What is the highest power available for reading glasses?

Question

I tried 2 readers which were actually prescribed to me, but the only way I could read with those was if I hold the book like 2 feet away from my face. How high does the prescription go? Do I need a higher or lower number?

Answer 1

The higher the +ve power, the shorter the working distance.

And because things held closer look bigger, also the *apparent* magnification.

But the longer working distances will be lost, and the shorter the focus the more restricted the range of distances at which it offers good focus: the specified working distance becomes more and more critical.

Because of this, while people still have some useful re-focussing power (accommodation) of their own (45-60 years, roughy) it's generally an error to jump to too high a reading add too soon, except to suit special work or hobby requirements: toy soldier painting, needlework...

Equally, tasks done at longer distances, computer screen, decorating, may start to need additions lower than the standard reading one.

Assuming no distance correction is required, and a person over 60 with effectively no useful accommodation of their own, a +3.00 reading power will focus at approximately 13-15 inches.

A +4.00, 10-11 inches.

A +2.00, 19-22 inches.

I've given up to +5.00, even +6.00 add as required but, beyond that, often more specialised telescopic glasses perform better.  Operating spectacles, binocular headband magnifiers...