What is the typical "prescription" (for lack of a better word) with someone who has 20/10 vision naturally, not that they need glasses, but what are their spherical and cylindrical numbers usually when checked?

Usually such a glasses prescription would be Zero (or perhaps slightly plus if you are older). Many people make the mistake of thinking of the prescription number as some sort of marking on a "vision rheostat." That is, the more you crank up the number, the better your vision gets. This is not at all the case. The number of diopters in a glasses or contact lens prescription is a measurement of the focal distance in (inverse) meters. It says very little if anything about the visual acuity itself.

_Written by J. Trevor Woodhams, M.D. - Chief of Surgery, Woodhams Eye Clinic