A while ago I was lurking on Twitter and saw some film critics having a conversation about the eye lighting in giallo films (which are basically Italian horror and noir films from the ‘60s and ‘70s). Someone pointed out it was the same weird eye lighting they have in TOS. They speculated that it may have come from American noir but no one seemed to know for sure.
I did some research of my own and found out that:
a) It was probably made popular by the 1931 Dracula
b) It is now commonly known as a “Shatner light”
c) A lot of people also associate it with Morticia Addams