Generating Eye Textures

Good afternoon. It's been a while since I've posted for anything related to Substance Designer, and I'm kinda stumped as far as generating this specific pattern that goes over the fibers of the iris, and I was wondering what would go into creating such a detailed pattern. 

This reference is from a generator from Blender (it's mind-blowingly detailed).

I'm also working on my own eyes for my game projects, but after seeing this, I am now wanting to get my eyes to this level of detail. Below is the image from Unity and my procedural eye and while it looks passable from a distance, I know there is a way to recreate that insane shape.

Any pointers would be helpful