I remember when I was young, staring at clothes hanging in my closet while laying in bed, with dim light from a nightlight. The clothes would begin to sway back and forth, and move different directions. I had large tapestries on the wall, one with a river and horses by it. If I stared at it, the horses tails would swish around, and they would bend down to drink water from the river. This phenomena still occurs in adult life in dim light, if I stare at things at night. They will distort or begin to move. I'm glad you posted about this topic, as I had not considered what may be the cause, and often times I forget about it because I am seldom in dimly lit areas with my eyes open. I have noticed if I relax my focus when looking at documents, or even a post on this page, the paragraph will segment, and parts of it will be closer to me than others, and some of the sentences will float behind others, and that is in good lighting, as soon as i move my eyebrow and focus harder the words go back where they are suppoosed to be. I don't know what thats about.