I have had similar hallucinations before, mainly seeing shadows out of the corner of my eyes.

But to throw a new idea out there -- maybe those ripples and other movements are actually sounds, not hallucinations. Synesthesia. Seeing sound, feeling sound, hearing colours, tasting shapes... one sensation provokes another. I see sound in colours and shapes, and at first I just assumed that they were hallucinations, like the flies.^^ But if they are in shapes or colours, maybe try experimenting with some sounds, or other senses that might provoke them.

"syn·es·the·sia also syn·aes·the·sia (sĭn'ĭs-thē'zhə) pronunciation
n.

1. A condition in which one type of stimulation evokes the sensation of another, as when the hearing of a sound produces the visualization of a color.
2. A sensation felt in one part of the body as a result of stimulus applied to another, as in referred pain.
3. The description of one kind of sense impression by using words that normally describe another. [from answers.com]"