Tokyo Ghoul re: Season 2 - What did Orca notice about Arima in his fight with him? In the latest Tokyo Ghoul re: Season 2 episode 13. There is a fight scene between ccg investigators and Orca. In that scene what was Orca talking about Kishou Arima's eyes? He said that there is something strange about Arima and then he noticed something about his eyes. What was it that he noticed?
There are spoilers ahead for the Tokyo Ghoul:re manga.

What did Orca notice about Arima in his fight with him? In Chapter 65, during their fight, 


  Orca noticed something about Arima's eyes.  He also notices Arima's strange timing and uneasy feeling.


It was revealed in Chapter 83 that 


  Arima is a half-human, with a ghoul and a human parent. There are two possible outcome for the child when a ghoul and a human copulate: a half-human or a one-eyed ghoul. Half-humans are indistinguishable from humans (they can eat normal food, unlike ghouls) except they have improved physical capabilities and shorter lifespans. Arima, along with many others, were 'failures' raised by the Sunlit Garden.


What does this have to do with Arima's eye? 


  Since Arima is a half-human, he has a shorter lifespan than a normal human. This also brings about the effects of accelerated aging. Arima revealed after his fight with Haise that he has glaucoma and that his eye is close to not being able to see anything.