Eye Color change spells are at this point Illusions, as biokinesis is needed to change the amount of genes of each color in the chromosomes in your eyes.
(Note that the human eyes are already flawed and biokinesis can make it worse.)
You can use these spells to make your eyes appear another color, a spiritual pair of colored contacts, if you will. But if you don't keep at it they will fade and your eyes will appear as they were to everyone around you.
Typically in the use of these spells you won't be able to see a difference, but other people will. It won't be drastic and it sometimes is barely noticeable.