Dietary Fat and AMD

The July issue of Archives of Ophthalmology contained important information on dietary fat and the risk of AMD. Chua et al. reported results of the large Blue Mountains Eye Study in Australia. People who had the lowest quintile, (lowest 20%), of dietary fat consumption had a 70% increase of early AMD compared to those who had a moderate intake. That means a very low fat diet is not good for you if you’re at risk for AMD. Those who ate fish at least once a week had a 42% risk reduction in early AMD and a 56% reduction in late AMD compared to those who ate fish less than once per month. Those who ate fish three times a week had a 75% reduction in late AMD compared to those who ate fish once a month. The consumption or lack of consumption of butter, margarine, and nuts seemed to have little effect.

Seddon, George, and Rosner, in this same issue, reported the results of a dietary survey on elderly male twins who had served in the United States armed forces. They found that those who ate at least two servings of fish a week had a 32% reduction in the risk of AMD compared to those who ate less than one serving per week. Those in the top 25% of dietary intake of omega-3 fatty acids had a 44% decrease in the risk of AMD compared to those in the lowest 25%. This protective effect was wiped out however, in people who also had a high dietary intake of omega-6 fatty acids or linoleic acid. Linoleic acid is found in beef, pork, lamb, and processed foods cooked in vegetable oils.

So, if you are at risk for AMD, you should not limit your fat intake. But you should increase your intake of omega-3 fatty acids and decrease your intake of omega-6. The ideal ratio of omega-6 to omega 3 is 3:1 or 4:1 not the 10:1 or even 50:1 ratio found in some American diets. That means you should eat more fish, walnuts, flaxseeds and tofu. Eat less beef, pork, lamb, processed foods, trans-fats, and vegetable oils. The best oils to use are canola, olive, and flaxseed. The worst oils are corn, peanut, safflower, and sunflower. I found this site helpful for the content of various oils: http://math.ucsd.edu/~ebender/Health%20&%20Nutrition/Nutrition/oil_good.html (or http://tinyurl.com/ed2d3).

References:

1. Chua B, Flood V, Rochtchina E, Wang JJ, Smith W, Mitchell P. Dietary fatty acids and the 5-year incidence of age-related maculopathy. Arch Ophthalmol. 2006 Jul;124(7):981-6.

2. Seddon JM, George S, Rosner B. Cigarette smoking, fish consumption, omega-3 fatty acid intake, and associations with age-related macular degeneration: the US Twin Study of Age-Related Macular Degeneration.
Arch Ophthalmol. 2006 Jul;124(7):995-1001.

Patients with AMD Need Your Help

When I see patients who suffer from AMD, I ask them if they have access to a computer. In Iowa, fewer than half of them use a computer although many had children who could search the internet for them. I am still worried however, that we’re not getting new information about AMD to the people who need it the most. Patients don’t know about AREDS vitamins. They also don’t know what to watch out for so they delay seeing their eye doctor. By that time, the neovascularization is often advanced with scarring and the treatment outcome in not nearly as good as if it’s caught early. Some patients don’t even see the doctor until their second eye is involved. They tell me that they thought they were just getting old and that there was nothing that could be done.

Please let me know if you see an article on AMD in any popular press magazine or publication. We can then pass this information on to patients and doctors. If you have a chance to speak or write to any editors, please let them know that this is a very important subject that needs coverage.

Thanks

Lucentis is Here- Now What?

Lucentis has been approved and is available for use at a cost of around $2000 per dose. Many retinal experts have been using intravitreal Avastin for almost a year now and are pleased with the results. Avastin is much cheaper, around $100 a dose or less, depending on the compounding pharmacy. Doctors are wondering whether Lucentis is worth the difference in price. Patients, who often have to come up with th 20% co-pay, are wondering the same thing.

I asked my friend, David M. Brown* about Lucentis versus Avastin. Dr. Brown and his colleagues have been the leading recruiters in most of Genentech’s trials on Lucentis. He estimates that his group has given about 1700 injections of Lucentis. The group has also given Avastin to many patients who were not eligible for one of the trials. Following are my questions, (in italics), with his answers:

1. Is Lucentis better than Avastin?

I think it is. After the first injection of Lucentis, about 70% of patients come back at one month and have no fluid in or under the retina. That figure jumps to about 90% after two injections and 95% after three injections.
After the first injection of Avastin, I would estimate that about 40% of patients have no fluid by one month. After the second and subsequent injections of Avastin, about 70% have no fluid but that percentage seems to level off even after additional injections. So I think Lucentis works faster and in more patients than Avastin.

