"A Daruma!?"
Bro that's like a Kasha, no?
Those were introduced in an earlier chapter, and it was pretty apparent why they called them Daruma if you're familiar with a particular bit of Japanese trivia that pops up from time to time in manga and anime. The time you spend traveling through one is accompanied by the thing saying something, and if it stops saying it while you're inside it's kind of like the "daruma" game in Japan, which is similar to Red Light, Green light if you're more familiar with that. Except, rather than losing a round of a simple game because you're caught still moving when it's time to be out of that thing, you're trapped inside of the space used to travel through the "Daruma." I believe it's a bit on the permanent side, too.
But her glasses are specifically there to block it, since otherwise she gets a headache. The guy in the previous chapter with the same ability is shown removing his glasses to use the ability, yet here Iris does not remove her glasses
The glasses are probably limiting rather than blocking. I feel like "blocking" an innate sight ability like hers would be more like wearing a blindfold, kind of all or nothing. Also, if it's just a limiter that explains why she can still see more than average even with them on, but isn't seeing too much.