I can understand your emotions but here are some facts which you need to understand :
1. We can not replace someone's eye as a whole. To be simplified we can not put someone's whole eye in place of other's eye.
2. Whenever we get an eye donation, normally we use its cornea for replacing other patient's opacified cornea. It is called corneal transplantation.
3.If some one has only corneal problem (that means he doesn't have any other cause of blindness) which leads to blindness in him, we can treat it with donor corneal transplantation.
I hope I am clear enough.