Marcus Gunn Pupil
Marcus Gunn pupil which is also known as Afferent Pupillary Defect(APD) a condition of the eye where the pupil does not dilate appropriately to the level of light reaching it, resulting in one pupil appearing larger than the other.
Causes
Causes of APD include Optic Neuritis, glaucoma and optic nerve tumour. In multiple sclerosis, APD is usually associated with damage to the optic nerve resulting from Optical Neuritis.
Test
The Swinging Flashlight test is used to diagnose Marcus Gunn pupil, where there are abnormal pupil reflexes. Marcus Gunn pupil can also be seen in eyes with extensive retinal pathology.
Equal pupil size
