The one-off jab that could stop the most common cause of age-related blindness in elderly
15:53 GMT, 9 April 2012
A chemical that will stop people from developing the most serious form of age-related macular degeneration has been found by scientists.
Given as a one-off injection, it would keep the disease at bay, allowing elderly men and women to continue to everyday activities from reading the newspaper to driving or watching TV.
The most common cause of blindness in the elderly, age-related macular degeneration affects a quarter of over-60s in the UK and more than half of over-75s.
Hope: The one-off jab of the newly discovered chemical could offer many elderly sufferers of macular degeneration the chance of lasting sight
The number of sufferers is expected to treble in the next 25 years as the population ages but there are few treatments – and no cure – for the condition.
Caused by the deterioration and death of the cells in the macula, the part of the retina used to see straight ahead, robs sufferers of their central vision. The more common ‘dry’ form affects the eyes gradually, sometimes over many decades.
But one in seven of those with dry AMD will develop the more ‘serious’ wet form and lose their central vision almost immediately.
The breakthrough, from Trinity College London, could prevent dry AMD turning into the more serious form, allowing people to continue going about their day-to-day lives.
In tests on animals and on human eyes
donated to medical research, a husband and wife team of scientists
showed an immune chemical called IL-18 to be crucial to the conversion
to the more serious form of the disease.
Age-related macular degeneration is the leading
cause of blindness among the elderly in the developed world. These
pictures show how it affects the eye
They believe that increasing levels of IL-18 in the eye will stop the process in its tracks in people.
Dr Matthew Campbell said: ‘It means if you take someone with dry AMD and inject IL-18 into the retina, you could potentially prevent them from ever getting wet AMD.’ However, he stressed that the research is at an early stage.
Dr Sarah Doyle, his wife and fellow researcher, said: ‘Our results directly suggest that controlling or indeed augmenting the levels of IL-18 in the retinas of patients with dry AMD could prevent the wet form of the disease.’
There are drugs that can be used to improve vision in those with wet AMD. But they are given late in the course of the disease and have to be regularly injected into the eye.
Another treatment, called photodynamic therapy, is only suitable for around a fifth of patients.
Common: The breakthrough treatment could strike a major blow against macular degeneration, which currently causes blindness in one in four over 60s in the country
In contrast, it is possible that a jab that boosts IL-18 levels will be a widely suitable one-off treatment.
The researchers, who detail their work in the journal Nature Medicine, are trying find a way of inserting gene for IL-18 into people’s eyes. Ferried into the eye inside an empty virus shell, it would ‘switch on’ and produce IL-18 when needed.
Given routinely to people with dry AMD, it should stop them developing the more serious form.
Dr Campbell said: ‘Essentially, it’s vaccination. More work needs to be done on this disease because the population is getting older and it is going to get more prevalent.’
If animal trials are successful, the treatment may be given to patients for the first time in around five years.
Widespread use is around a decade away and dependent on any drug being shown to be safe and effective in stringent, large-scale trials.
Avril Daly, of charity Fighting Blindness Ireland, which part-funded the research, said that a treatment that stopped dry AMD from turning into the more serious form would make a huge difference.
‘Anything that could prevent the onset of wet macular degeneration would be a huge relief and a huge benefit, not only to the individuals themselves but also to the healthcare service.’