The purpose of the iris is to control the pupil size. Genetics play a role in determining eye color, and there are countless eye color combinations.
Colored Part of the Eye - All About Vision
Eye color - Wikipedia
May 08: Iris Day
9 Top Types of Iris for the Flower Garden
Iris of the Eye Definition, Function & Parts - Video & Lesson
Why do our eyes come in different colours? - BBC Science Focus
Macro Blue Yellow Eyes Iris Pupil Macro Eyes Close Face Stock
What Is The Rarest Eye Color?, Blog
Iris Block's Instagram, Twitter & Facebook on IDCrawl
Iris Day: 12 Things You Don't Know About the Iris Flower - Flower
7 interesting facts about the human eyes
Why does your iris have a colour? - BBC Science Focus Magazine
The 4 Main Types of Iris Patterns You Should Know (With Images)
Macro Blue Yellow Eyes Iris Pupil Macro Eyes Close Face Stock
Blog – Page 11 – Weber Vision Care