Here is a possible answer. When girls close their eyes it means they like kissing you. if open it is otherwise
What the hell kind of thread is this? You're both supposed to close your eyes when you kiss...it's more intimate and less awkward: How to Kiss for n00b virgins.
Well, I can only speak for myself, but I think it's something to do with the fact I need to club them on the head beforehand.
Just to enjoy the pleasant feeling of the kiss received from the other half. You can enjoy only when you close your eyes