My Friend Just Walked Into My Room Stating That She

My friend just walked into my room stating that she noticed a small difference in her eye color. Mainly along the outer rim of her iris. I saw the small discoloration, but automatically knew that it wasn't any typo of cataract due to those usually forming from the pupils out. Her vision is fine, and it doesn't itch. But what could this small change of color to her iris be? The best way to describe it would be thinking of her eye as class, and there being a small chip in her iris. You have to really stare to see it. Any advice?