No eyes
The last pair of glasses I bought before my previous eyeglasses insurance went belly up were the subject of a massive argument with my eye doctor. He had decided that since my vision was getting old that I should have bifocals, and didn't believe that having to twist my head around to peer through the little tiny near-vision window of a pair of bifocals would be a pain. After long argument, he wrote me a single-vision prescription. It sucked. But because I was unemployed I couldn't actually spend the money to get a better prescription, and I've had to deal with these glasses for the past couple of years.
While wearing them, I've watched my eyes fight to be able to focus through them, and in the past six or seven months they've officially given up; unless I've got very very bright light, I have to take my glasses off to see anything close up, and then my eyes don't like to readjust to the terrible prescription again.
Enough. I suspect that I'm old enough so that my eyes won't be focusing between near and distant vision ever again (barring a miraculous cure for both mortality and aging body parts), but I'm going to hunt down the nearest eyedoctor this week and get a new eye exam that, for a change, doesn't prescribe for driving automobiles or being an army sharpshooter in the Sudetenland.