Artificial Retina Offers Hope for Macular Degeneration Patients
For millions of Americans and people around the world, age related macular degeneration (AMD) threatens their vision. But an international team of scientists is offering hope in the form of an artificial retina that could restore sight to people with this common cause of blindness.
Artificial retina may help restore vision
Age related macular degeneration is a degenerative eye disease that affects central vision and leaves individuals with only peripheral sight. An estimated 2 million Americans and 25 million people around the globe have macular degeneration, which is the leading cause of blindness among people older than 50.
As the surge in Baby Boomers grows, the prevalence of macular degeneration is expected to rise significantly. This expectation has prompted research into ways to prevent and effectively treat the disease, and the work of researchers at the University of Strathclyde and Stanford University in California is an example of that effort.
The research team is developing a thin silicon artificial retina designed to be implanted in the eye. Unlike currently available artificial retinas, the new device will be much easier to implant and operate.
According to Professor Daniel Palanker, of Stanford, “The current implants are very bulky, and the surgery to place the intraocular wiring for receiving, processing and power is difficult.” The new artificial retina is different because “the surgeon needs only to create a small pocket beneath the retina and then slip the photovoltaic cells inside it.”
Those photovoltaic cells drive the device to transform near infra-red light to electrical current that stimulates neurons in the retina, which are still viable in people with age related macular degeneration. This in turn elicits visual perception.
To make the process work, people with this artificial retina would need to wear video goggles, which deliver energy and images directly to the eye. Thus far, the artificial retina has tested well in the lab, and work continues on improving the technology.
Other help for macular degeneration
Researchers at Stanford and the University of Strathclyde are not the only ones working on artificial retinas. The US Department of Energy Office of Science is conducting the Artificial Retina Project, which is a multi-institutional effort “to develop and implant a device containing an array of microelectrodes into the eyes of people blinded by retinal disease.”
The goal of the Artificial Retina Project is to design a device that contains hundreds to thousands of microelectrodes that will help restore limited vision to individuals with macular degeneration and retinitis pigmentosa. A phase II clinical trial is currently underway.
More immediate help for macular degeneration comes in the form of drugs, including Avastin and Lucentis (bevacizumab and ranibizumab, respectively). These drugs were recently the focus of a two-year, head-to-head comparison, and both medications were found to be effective, although one is much more affordable than the other.
Results of the National Eye Institute’s Age-Related Eye Disease Study (AREDS) recommended that individuals with dry macular degeneration (the most common form of the eye disease) take high doses of certain nutrients, which may reduce the risk of progressing from intermediate dry macular degeneration to advanced wet disease. Those nutrients include vitamin C (500 mg), vitamin E (400 IU), beta-carotene (15 mg), copper as cupric oxide (2 mg), and zinc (80 mg).
Other research has indicated that omega-3 fatty acids can be beneficial for AMD. The antioxidants lutein and zeaxanthin also have been associated with a reduced risk of macular degeneration.
Continuing advancements in the development of an artificial retina will hopefully soon help restore vision to those who suffer with age related macular degeneration.
Sin HP et al. Lifestyle modification, nutritional and vitamins supplements for age-related macular degeneration. Acta Ophthalmol 2012 Jan 23. DOI:10.1111/j.1755-3768.2011.02357.x
University of Strathclyde
Image: Wikimedia Commons