Blue I Bay

Explain the genetics behind why this foal has blue eyes.

photo:
http://commons.wikimedia.org/wiki/File:Poulain_yeux_bleus_1.jpg

It would make sense, if he had a wide blaze or a bald white face marking, where the white fur touched the eyes, but he doesn't have a wide white blaze.

On this big horse, a blue eye would make sense:
http://commons.wikimedia.org/wiki/File:Avondalefarm_jacko.jpg