Strange vision problem. Individually, each eye sees clearly, but images overlap !

This problem is difficult to explain, but here goes. Imagine a carpet with a baseball underneath it. Now imagine looking at that carpet while at floor level. The edge of the carpet will look like a flat line except near the baseball, where you will see a bulge. That's what I see with my right eye whenever I look at a horizontal line (a line of print when I'm reading, a house roof line, a telephone line, the top and bottom edges of a billboard, a shelf, etc.). Now, imagine that bulge turned upside-down, so that it looks like a shallow depression in the carpet. That's what I see with my left eye. So, with my left eye closed, my right eye sees a bump at the point of focus on any horizontal line. And with my right eye closed, my left eye sees a depression at the point of focus on any horizontal line. Except for either a bulge or depression, the image is perfectly clear. However, when I look at horizontal lines with both eyes, things are blurred at the point of focus, as if what I'm looking at is a vibrating string. When reading, this blurred area will move across the page as my point of focus moves along the line of print. I can make out the words, but it's annoying. When driving, because of this strange condition, a sign with two lines sometimes looks like is has three lines.
I have my eyes checked regularly. Each is corrected to 20/20. I have had an OCT scan done, with no abnormalities noted. My left lens has a small downward prism adjustment - this was done in an attempt to correct my problem, though the adjustment seems to me to be in the wrong direction. The problem exists whether or not I am wearing my glasses.
Please, tell me what's wrong with my eyes. It's driving me nuts!