Turmeric could offer hope for millions of people battling the common eye condition glaucoma, researchers believe.
Scientists have found a derivative of the spice used in curry - curcumin - can be used in eye drops to halt vision loss.
Trials showed eye drops containing curcumin, responsible for turmeric's yellow colour, slashed the loss of crucial retinal cells in rats.
Glaucoma, one of the leading causes of blindness, mainly involves the loss of retinal ganglion cells, located near the surface of the retina.
The condition strikes 60 million people across the world, estimates suggest, and is most prevalent among the elderly.
Evidence already exists to show curcumin can protect retinal ganglion cells from dying off, when taken as a tablet.
But the compound has poor solubility, meaning it does not dissolve easily and can take a long time to enter the bloodstream.
Patients would, therefore, need to take up to 24 curcumin tablets a day to see enough benefit from the compound.
The new British study delved in to other ways of delivering curcumin, in hope of finding a more reliable method.
Researchers at University College London and Imperial College London led the trial, published in Scientific Reports. They claim their findings, based on human cells and rats, pave the way for a more reliable method to deliver curcumin to patients.
Eye drops are the main treatment for glaucoma, according to the NHS. They all work by reducing the build-up of pressure in patients' eyes.
Delivering curcumin as eye drops increases the compound's solubility factor by almost 400,000 times. And it localises the curcumin in the eyes instead of throughout the body, meaning it can get to work almost immediately.
Professor Francesca Cordeiro, who led the study, described curcumin as an 'exciting' compound.
The study was first conducted on retinal ganglion cells in the lab, before moving onto testing the eye drops in rats who were given the eye drops twice daily for three weeks and had much lower levels of retinal ganglion cell loss than their counterparts. No side effects, including irritation or inflammation, were noted by the team of researchers.
Professor Cordeiro said: 'As we live longer, diseases such as glaucoma and Alzheimer's are steadily increasing.
'We believe our findings could make a major contribution at helping the lives of people affected by these devastating diseases.'
