The inevitable question of why people close their eyes when kissing. There is a plethora of theories around the topic: the biological theorem is that the lips have a similarity to the woman's vagina and when kissing the homonoclus functions of a person's brain is overinformed and there is a chance of sensory overload.
Another theory of the kissing action is that our eyes can't focus in stereo in that close range and therefore we close them.
Maybe it is a simple explanation: shyness. Or that the other one is ugly to look at. (Strait Times)