Eye Textures and Patterns Help

Hello , I wanted to know if anyone could tell me how exactly you make or incorporate patterns and textures into eyes.
Say I wanted to make one set of eyes have swirly shapes or another set with say a plastic look , how would I achieve these things?
Also what would you reccomend as being the best way to create eye colours , any links to tutorials or advice would be greatly appreciated.

Thank you very much everyone.

A quick google search turned up this tutorial for painting eyes that might give you some ideas.

As for making them look like plastic or other materials (as opposed to wet), that mostly has to do with the specular highlights. Normal eyes, because they're wet and very shiny, have specular highlights with sharp edges (for example, the highlights are often done as window shapes, or show the reflection of the photographers lights). Plastic has more diffuse specularity, meaning the specular highlights aren't as sharp or focused).

Great stuff, Chip, but to get a little more basic for a second, Amberletti, have you downloaded the eye template? You'll find that, and all the other templates, on the downloads section of this website. Download the fashion design guide along with it, and read it for a basic understanding of how to use the templates.