Refractive power of lens?

[dslc1000]

Hi! I have one specific question. Can anyone tell me what the refractive power of the lens is (...the one in the eye that is...)? I'm mostly interested in the maximum refractive power it can reach during accomodation.

I've done a few google searches on it, and found some stuff, but it seems to contradict what I have in my own textbook. My textbook says a dozen diopters, while a website I have just visited states that the upper limit during accomodation is ten diopters, while the lower limit is infact zero diopters! (..I might have even read twenty diopters somewhere...although that doesn't seem right...)

What I basically want to know is: if two parallel rays were to strike the lens during maximum accomodation (i.e. when its refractive power is greatest) , how far behind the lens would they be focused?

Thank you for taking the time to answer such an odd question! (...if anyone does...)

[Cap'n Refsmmat]

Can that even be measured?

[dslc1000]

I think it must be the case that it can be Cap'n Refsmmat, but I'm not sure how.