from my logical standpoint, no, magic doesn't work that way. it is a way to help you through problems in life. if you want red eyes, buy contacts.
i've heard of eye colour spells even before i joined wicca. i've never done it myself, but to change something set in your DNA by thinking really hard and saying something, i don't think it would work. if you are telling the truth though [which i take pretty much anything claimed online with a grain of salt] that is an interesting result, so i guess it would work. on a side note, ever seen the movie The Craft?