A team of researchers recently took a closer look at a treatment that is commonly used for a very common eye disease. James Folk, MD, an eye specialist at University of Iowa Hospitals and Clinics and professor in the Department of ophthalmology and Visual Sciences , has these comments:
For those of us not familiar with the eye disorder involved here, can you please tell us, what is age-related macular degeneration?
Age-related macular degeneration is a disease of the retina in the eye. The retina is a thin structure that lines the back of the eye and absorbs the light coming into the eye. It forms a picture and sends that to the brain.
The very central part of the retina is called the macula, and this center part is specialized to give us very fine or detailed vision. This vision is the one we use, for instance, for driving or reading. Age-related macular degeneration is the leading cause of visual loss in people over the age of 60.
There are two main types: there's the dry form of macular degeneration in which the cells more or less just slowly die off and the vision slowly gets worse. And then there's the more rapid, wet form of macular degeneration, where abnormal blood vessels grow up under and around the retina and cause hemorrhage and scarring and fluid to accumulate, and this is called the neovascular, or wet form of AMD.
What treatment did this particular study focus on?
Early in the disease, we see deposits that are called drusen; they're yellow deposits that form underneath the retina, and when we analyzed them at The University of Iowa, they contained a lot of different materials, almost like this was a junkyard of old cellular components that had been discarded. We wondered, since these accumulations actually separate the retina from the nourishing blood vessels, whether getting rid of these drusens early on might prevent vision loss or might prevent the new blood vessels from forming. We knew that laser treatment actually caused the drusen to go away, so we wondered if we applied very light laser treatment, would that improve the visual prognosis of these people.
Briefly, what were the findings?
In a nutshell, we found that the laser treatment really didn't have any effect one way or the other. It didn't slow the disease onset, but it didn't hasten it, either. So it was really the two groups, the group that had the laser and the group that didn't have the laser, did pretty much the same.
What are the ramifications of this result?
First these results can seem pretty disappointing, at least we know this treatment doesn't work. The study from here and other centers involved more than 1,000 patients who were watched very closely and had photography done every year. We're now analyzing the results and we know, for instance, the people who had a lot of drusen tended to form the dry form of macular degeneration; and those who had fewer drusen, it didn't matter, they could still form the wet type of macular degeneration. So there's a lot of information we're now mining to determine what actually causes visual loss and this is really going to direct our research in the future.
You might know your vision is getting bad, but are there any telltale signs, anything that might lead somebody to say, I should go in and get it looked at, that I might be in the early stages of this disease?
If somebody develops new symptoms, like floaters or vision loss, he should go see an eye doctor right away. For macular degeneration, specifically, you would notice blurred vision or you might notice distorted vision. The distorted vision is because the fluid is accumulating in the retina. Some older patients just say "Well I'm getting old and maybe that's a part of the aging process," or "Maybe its part of a cataract." But when it happens fairly quickly, they should see an eye doctor, because the sooner we can see these patients and treat them, the better the prognosis.
What other treatments are available for AMD?
There are a lot of other treatments available and we've been involved in all of them. The best treatment right now is called Lucentis, which is actually an antibody to the molecule that causes the new blood vessels to grow and leak. This antibody can cause visual improvement in people who have wet macular degeneration. Before this, people usually lost vision after they developed the new blood vessels, but now they can regain it. But once again, the sooner you get to these people, the better their final outcome.
Are there any promising new treatments on the horizon?
There are a lot of new treatments and they're mainly drug treatments at this time, trying to block the various forms of new blood vessels from forming in the first place. The Carver Center for Macular Degeneration at Iowa is actually trying to focus even earlier than that-an ounce of prevention is worth a pound of cure. We're finding genes that are genetic factors that are involved in the disease and proteins that are involved in the disease, and what we hope to do by that is have some therapies that can be developed, perhaps even in a pill form, that will at least prevent or slow down this disease until much later in life.
If people are interested, would like more information on this disease, what can they do regarding this?
They can visit the Carver Center for Macular Degeneration site or MedRounds. They can also contact the Center for Macular Degeneration at Iowa at 335-8270. |
