"To suppose that the eye with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I freely confess, absurd in the highest degree."- Darwin, my emphasis.

GUEST seems to think that Darwins word is regarded as some sort of bible-like pronouncement, that can never be argued with or denied, by those who belive in evolution. A mis-understanding of what a scietific theory is ,and of those who accept it as true is the problem here.

I'll join the chorus round here. Go read a Richard Dawkins book. For a very good explanation of the evolution of the eye, see 'Climbing Mount Improbable'

In a very brief summary, it shows how a complex eye can evolve from a simple one, in only gradual changes, all the way back to a cell or patch of cells that can differentiate between light and dark.
BTW, the eye has evolved more than 40, and probably more than 60 times, in nine different main designs