Sphere Power: +1.00 to -4.00
Cylinder Power: +2.00 to -2.00
Extended Range Available
If you're ADDing for a laptop distance that needs to be added in.Look at the online sites and look at the lens choices:
http://www.eyeglasslensdirect.com/SearchResults.asp?Cat=282
So I really like Trivex over standard polycarbonate or plastic.
http://www.eyeglasslensdirect.com/Trivex-Single-Vision-Lense...
You can easily drill Trivex so you can have rimless if you want. Polycarbonate cracks more easily.
So know your prescription and frame type. Learn about lens materials, lens types (single vision, progressives, free form, ...), tints, coatings, .... This seems like a lot to know but imagine your optometrist trying to figure out everything in 20 minutes. It's better if you do some homework.
All that said, I went to Berkeley and I use their School of Optometry. They don't mind at all if I ask questions and if I'm pretty direct.