"Now that you say it Rainbow, that is an odd thing indeed. What else could create such a thing? Genetic disorder perhaps? I have read it somewhere that it is possible due to the genes, the color of a ponies irises can change," spoke Twilight on response after she was given the opportunity to think a bit more over the matter. Her mind brought up memories and in each of them, Rarity was seen without her glasses. "Though it doesn't happen overnight, it takes it time so..."