Not enough headdesk in the world

I was relaxing with a fluffy vampire novel* and I came across this:

The blue of my eyes had become gleaming silver, the pupils dilated to pinpricks.

I had to read it at least twice to really comprehend that yes, the author had actually written that and their proofreading pool and/or editor hadn't caught it. And then I looked up "dilate" again, just to be absolutely sure that my definition was in fact correct. Way to yank me out of the narrative with egregious biological impossibilities, book.

* I am a simple girl with simple needs, and one of them is reading about superpowered people who get to solve most of life's problems by ripping its head off.