Recently I purchased my now third pair of eyeglasses from Zenni Optical. Have you ever even paid attention the the PD or (pupillary distance) on your prescription from the eye doctor? I know I hadn’t until my first order of eyeglasses. After reading up on the topic online I found that people are really making a big deal of this having to get your PD measurement. Honestly, I don’t understand what the big deal is. When you can get a nice pair of glasses for under $20 at Zenni Optical then you are still saving a ton of money even if you have to pay your eye doctor $30-$40 for a measurement. But, let’s back up just a minute, if you look into what your PD really is you will see that it’s not as crucial a measurement as you might think. It is simply the distance between your pupil. You can have your optician take this measurement or you can do it with a mirror and a ruler. Oh by the way, I just held a ruler up to my nose and looked in the mirror, take it in milimeters, took a guess and have had now three pair of glasses that have fit me perfectly.