What do you think my son seeing?

[Mysti11]

Hello all, I’m new here. I posted earlier in another section of SF and it brought me here.
I have a 9yr old son who has told me on a couple occasions that he sometimes sees colored dots. Large and small sometimes moving from one side to the other or falling. I asked if it was after rubbing his eyes and he said no but he sees them better in a dimly lit room.
He has mentioned seeing a large yellow dot over his teacher’s head and has said when he’s somewhere where there are a lot of people around (grocery store) he sees these dots hovering over some people’s head but not all and said the colors are mainly primary but also mentioned brownish yellow.
I’ve thought of ocular migraines or synesthesia but he shows no other signs of either and he visits the eye doctor regularly but it’s weird that he sees these floating above some people. He’s not bothered by it at all.
Any suggestions or advise? Thanks in advance.