Researchers including one of Indian origin are developing a non-invasive eye test which may one day help detect Alzheimer's disease even before the symptoms appear. According to scientists Alzheimer's-related plaques can build up in the brain two decades before the onset of symptoms such as memory loss and cognitive decline appear. The non-invasive technique -- called optical coherence tomography angiography -- shines light into the eye allowing a doctor to measure retinal thickness as well as the thickness of fibres in the optic nerve. The test detected evidence of Alzheimer's in older patients who had no symptoms of the disease.
