Pat, it turns out, has been provisionally diagnosed with corneal dystrophy, also called Fuch's endothelial dystrophy. The endothelial cells at the back of the cornea deteriorate, causing the cornea as a whole to swell and blister. No known cure other than corneal transplant, though there are some treatments.
Oh, by the way: filkferengi, I got the Beethoven CDs. Thanks!