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New Research from Google Labs: Using Machine Learning to Detect Diabetic Eye Disease

the Google logo

The highly regarded Research Labs at Google are charged with "tackling the most challenging problems in computer science and related fields," including eye care and ophthalmology. A groundbreaking project, announced in 2014 and still in development, was the creation of a prototype "smart" contact lens to monitor blood glucose levels continuously for people with diabetes.

Most recently, in this month's Journal of the American Medical Association, Google Research Labs announced yet another groundbreaking diabetes-related advance: Using machine learning and artificial intelligence to screen for diabetic retinopathy and diabetic macular edema in patients with diabetes. According to Google, "Automated diabetic retinopathy screening methods with high accuracy have the strong potential to assist doctors in evaluating more patients and quickly routing those who need help to a specialist."

Although this is a potentially significant breakthrough, study lead authors Lily Peng, M.D., Ph.D. and Varun Gulshan, Ph.D. urge caution, noting that "These are exciting results, but there is still a lot of work to do. Further research is necessary to determine the feasibility of applying this [screening technique] in the clinical setting and to determine whether [its use] could lead to improved care and outcomes compared with current ophthalmologic assessment."

The Research from the Journal of the American Medical Association (JAMA)

This new Google research, titled Development and Validation of a Deep Learning Algorithm for Detection of Diabetic Retinopathy in Retinal Fundus Photographs, has been published "online first" as a freely available article in the November 29, 2016 edition of JAMA, an international peer-reviewed journal published monthly by the American Medical Association and the most widely circulated medical journal in the world.

The authors are Varun Gulshan, PhD; Lily Peng, MD, PhD; Marc Coram, PhD; Martin C. Stumpe, PhD; Derek Wu, BS; Arunachalam Narayanaswamy, PhD; Subhashini Venugopala, MS; Kasumi Widner, MS; Tom Madams, MEng; Jorge Cuadros, OD, PhD; Ramasamy Kim, OD, DNB; Rajiv Raman, MS, DNB; Philip C. Nelson, BS; Jessica L. Mega, MD, MPH; and Dale R. Webster, PhD.

They represent the following organizations and institutions: Google Inc, Mountain View, CA; the University of Texas, Austin; EyePACS LLC, San Jose, CA; the University of California, Berkeley; the Aravind Medical Research Foundation, Madurai, India; Shri Bhagwan Mahavir Vitreoretinal Services, Chennai, India; Verily Life Sciences, Mountain View, CA; and Brigham and Women's Hospital and Harvard Medical School, Boston, MA.

First, Some Terminology

Here is a brief explanation of some key terms used in this artificial intelligence research:

  • Machine learning: A type of artificial intelligence that provides computers with the ability to learn without being explicitly programmed. Machine learning focuses on the development of computer programs that can teach themselves to grow and change when exposed to new data. (via
  • Algorithm: A step-by-step problem-solving procedure.
  • Fundus: The interior rear surface of the eye, which includes the retina, optic disc, and macula.
  • Fundus camera: A specialized low-power microscope with an attached camera designed to photograph the fundus; i.e., a retinal fundus photograph.

About the Research

Excerpted from Deep Learning for Detection of Diabetic Eye Disease, via the Google Research Blog:

Diabetic retinopathy (DR) is the fastest growing cause of blindness, with nearly 415 million diabetic patients at risk worldwide. If caught early, the disease can be treated; if not, it can lead to irreversible blindness. Unfortunately, medical specialists capable of detecting the disease are not available in many parts of the world where diabetes is prevalent. We believe that Machine Learning can help doctors identify patients in need, particularly among underserved populations.

A few years ago, several of us began wondering if there was a way Google technologies could improve the DR screening process, specifically by taking advantage of recent advances in Machine Learning and Computer Vision. In [our article], we present a deep learning algorithm capable of interpreting signs of DR in retinal photographs, potentially helping doctors screen more patients in settings with limited resources.

