Was thinking about dōjutsu from Naruto again, as one does, and I thought, “Does each tomoe in a Sharingan have it’s own fovea*?” Google reported that birds have more than one fovea per eye: one for binocular focus and one for peripheral vision.
So while I’m now pretty sure Sharingan don’t, Byakugan do. (Caged “Bird” indeed. Though I feel like that one might have been more for the bird cage/Tanabata implications than the biology.) Speaking of birds, it’s possible that Hyuuga are able to see chakra so well because they also share the avian adaptation of being tetrachromats.**
Unfortunately, this means that polycoria*** is looking more and more likely as an IRL biological method for tomoe formation. If it is polycoria, then are the tomoe always there but only visible when chakra is channeled into the eye? Or maybe the tomoe are actually just where the pigment goes when the rest of the iris turns red- and the hypnotic eye is actually a movement thing where seals are being formed? Do they have red tapetum lucidum instead of pigment being stripped away?
@odditiesinnaruto Any thoughts?
* Fovea: the portion of the eye in the center of the retina (where light focuses) that has the densest amount of cones and thus the sharpest vision
** Tetrachromacy: having four (4) sets of cones, rather than the human standard three (3), thereby being able to see more wavelengths on the spectrum of light than the 400 - 700 nm portion humans typically observe
*** Polycoria: when there are tears in the iris that lead to the formation of one (1) or more extra pupils. People with this condition tend to be photosensitive and/or have blurred, dimmed or doubled vision. (Don’t google this unless body horror doesn’t freak you out. I found it mildly creepy and my mom freaked out completely when she saw what I was looking at, so.)
