swinging flashlight test


Marcus Gunn pupil

A change in the pupillary reflex, caused by unilateral optic nerve or retinal disease.
Method
A light is shone, first on one eye and then the other, with the opposite eye covered; the affected eye demonstrates a slight contraction or dilation of the pupil.

swinging flashlight test

Neurology A test for comparing direct and consensual reactions of each pupil, to ID afferent pupillary defects. See Marcus Gunn pupil.

swinging flashlight test

A test used to detect a relative afferent pupillary defect or Marcus Gunn pupil. Direct light is shone into the normal eye; both pupils constrict equally due to the consensual response. Light is quickly swung over to the contralateral pupil, which appears to dilate as a result of a relative decrease in the optic nerve fiber function in the affected eye. This response is seen in asymmetrical optic nerve diseases such as glaucoma, optic neuropathy, and optic neuritis.