Mod Name: DIY Centralized Heterochromia psd file 
Mod Type: Face (Eyes)
Author: Stonedrose
Replaces: Iris Shader (iri_a.mtrl)

How To:

I have tried to make this as simple to use as possible.  There are two hue layers, 'outer colour' and 'inner colour' using this hue layers simple slide the bar across til you find the colour you want. You can even experiment with saturation and lightness too! Once your happy simply save the psd and import it into Textools or Penumbra! 

I have attached my preferred setting on Textools which also includes the emmisive as the spotlights will 'glow'