A method of detecting injury to the brain such as stroke, concussion and cognitive dysfunction using a contrast agent and light source. The blood ocular barrier is disrupted when said injury occurs, allowing the entry of contrast agent into the aqueous and vitreous humor. An exemplary method comprises injecting a contrast agent into a peripheral location and then testing for leakage of contrast agent into the eye cavity by observing for light reflection, when a beam of light incidents on the contrast agent
