Considering the generally G-rated fare of Silver Age comics, there were certainly enough of these types of advertisement that seemed aimed at more prurient adolescent fantasies than being a superhero. Most of the ads included an attractive woman, just in case your own imagination didn't trigger all the possible uses Spy-Pen or similar devices had for you.
The "scientific optical principle" that the X-ray specs really worked under apparently was simply that a small feather inside the glasses made you think you were seeing something you weren't.
You've gotta love the zombie-like way she's got her hands out in front of her.
