Eyes evolved multiple independent times in convergent evolution.

Almost all the vertebrates have eyes. Those few that doesn't lost their eyes through evolution and live in deep ocean of in caves where there is no light.

Going back from vertebrates into other chordates, we note that tunicates have very simple eyes in their larval stage and lose them as adults. So, it is likely that the common ancestor of vertebrates and tunicates already had eyes. Going back into the evolutionary tree, lancelets have very simple eyes and have more than two, so it is here that things start to get interesting.

Going further back into the evolution tree, we look into other deuterostomes, where we find equinodermatas and hemichordatas, which does not have eyes.

So, the common ancestor of all chordates should have primitive eyes. Those became more complex as they evolved until the appearance of the first fish.

Parallel to that, in convergent evolution, Panarthopodas (arthopodes, tardigrades and onychophora) also developed eyes and some mollusca too. So, eyesight evolved at least three times independently in the animal kingdom except if this was a crazy result of horizontal gene transfers (which is possible due to participation of viruses and parasites doing strange things).

Also, some jellyfishes also have eyes and some nematodes and annelids also sense light, but they have no eyesight yet.

Let's focus on chordates. The primitive eyed chordate probably had a very poor and simple vision, like lancelets do today, and likely fed on plancton and detritus living in the late Eadiacaran or early Cambrian, it could also eat small invertebrates. The line between sensing light and having true eyesight is blurry, but it was crossed somewhere by an early chordate. Also, the animal kingdom was very poorly developed at those times. So, it was in fact a predator, but not in the sense that you were thinking, it was not anything similar to apex predators we have today, since even a herbivore animal is also a predator of plants. Also, the apex predator at the time were probably jellyfish, which never developed eyesight because they lack brains, only having very simple and rudimentary nerve networks.

In fact, a couple of years ago I had read out somewhere (don't remember where though) that one hypothesis about what triggered the Cambrian explosion was the evolution of eyesight in animals starting an arms race. This could make many animals orders coevolving really fast or become extinct, and even plants would also quickly evolve spines, toxins and thick protective coats against better herbivores, leading to a Cambrian world much different than the previous Eadiacaran world.

So, no, the eyes didn't evolved into a predator because it was a predator. The first eyed animals had very poor eyesight without any depth perception. It likely evolved firstly to avoid the sun, or to locate the sun and floating algae, avoid dangers (including predators) and to better locate food (which is not the same thing as hunting, since searching for cabbage is not what people would call as hunting). But once it developed, it started to evolve quickly both for predators and prey.

After the first fishes appeared in mid-Cambrian, those who tended to be prey needed to scan the environment better to detect, evade and hide from predators and they did that by gradually moving their eyes to the sides of the head. Those who were predators, needed to attack the prey precisely in order to ensure it won't escape, evolving better depth perception with binocular vision which is better done by having both eyes in the front of the skull. Invertebrates with eyesight did roughly the same thing. So neither the evolved first, they both co-evolved together. Or if one did evolved first, it was by a very small margin. Also, since the first sighted animals had very poor eyesight, they could not perceive depth, that only came after some reasonable eyesight was evolved.

Also, flying animals, even when being prey, also needed very good depth perception without losing panoramic vision, which they attained by having very specific head shapes. But this only happened much later, roughly into late Silurian or early to middle Devonian for insects, into the late Jurassic for pterodactyls, into the middle Cretaceous for birds and middle or late Eocene for bats.

Animals and plants without eyesight were limited in developing toxins, poisons, carapaces and spines as a defense, but some sighted animals needed to develop those too as protection from predation.