This will give you Life Time Access To Mega Eye Shader 

Mega Eye Shader is a shader with many options, think of it as a “build your own” eye shader, with all of the effects in here you can make mostly anything your heart desires.

This shader currently has over 40+ tabs and gets updated regularly, with this purchase you also get access to all future updates.
 
This also comes with access to SDForge (Pupil Editor) so you can create custom pupil shapes in mega. 

This shader also comes with an optimizer to try and prevent harsh lag from the shader.
 
Are you planning on using this shader for commercial use? If so you do still need to buy the commercial use from my site. DM ch5n3o4 on discord for more info on commercial use.