Sport45 : Your focus is on the pencil rather than the doorknob. Try playing with your focus until you see 2 pencils and one doorknob. One pencil will be more distinct than the other.
Right eye dominant: the left pencil will be most distinct, and aimed at the dorknob.
The eraser being under the right doorknob tells me the same thing. Focusing on the doorknob both pencils look pretty much the same. If I stare at the doorknob long enough one pencil image or the other (seems random) will go away entirely.
For target shooting (round black bulls on paper) I close my left eye or wind up with a headache along with a bad score.
The last time I qualified for my carry permit I used both eyes and point shot well enough to pass.
If I have time to aim I'm closing my left eye. If I don't have time to aim I won't. YMMV