Ted Williams claimed to have 20/10.
Sometimes by expressing a problem or a question to others, I can visualize a solution or answer. To answer my own question, it appears to me that the macula is not degenerating. So even if drusen covers the macula, the macula still gives me good central vision. The drusen is not interfering with my vision (so far as I can tell), so whether it covers the macula or not is immaterial. But what is causing the formation of the drusen? Where is it coming from?