dilated pupil

Last reviewed 07/2021

Causes of constant pupillary dilatation include :

  • mydriatics
    • parasympathetic paralysis, e.g. atropine - acts via the oculomotor nerve
    • sympathetic stimulation, e.g. cocaine, adrenaline
  • third nerve lesion } these are associated
  • Holmes-Adie pupil } with near / light
  • Parinaud syndrome } dissociation
  • lesion of optic nerve:
    • pupil reacts sluggishly to direct light
    • there is normal reaction to consensual light and accommodation
  • deep coma
  • other lesions of the eye:
    • trauma to the iris
    • ischaemia of the iris
    • cataract
    • vitreous haemorrhage
  • congenitally dilated pupil