Nothing changes physically. Some people claim the cheeks and orbital region look more sunken because they are then comparatively less pronounced. IMO, they either look good or bad and it's not a reason to reconsider advancing the jaws. I.e. not advancing retrusive jaws because they help your retrusive cheeks look more defined doesn't make sense to me. Two bad =/= good.
There are plenty of before/afters I've seen that show this to some degree, and I think the afters look better always, despite the then-relatively deficient cheek area.