A 58-year-old man from Delhi presents to the ophthalmology clinic for routine eye examination. He is asymptomatic and has no ocular complaints. On examination, visual acuity is 6/6 bilaterally. Intraocular pressure (IOP) measured by applanation tonometry is 28 mmHg in the right eye and 26 mmHg in the left eye. Gonioscopy reveals open angles bilaterally with Shaffer grade III. Optic disc examination shows a cup-to-disc ratio of 0.7 with superior and inferior notching. Visual field testing by automated perimetry shows a superior arcuate defect in the right eye corresponding to the inferotemporal optic disc changes. The patient has no family history of glaucoma. What is the most appropriate next step in management?