A Hereford bull breeder from South Africa told me that eyeset is one of his key selection criteria for bulls given the tall but sparse, rough, forage his cattle have to graze. He says it cuts down on irritated eyes and pinkeye as I recall. 

Basically looking at a bull from the front you do not want to be able to see his eyeballs.  Looking at different bulls, there is quite a difference between them in this "eyeset".

edit to add: if you look at steer #82 I posted a pic of below you will see he inherited a very similar eyeset to his sire 72. But the eyes are slightly more visible from the front, most likely due to the influence of his dam.