The European Research Council-funded programme was carried out by a team from the Nutrition Research Centre Ireland at Waterford Institute of Technology on participants who were all diagnosed with age-related macular degeneration (AMD).
Those living with AMD could have expected to experience a deterioration in their vision over the two years of the clinical trial. But instead, those receiving carotenoids showed a significant improvement across 24 out of 32 vision tests.
The study found 40% of participants had a “clinically meaningful improvement” in their vision after 24 months.
AMD impacts 7.2% of Irish adults aged 50 and over and is the most common cause of blindness.
Volunteers in the trial received three different supplements of carotenoid, meso-zeaxanthin, zeazanthin and lutein, which make up macular pigment. Carotenoids are naturally-occurring pigments that give many fruit and vegetables their colour.
Improvements in vision were particularly marked among those receiving all three carotenoids compared to those receiving only zeaxanthin and lutein.
Results from the study — the first of its kind in the world — are published in Investigative Ophthalmology & Visual Science (IOVS), the most respected, peer-reviewed journal in eye science.
The trial was led by Professor John Nolan, co-founder of NRCI and now Howard chair of human nutrition at WIT, along with colleagues from NRCI, Queen’s University Belfast, the University of Georgia, and University College London Institute of Opthalmology.
Prof Nolan said: “These are hugely exciting findings and build on previous work that has been done at our centre and elsewhere.
“AMD and the impaired vision that comes with it are a huge burden for patients and their families.
“The disease also brings a considerable economic burden, especially in its later stages,” he said.
“So, there’s a huge prize in finding an early intervention that can avert the need for expensive therapies and supports.”
He said the findings are the culmination of “a tremendous body of work by a diverse group of committed people going back over several years”, and he also paid tribute to the volunteers who participated in the trials.
“It’s been both humbling and rewarding to work with these people and to see the difference in their quality-of-life as the decline in their vision is arrested and they begin to notice a distinct improvement.”