Just as one would expect, it appears that antioxidants can protect against this type of damage. Note that the study was in rats, but we have every reason to think it would work in humans. In particular, several studies showing that dietary antioxidants protect skin from sunlight in humans; it's should be essentially the same thing for the eyes.

This is not in the least surprising. Dietary antioxidants also protect the skin during sunlight exposure.

Oxidative stress likely also plays a role in diabetic retinopathy. It plays a role in the aging process itself. That said, there is probably a limit to protective powers of antioxidants. Nonetheless, I don't think that that limit has ever been realized in any population. I doubt we've even come close in rats.