Getting older is fun.

Hmm... down the rabbit hole.  A websearch on non-prescription bifocal reading glasses (because I need them), led to an marketing blog explanation of bifocal, which led to the discovery of a paper on the theoretical mechanics of identifying whether or not the document was a translation or the root source and if so, the source language of a translated document in a published journal and the concept of a field of study devoted to linguistics relating to statistics.

I never did find a cheap source of say... 1.50 and 2.00 diopter reading glasses.  (About $0.99 at the local 99cents store for cheap single focus).  But I did find a pretty good definition of why...


The links in text:

http://opticstoreonline.hubpages.com/hub/non-prescription-bifocal-eyeglasses

http://www.tandfonline.com/doi/pdf/10.1080/09296170500500983#.U4EOsvldVV4

http://en.wikipedia.org/wiki/Quantitative_linguistics

http://www.eschenbach.com/products-reading-glasses-progressive.htm

http://www.focusers.com/diopter2.html