Spend some time with it This app works pretty well but you have to spend some time and follow the instructions. Once I made sure the reference card was in the same plane as my eyes and the camera was arm's length away (so that it doesn't distort as much) I started getting results within 1.5mm of each other. I took several shots, averaged them, and came up with a useful number. Took about 15 minutes to get it right. Galaxy S7 with the back camera so I could use flash.
Accurate if you know how I tried about 6-7 times and knew the results weren't correct because the card wasn't parallel to the camera or my head wasn't. I finally decided to stick the card to my forehead, so at least if my head was good everything else would be. The next hurdle was that I was trying to align the green outline of the digital card to my card and that always yielded slightly off results. Just focus on putting the center marks on the outside radius and it will be golden. PD was verified by OD later :)
Worthless... while I was using it for my own glasses' purchase, I thought I might also be able to use it in my math classes. Unfortunately, the variation in results make it useless for both purposes. I got readings of 48.7, 54.7 and 60.6; I used zoomed in pictures and was exacting in placing the green bar's endpoints. Very disappointing.
It would be nice if you could toggle a super slow movement of the alignment circles. Other than that it's fairly accurate if you set it right.
Worthless Better to jus go in to any eyeglass store to get the right number. This was off by 15 to 20 every time. To late for the first pair of glasses I order trusting this worthless app.
Don't pay for this Used it when brought it this afternoon then when I went back into it, it wouldn't open. Waste of time and money
v2.0.3 - ability to call the app from other apps and get PD results http://goo.gl/6f8EaI
v2.0.0 - improved design, usability, performance and accuracy