High-resolution Fourier domain optical coherence tomography (FD-OCT) B-scans through the center of the optic nerve in an age-matched left eye (A), the patient's right eye (B), and the patient's left eye (C). The retinal nerve fiber layer (RNFL) is indicated (arrow). The photoreceptor layer is highlighted with a dashed-line box (– – –) at the nasal aspect and a solid-line box (——) at the temporal aspect of the optic nerve. The photoreceptor layer in A has three distinct lines corresponding to the retinal pigment epithelium (RPE) (arrow 1), Verhoeff's membrane (arrow 2), and the inner and outer photoreceptor segment junction IS/OS (arrow 3). Altered photoreceptor layers are shown in B–C, each with two broad bands corresponding to the RPE (arrow 1) and indistinct Verhoeff's membrane and IS/OS (arrow 2). N, nasal; T, temporal.