Don't use progressives or bi-focals. Do this:
Take a tape measure and measure the exact distance to your monitors when working.
Go to an optometrist and get a written prescription for that exact distance (bring the tape measure with you*) including the "PD", pupillary distance, at that range. Do not buy the glasses from them.
Go to Zenni Optical
http://www.zennioptical.com/u6... ...and order some $6.95, single vision prescription glasses from them that fit your PD size.
Add the standard anti-reflective coating for $4.95
For about $12 you have custom computer glasses.
* Yes, I actually do this. And, yes; I'm a nerd.