I'm due for bifocals, actually should have them by now but keep putting it off every year. I prefer setting my glasses atop my head when I read and then putting them back on when I need to see anything beyond about a foot. So tonight when I was sketching a self-portrait using Photo Booth as a sort of mirror, I realized that I needed my glasses to see my face on my laptop screen but then had to look under them to focus on my drawing. And I was trying not to move my head too much so I struggled between maintaining my head position while at the same time looking down under my glasses at my drawing. The compromise seemed to be viewing my drawing half through my glasses and half under them, a split view with an odd mix of focus and blur. This resulted in a somewhat blind-contour drawing with a bit of distortion, along with a slight eye-ache. But I ended up with a nice sketch and my daughter's hour-long Irish dance lesson seemed to go by much more quickly.