One of the most common ways to detect diabetic eye disease is to have a specialist examine pictures of the back of the eye and rate them for disease presence and severity…. Interpreting these photographs requires specialized training, and in many regions of the world there aren’t enough qualified graders to screen everyone who is at risk.

Working closely with doctors both in India and the US, we created a development dataset of 128,000 images which were each evaluated by 3-7 ophthalmologists from a panel of 54 ophthalmologists. This dataset was used to train a deep neural network to detect referable diabetic retinopathy.

We then tested the algorithm’s performance on two separate clinical validation sets totaling [approximately] 12,000 images, with the majority decision of a panel 7 or 8 U.S. board-certified ophthalmologists serving as the reference standard. The ophthalmologists selected for the validation sets were the ones that showed high consistency from the original group of 54 doctors. The results [reported in more depth below] show that our algorithm’s performance is on-par with that of ophthalmologists.

These are exciting results, but there is still a lot of work to do. First, while the conventional quality measures we used to assess our algorithm are encouraging, we are working with retinal specialists to define even more robust reference standards that can be used to quantify performance.

Furthermore, interpretation of a 2-D fundus photograph, which we demonstrate in this paper, is only one part in a multi-step process that leads to a diagnosis for diabetic eye disease. In some cases, doctors use a 3-D imaging technology [i.e, optical coherence tomography] to examine various layers of a retina in detail.

More about Diabetic Eye Disease

Diabetic Retinopathy

Although people with diabetes are more likely to develop cataracts at a younger age and are twice as likely to develop glaucoma as people who do not have diabetes, the primary vision problem caused by diabetes is diabetic retinopathy, the leading cause of new cases of blindness and low vision in adults aged 20-65:

NEI example of seeing with diabetic retinopathy: many blind spots and overall blurriness

How a person with
diabetic retinopathy might see

  • "Retinopathy" is a general term that describes damage to the retina.
  • The retina is a thin, light-sensitive tissue that lines the inside surface of the eye. Nerve cells in the retina convert incoming light into electrical impulses. These electrical impulses are carried by the optic nerve to the brain, which interprets them as visual images.
  • Diabetic retinopathy occurs when there is damage to the small blood vessels that nourish tissue and nerve cells in the retina.
  • "Proliferative" is a general term that means to grow or increase at a rapid rate by producing new tissue or cells. When the term "proliferative" is used in relation to diabetic retinopathy, it describes the growth, or proliferation, of abnormal new blood vessels in the retina. "Non-proliferative" indicates that this process is not yet occurring.
  • Proliferative diabetic retinopathy affects approximately 1 in 20 individuals with the disease.

Four Stages of Diabetic Retinopathy

According to the National Eye Institute, diabetic retinopathy has four stages:

  • Mild non-proliferative retinopathy: At this early stage, small areas of balloon-like swelling occur in the retina's tiny blood vessels.
  • Moderate non-proliferative retinopathy: As the disease progresses, some blood vessels that nourish the retina become blocked.
  • Severe non-proliferative retinopathy: Many more blood vessels become blocked, which disrupts the blood supply that nourishes the retina. The damaged retina then signals the body to produce new blood vessels.
  • Proliferative retinopathy: At this advanced stage, signals sent by the retina trigger the development of new blood vessels that grow (or proliferate) in the retina and the vitreous, which is a transparent gel that fills the interior of the eye. Because these new blood vessels are abnormal, they can rupture and bleed, causing hemorrhages in the retina or vitreous. Scar tissue can develop and can tug at the retina, causing further damage or even retinal detachment.

