Macular degeneration (AMD) is the third most common reason for blindness worldwide and the most common cause in the UK. Results have been announced of a very limited trial of a new stem cell technique which has restored vision to two patients of Moorfields Eye Hospital in London.
The study is a major milestone for the London Project to Cure Blindness, a partnership between Moorfields Eye Hospital NHS Foundation Trust, the UCL Institute of Ophthalmology, and the National Institute for Health Research (NIHR).
The macula is an area of the retina where partitular acuity means someone is able to see details and is vital for tasks like reading. There are two “types” of AMD (statistics given are for the UK):
Dry AMD
Dry AMD develops when the cells of the macula become damaged by a build-up of deposits called drusen. It's the most common and least serious type of AMD, accounting for around 9 out of 10 cases.
Vision loss is gradual, occurring over many years. However, an estimated 1 in 10 people with dry AMD go on to develop wet AMD.
Wet AMD
Wet AMD – sometimes called neovascular AMD – develops when abnormal blood vessels form underneath the macula and damage its cells.
Wet AMD is more serious than dry AMD. Without treatment, vision can deteriorate within days.
Both the patients involved in the initial trial had the wet form although the team believe the technique is applicable to both. Current treatments involved injections into the eye and at best stop progress of the disease. The excitement over this trial is that both patients showed an improvement in vision, being able now to read 60 to 80 words a minute.
The technique, published in Nature Biotechnology, starts with embryonic stem cells. These are a special type of cell that can become any other in the human body. They are converted into the type of cell that makes up the retinal pigment epithelium and embedded into a scaffold to hold them in place.
The living patch is only one layer of cells thick - about 40 microns - and 6mm long and 4mm wide. It is then placed underneath the rods and cones in the back of the eye. The operation takes up to two hours.
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Only one of the patients’ eyes was treated for fear of long term side effects like the eye developing cancer. Eight more patients will be treated as the trial enters its next phase.
Prof Pete Coffey, from the UCL Institute of Ophthalmology, said: "This study represents real progress in regenerative medicine.
"We hope this will lead to an affordable 'off-the-shelf' therapy that could be made available to NHS patients within the next five years."
Note that this stem cell research was, in effect, government financed. Moorfields and the UCL are partners in the Francis Crick Institute which is one of the world’s leading biomedical research institutions. If you are visiting London, forget Madam Tussaud’s wax museum, the nearby Crick has some fascinating public exhibitions which are free to enter.
PLEASE NOTE
These are comparatively early results from a very limited if hopeful trial.