LASIK involves the creation of a superficial partial thickness corneal flap (see figure below).
In regular lasik, the flap is cut with a "microkeratome", a specilaised highly refined instrument which uses an oscillating blade. Intralasik uses a secondary laser to cut the flap instead of a blade.
Laser is performed underneath the flap, and then the flap is replaced.
Healing is very rapid, and most people see well enough to function normally the next day.
A thick and very regular cornea is required for this technique.
Lasik is the preferred technique for far-sighted (hyperopic) candidates as results tend to be better with this technique. It is also favored by those whom a rapid recovery and a return to full activity within the shortest possible time is of overiding importance.