Exam

Pupil

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Pupil, Pupil Disorders

  • Anatomy
  1. See Pupil Constriction (Miosis) for Neuroanatomy of Pupil Constriction
  2. Variable sized circular hole in pigmented iris
  3. Hole size controlled by 2 muscles
    1. Sphincter pupillae
      1. Circular muscle constricts pupil (Miosis)
      2. Parasympathetic fibers on CN3 from Edinger-Westphal Nucleus innervate the ciliary Ganglion
    2. Dilator pupillae
      1. Radial muscle dilates pupil (Mydriasis)
      2. Sympathetic inputs via:
        1. Hypothalamus
        2. Ciliospinal center of Budge and Waller
  • Findings
  1. Pupil Normal in
    1. Conjunctivitis
  2. Pupil size changes
    1. Pupil Constriction (Miosis)
    2. Pupil Dilation (Mydriasis)
  3. Pupil distortion
    1. Posterior synechiae
      1. Inflammatory adhesion between lens and iris
    2. Tear drop-shaped pupil
      1. Suggests Globe Rupture with iris prolapse
  4. Pupil fixed, mid-dilated, slightly irregular
    1. Acute Glaucoma
  5. Absent Pupillary Light Reflex
    1. Structural lesion
    2. Hypothermia
    3. Barbiturate or Opiate Overdose