A 75-year-old man is referred by his family doctor for suspicion of glaucoma because his confrontation visual field is abnormal inferiorly in the left eye, but some clues raise suspicion for a nonglaucomatous optic neuropathy. Various optic neuropathies can mimic glaucomatous visual fields or cupping. Clues that raise the suspicion of nonglaucomatous cupping are pallor of the rim, reduced central acuity or color vision loss out of proportion to disc cupping, atypical visual field defects, discordance between visual fields and cupping, marked relative afferent pupillary defect, and patient age less than 50 years old. When optic atrophy is suspected to be from an old nonarteritic anterior ischemic optic neuropathy (NAION), but prior optic nerve edema cannot be documented, appropriate imaging of the orbits is recommended to eliminate a compressive or infiltrative lesion.