Upon close inspection, I’ve noticed that the white parts of Turtonator’s eye are technically not part of its eye. When happy, the black dot “curls” into a half circle, which means that it’s technically the whole eye.
Now, I imagine the designers intended for both the black dot and white part to be considered the whole eyeball, and that’s how I see its eye too. However, it did make me pause when I inspected Turtonator’s face closely.