It is feared that the UK could face a “Blindness epidemic”, the Daily Express has claimed today. The newspaper has reported that Britain faces a sight loss epidemic, caused by progressive eye conditions, that is being grossly underestimated by the NHS.
The story is based on research that estimates the number of people affected by advanced age-related macular degeneration (AMD . AMD affects the part of the retina at the back of the eye that is responsible for central vision. It is the most common cause of age-related sight loss in the developed world. AMD is thought to affect half of the 370,000 people registered as blind or partially sighted in the UK.
The study estimates that the current UK prevalence of late stage AMD is actually 2.4% of the adult population (513,000 cases and that this figure is set to rise by one-third over the next decade, totalling nearly 700,000 cases by 2020.
AMD is a progressive condition that causes loss of vision and leads to loss of independence. Therefore, it is important to have an accurate estimate of projected numbers who have, or will develop, this disorder. While estimates provided by this research are higher than previous ones, they do not represent an ‘epidemic’ or an increase in cases of the disorder per se. Indeed, the risk of AMD increases sharply with age and the principal reason for the projected increase in cases by 2020 is the growing proportion of elderly people in the UK population.
Where did the story come from?
The study was carried out by researchers from the University of London and was funded by the Macular Diseases Society. A spokesperson for the society reportedly called for the government to give AMD a higher priority.
The study was published in the peer-reviewed British Journal of Opthalmology. It was generally covered accurately in the papers, aside from the Daily Express’ alarmist headline predicting a forthcoming ‘blindness epidemic’.
What kind of research was this?
Age-related macular degeneration affects the macula, a highly sensitive part of the retina at the back of the eye that is responsible for central vision. As the name implies, the condition is associated with ageing, and it is a leading cause of visual impairment among the elderly. As AMD progresses a person will gradually lose the ability to see things in their central field of vision, which is needed for important activities, such as reading, writing and driving. There are two different types of the disease: dry AMD and wet AMD (also called neovascular AMD or NVAMD . Wet AMD involves the formation of new blood vessels.
Dry AMD, the most common form, is associated with a gradual breakdown of the cells in the retina. Dry AMD is usually subdivided into early and late stages. In early-stage dry AMD there may be a few characteristic yellow deposits (known as drusen under the retina, but there is minimal effect on vision. In advanced or later-stage dry AMD, there will be both drusen deposits and breakdown (atrophy of the retinal cells.
This later-stage dry AMD is sometimes called ‘geographical atrophy’ and is associated with gradual loss of vision.
A small proportion of those with dry AMD will go on to develop wet AMD. This is where new and abnormal blood vessels start to grow in an attempt to re-supply the damaged retina with oxygen and nutrients. These vessels are fragile and can leak blood and fluid, causing more sudden and rapid loss of vision than dry AMD.
While little can be done to prevent the progression of dry AMD, the blood vessel growth of wet AMD is usually treated by laser, photodynamic (light drugs or injections of drugs that prevent the growth of the abnormal blood vessels (called anti-vascular endothelial growth factors, anti-VEGFs .
The authors point out that AMD is a major cause of eye disease, accounting for more than half of those registered as blind or partially sighted in the UK. However, they add that registered numbers do not reflect the full proportion of people who experience visual loss caused by the condition, and that estimates of incidence vary. They argue that accurate estimates are needed to help provide sufficient healthcare in the future.
This research was an analysis of the data from a recent systematic review and meta-analysis of the prevalence of ‘late’ AMD. This was based on 31 populations of European ancestry, ranging in age from 50 to 97 years. They used these figures to produce models to estimate the prevalence and incidence of late AMD in the UK population, both now and in the future. They then constructed separate models to look at the prevalence of:
- late/advanced dry AMD (or geographical atrophy [GA]
- wet AMD (or neovascular AMD, NVAMD
- late AMD overall (both GA and NVAMD
‘Prevalence’ is a specific term referring to the number of cases of a disease within a population at any given time. The related term ‘incidence’ refers to the number or rate of new cases that develop in a specified period.
