Not quite true. The human eye contains, in effect, two different imaging
systems: the fovea, and the rest of the retina. In the vicinity of the
fovea you get good colour vision and very high resolution -- it's what
you see the 'l' in 'resolution' with, and it covers a couple of degrees
(at most) of the field of view. The rest of the retina combined has
about the same number of photoreceptive cells, and covers a much wider
field; it's less sensitive to colour, much lower resolution, but is
functional in very low light levels.
I think there are some figures for visual data sensitivity in Foley, Van
Damm et al, but it's a while since I had to read that (read: since I last
had anything to do with real-time photorealistic rendering for
simulator graphics engines). About 4kx4k pixels springs to mind ...
-- Charlie