I am sorry if this has already been posted but i didn't have time to look for it. Anyways i have a theroy.

 

KOD, Chapter 27, A Plain wooden box page 600, " Hunching his shoulders and pulling his cloak around, him he leaned on the pommel of his saddle and watched the night for Vanin. Women! He would give up all of his luck-well, half-if he could understand women."

 

Maybe giving up half of his luck on winning battles means giving up half the light just to understand women.

Yep it's been discussed a few times, and most theories point to the same thing. He'll rescue Moiraine from the Tower of Genjhi, and at some point before entering the tower will remove one of his eyes so the Finns can't see through it anymore. His medallion also gives him a clue as to which eye through which they see.