2010-12-16 James MCulley MD Dry Eyes and the Role of Lifestyle, Nutrition and Omega-3 Fatty Acids
Nutrition and Omega-3 Fatty Acids
An Interview with James McCulley, MD
December 16, 2010, by Kirkham R. Hamilton, PA-C
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KIRK HAMILTON: Hi, my name is Kirk Hamilton, your host of Staying Healthy Today, and our mission is simple: To provide you credible usable health information from interviews and our educational resources to help you Stay and Be Well in the busy modern world. Please take a few moments before or after listening to this interview to browse through the Prescription2000.com website, the home of Staying Healthy Today Radio, for our free educational services.
Today's show topic is Dry Eyes and the Role of Lifestyle, Nutrition, and Omega-3 Fatty Acids. Our guest today is Dr. Jim McCulley, professor and chairman for the last 30 years of the Department of Ophthalmology at the University of Texas Southwestern. He has published more than 260 articles in peer reviewed journals and most recently co-authored an article entitled "Pilot Prospective Randomized Double-Masked Placebo-Controlled Trial of an Omega-3 Supplement for Dry Eye" in the journal of Cornea in 2010.
Welcome Dr. McCulley. Thank you so much for taking time out of your busy day to be with us.
DR. JAMES MCCULLEY: My pleasure.
KIRK HAMILTON: So tell me. How does an ophthalmologist who is a chairman of a medical school ophthalmology department come to study omega-3 fatty acids and dry eye syndrome?
DR. JAMES MCCULLEY: I developed an interest in the ocular surface when I was in training years ago at Massachusetts Eye and Ear Infirmary. And I took some of the insights that I had at that early stage of my career and pursued them, and have had over 25 years of NIH funded research evaluating the tear film and the ocular surface and in particular the lipid component of the tear film. And I think what got me started in it was having an insight into potential pathophysiological mechanisms that made more sense than what we were being taught at the time.
KIRK HAMILTON: Well tell me then how prevalent is dry eye syndrome and what is the kind of ... or dry eye...I said syndrome, maybe it's not a syndrome. And then what's the prevalence of it and what's the biochemistry of it?
DR. JAMES MCCULLEY: Well dry eyes may be a syndrome or it may be an isolated event. There're many different types of dry eyes. As a group dry eye is one of the most common reasons that a patient seeks care from an ophthalmologist. So it's very common. There're many different types. The tear film is a multilayered structure and it has three principle layers. One is a layer over the cells which is a surfactant layer. It converts the hydrophobic layer of the ocular surface cells into a hydrophilic environment that will support the majority of the tears which are water and other...many other molecules. And then to keep that watery layer from evaporating or running off there is then a lipid layer that prevents evaporation and keeps the tears from overflowing the lids. So there can be abnormalities in any one of the three layers. The abnormalities are going to vary tremendously. There's a very long list of associated systemic diseases, drugs, environmental factors that can lead to dry eye. And the dry eye could be associated, as I've implied, with a systemic disease or the dry eye can be just related to abnormalities in the tear film or in the structures that produce each of the three layers of the tear film.
KIRK HAMILTON: So the fatty acid component, let's stay with that for a moment. It seems like there's two things that it could possibly affect. One, it's part of the protectant layer that keeps the moisture in so to speak of the other components, and two, the fatty acid could also modulate inflammation which may also aggravate the eye. Is that correct?
DR. JAMES MCCULLEY: Well that's correct, but it is simplifying something that can't quite be simplified that much depending on the direction you're coming from. The lipid layer is the outer layer and it does have fatty acids in as a component of that lipid layer. But it's a very very complex set of lipid molecules. Fatty acids are only one component of it. If we're talking about an omega-3 fatty acid which is an essential fatty acid which means our body cannot make it, we have to ingest it. Then the omega-3s theoretically could be a component in the lipid layer, or the omega-3s could, as you've suggested, be playing a role as an antiinflammatory agent.
KIRK HAMILTON: What happens, if you have continuous dry eyes? What kind of things can occur? Do you end up having an increased incidence of let's say pterygiums or is it just irritating and frustrating, or what bad things can happen to your eye?
DR. JAMES MCCULLEY: Well it can be anything from something fairly straightforward and easily dealt with to a situation that can be blinding. Pterygia typically are not a component of it. But the first thing that one typically will notice if there is a dry eye is some fluctuation in the quality of vision. The next thing is going to be beginning surface drying over the cells and then cells die and dry. And anytime one perturbs normal physiology no matter what part of the body, there's going to be a predictable response called inflammation. So inflammation then would kick in and the inflammation can be a manifestation of the irritation. It can make the dry eye worse. And then one goes then further with it. There can be significant drying of the surface that not just results in fluctuation of vision, but significant decrease in vision. The compromise of the surface cells, the drying of those cells, potentially allows the portal for infectious agents to get into the cornea which can then result in bad infections and potential blindness.
