Can Sharingan user have a pair of normal set of eyes transplant into them? We all know Mangekyo Sharingan will blind its user over time right? And the only way is to transplant a set of new eyes from a close Uchiha into them and gains Eternal Mangekyo. 

*So, I'm wondering if the new set of eyes isn't from Uchiha bloodline. I mean , a normal person without kekkei genkai? What would happen then? *
I suppose he should be able to see but no longer be able to use the Sharingan. It is not explicitly known what activates the Sharingan in an eye. But it is highly likely that it is hard coded in an Uchiha eye balls, since using those eyes, a person who is not from the Uchiha clan is able to use the Sharingan. Just like Kakashi and Danzo for instance.

From the same logic, an Uchiha should be able to see using normal eyes from another person but no longer be able to use the Sharingan. The ability is hard coded inside the eyes. The weakening of the sight in case of excessive use of Mangekyo Sharingan would also be nullified in case of normal eye transplants. Just like a normal eye transplant to a blind person.