I was on an underground train the other day (go me), traveling from... King Cross to Pimlico I think, when I noticed a woman sat on the train struggling to read something on the wall opposite, probably a tube map. From her expression it was a little bit too small for her to comfortably read, but not so small that it was worth actually standing up and moving closer to the map.
And I noticed that she did something.
She opened her eyes as wide as she could (makes sense), and opened her mouth and bared her teeth.
Now I'm no doctor - or dentist, optician, phlebotomist or other healthcare professional - but I'm willing to come out right here and say that there is no evidence that opening your mouth makes you see better. Unless your taste receptors perhaps contain some sort of extra sensory perception (but only in a line of sight context).
Perhaps it's part of trying to get closer to the map without standing up - your eyes are being unreasonably held back by your skin (that pesky skin) and so the logical approach is to attempt to push hard enough with your neck to punch straight through your skin to get a few inches closer.
Or you could always just stand up and walk a step or two. As the kids say - #JustSaying