https://e621.net/posts/4540690

As I was making this post I noticed that the no_iris tag implies invalid but no_irises doesn't so I used that one. But since no_iris isn't aliased to no_irises I'm wondering if it's just a desire path around the invalidated tag. Is/should no_irises an invalid tag as well? If so, what is the right way to tag eyes like that picture?

Looks like a leftover from topic #19466. I would say it should be aliased to invalid_tag as well, but I could see it being disambiguated instead (to choose between empty_eyes, no_pupils, & no_sclera).