On Feb 28, 10:51*am, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

I've found that most eye tests end up recommending a lens that is just a
bit too 'strong'. *When the image you see goes from clear to SHARP and
more contrasty than before, the correction is too strong.

WHAT?!? Sharpest and highest contrast are what define the word
"focus". Why in the world would you want anything less than the
sharpest focus? How could that make your eye muscles work harder?

I made a fixture for autofocusing a scanner module. The entire
procedure consisted of adjusting the mechanism to produce the highest
peak-to-peak output when looking at a black & white test pattern.
That, by definition was the focus point - whitest whites and blackest
blacks = highest contrast = properly focused.