Clinical Trial for Macular Degeneration Seeks a New Way of Seeing

Plasticity may be the key in helping AMD patients see better.

The brain's ability to reorganize itself to compensate for vision loss, the ability called plasticity, may be the key in helping those with age-related macular degeneration (AMD) see better. This theory is the moving force behind a study between Emory Eye Center and the Georgia Institute of Technology (Psychology). Patients who have retinal damage as a result of AMD sometimes begin to see by using other parts of the intact retina. By "training" these patients to focus on using those good retinal cells, they may experience increased visual acuity.

Susan Primo, OD, MPH, of Emory Eye Center, says the Phase 2 portion of the clinical trial "Age-Related Macular Degeneration and Cortical Reorganization" will help bridge the knowledge gap between cortical plasticity and visual function.

"Results from these studies will begin to provide answers for how behavioral improvements in AMD patients can lead to changes in underlying brain activity and, most importantly, how we can influence those changes to maximize use of remaining vision," Primo says. "Once this link is made, clinicians and healthcare engineers can use the information to design and implement rehabilitation therapies and technologies that will expedite efficient use of fixation strategies ultimately fostering cortical reorganization."

Phase II Results

AMD is the leading cause of blindness in the elderly, accounting for 10 million people who have reduced vision in the United States. AMD is a disease associated with aging that gradually destroys sharp, central vision. Central vision is needed for seeing objects clearly and for common daily tasks such as reading and driving. Middle-aged people have about a 2 percent risk of getting AMD, but this risk increases to nearly 30 percent in those over age 75. More than 200,000 develop AMD each year in this country alone.

"Visual rehabilitation is entering an exciting area of research that expands our current understanding of neuroplasticity of the visual system," says Timothy W. Olsen, director of Emory Eye Center and a retina specialist. "Findings from this study and others may help us understand the tremendous capacity of our central nervous system, especially as it relates to sensory deficits. Combining expertise of the Emory Eye Center with Georgia Tech opens exciting new opportunities in vision research."

Phase 1 of the study appears in the December edition of the journal Restorative Neurology and Neuroscience. Phase 1 of the trial at Emory involved seven patients, and the Phase 2 portion at Emory will have 10 patients. The goal will be to study hundreds of patients in the near future. Reporting of results can be expected in late 2009.