Now that I've had mine awhile I'm developing a theory that may or may not be true.
I had numerous problems obtaining focus, but was able to verify that if held correctly, and close to my eyes, the entire screen would be in focus.
But during watching or playing it wouldn't really stay that way.
I believe though that a mental sort of change has taken place, where my brain has almost reconfigured itself to see through these things. Maybe some people already have that talent acquired, either from watching a lot of 3d or even just wearing regular glasses.
At any rate, there was a point during a 3d session of GT5 where I realized everything was in focus and I wasn't even trying.
I did some tests and confirmed a few things. One, my perception through these, for whatever reason, presents a sort of 'split eye' view, that is-- there is a barely perceptible obscuration between both my eyes (it could be simply my nose, seriously: sometime become aware of your nose (mine is not particularly big) and you will notice that it always occupies your vision. We block it out mentally, having had it there since forever. But I bet that when your eyes are physically close to something, but focusing far away, that nose perception comes to the fore, because your vision is operating in a new way)). After I ignored this 'center divide', I could look to the farthest edges of the screen and they would be in focus. I was not straining to focus, as I had before. It was exactly like when I'm in a theater and I focus on some part of the screen for whatever reason.
I first started to notice this brain/vision thing when I was playing GT5 for the first time in 3d, and I noticed the 30 fps framerate and it bothered me at first, so I rented Bolt, a 3d movie I'd seen in theaters, the first time I saw the new 3d and was very impressed.
I watched it and after 15 minutes felt too fatigued, switched to my projector and watched about 10 minutes but was suddenly craving the 3d again. And realizing also that, without thinking about it, as I was watching in the glasses it was like I was in a theater, and watching on my projector was like... renting a movie. That is, in the glasses, what was happening on the screen seemed to be of very large import; this happens in theaters-- it's so big, it strikes the consciousness in a different way than say, from a 50" screen (which is what I use for my projector).
Another thing I noticed just before this time is that there is a disconnect with your brain, where you are aware that millimeters away from you are all these optics. Your brain and your eyes are aware of that, yet your eyes are expected to focus on infinity.
I think my brain was fighting this. Once I accepted that this is like a Viewmaster, and that the plastic bits around are just part of the tech, I was able to dismiss them mentally, and my brain accepted the far vision, where my eyes were to be focused on the screen.
I think it requires a small change mentally-- it's only taken me a couple days. But I think this may be part of the problem for folks who, like me, went into this imagining putting on some tech and immediately being plunged into a totally dark chamber with a glowing screen up in front of you, and no reflections on optics just a tiny breadth away.
Another thing. These optics get greasy real easy. You gotta be careful not to let them touch your forehead (or maybe I have greasy eyelashes? Sheesh) or they'll get oil and this really doesn't help, so I keep a cloth and a lil lens cleaner near these, now.