Colour-Blind Mangekyo Sharingan?

[HouseMD]

I was just thinking, since the sharingan is red in the centre (the pupil) it means that it reflects all of the red-light that hits the eye (We see things because light is reflected from objects into our eyes). The normal sharingan doesn't seem to have to this problem since it's pupil is black (The middle part), but Kakashi's and Itachi's Mangekyo Sharingan's pupil is red, while Sasuke's and Madara's is Black.

Guess Sasuke shouldn't be colour-blind in order to fight Naruto, he is wearing red after all xD

Edit: Found a pic of all of teh sharingans

Spoiler

[kaiten]Please put large size pics in spoiler tags. Thanks[/kaiten]