As the population ages, the number of people suffering loss of vision in later Iife is expected to increase. An estimated one in ten people aged over 65 will develop visual disturbance because of a condition known as age-related macular degeneration (AMD).
The macula is an area at the back of the eye containing photoreceptive cells that enable us to see. These cells require nutrients, supplied by cells in the Retinal Pigment Epithelium (RPE). AMD is not painful but leads to irreversible damage to these cells. As a result, vision is distorted, changing the shape of objects, blurring sight, or causing black spots or gaps in particular areas of vision. It can lead to blindness and usually affects both eyes, although may start in only one.
There are two types of AMD: wet and dry. Wet AMD occurs when abnormal blood vessels grow into the macula and leak blood and fluid, leading to scarring that causes rapid loss of sight in the affected parts of the eye. It needs urgent treatment. If caught early enough, drugs can be injected that may stop or slow the development of the abnormal blood vessels but the success of treatment is variable. Dry AMD is a gradual degeneration of RPE cells over a period of months or even years. As retinal cells naturally die off, they are not renewed or replaced, leading to loss of vision. There is no treatment for dry AMD.
Doctors at Moorfields Hospital in London have now developed a pioneering approach that uses stem cells to try to re-create the layer of RPE cells damaged by AMD. The first operation took place last month and, although it is too early to judge its success in restoring vision, the doctors report that the implanted cells are in the correct position and appear to be healthy. The team suggests that it will take until at least Christmas 2015 before the impact on the patient's sight will be known. The trial is planned to involve 10 patients who suffer from wet AMD but it is thought the same principles may extend to treating dry AMD in its early stages.
Welcoming the news, Andrew Clayton of Penningtons Manches' clinical negligence team said: "Age-related macular degeneration is a huge and growing problem. By 2020, it is expected that around 700,000 people in the UK may have late stage AMD. Loss of sight is not only devastating for those affected but also has a substantial social and economic impact, not least in the additional care that sufferers need.
"Injections for wet AMD were approved for widespread NHS use relatively recently and they have helped many patients but cannot restore sight. They can only halt the progress of the condition and are expensive.
"The costs of stem cell surgery are not yet known, with the trial receiving funding from the pharmaceutical company, Pfizer. But the hope of restoring to vision to the millions affected by AMD is priceless. The NHS will need carefully to weigh the costs against the benefits but many will be waiting for the trial results and hoping for a breakthrough in restoring vision."