Final answer:
a. Plaquenil (hydroxychloroquine) is the medication that necessitates an eye exam before starting treatment, due to the risk of retinopathy.
Step-by-step explanation:
The medication that requires a patient to have an eye exam prior to starting treatment is Plaquenil (hydroxychloroquine). Plaquenil is known to potentially cause retinopathy, which can lead to vision changes and damage to the retina. An initial baseline eye examination is recommended within the first year of starting the medication, followed by regular monitoring every 5 years unless risk factors are present which might require more frequent exams. The other medications mentioned, such as methotrexate, anaprox, and diclofenac gel, do not commonly require baseline eye exams prior to treatment.