Age-Related Macular Degeneration (AMD), and its associated vision loss, is known to affect legendary actress Dame Judi Dench, 86, and famed novelist, Stephen King, 73. Both have spoken publicly of their eye conditions. Dench and King are not outliers. They’re just two of the many millions of people affected by this potentially devastating disease which gradually steals the central vision. In this three-part series we will explore why chronic disease is a new phenomenon. We will accomplish this by exploring the history of AMD and by extension all chronic disease.
AMD is the leading cause of irreversible vision loss in people over the age of 65 in developed nations.1 By 1994, some 15 million Americans over the age of 50 were estimated to have been affected by AMD.2 Globally, some 196 million people are expected to be afflicted with the disease in 2020, with that number projected to rise to 288 million by 2040.3 For people between 45 and 85 years of age, this translates to 8.69% with some degree of AMD. In 1992, in the United States, nearly one in three adults over the age of 75 was determined to be affected by AMD.4
Even worse, as of 2002, the World Health Organization (WHO) determined that 8.7% of the world’s blindness and severe vision loss, numbering some 14 million people, was secondary to AMD.5
The macula is the central retina, accounting for only four percent of the total retinal area. It is only 6 millimeters across – almost exactly one-fourth of an inch. Arguably, this is the most important six millimeters in our bodies.
Orthodox ophthalmology has found many associations with AMD, but the underlying cause has remained elusive. As written in Albert and Jakobiec’s 1994 edition of Principles and Practice of Ophthalmology, which serves as a major reference for ophthalmologists, “Since the cause or causes of AMD are unknown, we lack the means for its prevention.”6 This statement remains true for orthodox ophthalmology today.
For decades, AMD has primarily been associated with aging (hence “age-related”) and, more recently, genetics. Although increased AMD prevalence has been associated with heart disease,7 type 2 diabetes,8 obesity,9 and metabolic syndrome,10 there generally has not been any suggestion that these conditions are the cause of AMD.
In August 2016, at the Ancestral Health Symposium, for the first time publicly, I proffered the following hypothesis:
The ‘displacing foods of modern commerce’ are the primary and proximate cause of AMD.
For those who are familiar with the late Weston A. Price, whom many nutrition researchers consider the ‘Father of Nutrition,’ the term ‘displacing foods of modern commerce’ will be quite familiar. This term equates essentially to refined white flour, refined sugars, most vegetable oils (primarily polyunsaturated oils), and trans fats – in short – man-made, processed foods.
I first developed this hypothesis in late 2013, but it would take nearly three years of investigative journalism, interviews, and our fundamental research, all of which culminated in the authoring of a book on this subject. That book, Ancestral Dietary Strategy to Prevent and Treat Macular Degeneration, was published in September 2016.
Why Diet – Not Aging or Genetics – as the Cause of AMD?
In late 2013, it occurred to me that if macular degeneration was all about aging and genetics, as orthodox ophthalmology asserts, then the prevalence of the disease should have been the same a century ago, as it is today – correct? This should be the case, since we generally believe that our DNA is stable over very long periods, i.e., up to many thousands of years. And our DNA, the master architectural plan of our bodies, is also generally believed to be nearly immutable.
Evolutionary biologist and paleo diet founder, S. Boyd Eaton, MD, wrote:
Our genetic makeup, especially that regarding our core metabolic and physiologic characteristics, has changed very little between the emergence of agriculture, roughly 10,000 years ago, and the present.”11
With that fundamental concept, I asked myself two questions:
- Was AMD always as prevalent as it is today?
- When could ophthalmologists even see the retina?
The latter question, because obviously, ophthalmologists would have to visualize the retina to make the diagnosis, or even characterize macular degeneration. If the evidence favored AMD as being an unusual or rare disorder in the past – and ophthalmologists were collectively able to visualize the macula simultaneously – then that evidence would strongly be in favor of an environmental factor at work. The suspected environmental factor, as we now know is the case with most chronic metabolic diseases such as heart disease, hypertension, type 2 diabetes, cancer, obesity, and numerous other diseases of civilization, is “Westernization” of the diet.12
The History of AMD in the U.S. and Worldwide
It may come as a surprise to the lay public, but we physicians have virtually no education about the history of medicine, even within our specialty. As far back 1896, just before the American Academy of Ophthalmology was founded, German physician Rudolph Virchow said:
It is one of the worst aspects of our present developmental stage of medicine that the historical knowledge of things diminishes with each generation of students. Even independent young researchers can normally be assumed to have a historical knowledge of no more than three to five years at a maximum. Anything published more than five years ago does not exist.13
Virchow’s statement remains just as true today.
