Relative afferent pupillary defect is a response shown in swinging light test which illicit an unequal response of pupil to light stimulus shone back and forth between both eyes. It is a test used to show optic nerve damage or retinal diseases. The examiner swings the light and pupil dilates when light is swung from normal to affected eye. Normal pupillary reflex is equal and simultaneous constriction on light stimulus. Constriction is produced depending on the severity of the condition only. The condition presents as blurred vision, vision loss or headaches. Management is done by diagnosing the underlying cause and treating it such as glaucoma management.