Well, honestly, pretty much nothing special - the same things your average non-ghostly, non-glowing eyes see.
In fact, this owl isn't isn't so much a study in scarlet as a lesson in albinism - one of nature's most spectacular genetic doodles.
Albinism, in both animals and people, happens when there's little to no melanin present at birth. Melanin is nature's crayon, a chemical that infuses skin, hair and eyes with color.
Sometimes, it gives the eyes an unearthly red hue. But it's actually the blood vessels you see inside those orbs that are visible through the colorless iris.
Hence, this spectral stunner.