Each of the two subjects taking part in our test had to wear three different spectacle frames, and for each frame we made 10 different measurements. For this repeatability study, the measurements were not made in immediate succession. It was only after each series of measurements (with a given spectacle frame and for each subject) that we initiated a second series; in other words, each time we had to install the measurement apparatus(FRED) on the frame and adjust the posture of the subject in front of the (iPad) device.

This method is designed to reproduce a real-life situation in an optician's clinic and demonstrates the precision with which the software is able to reproduce the results on each subject. All the measurements were made by the same examiner, who had been briefed in advance by a company representative. Prior to this study, we had carried out many other experimental measurements which have not been included in this report. The envisaged parameters were as follows: total pupillary distance (PD), monocular PD for the right eye and for the left eye, height of the right eye and of the left eye from the bottom of the frame, pantoscopic tilt, wrap angle (curve of the frame) and vertex distance (distance between the lenses and the eye).

For these measurements, the parameters must be constant for each subject and spectacle frame (total pupillary distance, monocular PD for right eye and the left eye, height of the right eye and of the left eye from the bottom of the frame, pantoscopic tilt, wrap angle and vertex distance). The pantoscopic tilt depends on the position of the subject's head when the measurement is made. The measurements are made using the SmartMIRROR©, the latest product from ACEP, which makes it possible to make nearsightedness measurements by means of simulation software using two photos taken successively by the device's on-board camera: one for nearsightedness and the other for long-sightedness. Each subject was asked to look directly and naturally at the Smart Pad© camera.