AMD is a progressive, chronic disease of the macular, the central area of the retina. The retina is the light sensitive layer of tissue that lines the back of the eye and transmits visual information via the optic nerve to the brain.
There are two forms of AMD, wet and dry. Dry AMD generally occurs gradually over a long period of time, sometimes years, and early signs may not be apparent. Wet AMD can occur suddenly.
The major risk factor for AMD is simply age, anyone over the age of 50 is at risk of developing AMD. Other risk factors include frequent or prolonged exposure to UV light, a family history of the condition, smoking, poor diet and high blood pressure.
As there is often no early warning signs, regular dilated eye exams with a macular check is the best for early detection of AMD. People over 50 are also encouraged to regularly use an Amsler grid to check for symptoms of macular degeneration. You should seek immediate advice from an eye care professional if there are any sudden changes in your vision such as straight lines become wavy, blurred or appear missing.
Patients with macular degeneration lose the ability to see fine details. The loss of central vision affects the ability to read, drive, and recognise faces. It can mean no longer being able to enjoy watching television or safely pouring hot water. The condition can limit employment opportunities, and leads to falls and injuries.
Reduced independence associated with vision loss can be very distressing. It may lead to a sense of isolation, and can be a contributing factor to the development of anxiety and depression. In advanced stages, AMD is classified as functional blindness.
The total cost of vision loss in Australia associated with macular degeneration was estimated at approximately $5billion in 2010.
Early detection and treatment has been shown to slow the degenerative process in some cases. Currently, treatment is available for wet AMD with regular injections into the eye. However there is no treatment for the dry form of AMD.
Research at the Queensland Eye Institute is focussed on repairing the structural changes that occur in the early stages of AMD development with the aim to slow the progression of, and possibly even prevent vision loss.
Dr Audra Shadforth is leading the project with Professor Damien Harkin and a team of researchers at the Queensland Eye Institute.
Our eyes contain photoreceptor cells which convert light into signals our brain can understand. These rely on a layer of support cells, known as the retinal pigment epithelium (RPE) to supply nutrients and remove waste.
As we age, RPE cells can become inefficient and die. When this happens, photoreceptor cells start to die too, resulting in a loss of central vision. This is known as Age-related Macular Degeneration (AMD).
The intention of our research is to develop a biomaterial membrane which can support a layer of stem cell-derived RPE cells that could be implanted into the patient’s retina through surgery. The new RPE cells will support the photoreceptors, providing nutrients and removing waste, allowing them to once again function normally.
A major advantage of this approach is the potential to reconstruct the damaged retina, replacing the tired cells as well as their supporting membrane, using stem cells and biomaterial constructs. The implanted cells and a biomaterial template will support the function of the photoreceptors cells while repairing the damaged structure.
We are currently undertaking pre-clinical studies, working towards clinical trials with the aim to have a product on the market in the next 5-10 years.