That's not his eye though.
I don't see why Madara doesn't have eyes though.
Edit: Actually, it could be that Kabuto revived Madara as an old man and regressed his body back to youth with his experiments, and since Rinne Tensei revives you in the state your body is in and that was technically Madara's body now, he kept his youth. Since Rinne Tensei undos Edo Tensei, he lost all effects of Edo Tensei(immortality, unlimited chakra and his eyes), but kept the result of the experiments(Hashi's face and his youth) since those were administered after he was Edo'd.