Final answer:
The nurse should instruct the patient to monitor and report visual disturbances when starting therapy with digoxin.
Step-by-step explanation:
The nurse should instruct the patient to monitor and report any visual disturbances to the provider when starting therapy with digoxin. Visual disturbances such as blurred vision, yellow-green halos around objects, and changes in color perception can be signs of digoxin toxicity. It is important for the patient to report these adverse effects promptly so that the healthcare provider can assess and adjust the treatment if necessary.