Ah, if it was truly blind in one eye that would be a retinal artery occlusion which is a stroke equivalent, just affecting the retina itself instead of the brain. That one you can see black sometimes. If it's the visual brain centers in the occipital lobe, it'll be half the vision in each eye, and that's the one where field of view is just narrower and you don't really perceive any dark area.

But as you said, point is this stuff is confusing, if any doubt, go to the hospital. Doctors would much rather a false alarm than people showing up too late to do anything.