What did the research involve?
The researchers based their models on a meta-analysis of 31 population studies featuring a combined population of 57,173 participants. They say it is the most complete meta-analysis of late AMD prevalence in white populations. The study populations were from Europe, North America and Australia, which they say are largely similar to the middle-aged and older population of the UK.
They applied these figures to the UK population aged 50 to 97 years old, calculating prevalence using statistics for the years 2007 to 2009 obtained from the Office of National Statistics. They calculated prevalence in the UK by year, by age (from 50 to 97 years , by gender and for both genders combined.
They used projections of numbers within these age groups in the UK population to calculate prevalence figures up to 2020. Their estimates allow for a 95% ‘credible interval’, representing the range within which true prevalence is expected to lie with a 95% probability.
The researchers then used the models of age-specific prevalence to estimate the annual incidence (new cases of age of late AMD overall, GA and NVAMD in men and women between the ages of 50 and 97 years.
What were the basic results?
Overall prevalence of late AMD in the UK population aged 50 or over was 2.4% (95% credible interval [CrI] 1.7% to 3.3% . This is equivalent to 513,000 cases (95% CrI 363,000 to 699,000 and is estimated to increase to 679,000 cases by 2020.
- In those aged 65 or over, prevalence of late AMD was 4.8% and in those aged 80 or over, 12.2%.
- Prevalence of GA was 1.3% overall (95% CrI 0.9% to 1.9% , 2.6% in those aged 65 and above (95% CrI 1.8% to 3.7% and 6.7% in those aged 80 and above (95% CrI 4.6% to 9.6% .
- Prevalence of wet AMD (NVAMD was 1.2% overall (95% CrI 0.9% to 1.7% , 2.5% in those aged 65 and above (95% CrI 1.8% to 3.4% and 6.3% in those aged 80 and above (95% CrI 4.5% to 8.6% .
- The estimated number of cases of late AMD were 60% higher in women than men (314,000 cases in women, 192,000 in men .
- The authors say that by 2020 there will be 394,000 women and 285,000 men (679,000 in all with late AMD. This equates to an increase of a third over current rates.
- They calculate that until 2020 there will be 71,000 new cases of late AMD each year, with higher numbers in women.
- Annual incidence (new cases each year of late AMD overall was estimated at 4.1 per 1,000 women (95% CrI 2.4 to 6.8 and 2.6 per 1,000 men (95% CrI 1.5 to 4.4 .
How did the researchers interpret the results?
The researchers say that their review provides the best estimates of the prevalence and incidence of late AMD in the largely white older population in the UK, and suggest that by 2020 cases of AMD will increase steadily by one-third. The authors say these evidence-based estimates are higher than previous estimates, and argue that they can be used to help plan both social and healthcare support, now and in the future.
Conclusion
This study has provided estimates of the current prevalence and incidence of late-stage AMD in the UK (including late-stage dry AMD and wet AMD . It predicts that the prevalence of the condition will rise over the coming decade. These late stages of AMD can lead to loss of vision and of independence, so it is important to have an estimate that is as accurate as possible of projected numbers who have, or will develop, this disorder.
It is important to point out that the projected increase in numbers of those with the disorder is not due to an increase in the condition per se but to the UK’s ageing population. It is also worth noting that these estimates are based on complex statistical models and, as is clear from the results, the probable range within which true prevalence lies is quite wide.
The authors also point out that their figures are based on cases of AMD in ‘either eye’ so may overestimate the potential visual loss associated with the condition, though, as they say, late stage disease in only one eye may still need treatment.
Links To The Headlines
Blindness epidemic fear. Daily Express, February 14 2012
Number of Britons suffering macular degeneration to rise by a third by 2020. Daily Mail, February 14 2012
Progressive blindness cases to rise by a third in a decade. The Independent, February 14 2012
Links To Science
Owen CG, Jarrar Z, Wormald R et al. The estimated prevalence and incidence of late stage age related macular degeneration in the UK. British Journal of Ophthalmology, [Online First] February 13 2012
Much of Heartland Institute's work funded by one anonymous donor, but some corporations also gave cash, documents show
A libertarian thinktank devoted to discrediting climate change received funds and other support from major corporations including some publicly committed to social responsibility, leaked documents reveal.
