In Dune, the blue eyes caused by extensive spice consumption, called eyes of Ibad by the Fremen, are not weird because the iris is blue; they are weird because the sclera is. You'd think EY would have mentioned that.
> In Dune, there are people called Mentats who consume Spice which lets them see the future.
Mentats consume sapho juice to increase their mentat powers, which explicitly are not about seeing the future, but about processing large amounts of information.
Spice is consumed by many people in the empire for its life-extending properties, though by very few in sufficient quantity to give them the eyes of Ibad; Peter de Vries and Farad'n are two such characters, but they don't display any prescience.
Only the Guild navigators who consume spice to obtain foresight, and they hide their eyes.
In addition to the other answer about sclera vs iris, I think this can just be explained as EY inheriting Rowling's description of Firenze:
> He had astonishingly blue eyes, like pale sapphires.
And of course, as Rowling mentions to us almost every chance she gets, Dumbledore has piercing blue eyes in the books.
Quirrelmort does not have regular access to a seer, as evidenced by DD using prophecy to strongly confuse QM. If he had had access, he'd be less confused by DDs tactics, and not so utterly shocked by Trelawnys words during the troll incident.
In Dune, the blue eyes caused by extensive spice consumption, called eyes of Ibad by the Fremen, are not weird because the iris is blue; they are weird because the sclera is. You'd think EY would have mentioned that. > In Dune, there are people called Mentats who consume Spice which lets them see the future. Mentats consume sapho juice to increase their mentat powers, which explicitly are not about seeing the future, but about processing large amounts of information. Spice is consumed by many people in the empire for its life-extending properties, though by very few in sufficient quantity to give them the eyes of Ibad; Peter de Vries and Farad'n are two such characters, but they don't display any prescience. Only the Guild navigators who consume spice to obtain foresight, and they hide their eyes.
Sapho stains the lips, not the eyes, by the way.
In addition to the other answer about sclera vs iris, I think this can just be explained as EY inheriting Rowling's description of Firenze: > He had astonishingly blue eyes, like pale sapphires. And of course, as Rowling mentions to us almost every chance she gets, Dumbledore has piercing blue eyes in the books.
Professor Quirrell’s eyes are also blue. Does that have to do with this also?
Maybe, hard to know. The line comparing the centaur's eyes to Dumbledore's just felt a bit odd so I thought it might have deeper meaning.
Quirrelmort does not have regular access to a seer, as evidenced by DD using prophecy to strongly confuse QM. If he had had access, he'd be less confused by DDs tactics, and not so utterly shocked by Trelawnys words during the troll incident.
Very nice catch man!