Diagnosing Diabetic Eye Disease

Diabetic retinopathy usually has no early warning signs. It can be detected only through a comprehensive eye examination that looks for early signs of the disease, including:

  • Leaking blood vessels
  • Macular edema (swelling)
  • Pale, fatty deposits on the retina
  • Damaged nerve tissue
  • Any changes to the retinal blood vessels

To diagnose diabetic eye disease effectively, eye care specialists recommend a comprehensive diabetic eye examination that includes the following procedures:

  • Distance and near vision acuity tests
  • A dilated eye (or fundus) examination, which includes the use of an ophthalmoscope. In a dilated eye examination, it is the pupil that is dilated—not the entire eye. This allows the examiner to see through the pupil to the retina. Visual acuity tests alone are not sufficient to detect diabetic retinopathy in its early stages.
  • A tonometry test to measure fluid pressure inside the eye.
  • A fluorescein angiography test, if more serious retinal changes, such as macular edema, are suspected. Fluorescein angiography is an eye test that uses a special dye and camera to look at blood flow in the retina.
  • Optical coherence tomography (OCT) testing may be used to gain a clearer picture of the retina and its supporting layers. OCT is a type of medical imaging technology that produces high-resolution cross-sectional and three-dimensional images of the eye.

More about the Study from JAMA

Excerpted from the study's Key Points and Abstract, with the full article, including outcome measures and results, available online:

Question: How does the performance of an automated deep learning algorithm compare with manual grading by ophthalmologists for identifying diabetic retinopathy in retinal fundus photographs?

Objective: To apply deep learning to create an algorithm for automated detection of diabetic retinopathy and diabetic macular edema in retinal fundus photographs.

Design and Setting: A specific type of neural network optimized for image classification called a deep convolutional neural network was trained using a retrospective [i.e., past records] development data set of 128,175 retinal images, which were graded 3 to 7 times for diabetic retinopathy, diabetic macular edema, and image gradability by a panel of 54 US licensed ophthalmologists and ophthalmology senior residents between May and December 2015. The resultant algorithm was validated in January and February 2016 using 2 separate data sets, both graded by at least 7 US board-certified ophthalmologists with high intragrader consistency.

Main Outcomes and Measures: The sensitivity and specificity of the algorithm for detecting referable diabetic retinopathy (RDR), defined as moderate and worse diabetic retinopathy, referable diabetic macular edema, or both, were generated based on the reference standard of the majority decision of the ophthalmologist panel. The algorithm was evaluated at 2 operating points selected from the development set, one selected for high specificity and another for high sensitivity.

Finding: In 2 validation sets of 9,963 images and 1,748 images, at the operating point selected for high specificity, the algorithm had 90.3% and 87.0% sensitivity and 98.1% and 98.5% specificity for detecting referable diabetic retinopathy, defined as moderate or worse diabetic retinopathy or referable macular edema by the majority decision of a panel of at least 7 US board-certified ophthalmologists. At the operating point selected for high sensitivity, the algorithm had 97.5% and 96.1% sensitivity and 93.4% and 93.9% specificity in the 2 validation sets.

Meaning: Deep learning algorithms had high sensitivity and specificity for detecting diabetic retinopathy and macular edema in retinal fundus photographs.

Additional Diabetes Information

Diabetes and diabetic retinopathy
In the News
Low Vision
Medical Updates

New Research: Can Proteins that Characterize Alzheimer's Disease Contribute to an Understanding of Macular Degeneration?

Photograph of a retina with wet age-related macular degeneration

A retina with wet AMD

New research from the University of Southampton, England is investigating the mechanisms that contribute to the development of age-related macular degeneration (AMD) – particularly the presence of the beta-amyloid proteins that also accumulate in the brains of people with Alzheimer's disease.

According to study co-author Arjuna Ranayaka, Ph.D., "We know that AMD is caused by a combination of genetic, environmental, and lifestyle risk factors, but this novel discovery could open up new possibilities to understand how the aging retina becomes damaged. Such advances are important if we are to develop better AMD treatments in the future."

Please note that this research does not indicate that age-related macular degeneration can result from Alzheimer's disease, or that one condition can contribute to the development of the other. What the research does indicate, however, is that studying the behavior of Alzheimer's-related beta-amyloid proteins can provide insight into the retinal damage that accompanies macular degeneration.

