What is needed to do radiometric dating
(The exact size that is "perfect" depends on the brightness of the lighting in a particular environment.) An example of a narrow aperture lensless eye is found in the chambered nautilus. To get a lens, a ball-shaped mass of clear cells with a slight increase in the refractive index is needed.Once this mass is formed, it can be refined with very slight increases in the refractive index to produce greater and greater visual acuity.
There are just a few problems with this "theory" of eye evolution however.Reason tells me, that if numerous gradations from a simple and imperfect eye to one complex and perfect can be shown to exist, each grade being useful to its possessor, as is certainly the case; if further, the eye ever varies and the variations be inherited, as is likewise certainly the case and if such variations should be useful to any animal under changing conditions of life, then the difficulty of believing that a perfect and complex eye could be formed by natural selection, though insuperable by our imagination, should not be considered as subversive of the theory.Darwin was at a loss to explain exactly what was happening, but he proposed a stepwise evolution of the human eye by showing examples of differences in the eyes of other creatures that seemed to be less complex.There will come a point when the aperture is the perfect size.A bigger aperture gives worse eyesight, and a smaller one gives worse eyesight.The necessary faith in such a scenario increases even more when one considers the fact that even a simple light sensitive spot is extremely complicated, involving a huge number of specialized proteins and protein systems.
In other words, for the miracle of vision to occur, even for a light sensitive spot, a great many different proteins and systems would have to evolve simultaneously, because without them all there at once, vision would not occur.
All they can tell is if the environment around them is light or dark.
However, other largely translucent creatures do have pigmented cells.
Moving in space is the most frustrating damn thing ever.
Think about trying to maneuver on infinitely slippery ice. If you want to move to the right you need to chuck a bunch of stuff to the left, and if you want to turn one way you have to chuck a bunch of stuff in the other.
The entire bodies of some creatures with eyespots are largely translucent.