Physical examination maneuver
Physical Exam
Swinging Flashlight Test
also known as Alternating light test
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Video coming September 2026
How to Perform
In a dimly lit room, have the patient fixate on a distant target or your nose. Shine a bright light into one eye for two to three seconds and note the pupillary constriction, then swing the light rapidly across the bridge of the nose to the other eye and observe its response, alternating back and forth every few seconds. Normally each pupil holds its constriction as the light arrives. An abnormal response is when the illuminated pupil dilates as the light swings onto it rather than holding constriction.
How to Interpret
Showing 2 of 7 findings
Glaucoma
Relative afferent pupillary defect, detecting asymmetric cup-to-disc ratio
Rule in
Somewhat helpfulDerived CI
Rule out
InconclusiveWide CI
Evidence:Limited
Multiple Sclerosis
Relative afferent pupillary defect, detecting retinal nerve fiber layer loss
Rule in
Somewhat helpfulDerived CI
Rule out
Not helpfulDerived CI
Evidence:Limited