I was just riding a bike I stopped suddenly, fell, got a small cut on my hand, and I have a scar on my knee from it. I it was a few months ago and it was only once. I was fine i cleaned it off and was getting ready to turn back. I suddenly started to lose my vision and hearing. it looked like the sun was setting but much darker. and I heard a weird quiet ringing it my ears. I have no past medical problems that's I'm aware of and I'm not that old either. it was over after a few minutes but my vision seemed a little worse than before, I couldn't find anything online that could help me figure it out. I'm sorry if this isn't enough information