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Swinging Flashlight Test

Aka: Swinging Flashlight Test, Marcus Gunn Pupil

Indication
1. Anisocoria (Unequal pupils)
Technique
1. Check left eye response (direct and consensual)
  1. Shine light on left eye and check left pupil reflex
  2. Shine light on right eye and check left pupil reflex
2. Check right eye response (direct and consensual)
  1. Shine light on right eye and check right pupil reflex
  2. Shine light on left eye and check right pupil reflex
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
Abnormal: Afferent lesion (Retina or Optic Nerve)
1. Known as Marcus Gunn Pupil
2. Intact consensual light reflex
3. Paradoxical Pupil Dilation to direct light
  1. Occurs on moving light from opposite to affected eye
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

Family Practice Notebook

Patients should address specific medical concerns with their physicians.

Although access to this page is not restricted, the information found here is intended for use by medical providers.

This page was written by Scott Moses, MD, last revised on 10/21/2007 and last published on 5/18/2012.

This is one of 5740 pages in the Family Practice Notebook