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Questions and answers from webinar
Below are the questions asked by attendees at the 6th October 2011 webinar, and answers provided by Dr. John Nolan.
What is the difference between cigarette smoking and other forms of smoking, e.g. cigars?
This is a very good question; the literature that is available deals mainly with cigarette smoking. A lot of it depends on ingestion and puffs, for example, around cigars: a lot of people will not inhale cigar smoke. The risk factor that we know of is directly related to cigarette smoking. The advice of my medical colleague, Professor Stephen Beatty, would also be to minimise or reduce other forms of smoking as well, as it is likely that it could affect circulation of carotenoids, for example, in a similar way to tobacco smoke.
How can we protect ourselves against common light sources, e.g. computer monitors?
Another very good question. The problem now is that a lot of the light sources that we are exposed to, and a lot of these energy saving light sources contain a lot of blue light in order to have energy saving components, and I believe this to be detrimental. The pigment that I refer to in my lecture, macular pigment, is the body’s natural defence system against such light damage and obviously we don’t envisage wearing our sunglasses in front of our computers, so the body’s natural defence against that is of course around optimising nutrition with the macular carotenoids: lutein, zeaxanthin and meso-zeaxanthin. We have seen in our own laboratory that you can enrich and enhance your body’s natural macular pigment level, which will reduce the damage caused by blue light. Visual performance is also enhanced if one optimises the yellow macular pigment.
Are macular pigment levels hereditary?
I believe so: we published a paper in Experimental Eye Research in 2006 (Nolan et al, Risk factors for age-related maculopathy are associated with a relative lack of macular pigment) that showed that subjects with family history of AMD had significantly less macular pigment when compared to subjects with no known family history. This finding remained true even when we controlled for diet, serum and other factors. Subsequent studies have shown, however, that you can intervene in such patients by appropriate supplementation, so we were able to supplement such individuals and rebuild pigment in those people who were deficient in it.
What is your opinion of Macushield against Ocuvite/Lutein-based supplements?
Macushield and Ocuvite Lutein are two products currently on the market for AMD. I have worked as a consultant for both Macuvision Europe and for Bausch & Lomb who manufacture these products (respectively), and what I have seen is that Macushield is unique in that it contains meso-zeaxanthin. The meso-zeaxanthin component appears to be showing great potential in terms of rebuilding central macular pigment (central dip paper here). My recommendation, based on the science that I have been involved in, is that a carotenoid formulation containing all three of the macular carotenoids such as that which Macushield offers, is the one I would recommend. Bausch & Lomb have also done significant work with their supplement, Ocuvite Lutein, and we have shown positive effects of supplementation of the Ocuvite Lutein product also, but I believe meso-zeaxanthin to be a very important component of macular pigment.
Can supplement such as Macushield reverse to a partial extent AMD in patients currently with the condition?
While there are many case studies, even within our own clinic at the Institute of Eye Surgery and the Institute of Vision Research in Waterford, where we have seen dramatic effects in some patients, I will have to say that such a question is currently being asked and hopefully will be answered by a proper clinical trial which I am conducting with my research team here in Waterford. On a case by case basis we have seen it to be extremely positive in the context of a gold-standard clinical trial: data and research are currently ongoing in that area. I would, for now, suggest that the potential that macular pigment supplementation and meso-zeaxanthin supplementation offer is for the at-risk population, and I think that’s where the opportunity for the optometrist is. There is now literature in support of making that clinical decision.
Could you have a word with fellow ophthalmologists as to the benefits of recommending Macushield to offspring of ARMD patients?
It is true that the medical ophthalmologist is not always in favour of a nutritional supplement, because they may question the amount of studies published. Over the last ten years I have seen that this has changed dramatically, particularly in Ireland. The Irish ophthalmologist has definitely learned more about the science that is available, and I would challenge the medical ophthalmologist by saying that not recommending supplementation is really not an option now, based on what the scientific literature shows. I would challenge the ophthalmologist to look at the scientific literature, because it is available: we’ve just published* a significant review ourselves on the rationale behind such supplementation, and while I agree that it is not conclusive, as many medical diagnoses are not, it is an extremely understood rationale as to why supplementation would protect against it, and there is a significant and growing body of evidence, so I would happily have a conversation with any ophthalmologist about that.
*We will provide a link to this paper when it becomes available
Can optical coherence tomography (OCT) measure macular pigment?
No. The company I mentioned in my lecture, ebiga-VISION, offers all the technologies needed for AMD screening and risk assessment, and this company has the macular pigment measuring device that I would recommend. You (the optometrist) have been exposed to many flicker devices and I have seen the challenges and difficulties of using these devices, but I will tell you that the flicker device from Brown University in the US, which is now being distributed by ebiga–VISION in Germany, is the device that I would recommend. OCT or fundus imagery does not measure macular pigment right now.