From Experimental Eye Research

This new research regarding the potential role of beta-amyloid protein (explained below) in the development of macular degeneration has been published in the December 2016 edition of Experimental Eye Research. The primary goal of Experimental Eye Research is to publish original research on all aspects of experimental biology of the eye and ocular tissues "that seek to define the mechanisms of normal function and/or disease."

The authors are George Taylor-Walker, Savannah A. Lynn, Eloise Keeling, Rosie Munday, David A. Johnston, Anton Page, Jennifer A. Scott, Srini Goverdhan, Andrew J. Lotery, and J. Arjuna Ratnayaka, from the University of Southampton and the University Hospital Southampton NHS Foundation Trust, United Kingdom.

What is Beta-Amyloid?

In its most basic form, beta-amyloid (BAY-tuh AM-uh-loyd) is a single protein fragment, snipped from a larger protein found in the fatty membrane surrounding nerve cells. Because it is chemically "sticky," these protein fragments tend to clump or cluster, gradually building into hard, insoluble "plaques" in the brain that are one of the hallmarks of Alzheimer's disease. As they cluster, these beta-amyloid plaques erode synapses, which are the connections between nerve cells that help to conduct nerve impulses. Synapses are essential in encoding, consolidating, storing, and retrieving memories.

However, there is much that is still unknown about beta-amyloid, as evidenced by the discouraging results of a recent clinical trial for an experimental drug targeting amyloid buildup in patients with Alzheimer's disease. According to the New York Times,

An experimental Alzheimer's drug that had previously appeared to show promise in slowing the deterioration of thinking and memory has failed in a large Eli Lilly clinical trial, dealing a significant disappointment to patients hoping for a treatment that would alleviate their symptoms.

The failure of the drug, solanezumab, underscores the difficulty of treating people who show even mild dementia, and supports the idea that by that time, the damage in their brains may already be too extensive. And because the drug attacked the amyloid plaques that are the hallmark of Alzheimer's, the trial results renew questions about a leading theory of the disease, which contends that it is largely caused by amyloid buildup.

No drug so far has been able to demonstrate that removing or preventing the accumulation of amyloid translates into a result that matters for patients: stalling or blocking some of the symptoms of dementia.

About the Macular Degeneration/Amyloid Research

Excerpted from Macular degeneration: Study sheds light on Alzheimer's proteins in retina, via Medical News Today:

For their study, [the researchers] used cell cultures and mouse models of macular degeneration (AMD) to investigate mechanisms of Alzheimer's beta-amyloid accumulation inside retinal cells. They were particularly interested in the speed with which the amyloid proteins find their way inside the retinal cells.

The researchers found the retinal cells internalized the amyloid proteins within 24 hours of being exposed to them.

They also discovered that the amyloid proteins are retained inside the retinal cells, where they gradually impair a molecular mechanism reliant on the protein encoded by the MAP-2 gene. Among other things, MAP-2 mechanisms help to maintain important structures inside cells called microtubules.

[Study co-author] Dr. Arjuna Ratnayaka says they were surprised at the speed with which the amyloid proteins entered the cells, and he suggests the finding may help explain how a healthy retina can switch to a diseased, AMD retina.

The team plans to continue its research, particularly assessing how the amyloid beta proteins penetrate retinal cells and begin to cause internal damage – beginning the framework for preventative options or treatment methods. The hope is that the continuing work will lead to measures to prevent or treat AMD.

More Information about Age-Related Macular Degeneration

NEI image of how someone with macular degeneration sees: overall blurriness with a blind spot in the center

Looking at the world with AMD

Age-related macular degeneration (AMD) is a gradual, progressive, painless deterioration of the macula, the small sensitive area in the center of the retina that provides clear central vision. Damage to the macula impairs the central (or "detail") vision that helps with essential everyday activities, such as reading and writing, preparing meals, watching television, and personal self-care.

AMD is the leading cause of vision loss for people aged 60 and older in the United States. According to the American Academy of Ophthalmology, 10-15 million individuals have AMD and about 10% of people who are affected have the "wet" type of AMD.

