I finally fixed it. Ages ago, I complained that PDF documents on my computer were going fuzzy in weird ways. This is the example I put up:
This is my list of for-real ancient Greek people, from which I pick character names. What happened was bizarre. I could open the list, and everything would be fine. Then right before my eyes, the list would slowly but surely turn unreadably fuzzy. I always thought it was because Adobe was rendering non-English, but that turns out not to be the case. It happens with mathematics textbooks too.
A lot of googling put the blame on the morphological filter in AMD's video driver, but that never really fixed it. I just lived with the fuzziness. But when it reached the point of interfering with my children's homework I put in a concerted effort, and discovered this in Adobe's config:
Turn off 2D graphics acceleration in Adobe. That fixes it. The reason people think it was the AMD driver is that, when you cripple the driver enough, Adobe can no longer do harm.
If this problem hits you, Go to Edit --> Preferences in Adobe Reader. Select Page Display. Disable as per the image. Done.