Are free radicals a trigger or a cause of AMD?
This is a very good question. We have seen a letter in Nature of Medicine showing that free radicals are indeed the trigger, so when I say that AMD is the result of free radical damage, it is in part, but it is also correct to say that free radicals trigger inflammation, and that link is in fact very well understood now, and for the first time it closes the loop between anti-oxidants and free radicals.
What exactly is blue light?
In my experience of lecturing to ophthalmologists and optometrists, there is a misunderstanding around light damage, and when I speak about light and blue light, the wavelengths of light must be understood. The easiest way to understand that is that very short wavelength light, which is ultraviolet (UV), has high energy. The wavelength next to UV is visible light, and at the high energy, short wavelength end of the visible light spectrum is blue light. So blue light, as seen in the colours of the rainbow, enters the front of our eye, the lens and the cornea, and because, being close to UV, and high energy and short wavelength, it’s damaging. So in summary, blue light is part of the visible light spectrum, it’s short wavelength and it’s damaging, and we’ve seen that in many in vitro studies with rats etc.
What are your views on Ocuvite Preservision which is prescribed by my local eye clinic?
Ocuvite Preservision is a success story based on what AREDS has shown, and because it contains a lot of antioxidants. I have been lucky enough to be able to study, in detail, eye nutrition and particularly macular pigment, and my recommendation remains: that appropriate dietary habits, coupled with a focused macular pigment supplement such as that which Macushield offers, because it contains all three macular carotenoids, is the best option for people with or at risk of AMD. My mother has early AMD and the supplement I recommend for her is Macushield, coupled with a healthy diet, and every now and then I recommend a multi-vitamin.
Is Macushield contraindicated with any other medication?
We have just published data in Investigative Optometry and Visual Science (IOVS) looking at the safety of consumption of Macushield (Connolly et al 2011, Supplementation with all three macular carotenoids: response, stability and safety), and it is notably the only study performed on eye nutrition to this extent. We worked with Claymon Laboratories, Dublin, where we looked at C-reactive protein and effects of contraindication, and to our knowledge, and based on the data we have, there is no contraindication – and this is another reason why I suggest Macushield over other supplements, because it is the only supplement that focuses solely on the macular carotenoids and not all the other antioxidants. For example, we know that beta-carotene may increase risk of lung cancer in cigarette smokers. In terms of contraindication for Macushield, there is no evidence to suggest so.
Would you recommend computer users change their screen backgrounds to darker/non blue themes?
I think optimisation of screen backgrounds to non-blue is a good suggestion. But if we think about it, the natural defence against day-to-day light exposure, which in part is unavoidable, is indeed our macular pigment. If we remember the monkey retina I showed you in my slides, look where it’s located: right at the centre of our vision, right where we have optimal visual acuity and colour appreciation, and right where AMD presents. So I think it’s optimal also in terms of optics to minimise blue light damage, but think of it from a health point of view, and what we can do in our retinas.
What filtration can protect the eye against blue light damage, i.e. What tint? Will photochromic lenses suffice? What is my specific recommendation to the patient on filters?
What wavelengths should we be trying to filter out? This is the discussion that I have been having with many commercial bodies as well, because they are obviously interested in what’s optimal for filtration. I am reluctant to answer this question at the moment, but we will note the question from the person and give a full detailed answer. I would think that you do not want to get rid of total blue, because filtering blue light 100% would have negative visual effects from appreciating the colour blue, which is important, so I am reluctant to answer it on that regard.
Apart from natural sunlight, which light sources are damaging? You mentioned computers.
I am not surprised that the eye specialist is interested in light sources and what is damaging. My colleague from Dublin Institute of Technology, Dr. James Loughman, advises our research group on this, and a lot of the new energy-saving bulbs, for example, he informs me, contain a lot of blue which can be very damaging. We will make available a list on our website of typical light sources that are damaging.*
*We will provide a link to a page listing typical light sources when it is completed
How does the flicker device from Brown University compare to the MPOD?
We have a paper coming out: Dr James Loughman is the primary author on this publication, and in terms of ease of use etc there are similarities and differences. In terms of accuracy, reliability and reproducibility, the Brown University device wins significantly on that front. The absolute data from the trial that was run to compare those devices will be available from that publication*. From my experience of measuring macular pigment for ten years and learning as the prototypes develop, the Brown University device that ebiga-VISION offers is, in my opinion, the scientific gold standard, and it has been optimised for clinical use, and I would absolutely recommend it.
*This paper is in press and we will provide a link to the abstract when it is available