Final answer:
The nurse should remind the patient that it may take months to restore vision after a corneal transplant.
Step-by-step explanation:
If a patient who received a corneal transplant 2 weeks ago calls the ophthalmology clinic to report that his vision has not improved with the transplant, the nurse should remind the patient that it may take months to restore vision after the transplant. This is the correct action to take because vision improvement after a corneal transplant can be a gradual process and may not happen immediately. Therefore, the patient should be reassured and encouraged to give it more time.