Super cool! I have never known about this, in fact I think animators like me tend to have the iris follow the upper lid down and up in the exact opposite way to stay true to the old rule that you should have the lid resting on the iris and not show too much white unless your trying to convey surprise. Awesome observation guys.
Yes, it is really cool! Really awesome breakdown! Thanks Tyler, this was seriously eye-opening for me. I now see that eye mechanics are actually doing some totally opposite motion than I previously though. Thanks again!