You seem interested in eye evolution - I wasn't sure if you were aware of the high degree of genetic conservation in the eye - the gene Pax6 is considered the master regulator of eye development - the same in binocular human eyes as in the compound eyes of the fruit fly. The same gene, Pax6 activates rhodopsin genes in insects and lens crystallin genes of vertebrates.
Recently, a group used the jellyfish Pax6 homolog (the jellyfish has surprisingly vertebrate-like eyes) in a study. Ectopic expression of the jellyfish Pax in fruit flies resulted in the formation of additional eyes:
Role of Pax genes in eye evolution: a cnidarian PaxB gene uniting Pax2 and Pax6 functions - PubMed
An additional tidbit to combat the "eyes-couldn't-have-evolved" argument, since a single gene has the evolutionary plasticity to function appropriately during development of different eye systems.