Just finished modeling a new eyeball. In this case I wanted a completely "water tight" Eyeball and cover entirely of quads, I need it for some things I'm playing around with. All of the other eyes I've made have high valence tri poles...

Cover

Eyeball

Combined rotational views, there is a 16 edged pole at the back but it's quads and being that it's at the back I figured it would suffice. UV mapping this eye will be a bit tricky... the edges need a bit more snugging but essentially this is the final geometry at base resolution.