LOL. Ace, why don't you just cut'n'paste and quote
your sources? This way the ridicule and laughter would
be directed at your sources instead of you. Well, there
would be some residual for posting it but so far
regurgitating hasn't been very successful in making
you look smart or earning you any respect.

-Quick

The need to begin wearing reading glasses regularly when reaching age
35 - 40 is due to presbyopia (pres-be-O-pe-uh), the medical term for a
condition that mimics farsightedness. It's virtually a universal
condition, and unfortunately, no refractive surgical procedures can
currently correct presbyopia.

Here is a technical explanation of presbyopia:
When your eye focuses on a distant object, the ciliary muscle
surrounding the lens relaxes; the lens thins and flattens. As you focus
at close range, the ciliary muscle contracts. The curvature of the lens
is increased, and the lens thickens. At about age 35, the problem of
focusing becomes noticeably symptomatic because your lenses will have
thickened naturally, and they will be harder and less pliable. The
ciliary muscles in your eyes also will have become weakened, will have
lost tone and will no longer be able to shape the lenses properly to
focus on near objects. This is because the image would be in focus
behind, rather than on the retina, thus causing blurring of close-range
vision.