The inner workings of the Heartland Institute were laid bare on Tuesday night after an "insider" emailed confidential documents detailing its strategy and fundraising network to DeSmogBlog, which monitors industry efforts to discredit climate science.
Much of Heartland's work to discredit climate change is funded by a single anonymous donor, the papers reveal. However, a 2012 fundraising plan also indicated that Heartland has in the past received funds from a host of major corporations for other projects – including companies that publicly support action on climate change.
Along with tobacco giants Altria and Reynolds America, and drug firms GlaxoSmithKline, Pfizer and Eli Lilley, major corporations have given over $1.1m in the past two years to the institute, and are planning to give another $705,000 this year.
Some of the companies included on Heartland's list of donors were surprising. Bill Gates, the founder of Microsoft Corporation, has vigorously promoted clean energy in a number of speeches, and his charitable foundation works on helping farmers in the developing world, who will be badly affected by climate change.
But Heartland claims in a fundraising document to have received $59,908 from Microsoft in 2011.
Microsoft said the donation to Heartland was confined to its global programme to provide free software licences to non-profits. "As part of that programme the organisation requested free software licenses, and Microsoft provided them, just like we do for thousands of other eligible non-profits every year," Katie Stainer, a spokeswoman for Microsoft, said in a statement.
"Microsoft's position on climate change remains unchanged. Microsoft believes climate change is a serious issue that demands immediate, worldwide attention and we are acting accordingly. We are pursuing strategies and taking actions that are consistent with a strong commitment to reducing our own impact as well as the impact of our products.
"In addition, Microsoft has adopted a broad policy statement on climate change that expresses support for government action to create market-based mechanisms to address climate change."
A spokeswoman for GSK said the $50,000 the company donated in the last two years was for a healthcare initiative. She could not comment on whether GSK would be working with Heartland in the future.
She said: "GSK absolutely does not endorse or support the Heartland Institute's views on the environment and climate change. We have in the past provided a small amount of funding to support the Institute's healthcare newsletter and a meeting."
General Motors Foundation, which is committed to social responsibility, has also made modest donations to Heartland, contributing $15,000 in 2010 and 2011, though for projects other than climate science.
There was no immediate response from the foundation, but GM itself defended its $30,000 donation. Greg Martin, GM's director of policy and Washington communications, said: "We support a variety or organisations that give careful and considerate thought to complex policy issues and Heartland is one of them."
He said GM's cash was not donated for a specific programme.
Diageo, the drinks company which owns Smirnoff, Johnnie Walker and Baileys, said its funding of Heartland was now under review. It gave $10,000 over the last two years, according to the leaked papers, and was projected to give another $10,000 this year.
A spokeswoman said the money had been given for a project on excise duty and the company did not agree with Heartland's views on climate change.
The leaked documents provide an intriguing view of the inner workings of an organisation that has been at the forefront of undermining climate change, and suggest Heartland is on the cusp of a fundraising blitz.
The plan proposes raising revenues by a staggering 170% this year, to $7.7m. Heartland proposes to do this in part by hiring a direct mail firm that has been prominent in Republican election campaigns. The firm Griswold & Griswold Inc promised to expand Heartland's donor list tenfold from 1,800 to 18,000 within the year.
But the cache raises an equal number of questions – such as the identity of an anonymous donor that has been a mainstay of Heartland. The unnamed donor, who contributed $4.6m in 2008, has since scaled back contributions. Even so, the donor's $979,000 contribution in 2011 accounted for 20% of Heartland's overall budget, the fundraising plan says
According to the fundraising document, Heartland hopes to bump that up to $1.25m in 2012.
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