AMD leads to an individual's central vision becoming blurry, dark or distorted due to damaged retinal cells.
"There is real potential that people with wet age-related macular degeneration will benefit in the future from transplantation of these cells," reports surgeon and project co-leader Prof. Lyndon Da Cruz of Moorfields Eye Hospital in London, UK.
Age-related macular degeneration (AMD) is a leading cause of vision loss among people aged 50 and older, while macular degeneration in general accounts for nearly half of all visual impairment in the developed world. The disease damages an area at the center of the retina known as the macula that is responsible for providing sharp, central vision.
When the macula is damaged, central vision can become blurry or distorted. Although AMD does not lead to complete blindness on its own, it can still have a huge impact on an individual's quality of life.
There are two types of AMD. The most common type is dry AMD, accounting for around 90% of macular degeneration cases. It is caused by the degeneration of the layer of retinal pigment epithelial (RPE) cells in the macula.
RPE cells are important for vision in that they support the light-sensing cells in the eye known as photoreceptors.
Less common and more severe is wet AMD, typically caused by abnormal blood vessels leaking fluid or blood into the macula region. Cases of wet AMD usually begin as dry AMD.
The London Project to Cure Blindness is examining whether transplanting RPE cells can be a safe and effective form of treatment for wet AMD. For the trial, RPE cells derived from stem cells are used to replace those damaged by wet AMD via a special patch that is surgically inserted behind the retina.
Prof. Da Cruz carried out the first of these transplants on a patient last month and, so far, no complications have been reported.
"We won't know until at least Christmas how good her vision is and how long that may be maintained," project co-leader Prof. Peter Coffey, of the University College London Institute of Ophthalmology in the UK, told BBC News, "but we can see the cells are there under the retina where they should be and they appear to be healthy."
Positive results could lead to treatments for other eye conditions
In full, the trial will assess 10 patients with wet AMD over the course of 18 months. After receiving the transplanted RPE cells, each patient will be observed for a year so that the safety and efficacy of the treatment can be monitored.
Prof. Coffey summarizes the team's thoughts on the project:
"We are tremendously pleased to have reached this stage in the research for a new therapeutic approach. Although we recognize this clinical trial focuses on a small group of AMD patients who have experienced sudden severe visual loss, we hope that many patients may benefit in the future."
If this new form of treatment is found to be successful, the researchers believe that it could also be used to help patients whose vision is being eroded by the early stages of dry AMD.
Prof. Da Cruz told BBC News that their research is a regenerative project, with the replacement of lost neural cells a form of treatment that had previously been impossible.
"If we can deliver the very layer of cells that is missing and give them their function back this would be of enormous benefit to people with the sight-threatening condition," he says.
All eyes now turn to late December, when the next reports from this exciting project are scheduled to be announced.
Earlier this year, Medical News Today ran a Spotlight feature investigating retinal degeneration disorders with a view to finding out how far away a cure for blindness is.