KIRK HAMILTON: We are talking with Dr. Jim McCulley, professor and chairman of the Department of Ophthalmology at the University of Texas Southwestern, about the role of omega-3 fats and dry eye. And so can you then, let's lead to your article that I was interested in. What role do omega-3 fats play and why did you choose to study them, and which particular omega-3 fats did you choose to study?
DR. JAMES MCCULLEY: Okay. There had been a lot of anecdotal reports of doctors talking about giving omega-3 supplements in one form or another to their patients and that the patients had significant improvement. But there'd never been a scientific study to prove indeed or show indeed that the omega-3 fatty acids had any real benefit. Having had my long interest in dry eyes on the ocular surface, I was somewhat intrigued by that. And one of my colleagues from training days, a fellow of the name Jeff Gilbard and I sat down and were talking one day and he had - he was an ophthalmologist but he had developed a company and one of his products was called TheraTears Nutrition® which contained omega-3 fatty acids and was hoped to be a product that a person could take by mouth and it would improve dry eyes. But again no real proof. So Jeff and I put our heads together and decided that I would do a study and his company would provide the funding for us to be able to carry out the study and we went forward from that. The decision about which omega-3s and the concentrations was made pharmacologically in Jeff's company, and the product that we used in our study was a commercial product called TheraTears Nutrition® . Whether it is unique for it's effectiveness in treating dry eyes or whether it's simply an example of a formulation that has omega-3s, we don't really know. What we did was specifically to test the commercial product against the vehicle control which was everything in the preparation except omega-3s.
KIRK HAMILTON: Well you know it's interesting because I was looking at the product obviously. I've used flax seed oil before and anecdotally it's helped some people with dry eyes. And you put the combination of both flax seed oil, which is alpha linoleic acid rich, and then you put also - or not you but the company had put in there, eicosapentaenoic acid and docosahexaenoic acid which comes from the fish oil. So you've got the full range there of omega-3 fats. Does that make sense to you?
DR. JAMES MCCULLEY: We covered our bases.
KIRK HAMILTON: Were there any other synergistic nutrients in there, put in there, or was it just the fatty acids?
DR. JAMES MCCULLEY: Well whether there were any other synergistic molecules in the preparation or not I don't know. I can tell you that if they...if there were other active molecules in the product they did not show themselves in the placebo control which had everything except the omega-3s.
KIRK HAMILTON: So bottom line of this study of this product. What did it show you if anything?
DR. JAMES MCCULLEY: Well it showed us that we had an increase in tear flow and tear volume which was fantastic. So it had a positive effect. The best guess is that it had that positive, well then let me back up. It had that positive effect in terms of increased tear flow, tear volume, very positive. It also resulted in improvement in patient's symptoms, also very positive. We tried to sort out how the omega-3s might have been affecting the dry eye condition. We did extensive lipid biochemical analysis of the meibomian secretions which are the source of the lipid layer of the tear film expecting that we might find omega-3s incorporated into the tear film and then possibly having a molecular role in the lipid layer, but we found no evidence of omega-3s in the lipids. On the other hand, we did have the very positive clinical results and symptomatic results, and therefore one is left with best guess, and what we know otherwise and then extrapolating to the probable reason for improvement in the dry eye patients and that would be the antiinflammatory effect of the omega-3s. And we do know that inflammation - well start off if one perturbs normal physiology some compromise in the tear film, then one's going to end up with inflammation. Inflammation tends to self perpetuate and make the condition worse. Presumably the omega-3s had an antiinflammatory effect which was the positive mechanism that led to the results that we got of increased tear flow and increased tear volume and improved patient's symptom.
KIRK HAMILTON: And there were no side effects per se?
DR. JAMES MCCULLEY: No side effects.
KIRK HAMILTON: Excellent. And how many pills was this concoction taken in a day? And how was it with meals, away from meals?
DR. JAMES MCCULLEY: It was taken in the mornings. And it was taken basically product label recommendation. And it was taken every morning for 90 days in our study.
KIRK HAMILTON: So it didn't have to be taken with a meal or anything?
DR. JAMES MCCULLEY: No. The dosage, they were softgel. I have the, you know the concentrations. What I would say to that it was taken based on product label. We did not alter the product label recommendation for taking TheraTears Nutrition®.
KIRK HAMILTON: And this would be considered more of a pharmacologic effect because you don't know if these people were fatty acid deficient or not because that wasn't assessed beforehand?
DR. JAMES MCCULLEY: No. What we did is to take patients with dry eyes. We asked them to alter, there were inclusion and exclusion criterias so we didn't, we tried to select out patients who had other compounding aggravating factors that might change during the course of the study. And we asked them to maintain the routine that they had been on, not changing it otherwise trying to be certain that the only variable was the, either the active product or the placebo.
KIRK HAMILTON: So from the results of this would this be something that you might further study or use in the, let's say the ophthalmology department of the medical school?
