Yes and no.
Some creatures have eyes that suit their situation. If they live in muddy rivers, or caves, then eyesight isn't worth much.
But for many, better eyesight creates opportunities. It might let a bird fly a bit faster through a forest, or let a bee see distant flowers on a slightly cloudier day. It might give a deer more warning of a predator, or of quicksand, or of brambles. It would let a male elk watch a bigger harem for strays and interlopers. It would let a mountain goat plan the best route. It would let a tree squirrel gauge tricky jumps. There are no end of scenarios where a small edge could be valuable - so valuable that it likely is passed on to the next generation.
And, on the other side, slightly worse vision is a negative edge, and it is just a bit uphill for it to be passed on to the next generation.