In "When We First Met", we spotlight the various characters, phrases, objects or events that eventually became notable parts of comic lore, like the first time someone said, "Avengers Assemble!" or the first appearance of Batman's giant penny or the first appearance of Alfred Pennyworth or the first time Spider-Man's face was shown half-Spidey/half-Peter. Stuff like that.
I thought about this the other day when I was doing an article about the original reasons for Superman's secret identity during the Silver Age (as I wrote that, I realized that it was actually the article I did about when Clark Kent first opened up his shirt to reveal Superman's S underneath his shirt that made me think about this).
The first time that we see Clark Kent with glasses is obviously very early on, as he shows up in Action Comics #1 (by Jerry Siegel and Joe Shuster) rocking the glasses when he changes into his Clark Kent secret identity for the first time...
That's the first time Clark Kent actually wears the glasses in a comic book, but what about when Clark Kent first started wearing glasses in the life of Clark Kent? This is a surprisingly not simple answer.
The reason is because when Superboy debuted in 1944's More Fun Comics #101 (by Jerry Siegel and Joe Shuster), young Clark Kent did not wear eyeglasses!
This obviously took the oddity of Superboy's secret identity to an absurd degree, because he's not even wearing a disguise! Superboy is just Clark Kent with a costume!
Don Cameron took over the writing duties on the Superboy feature in More Fun Comics #101 and sure enough, Clark Kent remained without glasses for essentially the entirety of 1945 (the series was a bi-monthly book at the time) Joe Shuster drew most of the stories, but Marvin Stein drew one of them (different inkers throughout, from Ira Yarbrough to John Sikela to Marvin Stein)...
Finally, at the end of 1945, Clark Kent just has eyeglasses out of nowhere in More Fun Comics #107 (by Cameron, Shuster and Sikela).
By the way, I just realized that it was actually my article about when Smallville was first shown to be in Kansas that made me think of this one, because when Superboy debuted, the name of his hometown was not revealed. While I was looking at those early stories, I was surprised to learn that Clark Kent didn't wear glasses in those original stories.
I believe later Superboy stories almost certainly made it so that Clark Kent pretty much "always" wore glasses, but it was More Fun Comics #107 that they finally popped up. That was before Crisis on Infinite Earths, though. What about in the years afterwards?