The number of people suffering from progressive blindness is set to rise by a third in the space of a decade, amid growing concern that the NHS has significantly underestimated the prevalence of the condition, new research warns.
Age-related macular degeneration (AMD) accounts for more than half of registered blind people in the UK. An ageing population means the number of severe or late-stage cases is expected to increase to 679,000 by 2020, according to scientists at St George's, University of London.
AMD places a significant burden on health and social care, especially if treatments are delayed, so it is imperative properly to plan specialist services and ensure the costs of diagnosis and expensive drugs can be met.
AMD affects part of the retina – the macula, a tiny area at the back of the eye the size of a grain of rice which is responsible for central vision, colour vision and fine detail.
People with the condition have difficulty reading, driving and recognising faces as it develops, and it can lead to social isolation, loss of independence and depression.
The epidemiological study shows how its prevalence increases exponentially with age: around one in 2,000 people have AMD at 60, increasing to one in five by the age of 90. This means that many sufferers are also likely to be dealing with other diseases and disabilities.
There are two types of AMD: wet, more sudden but treatable, is caused by tiny abnormal blood vessels growing in the macula which then leak and scar, leading to rapid sight loss.
It is treated by injecting relatively new drugs into the eye every month to prevent the blood vessels from growing – this appears to stop or slow down the disease in most patients. The NHS in England spent nearly £130m on the drug Lucentis in 2010 – the fourth-highest amount spent on a single medicine.
Dry AMD is a much slower process caused by atrophy or shrinking of the macula. No treatment is currently available, with most patients losing their central vision and requiring significant support and home adaptations in order to stay independent.
The new figures, published in the British Journal of Ophthalmology, are based on the most comprehensive analysis of its kind. The researchers analysed data from 31 European ancestry populations of AMD from ages 50 to 90, before applying this to the UK population.
The calculations indicate 40,000 new cases of late-stage wet AMD every year – 35 per cent more than estimated by the NHS treatments watchdog, the National Institute for Health and Clinical Excellence (Nice).
Another 44,000 people are expected to be diagnosed with dry AMD, making the need for treatments even more urgent than previously thought, said Dr Christopher Owen, senior lecturer in epidemiology and lead investigator.
Helen Jackman, chief executive of the Macular Disease Society, which funded the research, said: "This reveals the real impact of AMD and demonstrates the need for Government and the NHS to give this a higher priority.
"Macular degeneration is a devastating condition for many people and an urgent issue for society as a whole. We urge politicians and health and care planners to recognise the significance of this condition and ensure proper provision is made for people with AMD now and in future years."