What You Need to Know About Aging Macular DegenerationApr 18, 2014
Age-related macular degeneration is the leading cause of blindness in the world. If you’ve had a relative with macular degeneration, you know how heartbreaking it can be to watch them lose their eyesight. A little terrifying for you too. Are you next? Dr. Paul Bernstein from the Moran Eye Center tells you what macular degeneration is, why it happens, what the risk factors are, what you can do to prevent it, and some possible treatment.
Interviewer: If you've had a relative with macular degeneration you know how heartbreaking it can be to watch them lose their sight; and a little terrifying for you, too, because you've got to wonder if you're next. We're doing to discuss that next on The Scope.
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Interviewer: Coming up today on The Scope we're going to talk about macular degeneration. We're going to cover what it is, what are the risk factors that could help you get it, what you can do to prevent it, and some possible treatments. We're with Dr. Paul Bernstein of the Moran Eye Center.
First of all macular degeneration, or also called AMD, what's going on? There are two different types if I understand correctly.
Dr. Paul Bernstein: Yes, age related macular degeneration is the leading cause of blindness in the developing world. And there are two types and it affects the central part of vision called the macula. The macula is the area of the eye that is responsible for reading, driving, recognizing faces, and in age related macular degeneration there is a dry form, which is a slow form that progresses slowly over years if not even decades, it can eventually lead to central blindness in the eye.
And there is the wet form which involves growth of new blood vessels under the retina and this can have a much more rapid course and lead to loss of vision in a matter of days or weeks.
Interviewer: So the dry form, what exactly is happening in the eye?
Dr. Paul Bernstein: In the dry form initially it starts with deposits forming underneath the retina; something that we call drusen that are yellowish spots under the retina. The patient may have completely normal vision, and not have any symptoms. But eventually there is more malfunction of the cells of the retina and some of them begin to die in the center of the macula and that is why the center of the retina no longer senses light properly, and that can lead to blindness.
Interviewer: So it's like a camera not being able to sense light?
Dr. Paul Bernstein: That's correct; it's a problem of a camera with bad film.
Interviewer: And in the wet you're actually getting some growth back there and that's blocking your vision?
Dr. Paul Bernstein: That is disturbing the vision.
Dr. Paul Bernstein: It's interrupting the retina from having contact with its supporting cells, and eventually this can damage both types of cells as these blood vessels get in between these two layers and they can bleed. They can leak fluid, and eventually they can form scars and that's what leads to loss of vision there.
Interviewer: What's going on? Why are those starting to grow there?
Dr. Paul Bernstein: We don't know completely, but we understand that with age there is some malfunction of the cells and they for reasons that we don't completely understand start sending out signals and that seems to be an important factor for causing these blood vessels to start to grow underneath the retina. So it's kind of a malfunction; it's the wrong signals being sent out, that's correct.
Interviewer: All right, so who is at risk for age related macular degeneration? I think the name kind of gives you some sort of an indication?
Dr. Paul Bernstein: Yes, there are many risk factors, and certainly age is one of the most important ones. We know that age related macular degeneration is not very common in the people in the 50 to 60 year old range. Only a couple percent of people show the signs, but as we age it rises almost exponentially so that over age 75 at least 30% to 35% of people show at least some signs of age related macular degeneration.
Interviewer: So it's hereditary, so if you get old enough you're just going to get it?
Dr. Paul Bernstein: Well, there are a number of important risk factors for age related macular degeneration. And these genes are risk factors and we know of two very important ones; one on chromosome 1 related to complement and inflammation. And another one on chromosome 10 that we still don't quite understand, but if you have the wrong combination of genes that you've inherited from your parents it can put you at much, much higher risk. It can raise your risk three, five, even tenfold higher than the average population.
Other things that we also know as risk factors include being Caucasian; it is much more common in light skinned populations to have age related macular degeneration. And we also know in terms of modifiable risk factors that smoking is the number one modifiable risk factor. If you are a smoker, it increases your risk of developing the wet form of macular degeneration many fold and we certainly encourage our patients not to smoke.
And then the other area that I'm quite interested in is nutrition. We've learned that nutrition is very important in helping to prevent age related macular degeneration; specifically dark green leafy vegetables, orange and yellow fruits and vegetables, and cold water fish are certainly things that we recommend even in children at risk for age related macular degeneration because their parents have macular degeneration. And in the patients with macular degeneration we often recommend that they take supplements because it's often hard to change diet late in life.
Interviewer: How much do you know about the direct causation of diet?
Dr. Paul Bernstein: We know that diet is very important. And there is accumulating research that modifying diet can change the levels of the lutein and zeaxanthin which are from the dark green leafy vegetables that are actually accumulated in the eye. So we know that diet can make a difference, but as I said, when people are older changing their diet is difficult and that's why through the Areds 2 Study...
Interviewer: And what does AREDS stand for?
Dr. Paul Bernstein: AREDS stands for Age Related Eye Disease Study.
Dr. Paul Bernstein: And that most recently specifically looked at adding lutein and zeaxanthin, and omega 3 supplements to the vitamins that we already knew were effective against age related macular degeneration.
Interviewer: So what are some other things that you can do then? So you have these supplements, and do you really feel they are effective from what you've seen?
Dr. Paul Bernstein: I think they are, and I certainly . . . it's a big part of my practice, encouraging patients to take these supplements, because often my patients present they've lost vision in one eye, and they are very concerned that it's going to affect their other eye, because you can get by with good vision as long as you have good vision in one eye. But if you have age related macular degeneration that's significant in both eyes, it can be devastating to these otherwise well-functioning patients. We encourage them not to smoke. We also think that there is a negative role for excessive sunlight, so we encourage patients to wear sunglasses on bright sunny days. That's an easy thing to do.
Interviewer: And it sounds like all of these things that you're currently recommending are really pretty low impact? It's not like anything too serious. What's the risk of taking a few vitamins?
Dr. Paul Bernstein: We think that lutein, zeaxanthin, and the basic AREDS vitamins are very safe and few patients complain of side effects.
The other thing that I encourage my patients is to monitor their vision and to learn the early signs of age related macular degeneration, especially the conversion from the dry form to the wet form. With the wet form of macular degeneration we have developed very effective treatments now for this once almost universally blinding form of macular degeneration.
Interviewer: The wet form is actually treatable; dry form once it's started, not so much. Is that correct?
Dr. Paul Bernstein: That's correct. We are certainly looking at new treatments for the dry form, but currently the standard of care is just antioxidant vitamins and good diet.
Interviewer: Does the wet form always come before the dry form, or the dry form before the wet form?
Dr. Paul Bernstein: The dry form comes before the wet form. Okay, so and they almost always start with the dry form of macular degeneration, the slow form. The wet form can then rear its ugly head and we have to treat it and sometimes we get it back under control and still the dry form slowly progresses over time. Macular degeneration is a manageable disease; we'd like to make it a curable and a preventable disease, and that's what we're working on here.
Interviewer: If I have a family history of it can I get a genetic test and can you actually see if I have the gene mutations you were talking about?
Dr. Paul Bernstein: As a research tool, yes. We can and there are models that can predict that you have an increased risk. But it is I would caution a risk assessment, so not everyone even with the relatively high risk develops macular degeneration and other people develop macular degeneration for reasons that we don't completely understand. We are trying to figure out the role of the test still in clinical practice and in helping counsel people and that's part of further research that we will be conducting.
Recording: We're your daily dose of science, conversation, medicine; this is The Scope, University of Utah Health Sciences Radio.