Narrow Corridor

February 07, 2008

progressive lens layoutAs the image to the right shows, the layout of the different focal areas on a progressive lens introduce some interesting geometry into the lenses structure.  In an effort to produce a lens that mimics natural, un-corrected vision, without lines, the optimal corridor of vision can be rather small.  Not to mention the size of the near vision portion at the bottom of the lens.  When I ordered my new lenses we had the lens upsized to the largest lens the frame would support; I cannot believe that I would be able to wear glasses with a smaller progressive lens at all.

executive bifocalsThe portion of the lens that I believe is giving me trouble is the unlabeled portion on the image; the part to the left and right of the intermediate vision corridor.  What I want in my lenses are what is known as an executive, or Franklin, bifocal.

(Images are from All About Vision.)

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Mark H. Nichols

I am a husband, cellist, code prole, nerd, technologist, and all around good guy living and working in fly-over country. You should follow me on Twitter.