Uchiha's Bloodline Limit
The Uchiha familyís bloodline limit, which consists of red eyes with 2-4 pupils, Sharingan allows user to perceive motion clearer than normal eyes, sees through Ninjutsu and Genjutsu, copies motion and even ninja techniques, and can subliminally input ideas into its victim - Mangekyou can even induce extremely powerful hypnosis.
Parts of the Eye
All right, now first letís go a little more in-depth into what the eye is made of. The retina is a sheet of receptors at the back of the eye and is made up from two types of photoreceptor cells; rods and cones.
Rods detect light levels, which means they only pick up black and white images. In humans, these are more common near the edge of the eye. Now, there is only a limited number of space for rods and cones in the retina, so if you increase the count of one you have to decrease the count of the other.
Essentially, you must trade color perception for more detailed perception in black and white, which is largely what enables us to perceive motion.
Does that make even the least bit of sense? No? Crap, all right, how about rods detect motion and cones detect color, is that more understandable?
Okay, now since you canít really increase the sensitivity of a rod, you would have to increase the number of them. One way is to severely decrease the number of cones. Well, this wonít work without sacrificing color, and Uchihaís donít seem to be colorblind typically, so that must not be it.
Another way is to make the retina bigger, but in order to get to the level Sharingan is youíd have to have pretty damned big eyes.
Sharingan has Extra Pupils
Now, the obvious factor that sets Sharingan apart from normal eyes are the extra pupils, isnít it? But how would that help? Well, if rods are more common around the edge of the eye, increasing the amount of pupils would increase the number outer edges to be lined with rods. So, if the center pupil were devoted entirely to cones to retain a sense of color, then the space in the other pupils would be specifically for rods in order to get a better perception of motion, which is what the Sharingan is.
Now, the application of chakra to activate Sharingan could also be used to stimulate the portion of the brain used for memory retention, inspiring the userís memory to become eidetic in nature during the activation of Sharingan, and thus giving them not only exceptional perception, but also the photographic memory required to be able to instantly recall any abilities seen.
But, this is the purely scientific view, which gives us no insight into the subliminal messages, so I also have an easier explanation.
Central Pupil: Ability to see color.
First Sharingan Pupil: Motion perception.
Second Sharingan Pupil: Copies all motion perceived.
Third Sharingan Pupil: Prediction motion- inferring through rational physics the action about to take place.
Circle intersecting Sharingan Pupils: Ties pupils together for the ability to understand what one sees without getting confused. Without it, you would have three different eyes looking in three different directions and no idea what to focus on or whatís going on.
Hypnosis and Subliminal Messaging of the Sharingan
As for the hypnosis and subliminal messaging, thatís probably from watching the eye spin- have you ever had someone turning a spiral in front of you and speaking softly? It works if one knows what theyíre doing, so Iím gonna chalk it up to possible- after all, Iíve said it before and Iíll say it again- I donít know what chakra can do, so whoís to say it wouldnít work?
Thatís all I have on that, although I also have a report on the genetic probability of a Byakugan-Sharingan hybrid, but Iíll stop here for now.
Thank you for reading this, that is, if you could finish it without falling asleep or your mind exploding, and have a nice day.