Buying eyeglasses online can be very tricky. There are literally millions of places on the internet that sell eyeglasses. Most web-based internet optical retailers are offering eyeglasses at a cheaper price. Most of the discount retailers are offering eyeglasses for very cheap, but they are only offering one lens material. This material is usually something called CR39. Any stress or twisting of the frames may result in the lens chipping or breaking. If an optical website is offering Polycarbonate lenses at the same price as CR39, you may want to best deal on prescription glasses check cheapeyeglassesonline.ca. If you've been happy with a certain material in the past, stick with that.
You should look at frames very carefully. One great thing that some websites have are pictures that show a particular frame on a particularly shaped face. One thing that people almost never do when they order glasses online is write customer notes.