Short answer
Complex eyes may have evolved first in predator species, specifically in box jellyfish. Trilobites are another group of animals where complex eyes may have evolved first. The trilobites covered a vast range of species in many different flavors, with variable life styles and variable diets.
Background
The biggest question here is what is vision? If you call the sensation of light vision, then vision evolved perhaps 1.5 billion years ago (Williams, 2016) as a mechanism of phototaxis in unicellular, photosynthesizing microorganisms (prokaryotes); phototaxis being the moving towards light (Jekely, 2009). Also negative phototaxis existed early, as a protective mechanism against too much illumination. The present day relatives, tiny single celled algae, even have what you can call eyes, namely orange-colored eyespots (Fig. 1). These pigments, however, do not collect light, but block it to give direction to light. From there on evolution of vision becomes a much more complicated matter and can fill libraries.
Nonetheless, I think that's exactly what you are interested in since you are talking apex predators, i.e., I reckon, multicellular creatures, perhaps even with furry or feathered coats and clawed paws. If that is what you are looking for in terms of vision, we are further down on the path of visual evolution.
Cnidarians such as the box jelly fish are relatively primitive species that feature eyes (Fig. 2) and are thought to have appeared in the Precambrian Period between 635 and 541 million years ago. The trilobytes, marine arthropods, also featured relatively complex eyes and first appeared around 521 mln years ago. I think, from a quick search, that these taxa are among the first to have featured complex eyes (Williams, 2016). Both the cnidaria and trilobites (why I keep on typing trilobytes, I must be geeked) are considered predators, but trilobites may also have been detritus feeders, scavengers or even filter feeders. The cnidaria have their hallmark nettle cells with which they can paralyze their prey. Since the Cnidaria precede the trilobites, and are considered predators, I reckon we can hypothesize that complex eyes evolved first in predator species, although some attribute the first eyes to the trilobites.
References
- Jekely, Philos Trans R Soc Lond B Biol Sci (2009); 364(1531): 2795–808
- Williams, Eye (2016); 30(2): 173–8
Fig. 1. Eye spots in Euglena cells. source: ThoughtCo
Fig. 2. Eyes in a box jellyfish. source: box jellyfish