I'm hunched over my mannequin in SimLab, deep in concentration as I finish off the preparation for a class II silver filling on the lower right molar. I've been at this for about an hour, surgical loupes and all, and I'm starting to feel the stirrings of a headache right behind my eyeballs. Just as I'm finishing my prep, I hear someone approach.
"Okay, let's see what you've got for me to check off."
I look up and I see my two row instructors, with pens and gradebooks in hand, but there's one slight problem: I don't have two row instructors.
I'm going cross-eyed.As I start talking, I'm trying to uncross my eyes and focus on my instructor's face, but my eyes keep snapping back to their crossed position. She notices this, and her friendly smile suddenly disappears. Fortunately, she's able to diagnose the problem as something going on with my loupes. A few days later, I track down the vendor from Designs For Vision and talk with her. She measures my eyes and does a few tests, then checks and rechecks my prescription.
It turns out that there is nothing wrong with my eyes; my head is too big for my designer frames. When I put on the frames, the temples that hook behind my ears bend slightly outwards to accomodate my enormous head. That causes the portion of the frame with the lenses to bend outwards and cause the telescopic lenses (which are converging at a single point) to cross ever so slightly, but it's enough to cause eyestrain over the course of a procedure.
There's nothing I can do about it except change my frames... but that means I've got to upgrade to the Nerd Frames -- or, as affectionately dubbed by the upperclassmen "BCGs"
That stands for "Birth Control Glasses" because, they explained, as long as you're wearing them, you'll never get laid.
