Eye colour and vampire spells do not work. They were put on the site by inexperienced users in spell casters and they remain because the site administrator is busy fixing bugs and therefore can't delete the spells until he has a free minute. [Which is rare]
Why these spells do not work, magick is energy. The energy is a natural force found in the universe. It effects the energy around us to create change. It is a part of nature and cannot go against nature. If it effects energy there is a good chance the spell works. If it requires a sudden physical change, alteration of DNA, or goes against nature, the spell will not work.