Here is Susan gets native's response to my one eyed finch mystery:
This is pretty straightforward. Not Pirate Disease...It's called avian conjunctivitis. It has been ripping through the house finch population in recent years. Pine siskins, goldfinches and cardinals are also being affected, but on a smaller scale.
Here's what to do: Take down all your feeders and clean them with 1 part bleach and 4 parts water. It might even be helpful to take them down and keep them down for a week or so. But if it's really really cold, I would just keep them up. Also, rake under your feeders really well. (this is to rid the area of as much of the bacteria as possible.)
Next, sign up for the House Finch eye Disease Study at Cornell Lab of Ornithology:Cornell House Finch Eye Disease StudyYou sign up, get a user name, etc. Then you report both SICK and HEALTHY house finches at your feeders. They want to know what percentage of finches are getting this. I wouldn't try to capture any of the sick birds, though it's kind of easy, since you can sneak up on their bad side. Most rehabbers are in agreement that treatment, while it may be successful, might also cause resistant strains of this bacteria.
Thanks for the great info. If you're having similar issues with your finches I'd love to hear from you!