Wet (Neovascular) Macular Degeneration

In wet, or exudative, macular degeneration (AMD), the choroid (a part of the eye containing blood vessels that nourish the retina) begins to sprout abnormal new blood vessels that develop into a cluster under the macula, called choroidal neovascularization (neo = new; vascular = blood vessels).

Because these new blood vessels are abnormal, they tend to break, bleed, and leak fluid under the macula, causing it to lift up and pull away from its base. This damages the fragile photoreceptor cells, which sense and receive light, resulting in a rapid and severe loss of central vision.

Dry Macular Degeneration

Photograph of a retina with drusen

A retina with dry AMD and drusen

The dry (also called atrophic) type of AMD affects approximately 80-90% of individuals with AMD. Its cause is unknown, it tends to progress more slowly than the wet type, and there is not – as of yet – an approved treatment or cure.

"Atrophy" refers to the degeneration of cells in a portion of the body; in this case, the cell degeneration occurs in the retina.

In dry age-related macular degeneration, small white or yellowish deposits, called drusen, form on the retina, in the macula, causing it to deteriorate or degenerate over time.

Drusen are the hallmark of dry AMD. These small yellow deposits beneath the retina are a buildup of waste materials, composed of cholesterol, protein, and fats. Typically, when drusen first form, they do not cause vision loss. However, they are a risk factor for progressing to vision loss.

Risk Factors for Macular Degeneration

The primary risk factors for AMD include the following:

  1. Smoking: Current smokers have a 2-3 times higher risk for developing AMD than do people who never smoked. It's best to avoid second-hand smoke as well.
  2. Sunlight: Ultraviolet (UV) light is not visible to the human eye, but can damage the lens and retina. Blue light waves that make the sky, or any object, appear blue, are visible to the human eye and can also damage the lens and retina. Avoid UV light and blue/violet light as much as possible by wearing sunglasses with an amber, brown, or orange tint that blocks both blue and UV light.
  3. Uncontrolled hypertension: The National Eye Institute (NEI) reports that persons with hypertension were 1.5 times more likely to develop wet macular degeneration than persons without hypertension. It's important to keep your blood pressure controlled within normal limits.
  4. A diet high in packaged, processed food and low in fresh vegetables: NEI suggests that eating antioxidant-rich foods, such as fresh fruits and dark green leafy vegetables (kale, collard greens, and spinach) may delay the onset or reduce the severity of AMD. Eating at least one serving of fatty fish (salmon, tuna, or trout) per week may also delay the onset or reduce the severity of AMD.
  5. Race: According to NEI, Whites/Caucasians are more likely to have AMD than people of African descent.
  6. Family history: NEI reports that individuals with a parent or sibling with AMD have a 3-4 times higher risk of developing AMD.

You can read more about the full range of AMD risk factors at Risk Factors for Age-Related Macular Degeneration on the VisionAware website.

More about the Study from Experimental Eye Research

Edited and excerpted from the study Abstract and Introduction, with the full article available online:

Age-related Macular Degeneration (AMD) is a common, irreversible blinding condition that leads to the loss of central vision. AMD has a complex etiology with both genetic as well as environmental risks factors, and share many similarities with Alzheimer's disease. Recent findings have contributed significantly to unravelling its genetic architecture that is yet to be matched by molecular insights [i.e., the basic structure of molecules].

Studies are made more challenging by observations that aged and AMD retinas accumulate the highly pathogenic [i.e., causing disease] Alzheimer's-related amyloid beta group of peptides, for which there appears to be no clear genetic basis. Analyses of human donor and animal eyes have identified retinal amyloid beta aggregates [i.e., clusters] in retinal ganglion cells, the inner nuclear layer, photoreceptors, as well as the retinal pigment epithelium. Amyloid beta is also a major drusen constituent; found correlated with elevated drusen-load and age, with a propensity to aggregate in retinas of advanced AMD.

