The limit you're talking about is now 5.00 dioptres. Visit the CAA's website and find the .pdf file witht he Class I requirements in it - it's very comprehensive.
Off the top of my head, the CAA will consider someone who has had laser surgery, for a class I, one year after the procedure took place...as long as your eyesight was not outside the limts BEFORE the op.
Good luck,
V1R
P.S. There's loooooads on eyesight on the forums - just run a search.