Fabry Disease with Ischemic Optic Neuropathy
A 14-year-old boy went hiking on a mountain with an altitude of 3275 m. He felt periorbital discomfort and intermittent mosaic vision in both eyes. A sudden loss of vision in the left eye was noticed 3 days later. He visited a local hospital 1 week later. His best-corrected visual acuity was 6/6 in the right eye and hand motion at 20 cm in the left. He was unable to identify any plates with left eye using the Ishihara test, whereas the test was normal in the right eye. There was reported pain on eye movement. Faint epithelial opacity could be found in both corneas (Fig. 56.1). A relative afferent pupillary defect was found on the left side. A pale and swollen optic disc was found in the left eye (Fig. 56.2). Fluorescein angiography showed severely delayed filling of the left disc (Fig. 56.3). The visual field was near totally obscured in the left eye, and the visual evoked potential was poor on the left side. A peripheral blood examination including blood cell count, autoimmune profile, infectious agent, ESR, and CRP was negative. CT scan showed an enlarged left optic nerve with contrast enhancement (Fig. 56.4).