How to reduce melanin in iris?? or how can change my eye color permanently ???

Can't : No. There is no elective medication to change eye color. In individuals affected by the disease glaucoma, a therapeutic agent used to lower eye pressure, called a prostaglandin analogue, has a side effect of changing iris color. If you need glasses to see well, you could discuss with an ophthalmologist wether contact lenses are right for you. These can be colored.