Real Eye is comprised of 2 shaders: Iris and Eyeball. The blend file that comes with your purchase includes iris and eyeball objects with these shaders. The following is the documentation for Real Eye.
Importing Into Blend File
Adding the eye objects and shaders from the purchased blend file is as simple as selecting the objects, copying and then pasting them into your blend file. Alternatively they can be appended using the File menu in Blender.
For those unfamiliar how to navigate inside the shader window, this video is for you.
Change Iris Color
The iris has 4 common preset colors to chose from. Use one as a base color and change it to what you desire.
Vessel & Sclera Color
Real Eye allows you to change the color of the eyeball and blood vessels.
Add Second Eye Color
Some eyes have another color overlayed on top of the main eye color. Real Eye allows you to add any color you desire.
Totally change the look of the iris with the nodes contained in this frame.
Totally customize the blood vessels with the node values in this frame.
There are two options to control the pupil size; shape keys and the mapping node. Check out the video guide below to see them in action.
The blood vessel normal height can be altered to your desire. Watch the video below for a detailed guide.
Real Eye uses reflection and refraction qualities in Eevee. This means you ambient occlusion won't work in real time. A way around this is to create the AO using nodes in the shader. This isn't required in Cycles.
Find support videos and more products here: https://www.youtube.com/user/kenhes/playlists
Feedback and suggestions are welcome
Your purchase contributes to the Blender Development Fund as well as helping me create more products.