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Evolution predicts that we will see organisms and structures which produce the same result in different ways.

Similar selection pressures produce similar results. If there is an evolutionary advantage to getting off the ground, then evolution will (passively, of course) pursue that regardless of the starting point. If there is an evolutionary advantage to being able to process light, then evolution will develop that too - in different ways, depending on the available "machinery" when it starts to be an advantage.

It is very clear that the ability to see provides a massive evolutionary benefit. It is also clear from examining the eyes of living and extinct organisms that there are many ways of achieving that. Humans and other mammals have lensed camera-like eyes. So do fish. Cephalopods have similar lensed eyes, but with the retina turned the opposite way to that of mammals. Insects have compound eyes. Trilobites had compound eyes made from calcium carbonate (quartz). All give the organism the ability to process light.

There are other examples - wings, for example. Both birds and bats, who are unrelated to one another, have developed powered flight in completely different ways. The birds use feathers, the bats use membranes of skin. Other animals, particularly mammals and some reptiles and an amphibian or two, have a more primitive kind of unpowered flight (gliding). They have all achieved the same ends in different ways, exactly as predicted by evolution.

The examples of anatomical convergence can go on and on. But it also extends to the molecular level (link above):

A familiar molecular example is the case of the three proteases subtilisin, carboxy peptidase II, and chymotrypsin. These three proteins are all serine proteases (i.e. they degrade other proteins in digestion). They have the same function, the same catalytic residues in their active sites, and they have the same catalytic mechanism. Yet they have no sequence or structural similarity (Voet and Voet 1995, p. 394).

Evolution is the only mechanism which can consistently and reliably produce such remarkable convergence on so many levels. You can test this in the lab. Take two different, unrelated strains of bacteria, preferably different genuses to ensure that they are as dissimilar as possible. Subject them to a toxin. Both strains, although completely unrelated, will evolve resistance to the toxin. They will do it in different ways, but they will both evolve resistance.