Tectal Pupils

    • Pupil abnormalities caused by dysfunction of the dorsal midbrain
    • Attributed to disconnection in the pupil reflex pathway between the tectal midbrain and the Edinger–Westphal nuclei
    • Common causes: dorsal midbrain dysfunction from obstructive hydrocephalus, thalamic hemorrhage/infarct/tumor, pineal region or dorsal midbrain tumor
    • Uncommon causes: demyelination, traumatic brain injury
    • Core clinical features
      • Anisocoria
      • Both pupils are relatively large--even in dim illumination
      • Both pupils constrict minimally to a bright light and normally to a near target (“tectal light–near dissociation”)
      • Upgaze deficit
    • Possible accompanying clinical features (of “dorsal midbrain syndrome”)
      • Lid retraction (“Collier sign”)
      • Downgaze deficit
      • Convergence retraction on attempted upgaze
      • Fourth nerve palsy
      • Skew deviation
      • Esotropia or exotropia
      • Rotary (torsional) nystagmus
      • Seesaw nystagmus
    • Imaging features
      • Ventriculomegaly of obstructive hydrocephalus
      • Signal abnormalities of stroke in thalamus or midbrain
      • Signal abnormalities of tumor in thalamus, midbrain, or pineal gland
    • Bilateral tonic (Adie) pupils
    • Pharmacologic mydriasis
    • Traumatic, inflammatory, dysplastic iridoplegia
    • Botulism
    • Denervated pupils in autonomic neuropathy
    • Look for associated features of dorsal midbrain syndrome because…
    • Tip: tectal pupils do not occur in isolation; other features of dorsal midbrain dysfunction are ALWAYS present, especially an upgaze deficit
    • Perform brain MRI
    • Depends on the underlying condition

    Pupil Disorders

    Anisocoria Overview Physiologic Anisocoria Horner Syndrome Tonic (Adie) Pupil Argyll Robertson Pupil Pharmacologic Mydriasis Episodic Mydriasis Iridoplegic Mydriasis Mydriasis of Third Nerve Palsy Tectal Pupils