If you can spare 5 minutes, I’d like to share with you the latest key points regarding Age-Related Macular Degeneration or AMD for short. I’ve taken the liberty to distill 20 years of practice, many expensive hours of continuing education courses and the latest scholarly findings to present to you, in layman terms all the current findings of protecting yourself from early onset AMD. Like its name implies, this is a degenerative disorder of the retina affecting central vision. Without central vision, it is very difficult to recognize people’s faces, read normal sized print or perform daily tasks. Profound AMD reduces one’s vision to 20 times less vision than 20/20 (essentially 20/400 vision). It is typically associated with age, often older than 55 years. There are dozens of other disorders affecting the macula, or maculopathies as we call them in the doctor world – however these are usually directly genetic and slow progress is being made for treatment. More on these in future blogs.
AMD is the leading cause of blindness in the developed world. Despite many improvements in healthcare as a whole, there has been a 60% increase in AMD from 2000 to 2020 (projected) in the U.S. population. It would appear this is primarily due to lifestyle choices and possibly people living longer as well.
There are two facets of AMD to consider: Factors which are non-modifiable and those which can be modified by lifestyle choices.
Non-modifiable factors include age, heredity (genetics), sex, skin pigmentation and race.
- 70% of all AMD cases have genetic components
- Those which govern Complement blood function (an innate immune system function we all are born with), Oxygen metabolism, extra-cellular matrix governance (think space between cells within the tissue but not contained within capillaries) and cholesterol metabolism.
- Inherited disorders include variations in complement factor H (again, part of the immune system) which is a risk factor for the formation of drusen (non-malignant space-occupying collections of extra-cellular debris which mechanically damage delicate retinal tissues) which increase the risk for AMD progression. A nucleotide in the promoter region of HTRA1 or serine protease gene on chromosome 10q26 is a major risk factor for ‘wet’ AMD or the type where new blood capillaries grow – most destructive to vision. Smoking interacts with complement factor H increasing the odds of AMD by a factor of 5!
- TIMP3 gene mutation increases inflammation with increases likelihood of AMD.
- Should genetic testing be done? If so, whom should it be recommended for? If you have a parent, sister or brother with AMD, it is recommended you consider testing. Currently the test performed by “Macular Risk” is not reimbursed by Medicare, but is reimbursed by some private insurers. Here’s the link: https://www.macularisk.com/
Modifiable factors include behaviors such as Smoking, cardiovascular disease(and intervention), blood lipid status (cholesterol), hypertension (high blood pressure), excess alcohol consumption, accumulated UV/Blue light exposure, malnutrition, obesity and exercise (or lack of).
- Cigarette smoking dramatically increase atherosclerosis and creates an environment conducive to new blood vessel formation in the macula which is horribly damaging to vision.
- Low fruit/vegetable consumption increases risk AMD and cardiovascular diseases.
- Elevated C-reactive protein and/or homocysteine levels increase inflammation – a major contributor towards AMD. Serum Iron elevation increases cardio vascular disease which in turn increases AMD. These and several other markers may be obtained through blood tests your physician can order.
- Omega-3 essential fatty acids in absorbable triglyceride form are excellent to combat inflammation.
- Exercise has many benefits including greater blood perfusion to all body tissues and helps stimulate the body’s repair processes.
I’d like to note: should you posses a large genetic component of risk factors for AMD, all hope is not lost. Modern medicine tells us many genetic pre-dispositions are not a condemnation, rather an increased risk should certain environmental or lifestyle triggers be pulled. In other words, there is still much up to you to determine the ultimate course you take.
This brings us squarely to the nutrition piece. Why is this important? One must first understand some basics in the physiology and anatomy of the macula. The macula and its geographic center called the fovea are the only parts of the retina devoid of over-lying nerve fibers and support cells through which light must pass prior to reaching the photoreceptor layer. It is also the focal point of vision with a very high metabolic rate due to so many photons impacting this area. Therefore, it is particularly vulnerable to the ravages of harsher wavelengths of light such as ultra violet and blue or shorter spectra. A key defensive mechanism is the barrier of pigment comprised of lutein, zeaxanthins and meso-xanthins (often referred to as carotenoids) just above the photoreceptor layer. These critical pigments are protective and have been studied to be in low quantities in people with AMD. This pigment layer exists only present in the macula and is not present in other regions of the retina. Only through nutrition and supplementation can a person insure adequate levels of these pigments.
Tissues taken from healthy human donor eyes and those diagnosed with macular degeneration show diseased eyes have only 70% as much carotenoids as healthy eyes. Researchers have concluded that low macular pigment levels were a major cause of degredation of the macular tissue.
Johanna Seddon, MD at Tufts University advises: “Don’t smoke. Follow a healthful diet rich in dark green, leafy vegetables and low in (saturated) fat. Eat fish a few times a week. Maintain a normal weight and waist size. Exercise regularly and control blood pressure and cholesterol.” I would strongly recommend one obtains these carotenoids through diet versus pill form. Food sources such as eggs, brightly colored vegetables, spinach, kale and other ‘super foods’ provide the proper nutrients in a more bio-available form.
The National Eye Institutes AREDS studies (I & II) both reinforce the benefits of dietary supplementation with lutein, zeaxanthin, vitamins C, E and Zinc only for those who have already been diagnosed with intermediate or advanced macular degeneration. Studied supplements included “I-Caps” and B&L’s “Preservision”. These supplements reduced the progression of AMD by about 25% at year five.
Yes folks, everything is interconnected, interdependent and co-influenced. Just like nature’s ecosystem, our body is an organism which must be approached holistically. One simply cannot pop pills for eye health, skimp on exercise or partake in unhealthy habits believing the eyes will emerge unscathed while the body degrades. There are several advanced treatments for AMD including laser and pharmacological treatments, however they never restore lost visual function, rather reduce the rate of damage. I invite you to visit our office for a macular assessment today!