Age-related macular degeneration (AMD) is a disease that affects millions of Americans and is the leading cause of blindness among the U.S. population. Once started, the disease is irreversible. As a result, a significant amount of research has gone into figuring out how to either slow the progression of the disease or even reverse its effects.
What was the new insight in this research?
A team of researchers developed a new laser treatment that may slow and stave off the worst effects of the disease. The breakthrough came in the combination of two pieces of information. The first was the observation that AMD is a slow disease that takes many years to cause blindness. That means that there’s a long period of time that doctors have to jump in and stop the slowly destructive process before it’s too late.
The second piece of information was that earlier studies that had found that using lasers at low enough power in short enough flashes could help stop and even reverse some of the effects of damage in the eyes of diabetics. When applied to people with symptoms of AMD, other studies found improvements as well. Combining these ideas, the researchers wondered if the laser treatment might be used to treat people in the early stages of AMD to prevent signs of blindness from ever showing up.
How did the researchers test their laser?
To do this, the researchers embarked on studies in both mice and people. Doing this allowed them to get a better understanding of what was happening when eyes were treated with the rapid, low-power laser, called a nanosecond laser. They could observe the changes in mice and humans and then look at the eyes of the mice after they died to see what those changes looked like on a microscopic scale.
The researchers followed the people treated with the nanosecond laser for two years and compared them to people who hadn’t been treated. They found that the eyes of those treated with the laser had fewer signs of damage to the light-sensing portion of their eye, called the retina, than those who hadn’t had the treatment. A few even saw these effects completely disappear. This effect remained for the two years each person was followed. Another test of the retina found that the usual signs of disease progression had stalled, so that those treated with the laser didn’t seem to have the expected progression of their blindness.
The team then looked at the eyes of the mice for signs that the laser might have damaged the retina. Traditional lasers used for eye surgeries tend to leave a mark on these sensitive tissues at the back of the eye that never goes away. The team saw no sign of this sort of damage in the mice, even when they looked on a microscopic level. There were even indications that healing of the disease damage might be taking place.
How did the laser do this?
When they examined the mice eyes for genetic changes that might explain these effects, they found the laser seemed to activate genes important in controlling the space in between the different layers of the eye. When these genes malfunction, old debris starts to build up and cause damage. By reactivating these genes, the laser stimulated these housekeeping genes to remove the buildup causing damage.
What does this mean for you?
The fact that this laser has already been used in people and has been shown not to damage the retina at all means it could move very quickly into use for treating AMD in its early stages. That could mean years of sight added to those most at risk of blindness from AMD.