Eye Test Spots Alzheimer's Dead nerve cells in the retina could signal dementia's onset By Nick McMaster, Newser Staff Posted Jan 14, 2010 2:48 PM CST 12 comments Comments An eye test may help detect Alzheimer's. (Shutterstock) (Newser) – British scientists have developed an eye test they claim can identify the early stages of Alzheimer's. The researchers found that dead nerve cells in the retina correlate to damage in the brain to such a degree that tests for retinal damage could detect Alzheimer's. "Few people realize that the retina is a direct, albeit thin, extension of the brain," says the lead researcher. The test is in human trials now and could be available in 2 years. The test is performed by applying eye drops that mark dying nerve cells in the retina. The markers can be detected by taking an infrared photo of the eye—the scientists say more than 20 could signal the early onset of Alzheimer's. "The study of this disease has been hampered by the difficulty of following the progress directly in the human brain," the head of the Alzheimer's Society tells the Telegraph. "This research is very exciting."