Italian researchers hope the eye can be used as a pathway to treat Alzheimer's disease.
In the new approach, which has proved promising in clinical trials, nerve growth factor (NGF) is put in eye drops to stop the degenerative disease in its tracks.
NGF, discovered in the 1950s by Nobel prize winning Italian scientist Rita Levi Montalcini, has already proved effective against Alzheimer's when it is injected directly into the brain.
Other current methods are transplanting cells capable of producing NGF into Alheimer sites, or using viral vectors to take the key molecule there.
"But those techniques are very risky and highly expensive," said Luigi Aloe of the National Research Council's Neurobiological and Molecular Medicine Institute.
Working with Alessandro Lambiase from Rome's Campus University, Aloe has developed a technique to make sure the NGF in the eye drops reaches the brain areas affected by the disease.
"The development of this cheaper and less invasive method of delivery opens up the prospect of use on other degenerative diseases too," Aloe said.
The NGF drops would be used in the early stages of Alzheimer's to stop it spreading with devastating results.
The disease currently affects 15 million people worldwide, including four million Americans.
Over the next 20-30 years, America is set to see the number of cases rise above 10 million while Europe is projected to have some 15 million.
Aloe and Lambiase's study appears in the latest edition of the prestigious international journal Brain Research.
