The world's largest study of age-related blindness is getting under way - and you can help, writes Yvonne Cunningham
The adage you are what you eat seems particularly apt when it comes to your eyes. A diet rich in spinach, kale, cabbage, and peppers might help to keep your vision sharp.
Researchers at the Waterford Institute of Technology (WIT) are about to start the largest study of age-related blindness conducted anywhere in the world. And part of it relates to monitoring the foods its subjects eat.
The WIT team is recruiting volunteers for the the study, which will involve 5,000 participants more than 50 years of age. They will be monitored for 25 years for a substance in the retina known as macular pigment.
Macular pigment comes from carotenoids - a naturally occurring plant pigment found in nature. "More than 600 of these are found in nature and three of these make their way to the retina where they form a yellow spot at the back of the eye," explains Dr John Nolan, deputy director of the Macular Pigment Research Group at WIT.
"This yellow spot is called the macular pigment because it is located at the centre of the eye, the macula," he says.
"What's fascinating about the pigment is that it's dietary in origin, we're not born with it, you get it from a diet consisting of leafy greens, coloured fruits and vegetables, for example things like spinach, kale, cabbage, and peppers."
The reason the Waterford group is studying the pigment is that they think it protects against age-related blindness, notably an eye disease called age-related macular degeneration (AMD).
"We believe macular pigment is important because number one, it is yellow and it absorbs blue light and number two, it is a strong antioxidant. It is believed that blue light damage and oxidative stress play a major role in age related macular degeneration," says Nolan. "Macular degeneration is basically an eye disease that effects the central part of the eye that is responsible for your colour central vision."
The risk factors for AMD have already been established. "The three most important risk factors related to age-related macular degeneration are obviously increasing age, smoking cigarettes and having a family history of the disease," says Nolan.
Researchers at WIT have published studies showing that people that get AMD are deficient in macular pigment.
"Those three risk factors are establishing factors for AMD and it is also associated with having a significant lack of this dietary pigment in the eye, so if I'm a smoker and you're not a smoker you have more of this protective pigment than I do," says Nolan.
Known as a "longitudinal study" because it tracks people's condition for many years, it will measure macular pigment, looking for any link between pigment levels and AMD.
AMD is becoming more prevalent as the population ages. "If everybody lived till 120 then everybody would have macular degeneration. There are currently over 80,000 Irish adults registered with this condition. The numbers are increasing dramatically for the simple reason that we're all living longer," he explains.
Tests to measure levels of macular pigment have become widely available in the past few years. "When I started this research back in 2001, all macular related work was based in a science laboratory where people with white coats were doing their measurements, now its available to have your macular pigment measured by a variety of professionals such as opticians," says Nolan.
If low levels of macular pigment are detected early enough, a change in diet or taking supplements could eliminate the onset of AMD.
"If you are deficient from a very young age you're a lot more likely to get the AMD, so a 20 or 30 year old can get their macular pigment measured in a few minutes and if they're low they can during their 20s and 30s increase their pigment and in my opinion reduce the chances of getting AMD."
The research team is currently seeking volunteers to participate in the longitudinal study. For further information contact the Macular Pigment Research Office at 051-845505 or by e-mail MPRGRsesearch@wit.ie The group's web site is www.wit.ie/mprg.