So what are digital lenses? The traditional way of making a lens was to take a lens blank that is close to your prescription and use surfacing equipment (a diamond tipped wheel the same size as the lens) to grind your prescription into the center of the distance area of your lens (the middle of the lens if you wear lenses just to see distance, or the top of the lenses if you wear a bifocal or progressive. They a series of tools to clean and size you lens to fit into the frame. Leaving the rest of the lens to be similar, but not necessarily the same as the prescription you need. This leads to disortion in your perpherial vision.
With a digital lens a small diamond tip about the