There's been so much hype about stem cells that it is natural to react with scepticism when someone claims to be using them to develop a cure for blindness that affects 30 million people worldwide.
But when that someone is Professor Pete Coffey of Moorfields Eye Hospital in London, it's worth listening to what he says.
In a technique which sounds like replacing a SIM card in your mobile phone, Professor Coffey says that within five years he believes it will be possible to insert a patch of stem-cell derived retinal pigment epithelium tissue behind the fovea of the eye, to replace the drusen damaged tissue that leads to macular degeneration and is the leading cause of blindness in developed countries.
And what's more, he says the transplant technique is relatively straightforward and could probably be done on an awake patient as an outpatient procedure in 45 minutes.
Speaking to journalists at a recent Pfizer press briefing, Professor Coffey said the key breakthrough to make this a possibility has been the development of viable retinal pigment epithelium from use of human embryonic stem cells, which has been shown to work as well as natural tissue to support the rod and cone photoreceptors of the eye.
Some of the stem cell development work, by Japanese researchers, is Nobel Prize material, he said.
The technique forms the basis of the London Project to Cure Blindness, which is now about to start trials in humans after successful work in animal models.
Current treatments for AMD are invasive (injections into the eye), expensive and only work in about one in three patients with wet AMD. The new technique promises to be effective for both wet and dry forms of the disease, and to provide a long term cure rather than just arresting the progression of the disease. Of course, it's still not a reality.
There are regulatory barriers to the use of human embryonic stem cells, and there have been technical problems in getting the retinal pigment epithelium to sit on its carpet of Bruch's membrane.
But of all the many claims made for stem cell therapies, this one seems based on good science and tantalisingly close to reality.
