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I'm referring to the Zeiss Progressive Individual 2 for example.
From this URL http://www.allaboutvision.com/lenses/wavefront-lenses.htm
Sometimes, a proprietary measuring device is used for fitting and fabricating a specific brand of free-form, high-definition lenses.
One example is the Zeiss i.Terminal 2, a photo-capture system that automatically measures several fitting parameters — including the distance between the wearer's pupils (PD), fitting height, tilt of the frame (pantoscopic angle) and distance between the back of the lenses and the front of the eyes (back vertex distance) — to optimize the performance of Carl Zeiss Vision's Individual brand of customized high-definition lenses.
So it seems, these lenses involve more measurements of your eye, face, the glasses themselves, and the lens type in order to produce a lens as close to optimal as possible for you as an individual.
But what I don't know is if every vendor goes about the process of evaluating the patient in the same manner or if there are some proprietary products that are better than others.
I get what you're saying, it's hard to know if it's worth it since I've never experienced the supposed improved vision they tout.