Your brain needs glucose to function, if it's not got enough glucose it can get confused and start to struggle to do top level brain stuff - like correctly interpreting the messages your eyes are sending it.
That sounds a bit scary, but it is just a good motivation to treat your hypos nice and quick before it gets to that point - if you can, maybe stash a little tub of jelly babies in every room?
I have sometimes had vision disturbance as part of a hypo; floating lights a bit like migraine symptoms. But as soon as I get some sugar in me it resolves. I'm glad it resolved quickly for you too.