Seeing the container with the singular sharingan eye held within, Yahiko immediately knew what was needed to be done. As soon as Obito moved into the examination room and lay on the bed, Yahiko begins by sterilising his hands, Obito's eye socket and the replacement eye with aggressive medical chakra.
I'm going to need you to sit still while I do this, so... As he says this, Yahiko manifests his chakra into an ethereal pure chakra serpent, that bites Obito and puts him to sleep. He then removes the eye from the container and examines it before performing the transplant procedure.
Looks like a butcher removed this eye... at least he could have brought the head so someone with an ounce of medical knowledge could have... Yahiko drifted off in thought as he finished the transplant, before setting off to repairing the damage sustained to the eye during the removal from the original owner. Yahiko causes the degraded cells to regenerate, repairing the small damage that would have reduced the eyes use to its knew owner.
Now finished, Yahiko wraps Obito's head in a bandage to cover his knew eye before writing a note on the unconscious patients chart and leaving the room.
Patient is to not use this eye and rest for five days.