I was a -6.00 and it did take a while for my vision to stabilize. Also, at 9 months post-op I'm still having lots of problems with dryeye. I've heard that the higher your prescription, the increased risk of dryeye since they have to remove more tissue and destroy more nerves, and I think that might have been part of the reason I am still having problems. If you have even the slightest hint of dryeye now (discomfort from contacts, etc.) I would think twice about it. Glasses are MUCH nicer than painful dryeye.
However, this is just my experiece. As you can see, results vary widely and many people absolutely love their lasik. However, with a higher prescription, you will have a slower healing period, which can be hard to deal with for some people. If you are a worrier, just think how much you will worry when your comfort or your eyesight aren't working out that well for several weeks to months. Take your time...this is a big decision. Good luck!
