A 60-year-old woman is evaluated during a follow-up visit for Sjögren syndrome. She reports persistent eye discomfort described as a sandy or gritty sensation. She has had recurrent corneal abrasions and erosions. She has been using artificial tears with minimal improvement. She saw her ophthalmologist who inserted punctal plugs, but they caused excessive tearing and were removed. She otherwise feels well and reports no fever, chills, weight loss, rash, joint pain, chest pain, or dyspnea.

On physical examination, temperature is 36.7 °C (98.0 °F), blood pressure is 135/80 mm Hg, pulse rate is 75/min, and respiration rate is 18/min. The oral mucosa is dry. Moderately injected sclerae are noted. There is no cervical or supraclavicular adenopathy and no parotid gland swelling. Lung, heart, musculoskeletal, and skin examinations are normal.

Which of the following is the most appropriate treatment?