Despite this evidence, how such a potent driver of neurodegeneration might impair the neuro-retina remains incompletely understood, and studies into this important aspect of retinopathy remains limited. In order to address this we exploited R28 rat retinal cells which, due to its heterogeneous [i.e., dissimilar or diverse] nature, offers diverse neuro-retinal cell types in which to study the molecular pathology of amyloid beta.

For the first time, we reveal that retinal neurons rapidly internalized amyloid beta 1-42, the most cytotoxic [i.e., causing cell damage or death] and aggregate-prone [i.e., tending to form clusters] amongst the amyloid beta family.

To assess whether amyloid beta could realistically localize to living retinas to mediate such effects, we sub-retinally injected nanomolar levels [i.e., an extremely small concentration] of … amyloid beta 1-42 into wildtype mice.

Our novel findings describe how retinal neurons internalize amyloid beta to transiently impair MAP-2 in a hitherto unreported manner. Our insights suggest a molecular pathway by which this could occur in the senescent [i.e., aging] eye, leading to complex diseases such as AMD.

Additional Macular Degeneration Information

Low Vision
Macular Degeneration
Medical Updates

New Research from Canada and France: Can Your Gut Microbes Influence the Development of Wet Macular Degeneration?

Photograph of a retina with wet age-related macular degeneration

A retina with wet AMD

New research From Canada and France reveals that microbes in the gut might play an important role in the development of wet age-related macular degeneration (AMD). These findings indicate that it might be possible to prevent, or delay the development of, wet AMD by changing the balance of microbes in the gut through diet or other means.

According to study co-author Przemyslaw Sapieha, from the University of Montreal and McGill University, "Our research suggests that diets rich in fat alter the gut microbiome in a way that aggravates wet AMD. Influencing the types of microbes that reside in your gut, either through diet or by other means, may thus affect the chances of developing AMD and its progression."

From EMBO Molecular Medicine

The research, entitled Gut microbiota influences pathological angiogenesis in obesity-driven choroidal neovascularization (explained below), has been published "online first" in the November 15, 2016 edition of EMBO Molecular Medicine. EMBO Molecular Medicine is a peer-reviewed, online, open-access journal dedicated to research that combines clinical research and basic biology in a number of areas, including aging, genetics, gene therapy, immunology and inflammation, sensory defects, stem cells, and regenerative medicine.

The authors are Elisabeth Andriessen, Ariel Wilson, Gaelle Mawambo, Agnieszka Dejda, Khalil Miloudi, Florian Sennlaub, and Przemyslaw Sapieha, who represent the following institutions: the University of Montreal, Quebec; the Polytechnic School of Montreal; McGill University, Montreal; Pierre and Marie Curie University, Paris, France; and the French National Institute of Health and Medical Research, Paris.

First, Some Terminology

Here is a brief explanation of some key terms used in the research:

  • Microbiota: Microorganisms that typically inhabit a particular environment, such as the soil, a body of water, or a site on – or in – an organism. In this case, gut microbiota refers to the microorganisms found in the digestive tract/intestines.
  • Angiogenesis: Describes the growth of new blood vessels and plays a crucial role in the normal development of body organs and tissue. Sometimes, however, excessive and abnormal blood vessel development can occur in diseases such as cancer (tumor growth) and macular degeneration (retinal and macular bleeding).
  • Choroidal neovascularization: In wet macular degeneration, the choroid, a part of the eye containing blood vessels that nourish the retina, begins to sprout abnormal new blood vessels that develop into a cluster under the macula (neo = new; vascular = blood vessels).

About the Research

Excerpted from Gut microbes influence development of wet AMD, via Medical News Today:

[The research team] used [a mouse model of AMD] to show that a high-fat diet can cause an imbalance in gut microbes that leads to more permeable intestines, chronic low-grade inflammation, and ultimately increased formation of new blood vessels under the retina – a feature of advancing wet age-related macular degeneration (AMD).

The team behind the new study notes that while evidence points to overall abdominal obesity in men as a risk factor for progression to late-stage wet AMD, there is little understanding about the underlying mechanisms. Given there is also evidence that high-fat diets affect gut microbes – collectively known as the gut microbiome – they decided to investigate whether this might explain the link.

