The Excavated Optic Disc

    • Thinning (excavation) of the optic disc neuroretinal rim so that the optic disc appears pathologically cupped
    • Common causes: primary open angle glaucoma, optic disc coloboma
    • Uncommon causes: arteritic ischemic optic neuropathy, compressive optic neuropathy
    • Focal or diffuse thinning of neuroretinal rim tissue
    • Glaucomatous excavation
      • Rim thinning occurs first inferiorly, then superiorly, then temporally and finally nasally
      • Residual neuroretinal rim retains its pink color
      • Visual field nerve fiber bundle defects appear only when the neuroretinal rim becomes markedly thinned
    • Non-glaucomatous excavation
      • Residual neuroretinal rim appears white
      • Excavation is not as deep and the notching of the neuroretinal rim is not as great as in glaucoma
    • Large physiologic optic disc cup
    • Optic disc coloboma
    • Myopic optic disc, which is tilted so that the temporal portion of the physiologic cup appears excavated
    • Distinguish pathologic excavation of the optic disc from a large physiologic optic disc cup
    • Perform visual field examination
      • Should be normal in large physiologic cupping
      • Should show nerve fiber bundle defects in pathologic cupping, especially if advanced
    • Document the optic disc appearance by photography and/or optical coherence tomography
    • Schedule serial examinations to detect any increase in optic disc excavation or visual field loss
    • Trap: optic disc excavation caused by arteritic ischemic or compressive optic neuropathies (“non-glaucomatous cupping”) may resemble that caused by glaucoma, especially if the optic discs began with large cup-to-disc ratios
    • Overlooking glaucoma may lead to avoidable blindness
    • Trap: misdiagnosis of a myopic tilt or optic disc coloboma as glaucoma leads to fruitless treatment with intraocular pressure-lowering agents
    • Trap: misdiagnosis of “non-glaucomatous cupping” as glaucoma leads to delayed diagnosis of potentially vision-threatening or life-threatening optic neuropathies

    Abnormal Optic Discs

    The Elevated Optic Disc The Excavated Optic Disc The Pale Optic Disc The Small Optic Disc