It’s sort of like the evil eye, but in reverse: the good eye, brought on by an application of lead-based kohl makeup that was unknowingly poisonous to ancient Egyptians but also had anti-microbial properties. Plus there was the magical aspect of invoking the gods Horus and Ra with an application of the black makeup and further protective properties.
Makeup was for Everyone
In ancient Egypt, as modern archaeologists and Egyptologists can tell you, people from all classes, from laborers to royalty, applied kohl to their eyes. But this phenomenon of thick, black makeup has been known worldwide, and people still apply it in North Africa and Central Asia, says an article about the practice on Discovery.com.
Statues of an Egyptian priest and his wife. Both appear to be wearing kohl. (vlad_g /Adobe Stock)