Macular Degeneration Study Links Behavior, Visual Improvement

Jim Burress ATLANTA, GA (2008-12-11) Gina Lembo is an attractive and energetic 30-year old with Stargardt's Disease, a form of macular degeneration that appears in childhood.

"I see a clear picture; however, it's my peripheral. So we have a central vision loss."

It's unlikely Gina's condition will worsen. That's not the case for most macular degeneration, or "M-D", patients who develop it later in life. Their vision loss starts as a dark, central blur that expands over time.

So, like most with M-D, Gina uses her peripheral vision to compensate for her loss in central vision.

"So we don't see blank, we see a full picture, but it's going to look as though I'm looking to the left or up or down and not straight at you, when I feel I am"


Helping at her brother's pizza parlor in Norcross, Gina demonstrates how she compensates. It's a process of using peripheral vision, memorizing her surroundings and relying on her acute sense of touch as she demonstrates while cutting a lime.

"I very much use my sensory. I don't realize I do. And when people watch me they'll get very nervous that I'll slash my wrist or break something. But I have a system that works, and I've always done it that way."

Gina's brain--and her eyes--made her a perfect candidate for participation in a study by Georgia Tech and Atlanta's Emory Eye Center.

"The question we asked was, 'Does using those peripheral regions cause a change in the brain?'"


That's Eric Schumacher, a Georgia Tech psychology professor and the study's author.

He and a graduate student wanted to know how M-D patients' use of peripheral vision potentially re-wired their brains.


"It'll be different area in different patients, but it will tend to be stable within a patient they'll tend to choose one region to use as their PRL." meaning the part of the eye they use to see best.


Now this is where the science comes in. What we see straight-on largely comes from the part of our eye called the fovea. This fovea 'thing' lets us see small and vivid details, things like words on a page or the color of a traffic light.

But seeing is only partly done with the eye.

What the fovea senses is carried to the very back of the brain where the images are put together. It's an area just loaded with neurons that get all excited when we see. But in a patient with macular degeneration, those neurons don't get stimulated because the fovea doesn't send along any information.

Instead, they just sit there.

What the team found, though, is that that by identifying and stimulating parts of the eye that are strongest, those bored neurons can become re-energized.

"So that's the idea that something about the change in their behavior that they begin to use this one peripheral region drives reorganization of the primary visual cortex to begin to activate to that region."

In other words, the part of the brain the fovea stimulates in most people can become the same area M-D patients use. They won't see perfectly. But they might see better.

Dr. Susan Primo of the Emory Eye Center says the next step is to take that science to the bedside.

"...and in turn the patients will be trained to use that particular point and then to be able to use that every day in functioning, whether it is for work, school or for reading."

While science has long known the brain can reorganize itself, this study is the first to show a person's behavior can directly reorganize the brain, at least as it relates to vision.

Researchers stress the results are small steps in a long journey

Jim Burress, WABE News.