A new study says doctors could diagnose Alzheimer's disease sooner by using an eye scan. Researchers at Cedars-Sinai Medical Center in Los Angeles have developed a way to detect plaques related to the disease in the retina. The scans might allow doctors to detect Alzheimer's even before symptoms begin to appear. This is seen as a less expensive, less invasive way to diagnose the brain-wasting disease. The study is published in the latest edition of the journal "JCI Insight."