FIG. 4.

A 66-year-old diabetic woman with sudden painless vision loss, 20/40, an afferent pupillary defect, a nasal step, and unilateral optic disc edema in the right eye (A). The left eye was normal with cup-to-disc ratio of 0.2 (B). A presumptive diagnosis of nonarteritic anterior ischemic optic neuropathy was made. Because the transverse axial OCT showed anterior deformation with a W-shape in the right eye (C) vs V-shape in the left eye (D), we obtained an MRI (E) that showed a presumed optic nerve sheath meningioma. OCT, optical coherence tomography. Yellow line is a reference that joins the peripheral margins of Bruch's membrane layer. The white arrow highlights the anterior displacement or BML relative to the yellow reference line.