Pupil

Anisocoria

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Anisocoria, Unequal Pupil

  • See Also
  1. Pupil Disorder
  • Pathophysiology
  1. Images
    1. EyePupillaryReactionNeuroPath.png
    2. EyePupillaryReaction.png
  • Definitions
  1. Anisocoria
    1. Inequality between pupil diameters
  • Differential Diagnosis
  1. Congenital (normal variant in 20% of population)
  2. Argyll Robertson Pupil
    1. Complication of Tabes Dorsalis (Tertiary Syphilis)
    2. Mnemonic (Prostitute's Pupil): Pupil accomodates but does not react
      1. Pupil constricts during accommodation, but does not constrict to light
    3. Due to Midbrain lesion (superior colliculus, pretectal region)
      1. Typically bilateral lesions resulting in small, irregular pupils (bilateral Miosis)
  3. Adie's Pupil
    1. Sluggish pupil reaction to light with prolonged latency
    2. Pupil remains relatively dilated despite light exposure
  4. Third Nerve Palsy
    1. Ptosis
    2. Unilateral Mydriasis
    3. Eye Deviation "down and out" (due to intact CN 4 and CN 6)
  5. Optic Neuritis (e.g. Multiple Sclerosis)
    1. Mydriasis with Afferent Pupillary Defect
  6. Trigeminal Neuralgia
  7. Carotid aneurysm
  8. Aortic aneurysm
  9. Unilateral Intracranial Mass
  10. Glaucoma
  11. Amblyopia
  12. Horner Syndrome
  1. Iritis
  2. Cervical sympathetic paralysis
  3. Miotic drug (e.g. Pilocarpine)
  • Findings
  • Mydriasis (pupil dilatation) of one, but not the other
  1. Mydriatic drug (e.g. Atropine)
  2. Cranial Nerve III paralysis
  3. Acute Glaucoma
  4. Brainstem Herniation (non-reactive dilated pupil in comatose patient)