Fig. 6 Swinging flashlight test for afferent pupil defect. The patient is a 72-year-old man with right visual loss due to ischemic optic neuropathy. A. Pupils are equal in dim light. B. Illumination of right eye results in modest bilateral constriction. C. When the light swings to the left, there is more extensive constriction in both pupils. D. When the light swings back to the right, both pupils dilate.