Did you know that when a human sees something they like, their pupils dilate? Yes, it's true. Way back when, women in Italy used to put a drug in their eyes to dilate the pupils, so their suitors would find them attractive and pursue them. That drug they used is commonly called Deadly Nightshade, or Belladonna as the Italians put it.
So women made their eyes huge to trick men into thinking the women liked what they saw. Some ladies died from the effects, 'cause Deadly Nightshade is appropriately named for it's deadly consequences...
That practice has stopped since then, and dilated pupils usually means someone's just spent a few hours having bright lights shined directly into their eyes. Ah, how those opthamologists torture me.