A 68-year-old man of African heritage comes to your office complaining of progressive loss of vision over the last four months. First it started with loss of peripheral vision and later his central vision has also worsened. He gets headaches as he tries to see things more clearly than he can. His past medical history is significant for hypertension. He has a 30-pack-year smoking history. Family history is significant for MYOC gene carriers. On examination, his visual acuity is 20/400 both eyes. There does not appear to be a relative afferent pupillary defect (RAPD). Ophthalmoscopy shows symmetrically enlarged cup-to-disk ratio (0.8) and a highly asymmetric cupping in the right eye. Tonometry measures the intraocular pressure of 18 mm Hg in the left eye and 20 mm Hg in the right eye. Pachymetry reveals decreased thinning of the cornea in both eyes. Which of the following is the most likely cause of this patient’s vision loss?
