Hypoplastic Optic Neuropathy

    • Congenitally small optic disc, optic nerve, and optic chiasm
    • Often accompanied by other forebrain dysgeneses
    • Rare binocular variant called “superior segmental optic disc hypoplasia” (“topless optic discs”) associated with maternal diabetes
    • Visual impairment caused by deficient optic nerve axons
    • Clinical features
      • Small optic disc diameter in one eye or both eyes
      • Trap: may be diagnostically challenging because it is hard to get a good ophthalmoscopic view in infants and hard to distinguish the true margin of the optic disc
      • Inner pigment ring surrounding the margin of the optic disc and an outer pigment ring surrounding peripheral chorioretinal atrophy (“double ring sign”)
      • Variant called “superior segmental optic disc hypoplasia” lacks superior optic disc structure (“topless optic discs”) and has inferior nerve fiber bundle visual field defects but no brain anomalies
    • Possible imaging features
      • Small-caliber optic nerve
      • Absent septum pellucidum and hypoplastic optic nerves and chiasm (de Morsier syndrome)
      • Frontal encephalocoele
      • Absent or displaced posterior pituitary bright spot
    • Normal optic disc
    • Perform brain MRI, looking for a small-caliber optic nerve and other forebrain abnormalities
    • Look for ophthalmoscopic signs of optic disc hypoplasia if other forebrain or pituitary abnormalities have already been detected
    • Anticipate deficient growth hormone and adrenocorticotropic hormone, especially if the pre-contrast T1 MRI sequence shows that the “posterior pituitary bright spot” is absent or upwardly displaced
    • Alert the pediatrician that hypopituitarism places the child at risk of sudden death in a febrile illness
    • Expect poor vision in some patients with optic disc hypoplasia, but…
    • Trap: the correlation between optic disc size and vision is weak, so do not issue predictions about visual potential until you can assess vision adequately when the child is older
    • If you find superior optic disc hypoplasia, look for corresponding inferior nerve fiber bundle defects, and inquire if the patient’s mother was an insulin-dependent diabetic at the patient’s birth
    • Visual dysfunction will remain stable
    • Forebrain anomalies are more likely if hypoplasia affects both eyes
    • Hormone deficiency is more likely if brain imaging shows forebrain anomalies

    Optic Nerve And Chiasm Disorders

    Drusen Optic Neuropathy Colobomatous Optic Neuropathy Optic Pit Neuropathy Morning Glory Optic Neuropathy Hypoplastic Optic Neuropathy Typical Optic Neuritis Atypical Optic Neuritis Papillitis (Neuroretinitis) Non-arteritic Ischemic Optic Neuropathy Arteritic Ischemic Optic Neuropathy Posterior Ischemic Optic Neuropathy Hypotensive Ischemic Optic Neuropathy Radiation-induced Optic Neuropathy Diabetic Papillopathy Hypertensive Optic Disc Edema Papilledema Idiopathic Intracranial Hypertension (Pseudotumor Cerebri) Compressive Optic Neuropathy: Overview Optic Neuropathy of Graves Disease Optic Nerve Sheath Meningioma Sphenoid Meningioma Craniopharyngioma Pituitary Adenoma Pilocytic Astrocytoma (Optic Glioma) Carotid Aneurysm Suprasellar Germinoma Infiltrative (Neoplastic) Optic Neuropathy Paraneoplastic Optic Neuropathy Traumatic Optic Neuropathy Toxic Optic Neuropathy Nutritional Deficiency Optic Neuropathy Dominantly-Inherited Optic Neuropathy Leber Hereditary Optic Neuropathy Primary Open Angle Glaucoma