If I could manipulate the genes, I would change the eye color before and after of born. There are cases of heterochromia in the world, refers to a difference in coloration, usually of the iris but also of hair or skin.
Heterochromia is a result of the relative excess or lack of melanin.If I could change the color eyes I founded a special clinic to do it and cure the problem, cause of discrimination in some places.
Also for people that wanted to change their eyes, for beauty or change any style. Change the color eyes serves to cure eyestrain, because eyes clearer are more sensitives in light that dark eyes. Also for seasons with more or less light, for climate.
If I would manipulate the genes for change eye colors would be a big advance in the cience.