I believe mine expires every five years, but the first time I renewed it I did it through the mail. The last time, I only had to retake the eye test (at ten years). And the DMV made me wait a long time, with the eye test at every window clearly visible (and I think the same one, but I could be remembering incorrectly). I can see fine, but it would have been trivial to memorize it. Even if you can't see it while waiting, take a picture on your phone and zoom in. Memorize the lines you can't see. Plus, I'm not sure the employee was even listening to me as I rattled off the letters.

In my old state they had a machine you looked into. I had a harder time with that one, I'm guessing due to my mild astigmatism. But no chance to memorize it, because you don't see it until your face is in the machine; and all the lines were the same size, so you could have gotten any of them.