Not sure about the 'eyes,but the whites on smithville run different every year.In springs with steady weather,the run may last only a week.When we have cold fronts or heavy rains,it may last as long as a month.I have no clue what regulates it,I just catch'em.
I do notice in dec.,smaller whites move back up into the river with crappie,out of the main lake.As long as there is some open water,I can catch a few every time I go crappie fishing.