In medical school, internship, and right through my three-year ophthalmology residency, I learned virtually nothing about the history of medicine, nor the history of ophthalmology. When I began to research the history of macular degeneration, I was stunned to find that I couldn’t find a single resource whereby the history of AMD, the single most common retinal condition of our time, had already been researched. That led me on a search that would take months to complete, digging up antiquated textbooks from the 1800s as well as scientific papers published in the late 19th century and beyond. I did this with the assistance of reference librarians around the world and many book stores, particularly those that held historical medical textbooks, which are few. It was a journey that was laborious, intensive, and long. But these relics from medical history held astonishing facts that would not only be germane to my hypothesis but also turned out to support it.
So back to the question: When could ophthalmologists first visualize the retina?
The answer: In 1851 – this is because of the genius of German-born physician and physicist, Hermann von Helmholtz, who not only invented the ophthalmoscope but published the design so that it could be reproduced by manufacturers.14 The ophthalmoscope became the first device that eye-care providers would use to visualize the optic nerve, macula, vessels, and the rest of the retina. Within a decade, this technology had spread around the world. This also resulted in several retinal atlases having been produced during the 1850s and 1860s.15
Curiously, however, although these atlas images virtually always included the macula, as it is in the center of the view through the ophthalmoscope, none of these images ever characterized anything resembling AMD.
It would be 23 years following Helmholtz’s publication of the ophthalmoscope design before the first cases of macular degeneration were characterized. In 1874, in London, England ophthalmologist Jonathan Hutchinson described four cases that he had collected from his practice.16 After another eleven years of silence on the subject, German ophthalmologist Otto Haab, discussed the equivalent of macular degeneration in a lecture – in 1885.17 Yet another decade later, Haab published a paper in which he had evaluated some 50,000 ophthalmic patient medical records, and from these, he determined that macular degeneration was as rare as myopic maculopathy and traumatic maculopathy. These two conditions are very rarely detected in the retina.18,19 For perspective, in 24 years of ophthalmology practice, I have witnessed less than a handful of these latter two conditions combined, yet I would typically see that many patients with AMD in any half-day of practice.
The literature remained almost silent on the condition of macular degeneration until about 1930, even though the optic nerve and retinal conditions were subjects of great discovery, numerous papers, and the attention of many book chapters. If one is left to wonder about the widespread use of the ophthalmoscope, ophthalmologists Landolt and Snellen had collected some 86 versions of the ophthalmoscope by 1880, 140 versions by 1901 (on the 50th anniversary of Helmholtz design), and 200 models by 1913.20
In 1927, London, England, ophthalmologist Sir Stewart Duke-Elder published his first comprehensive textbook of ophthalmology. The eminent Duke-Elder, who would become the most dominant force in ophthalmology for more than four decades, was not only revered, but prolific. His 1927 textbook was 340 pages in length, yet failed to even mention macular degeneration, though that was typical for textbooks of that era.21 Thirteen years later, however, in Duke-Elder’s next comprehensive textbook of ophthalmology, he dedicated some 13 pages to the condition of macular degeneration, including 17 images, six of which were in full-color. He referred to macular degeneration as “a common cause of failure in central vision in old people.” 22 By the 1930s, macular degeneration had risen from the status of medical rarity to a somewhat more common condition of the macula. Duke-Elder, however, did not mention any known or suspected degree of prevalence.
Though this is in part supposition, I believe it is fair to say that Duke-Elder was likely not even aware of the condition of age-related macular degeneration, or its equivalent, in the year 1927. However, the condition had become intimately familiar to him by the late 1930s.
