Final answer:
Poor vision without corrective lenses can cause difficulties in safely self-administering insulin.
Step-by-step explanation:
The nurse should identify poor vision without corrective lenses as a factor that might cause the client to have difficulty safely self-administering insulin. When administering insulin, it is important for the client to clearly see the markings on the syringe or insulin pen to measure the correct dosage. Poor vision without corrective lenses can make it challenging for the client to accurately measure and administer the insulin. Therefore, the nurse should provide appropriate education and support to ensure the client's safety.