I Read In The Questions That The Melanin That Being

I read in the questions that the melanin that being produced in the eye is the same as the melanin that is being produced in the skin and the hair but the you can not change/lighten your eyes but there is a lot of ways to lighten your skin and hair why is that?
And do acutely hypnosis or bionkissis or the vegan raw food to Change the eye color
Ps I m trying to get my eyes lightened because my mother just passed away and I want to remember her by the most beautiful thing in her her beautiful eyes
Thanx