2. How many injections of Lucentis will a patient need?

It’s very variable. I would roughly estimate that the average AMD patient would need 5-7 injections of Lucentis the first year and then maybe 4-6 injections the second year. We had patients in the MARINA trial though, who still got recurrent fluid after 24 monthly injections.

3. So how will you treat the average patient with AMD?

I think that I’ll start with three monthly injections even if the patient has no fluid on the OCT after the first dose. My goal is to get rid of every bit of fluid in the retina, under the retina, and under the RPE and I mean every bit of fluid. If they are completely dry after the third injection, I’ll ask the patient to return in six weeks or anytime they have new symptoms. If they are dry, I’ll see them again in six weeks. If they stay dry, I will gradually lengthen the time between visits to two and then three months.

4. What if they still have fluid after three injections or develop a recurrence of fluid?

Then I’ll give them another round of injections, maybe three again.

5. So you’re willing to give injections every month for years if necessary?

I’m willing since many of these patients regain excellent vision. We’re starting a trial however, to see if half light dose or quarter light dose PDT along with Lucentis can get rid of the CNV permanently and not hurt the vision. We’re trying to see if PDT can selectively damage the new blood vessels and spare the surrounding choroid.

6. Anything else out there that looks promising?

The VEGF trap made by Regeneron seems to work well but it will be hard pressed to work any better than Lucentis since Lucentis gets rid of the fluid so quickly. If the VEGF trap could be injected less often than once a month though, or stops the leakage permanently, then that would be an advantage.

Thank you, Dr. Brown. This is valuable information.


*Greater Houston Retinal Research Center, Vitreoretinal Consultants, Methodist Hospital, Houston, Texas

Glare and Age-related Macular Degeneration by Mark Wilkinson

People who suffer from age-related macular degeneration often have problems with glare. This is particularly true if someone with AMD also has a cataract. Conventional sunglasses eliminate glare but also reduce the light entering the eye and decrease contrast so they often sharply reduce vision in someone with AMD. In this situation, specific filters should be tried to both reduce glare yet increase contrast.

Absorptive lenses can selectively eliminate specific portions of the visible and invisible light spectrum. Therefore it is possible to reduce glare yet keep the vision the same or even improve it. Eye doctors who specialize in visual rehabilitation can often pick the type of colored lens based on the person’s complaint, for instance if the glare is worse indoors or outdoors?

Usually gray/yellow, orange or plum colored filters work best in people with AMD. They reduce the glare, enhance contrast, and even improve rod (the cells that are outside the macula) function to a useful level in daylight conditions. The final decision as to which colored lens works best is up to the person with AMD. There is no one color of filter that works best for everyone so it is a trial and error process. The absorptive lenses can be placed in frames with shields on the tops and sides so the eyes are totally protected from light and glare that could go around the lenses. And don’t forget that a simple baseball cap, any other hat with a broad rim, or a visor will also reduce glare.

Lucentis is here!

The FDA approved Lucentis™ (ranibizumab) for the treatment of AMD last Friday. I’ve discussed the various types of treatment for wet AMD and Lucentis is currently the best. Almost all (95%) of wet AMD patients maintained their vision after one year of treatment. Maintaining vision is the most commonly used endpoint in clinical trials for treatments of wet AMD. It is defined as losing fewer than 15 letters or three lines of vision. Forty percent of patients treated with Lucentis however, had improved vision of three lines or more after one year of treatment. The average treatment gain in the whole group in the MARINA trial was 6.6 letters after two years of treatment.

Patients did best if given Lucentis once a month and the new blood vessels in wet AMD can leak and even grow after the medication is stopped. Patients ask if this means they will have to receive an injection of Lucentis once a month for the rest of their lives. Each injection carries the risk (albeit low) of causing a serious infection inside the eye called endophthalmitis. Retinal experts are trying different treatment schemes (see previous blogs) to determine if they can reduce the number of injections needed to control the neovascularization yet retain the beneficial effect on vision. For now though, it’s best to get Lucentis once a month at least until your doctor feels that the blood vessels in your eye are stable. Your doctor should follow you carefully after stopping Lucentis and you should report promptly any new symptoms of decreased or distorted vision.