Try to map out the spot: Make a grid in a drawing program with crosshairs in the centre. Close one eye. Keep looking at the crosshairs. Scan from the central f

Try to map out the spot: Make a grid in a drawing program with crosshairs in the centre. Close one eye. Keep looking at the crosshairs. Scan from the central focus point using your mouse and click when you can't see the mouse cursor. With a bit of trial and error you should be able to map out large regions you can't actually see in. (My dad did this years ago for a retinal detachment spot in his one eye.) More importantly: get an optometrist to check out your retina.