This can go from blindfolds, that have a bit more significance in the work, or characters being actually blind, like in the works by Voculus,
Hana's Secret by Lok'narash
One of my favourite kigurumi and doll series ever by Lok’Narash on Pixiv. The story on which is was based on is here: The Secret of Hana’s Facial Paralysis. I’ve also made an assisted translation of this work here. Hana’s Secret by Lok’narash Pixiv Soft Nana keeps saying she has facial paralysis, but in fact the reason is this ~~~~ T.T finally wrote the wrong word, should be forever…. ...