DR. JAMES MCCULLEY: Well. It's, in terms of studying further, we studied this extensively. We did not only look at biochemistry and clinical assessment of the patients and questionnaires. We also did fluorophotometry which allowed us to look at the production and volume of the aqueous tears. At this stage there would not be anything more that we would be doing ourselves. Now I could suggest to a person who might want to look for inflammatory markers in the tears that which is not something that we're involved with at this time, that they might look, you know pre-, during and after therapy to determine if there're changes in inflammatory markers in the tear film. And I would predict that there would be. But one would have to do the study to establish that.
KIRK HAMILTON: It seems like a fairly safe product. Would that be, I don't want to put words in your mouth. Does that seem something that's fairly reasonable to say?
DR. JAMES MCCULLEY: Oh I think the product is a very safe product. You know there are many things in medicine that we give patients that have side effects and some are predictable, some are not. These kinds of preparations are considered neutraceuticals and not pharmaceuticals and some of those preparations may have side effects that are on the market. This particular product has no known side effects so I think it's very safe and pretty much side effect-free.
KIRK HAMILTON: Are there any other lifestyle factors or nutritional things that you can put on a short list like the top five someone could do for dry eyes?
DR. JAMES MCCULLEY: Well there are medications that are known to cause or aggravate dry eyes. Avoidance of those is important. Some of the things that you know are more commonly used are antihistamines, some of the antidepressants, antidiarrhea drugs, just to name a few. Actually some antibiotics that can either cause or exacerbate dry eyes. So being knowledgeable about those kinds of medications and weighing the risks/benefit versus what they're being used for versus the dry eyes can be taken into consideration. There are environmental factors that can play a big role. Relative humidity is a key factor. So depending on the part of the country one lives in, if it really gets cold in the winter there's less water in the air. Depending on the typical heating systems in that part of the country, at least in Texas, it's blown hot air and that's from our heating system in the country, not from Texans. That's very drying. So wind, low humidity are conditions to take into consideration. Anytime we get on an airplane the humidity is going to drop substantially and the longer the trip the more it drops. Taking a vacation to a desert or to the mountains where the humidity is lower can play a real role in decompensating a person who has dry eyes or who's, you know marginally compensated, can tip them over. So those are some of the things. There are other things like alcohol that will dehydrate. If one has, you know a gastrointestinal problem that is leading to loss of fluids then that also can decrease the tear volume and exacerbate a dry eye. So those are some of the things. Another corollary situation would be if one lives in a polluted area. Polluted air is going to be somewhat of an irritant and if a person has a dry eye or borderline dry eye add pollution on top of it, it can tip a patient over. The same thing with allergies and in the allergy season. That if an eye is primed to be irritated from a dry eye and then you add another factor it's going to be exacerbating it. And then with the allergies, well you have an allergy, so what do you do? Take an antihistamine so that's going to dry the tears. So it can be a very complex vicious cycle.
KIRK HAMILTON: How about just simple hydration with water? Does that have anything to do with it?
DR. JAMES MCCULLEY: Well if you're dehydrated it's going to have a very negative effect. I don't think you can drink enough water to affect a dry eye in a positive sense. The main thing there is maintaining at least normal hydration. Past normal hydration, I don't think that there's any, there's going to be any role of fluids. Drink too much alcohol on the other hand, and that's going to lead to dehydration and that's going to exacerbate a dry eye.
KIRK HAMILTON: How about the artificial tears that you can get over the counter? Are those reasonable to try for a while? Are they, how do you assess them if you're a lay person?
DR. JAMES MCCULLEY: Well you know the omega-3 is going to have its impact on most likely as an antiinflammatory so it's going to have its impact on a manifestation of an underlying disease, inflammation. And one has to then approach the underlying disease as well. So what's the cause of the dry eye? Which of the three layers of the tear film is affected and one can then try to not only decrease the inflammation which exacerbates the condition but also try to treat the underlying cause. And if it's a systemic disease that has inflammation associated with it, then there're going to be systemic antiinflammatories that will be required beyond what the omega-3 fatty acids would provide. And if there is a decrease in tear production then one tries to supplement with an artificial tear and there're many different artificial tear preparations on the market. Some mimic one or the other layers of the tear, or multiple layers of the tear better than some others. And I have my favorites and some of it though is trial and error with the patient. So if I have an idea about what the underlying abnormality is in the dry eye that then leads to dryness and leads to inflammation and irritation and all the other things we've talked about then I will direct my topical therapy in addition to quite honestly the omega-3s with initial therapy. I will select my artificial tear based on what I think the underlying abnormality is.
KIRK HAMILTON: It's a perfect answer. Thanks Dr. McCulley. So I want to thank you for taking the time out of your busy day and keep up the great work. I was really appreciative of that article. So thank you very much for being on the show today.
DR. JAMES MCCULLEY: My pleasure. Thank you for having me.
KIRK HAMILTON: And I want to thank you the audience, for listening to this edition of Staying Health Today Radio. And until next time, Stay and Be Well.
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