I have been wearing glasses since the second grade
and have to get stronger prescriptions every 1 to 2 years.
in my search for a good eye glass deal I found  coastal.

check  them out.
http://www.coastal.com/firstpairfree?cmp=display&src=us_trf_dr&seg=G_12FPFhybrid_US

In 2010 I used zenni optical for my  glasses just had to get the puipilary distance from the doctor as well.
http://www.zennioptical.com/?gclid=CISKg5rKkrQCFU6mPAodlxsA4A

The internet provides the greatest savings so far for glasses then any thing else I have bought on line.

Good luck.