An asymmetric pupillary reaction to light is known as RAPD (relative afferent pupillary defect. It is also called Marcus Gunn Pupil. The cause is damage of optic nerve. The condition is the result of: optic neuritis, retinal disease or ischemic optic disease, severe glaucoma, trauma, radiation, tumor retinal detachment, severe macular detachment or from infections like CMV or herpes.