I was thinking the other day about the idea of the eye using a lens to focus light onto the retina at the correct distance, and was curious whether a digital distortion could ever be used to aid a farsighted person to read something (say this forum post?). The idea being that you could distort the image as if it were going through an optical lens, like your reading glasses, and thus allowing the proper focusing of the image onto the retina for a person given their prescription(this would obviously take many tests to be accurate). I was first thinking of something like a pincushion/barrel distortion, but I highly doubt such a simple distortion would be accurate. Thing is I have no way to test anything I create because nobody in my immediate vicinity needs reading glasses! and I have no way to relate to what they see without their glasses. It doesn't help that when I try to do research on something like this I get pounded with digital camera information and related software, dealing with lens correction and distortion. Thx for any info guys!