Found this intriguing, so I zoomed in on some pictures from the most recent press conference. His pupils do look blown-out from a distance, but in several pictures you can still see his irises are a dark blue. In pictures of "young Joe" you can see his eyes are a much lighter blue, but it is common for eyes to either darken or lighten as a person ages. In the picture in
this article about the conference you can see his eyes more vividly blue, but he's also wearing a blue suit which highlights that color. From a distance dark eyes tend to took black. He's also always had hooded eyes, which are now worse due to aging.
I wish there was a way we could monitor his pupil size during pressers. Like, if his eyes were super dilated at the beginning but as it goes on, they shrink.