• Physiology
  1. See Pupil
  • Technique
  1. Preparation
    1. Use a bright flashlight
    2. Perform in a semi-dark room (but light enough to see bilateral pupil reaction)
    3. Move the flashlight from directly in front of one eye, to directly in front of the other
      1. Maintain a constant distance between flashlight and eye
      2. Avoid maintaining a central point at nose (stimulates near response)
  2. Check left eye response (direct and consensual)
    1. Shine light on left eye for 3 seconds and check left pupil reflex
    2. Shine light on right eye for 3 seconds and check left pupil reflex
  3. Check right eye response (direct and consensual)
    1. Shine light on right eye for 3 seconds and check right pupil reflex
    2. Shine light on left eye for 3 seconds and check right pupil reflex
  • Findings
  • Normal response
  1. Direct Light Reflex
    1. Pupil constricts to direct light
  2. Consensual Light Reflex
    1. Pupil constricts to light shining on opposite pupil
  • Findings
  • Abnormal - Afferent lesion (RAFD, Marcus Gunn Pupil)
  1. Findings: Relative Afferent Pupillary Defect (RAFD)
    1. No pupil response to direct light
    2. Intact Consensual Light Reflex (when light shone in opposite eye)
      1. Paradoxical Pupil Dilation to direct light
      2. Occurs on moving light from opposite to affected eye (Swinging Flashlight Test)
  2. Causes: Optic Nerve Lesion (rarely at Retina)
    1. Ischemic Optic Neuropathy
    2. Optic Neuritis (e.g. Multiple Sclerosis)
    3. Optic Nerve compression or Trauma
    4. Glaucoma (asymmetric)
    5. Other Optic Neuropathy (e.g. infiltrative, radiation, infectious)
  3. References
    1. Broadway (2012) Community Eye Health 25(79-80):58-9 +PMID: 23520419 [PubMed]
  • Findings
  • Abnormal - Efferent lesion (CN 3 or pupillary Muscle)
  1. Affected eye loses consensual and Direct Light Reflex
  2. Unaffected eye maintains consensual and direct reflex