I had LASIK done a few years ago, the best $1000 I ever spent, and my Doc told me the exact same thing, 6 months with no diving. I hated to go that long without getting wet but I figured it was my eyes we were talking about and without them most of what I dive for would be gone. I checked with DAN and here's what they say...
Q: How long should I wait before going back into the water after Lasik surgery and what other effects might there be?
A: The Lasik laser procedure is performed many thousands of times each year. Risks are reported to be minimal and improvement in vision is said to be considerable. The physician performing the procedure will provide you with recommendations for activity following Lasik surgery. In general, it's suggested that you can return to all of your normal activities without disrupting the healing process in two weeks. However there is no specific data on when it's safe to return to diving, nor has there been any research on the effects of a mask squeeze and the negative pressure it can create on an eye that has had this procedure.
Considering the lack of specific data, in uncomplcated cases, a conservative recommendation would be to wait an extra two weeks to allow the eye extra healing time.
You might want to do a search on the board on this topic as it's been brought up before.