They don't come into contact with people exclusively at night - Thats untrue, but they do exist. I remember as a child how I would dread this person so much. He beat me & my friends up whenever he got the chance, destroyed one of my mothers plastic container's one day when I was bramble-picking. He looked sick in the sense that his skin was really pale, and his eyes were seemingly completely black.
You can claim this 12-13 year old was wearing state-of-the-art contact lenses, that you can only find in America, which is extremely unlikely, but that doesn't explain the sense of total dread/fear I'd feel whenever this kid was around.
Those of you who claim it's untrue - I humbly suggest you stop living by assumption's. Black-eyed children do exist.
I've seen him once or twice around town since my childhood, he's obviously older now to the point he's a young adult, but his eyes haven't changed. Still black.
Well next time you see him around town, ask him politely if you could take a pic of him and then kindly post it on here.