I wore prescription glasses for most of my life, and I have worked in places that you need good shades for most of my adult career (25 yrs +), mostly on or near the water.
NEVER scrimp on sun protection for your eyes, especially when you are on the water (light is bounced all over the place).
The best glasses that I have found to date by far are Maui Jim, yes they are expensive, but as with all things you get what you pay for. The glass and polarization is awesome. (They were designed originally by a sport fisherman). The fixtures and fittings have a limited lifetime warranty, so if the hinges rust they will replace them for you. I own 4 pairs now, the oldest being about 6 years old, and rust has never been an issue.
There are a number of the Maui Jim frames that will take prescription lenses. Maui Jim had a great customer service liaison, and I am sure that if you call them they can assist you.
My solution to the challenge of prescription lenses / dive masks? I had Lasik surgery for acute astigmatism about 10 years or so - it worked a treat, and paid for its self in no time as I no longer needed to purchase eye wear that need special lenses!
---------- Post added January 29th, 2013 at 09:21 AM ----------
fyi: my Oakly scratched very easy, my Maui Jim did not.
I have experienced the same issue, I'm not sure if its the salt water environment, but whilst they look cool, they are not suited for the dive life style.