Made with Teanmoon’s heterochromia mesh, made to match my feline eyes. They can be found under skin details, but can’t be used with most rings due to the texturing space they use (except the eyeball ring, which feels like some kind of faustian bargain situation). They function exactly like a regular eye and will respond to pupil/eye sliders as normal when equipped.
They come in all the same swatches as the eyes they match, including fantasy and sectoral swatches (do not install the individual files if you’ve installed the all-in-one).