The white part of the eye and veins were painted in zbrush, all other parts of the textures were created in substance designer.
RenderMan Render of finished eyeballs
Zbrush high poly and vertex color paint
substance viewport render
Substance graph snapshot. Allows for allot of customization of the iris
Renderman Render of some color variations.
renderman materials use black and white displacement maps instead of normal maps, set the model to smooth for it to render better,
