Worked in an optical practice in the UK. Man comes in complaining of bad vision. His asigmatism has increased by like 3 diopters. That's a [friggin] load and definitely shouldn't happen. Optician retested using different kit. Same result. Told him to come back in a week and we will retest it. This time we're looking at 4 diopters. They freak out. Recheck again, another optician checks it. Same result. They run through health, smoking, drinking, medicine. Nothing out of the ordinary. The guy looks stressed as [hell] put his head in his hands and put his thumbs against the side of his eyes. The optician asks if he does that a lot. Apparently whenever he's stressed he pushes the sides of his eyes. He's done it so much that he has physically changed the front of his eyeball and ruined his vision. We told him to stop doing that. Never thought we'd have to tell another human being to not squeeze their own eyeballs. Also had to tell a kid to not look at laser pointers, but he was just dumb as [crap].