Age-related blindness: The steps to take to avoid it
The most common cause of blindness in the UK is age-related macular degeneration. As the first ever Macular Week approaches, we how to reduce the risk.
The MI6 chief M in the Bond films, Dame Judi Dench was the epitome of sharp-eyed efficiency. But reality can be a world away from the movies and in real life, the veteran actress is far from sharp-eyed, as her vision has been badly affected by the eye condition, age-related macular degeneration (AMD).
Dench (80) is one of more than half a million people in the UK living with late-stage AMD, and now the first Macular Week (July 6-12) is aiming to draw attention to their condition and highlight what can be done to reduce the risk of developing it.
AMD, which mainly affects people over the age of 60, is the most common cause of sight loss in the UK. The prevalence of the condition roughly quadruples every decade from the age of 60, so one in 2,000 people are affected at 60, but by the age of 90, the figure goes up to one in five.
The condition causes central blindness, not complete blindness, sparing the peripheral vision (around the edges) and leaving dim images or black holes at the centre.
This means people with late-stage AMD may struggle or find it impossible to read, drive, identify faces, watch television, do fine detailed work, go up or down stairs safely and perform other everyday tasks. Dench, for example, now finds it difficult to read scripts and paint, and doesn't like to travel alone.
AMD can also make it more difficult to see contrast and can change the way colour is seen. But as peripheral vision isn't affected, people can often see out of the corner of their eye.
Cathy Yelf, chief executive of the Macular Society, explains that there are many types of macular disease, and while some are very rare genetic problems affecting younger people, the most common form is AMD.
"It's becoming more common because it's largely a condition associated with ageing. It's an urgent, public health issue," she stresses.
"With late-stage macular degeneration, you can't see faces, you can't read, you can't see the food on your plate and you can't drive. It can cause enormous depression and suicidal thinking."
Until recently, AMD wasn't considered a disease and was just seen as a natural part of ageing.
"We don't think of it like that any more," says Yelf. "We'd all be blind in our eighties if it was just a normal part of ageing. There are genetic and lifestyle reasons, particularly smoking, why some people get it."
The vision loss of AMD is caused by deterioration in the macula, a tiny area of the retina about the size of a grain of rice. There are two forms - known as 'wet' AMD and 'dry' AMD - which can sometimes occur simultaneously.
Indeed, Dench has wet AMD in one eye, and dry AMD in the other.
This most common form of AMD is the slow process of gradual deterioration of the macula, eventually leading to sight loss.
In the early stages of dry AMD, there are changes in the cells of the retina, and small clumps of lipids and cellular waste called drusen gather within it, interfering with the layers of the retina that support the photoreceptor rods and cones, and leading to cell death.
"Dry AMD is the slow death of the photoreceptor cells," explains Yelf.
"It's a bit like a carpet wearing out in patches, and it can take many months - or even years - for people's vision to decline considerably."
The first signs of dry AMD can be blurred vision, or seeing colours as more faded. There's no treatment for this form of the condition, although there's some evidence that nutritional supplementation can help slow down its progress.
In this type of AMD, tiny abnormal blood vessels grow into the macula, leaking, scarring and causing rapid sight loss.
People can see a change in their vision overnight, noticing that images are distorted and straight lines appear wavy. This is because light coming through the eye's lens hits the retina unevenly if the macula is swollen, distorting the resulting images.
"People can lose all their central vision within weeks if it's not treated," warns Yelf.
Wet AMD is treated with the relatively new drugs Lucentis and Avastin, which are injected into the back of the eye to prevent the growth of blood vessels.
"The treatment only slows down the progress - it's not a cure," says Yelf. "It may give people relatively good vision for a number of years, but it's not going to stop the AMD forever."
Winfried Amoaku, a consultant ophthalmologist who researches AMD at Nottingham University, explains that the success of wet AMD treatment depends on speed of detection and treatment. It's recommended that the first treatment is within two weeks of detection or onset, and should be followed up with regular monitoring and treatment.
"In other words, the earlier treatment is received, and the more regular the follow-up visits, the better the outcome," he says.
He points out that there are around 40,000 new cases of wet AMD every year, and stresses: "This number will increase as the population continues to age. We need to increase patient awareness about the condition."
Reduce the risk
The most important modifiable risk factor for AMD is smoking.
"People don't know that smoking can cause blindness," says Yelf. "It's very bad for your eyes."
Smokers are three to four times more likely to get AMD, and even giving up smoking in later life immediately reduces the risk.
Smokers who get wet AMD will have more severe symptoms and treatment won't work as well, says Yelf, who stresses that it's never too late to stop.
Genes are also a risk factor - Dench's mother had AMD, for example.
If you smoke and have the genes that make you more susceptible, you're 20 times more likely to develop the condition.
AMD risk factors are similar to those for heart disease, because of the vascular link, so eating a healthy diet including lots of green leafy vegetables like kale, and other vegetables containing lutein, including spinach, broccoli, peas, sweetcorn and lettuce, can help reduce risk, as can maintaining a healthy weight and reducing blood pressure.
Protecting the eyes from UV and blue light can also help keep eyes healthy.
The Macular Society recommends that people have their eyes tested regularly, as opticians can detect early AMD.
"If you know you've got the early signs of AMD, you can at least modify your lifestyle to help slow its progress," says Yelf, who points out there's plenty of practical help available both through registering as sight-impaired and receiving benefits, accessing low vision services to get better lighting, magnifiers etc, and getting help from support groups like the Macular Society.
"It's important to understand that while there's nothing that can be done medically for dry AMD, there are lots of things to help you get on with your life," says Yelf.
"As many of us will live into our 80s or 90s, we don't want to live with sight loss in those last years.
"People frequently say that of all the things going on with them in old age, this is the worst.
"It can be utterly devastating to lose your sight."
How to spot the tell-tale signs
- AMD affects more than 600,000 people in the UK and by 2020 almost 700,000 Britons will have late stage age-related macular degeneration (AMD)
- AMD usually develops as people grow older and it can also be genetic. More women tend to have the condition than men, but that's thought to be because women tend to live longer
- Although you cannot change your age or genes, current thinking is that protecting your eyes from the sun, eating a balanced diet with plenty of fresh fruit and vegetables, and stopping smoking may all help to keep your eyes as healthy as possible
- The Royal National Institute of Blind People (RNIB) provides a sight loss adviser service at both units in partnership with the Belfast and Western health trusts. Our sight loss advisors provide patients with practical and emotional support from the point of diagnosis
For further information please log on to www.rnib.org.uk or contact a member of our head office team on 028 9032 9373
For help and advice about macular disease, call the Macular Society's helpline on 0300 3030 111 or visit www.macularsociety.org
Stars struck with eyesight problems
- In 2012 Oscar-winning actress Judi Dench revealed that she had been diagnosed with macular degeneration. She admitted that she now has her scripts printed in enlarged type and needs a helping hand to go on the London Underground
- Stephen King, the doyenne of the horror novel, has a genetic pre-disposition to age-related macular degeneration which was diagnosed over 10 years ago
- Comedienne Roseanne Barr has revealed she has diminishing eyesight due to macular degeneration and glaucoma
- Skier Brian McKeever developed a form of macular degeneration - Stargardt's Disease - at the age of 19. With just 10% vision, he was chosen to represent Canada at the 2010 Winter Olympics and Paralympics. Although he didn't compete in the Winter Olympics, he has now won 10 gold and two silver Paralympic medals