I unfortunately don’t have screenshots of this, but Ochiai’s Kansen used a really subtle way to help indicate the delirium as the infection spread in the hospital. And it was the use of the exit sign. In America, our exit sign is the word light in red but in other countries, it’s the little man running lit in green. And so in the movie, as it progresses, the exit sign in the hospital switches between being lit red and then green.
As someone who is used to the red light for an exit, it took me awhile to grasp that as the person is getting sicker, they’re seeing an exit sign lit in red because that wasn’t the reality in Japan. Well, that, and I think they start to see in green hues when they’re sick, so that red also goes against that.
(It’s an awful movie though, I don’t recommend it – but it is an interesting way in which they use lighting as symbolism to convey madness.)