Two-Foot Glasses

June 16, 2009 8:11 AM

Where (online) can I buy +2.00 reading glasses with a focal distance of 24 inches?
posted by king walnut to Health & Fitness (5 answers total)

Dioptre power (you mention +2) is inextricably linked to focal length.

power = 1 / f

So +2 dioptres will focus at 0.5m.
posted by Tapioca at 8:58 AM on June 16, 2009

OK, interesting, thanks.
But... I have a pair of +2.00 and the focal sweet spot is about a foot.
posted by king walnut at 1:11 PM on June 16, 2009

You can buy glasses designed for a medium focal length (20-24in), sometimes labelled as computer glasses. See these links.

"Reading glasses" that you can choose from a store display are for close vision.
posted by Tapioca at 1:33 PM on June 16, 2009

Reading glasses that you choose from a store display are for any purpose you want, not exclusively "for close vision." Go to a store display and try on different strength glasses. You already know that 2.00 is too strong, so try 1.75, 1.50, 1.25, and (if they have them) 1.00. Maybe one of them will be close enough for your needs. (Bring along a piece of paper with small print and a tape measure so you can put the paper 24 inches from your eyes.)
posted by exphysicist345 at 8:56 PM on June 16, 2009

Seconding the idea of going to a store to try them out. I bought a +1.00 pair at Borders Books that focuses nicely at 24".
posted by dws at 9:58 PM on June 16, 2009