Chris A. Knobbe, MD, is an ophthalmologist and Associate Clinical Professor Emeritus, University of Texas Southwestern Medical Center, in Dallas, Texas, and the Founder and President of Cure AMD Foundation™. Dr. Knobbe is the author of the book, Ancestral Dietary Strategy to Prevent & Treat Macular Degeneration. Dr. Knobbe may be reached directly via the here.
- Van Bol L, Rasquin F. [Age-related macular degeneration]. Rev Med Brux 2014; 35(4): 265-70.
- Egan KM, Seddon JM. Age-Related Macular Degeneration: Epidemiology. In: Albert & Jakobiec, Principles and Practice of Ophthalmology.Philadelphia, PA: W.B. Saunders Company; 1994: 1266.
- Wong WL, Su X, Li X, et al. Global prevalence of age-related macular degeneration and disease burden projection for 2020 and 2040: a systematic review and meta-analysis. Lancet Glob Health 2014; 2: e106-16.
- Klein R, Klein BE, Linton KL. Prevalence of age-related maculopathy. The Beaver Dam Eye Study. Ophthalmology. 1992; 99: 933-43.
- Resnikoff S, Pascolini D, Etya’ale D, et al. Global data on visual impairment in the year 2002. Bulletin of the World Health Organization 2004; 82: 844-851.
- Egan KM, Seddon JM. (1994) Albert & Jakobiec: Principles and Practice of Ophthalmology. Basic Sciences (Philadelphia: W.B. Saunders Co.), p. 1273.
- Sun C, Klein R, Wong TY. Age-related macular degeneration and risk of coronary heart disease and stroke: the Cardiovascular Health Study. Ophthalmology. 2009; 116(10): 1913-1919.
- Klein R, Deng Y, Klein BE, et al. Cardiovascular disease, its risk factors and treatment, and age-related macular degeneration: Women’s health initiative sight exam ancillary study. Am J Ophthalmol. 2007; 143(3): 473-483.
- Cheung N, Wong TY. Obesity and eye diseases. Surv Ophthalmol. 2007; 52(2): 180-95.
- Maralani HG, Tai BC, Wong TY, et al. Metabolic syndrome and risk of age-related macular degeneration. Retina. 2015; 35(3): 459-66.
- Muehlenbein, Michael P. (Editor) Human Evolutionary Biology. Cambridge, New York, Cambridge University Press, 2010, p. 491.
- Cordain, Loren. The Paleo Answer. Hoboken, New Jersey: John Wiley and Sons, Inc., 2012.
- Albert, Daniel M. The History of Ophthalmology. Cambridge, Massachusetts, Blackwell Science, Inc., 1996. p. xvi (Preface).
- Albert, Daniel M. The History of Ophthalmology. Blackwell Science, Inc., Cambridge, Massachusetts, 1996, p. 76.
- Albert, Daniel M., Edwards, Diane D. The History of Ophthalmology. Cambridge, Massachusetts, Blackwell Science, 1996. Pp. 191, 195-196.
- Hutchinson J, Tay W. Symmetrical central choroido-retinal disease occurring in senile persons. R Lond Ophthalmic Hosp Rep J Ophthalmic Surg. 1874; 8: 231-244.
- Haab, O. Zentralblatt für prakrische Augenheilkunde v. 9, p. 383-4, 1885.
- Haab O. Atlas und Grundriss der Ophthalmoskopie und ophthalmoskopischen Diagnostik. Atlas and outline of ophthalmoscopy and ophthalmoscopic diagnosis. München, Lehmann; 1895.
- Haab O. Ueber die Erkrankung der Macula lutea. On the disease of the macula lutea. Siebenter Periodischer Internationaler Ophthalmologen-Congress Heidelberg. 1888, p. 429.
- Keeler CR. A Brief History of the Ophthalmoscope. The Royal College of Ophthalmologists, London, UK, Accepted for publication 16 June 2003. Available at Optometry in Practice 2003; Vol 4: p. 138.
- Duke-Elder, W. Stewart. Recent Advances in Ophthalmology. Philadelphia, P. Blakiston’s Son & Co., 1927.
- Duke-Elder, WS. Textbook of Ophthalmology – Duke-Elder, Vol. III, Diseases of the Inner Eye. St. Louis: The C.V. Mosby Company, 1940. p. 2372 – 2373.