Luzerne's iPad App is based on an App/Hardware combination designed by ACEP, (see their version of the same app called the SmartMirror here: https://itunes.apple.com/us/app/smar...581653700?mt=8).

I do quite a lot of training for opticians on how to use the same app and I can say confidently that you can get accurate measurements with the iPad. Practice and a detail-oriented optician are a requirement but you can get consistent, accurate results if you take the time to work on it. The biggest complaint I get from the opticians I train on the app are that they end up spending an uncomfortable amount of time doing the boxing measurements while the patient is waiting because they have to be precise.

I would consider myself proficient and it takes me about 5 minutes to do both the distance/near pictures and measurements but that yields an accurate PD, Wrap, Panto and Vertex measurement. I also always recommend the tabletop stand with it because it negates the potential of human error with the Distance PD picture.

The only accounts I have done training with on the app that ended up not liking it were the ones using an older iPad where the camera wasn't allowing them a picture with enough quality for accurate measurements.