Board Thread:Theories and Speculation/@comment-1930928-20191128005957/@comment-4961229-20200406191213

I've argued with some people who claim that that makes them more susceptible to ocular genjutsu. I usually point out that even though they can see everything that's not the same as presenting an avenue for visual genjutsu to flow into their eyeballs. Otherwise, sensor nin like Karen with her Mind's Eye of the Kagura would be susceptible to visual genjutsu from 10 Km away without the caster even being aware of it.

While we haven't seen any Hyūga fight with their eyes closed, we did see Ao using his Byakugan with an eye patch all the time. Pretty much the same thing. All he has to do is activate it. And he can do that through the eye patch. No reason why eyelids would be any different on a Hyūga.

Closed eyes on a Hyūga should prove very effective against Sharingan and other visual genjutsu attacks, like Ephemeral. Kishi really should've addressed this, but he chose not to.