiction fans. Teens will find this a good introduction to his writing and - bonus! - it's the first in a projected trilogy.