I think you are on to something important here.
I may be deceiving myself, but I think I have a pretty decent stroke. It's much better than when I was a young man, back when I never seemed to miss, and yet these days I go in streaks sometimes where I miss almost as bad as the man mentioned in the OP. I'm just about dead positive that most of my misses have nothing to do with my stroke, but are somehow vision related.
I have very weird vision due to a shop accident about six years ago where my right eye got crushed by a chunk of wood off my table saw. I have always been strongly right eye dominant, but now my dominance seems to switch very easily depending on a lot of factors.
I see a ghost image of everything I look at. It is because the artificial lens implant they put in there has slipped and is no longer on center. The ghost image is only slightly lighter than the actual image, and it always appears at the 4:30 position in my visual field. If I have to drive at night, I see a trail of headlights shooting out at 4:30 from every single point source of light. If I am facing heavy traffic, I have to close the eye or I'd be completely disoriented by hundreds of false points of light.
The accident also torn my iris, so it is permanently dilated no matter how bright it gets. The light over the table causes considerable glare and subsequent loss of visual contrast. Here's a pic my wife took of me a couple years ago. Look at the tiny pupil in my left eye, then look at the right one. You can see the reflection off the lens implant because the pupil is wide open. Pretty creepy, eh?
Here's a mock-up of the difference between my eyes I did in Photoshop. Close to real life, except that's not what I actually "see" when both eyes are open since my brain seems to shut out much of the image from the right eye, leaving just enough info from the right eye most times to have some semblance of depth perception.
Gene, is anything that you can think of that might improve my ability to see if I'm on the correct line or not? I've been toying with the idea of putting a patch over it, but then I'd have no depth perception at all. Plus, I already tried it a little and it feels totally wrong.