They both have ONE eye!
Only when an Uchiha awakens both the powers of his Mangekyou Sharingan is when his eyes start to deteriorate. The collective strain of both those powers is what causes the blindness.
You all know......both Itachi and Sasuke almost lost their light while they were using their Susanoo!
As you can see, that while using his Susanoo, even the pattern of his Mangekyou Sharingan has completely disappeared...leaving nothing but empty redness.
You also know, Sasuke had first experienced any sort of effect on his eye sight right here, while showing off his Susanoo to Kakashi, after having over used it against Danzo. Before this he had only experienced pain in his eyes and head while facing the Kage, but no loss of light.
Only when an Uchiha has both his eyes and Mangekyou Sharingan, is when his eyes move toward the darkness.
Only when an Uchiha awakens both the powers of his Mangekyou Sharingan is when his eyes start to deteriorate. The collective strain of both those powers is what causes the blindness.
You all know......both Itachi and Sasuke almost lost their light while they were using their Susanoo!
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As you can see, that while using his Susanoo, even the pattern of his Mangekyou Sharingan has completely disappeared...leaving nothing but empty redness.
You must be registered for see images
You also know, Sasuke had first experienced any sort of effect on his eye sight right here, while showing off his Susanoo to Kakashi, after having over used it against Danzo. Before this he had only experienced pain in his eyes and head while facing the Kage, but no loss of light.
Only when an Uchiha has both his eyes and Mangekyou Sharingan, is when his eyes move toward the darkness.