The frame pivot on my old pair of glasses finally gave out...
...so I've switched to a newer pair I ordered as a backup. What I didn't realize is that I'd had them made with a newer prescription, one after a more recent eye exam showed I no longer needed any correction for astigmatism.
Now rectangular things in my field of view appear slightly trapezoidal.
ETA: Then again, this might be because the two eyes have proportionally different correction than they did before.