Gege Akutami created the Jujutsu Kaisen world with great detail and complexity. Just like the manga, the anime adaptation has done justice in explaining to the audience the lore and even the tiniest details related to the fantasy world. Seasoned anime watchers must know that most shonen anime like JJK, Naruto, Black Clover, and One Piece feature characters with a very specific design. Sometimes certain details about a character's get-up are left unexplained, and they simply go on to become a part of the attire rather than a phenomenon.
Source：https://www.cbr.com/jjk-why-jujutsu-sorcerers-cover-eyes/
