Grabbed that shot above on the Bangkok subway last week.
Look at those people, no clue that they’re working hard on ruining their eyesight.
Artificial lighting, pretty dim to begin with. A subway, in motion. Those three, faces just inches from those tiny screens. And the whole time the subway car is moving around, so their eyes are having to continually try to keep focus on those screens.
If I had to engineer the highest possible level of eye strain … there it is.
For one, how close is guy #1 to the screen? 20 centimeters maybe?
Just plug 20 cm into the myopia calculator. I won’t tell you the equivalent diopter number, you’ll have
to hop over to the link and check it out yourself. High myopia territory. He’s giving his eyes that stimulus, his focusing muscle that close-up strain. And you know that he’s not about to stop once he gets home, or to work.
This would be the time to take a break from close-up.
But you go to any major city and all you see is people hovering over tiny, glowing screens. Everywhere they go.
Not going to go any better than eating at fast food joints and sitting all day.
And the only way you could conceivable make this even less amazing?
Do it while wearing minus lenses, set up for increased distance vision.
Now you already have a questionable focal plane change, probably an overprescription anyway. Now add to that however many diopters her centimeter distance equals. How many net diopters is she looking through, at that little screen?
I see this in all cities that I travel to.
Worst definitely, in Asia. You can go to Berlin and have a reasonable amount of people be doing something other than playing games on their phones. But if you’re in Hong Kong, it’s almost comical. You can be on a bus that is so full that there’ isn’t enough room to move your arms. And literally every single person crammed in is locked in with their hands at eye level, screens, games. Everyone. I’d make a game out of trying to get on one city ride where one person wouldn’t be on their phone. Forget it, though. Affluent large Asian cities, completely overrun by smartphone use.
And incidentally too, almost the entire population behind lenses. Optometry must be loving life, right now.
The point of all this?
Don’t do that. Centimeter distance is a huge thing. If you absolutely have to be playing on your phone, take off your glasses. Push your distance, and challenge your eyes. Pretty hard to do on a smartphone, since the content is hugely distracting, and the small screen just makes you want to pull the thing closer.
And if you have kids, pay really close attention to those kind of habits.