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There are 3 possibilities large size of eyeball affecting on vision of human
1) There are more light gathering rods and cones of
someone with a larger retina than a smaller one, which would result in a
higher resolution image in the brain for a larger retina.
2) The number of cones and rods is the same on a
small or large retina, but each cell is larger and therefore gathers
more light, resulting in better low-light vision for someone with a
large retina. Or
3) The number and size of light gathering cells is
roughly the same for adults with larger or smaller retinas, but there
are larger gaps (and more supportive cells) between rods and cones in
larger retinas. This would result in equivalent eyesight among adults
with different sized retinas.