Scientists in the US have developed a simple eye test, which they say can detect dementia even when it is in its early stages.
The test, developed by a team led by Lee Goldstein of Brigham and Women's Hospital, Boston, is similar to those used to test for high blood pressure and diabetes, reported the online edition of BBC News.
Dementia is commonly defined as a decline in intellectual functioning that is severe enough to interfere with the ability to perform routine activities.
The new technique uses a non-invasive laser to study the lens of the eye and checks for deposits of beta-amyloid - the protein found in the brains of those with Alzheimer's disease.
The procedure, which worked in a trial on mice, could be used to detect the disease at its early stages as well as to track disease progression and monitor how people respond to Alzheimer's treatments.
Currently there is no simple test to make a diagnosis of dementia and it can only be confirmed with certainty by looking at someone's brain in a post-mortem examination.
The scientists believe the technology, known as quasi-elastic light scattering, may detect the very earliest stages of amyloid deposits in the lens, even when they appear completely clear to the naked eye.
The scientists, however, said that more work is needed before such a test could be made available to patients.