For their study, the researchers carried out a series of experiments using a mouse model of wet AMD. These included transplanting gut microbes from mice fed a normal diet and mice fed a high-fat diet into normal-weight AMD mice. They did this to eliminate the potential for obesity to directly influence the results.

The results showed that high-fat diets appear to hasten the formation of new blood vessels in the wet AMD mice by altering the gut microbiome. "Our study suggests that diets rich in fat alter the gut microbiome in a way that aggravates wet AMD. Influencing the types of microbes that reside in your gut, either through diet or by other means, may thus affect the chances of developing AMD and [its progression]," says [study author] Przemyslaw Sapieha.

About Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is a gradual, progressive, painless deterioration of the macula, the small sensitive area in the center of the retina that provides clear central vision. Damage to the macula impairs the central (or "detail") vision that helps with essential everyday activities, such as reading, preparing meals, watching television, playing card and board games, and sewing.

AMD is the leading cause of vision loss for people aged 60 and older in the United States. According to the American Academy of Ophthalmology, 10-15 million individuals have AMD and about 10% of people who are affected have the "wet" type of AMD.

Wet (Neovascular) Macular Degeneration

In wet AMD, the choroid (a part of the eye containing blood vessels that nourish the retina) begins to sprout abnormal new blood vessels that develop into a cluster under the macula, called choroidal neovascularization (neo = new; vascular = blood vessels).

Because these new blood vessels are abnormal, they tend to break, bleed, and leak fluid under the macula, causing it to lift up and pull away from its base. This damages the fragile photoreceptor cells, which sense and receive light, resulting in a rapid and severe loss of central vision.

What are the Risk Factors for Macular Degeneration? An Answer from Lylas G. Mogk, M.D.

Lylas G. Mogk, MD

Dr. Mogk is the is the author of Age-Related Macular Degeneration (AMD) on the VisionAware website; founding director of the Center for Vision Rehabilitation and Research, part of the Department of Ophthalmology at the Henry Ford Health System in Michigan; and co-author of Macular Degeneration: The Complete Guide to Saving and Maximizing Your Sight.

To understand what the risk factors are and what we can do to lower our risk for age-related macular degeneration, it's helpful to understand how macular degeneration develops.

First, advanced age and long-term environmental exposures together produce an increased number of free radicals: unstable molecules that damage the macula if they are not immediately neutralized by anti-oxidants.

Next, this initial damage causes inflammation; the inflammation then causes more damage, which results in more inflammation and the cycle continues, eventually scarring the macula and causing central vision loss.

To reduce the risk of AMD, we need to decrease our exposure to toxins, neutralize the free radicals that are produced by exposure to toxins, and decrease our inflammatory response. We can do that by addressing the first six of the ten risk factors listed below.

Top 10 Risk Factors for Developing Age-Related Macular Degeneration

The six risk factors we can control:

  1. Smoking: Current smokers have a two-to-three times higher risk for developing age-related macular degeneration than people have who never smoked.
  2. Artificial fats: Usually labeled "partially-hydrogenated vegetable oils," these artificial fats are pervasive in foods and particularly in low-fat bakery goods. Low-fat foods are good options if they've achieved their low-fat status through a process that physically removes the fat, as in skim milk or low-fat cottage cheese. Low-fat bakery goods are different, however. If you remove all or half the fat from a cake recipe, it won't turn into a cake; thus, when cakes and bakery goods are labeled low-fat or no-fat, it means they contain artificial fats, or laboratory-produced chemicals. These chemicals are not food and our bodies can't metabolize them.
  3. Sunlight: It is the blue wavelengths from the sun that damage the macula, not the ultraviolet (UV) rays. Read Helpful Non-Optical Devices for Low Vision: Absorptive Sunglasses for more information.
  4. A diet high in processed, packaged foods and low in fresh vegetables: Vegetable oils are added in the packaging process. These oils are rich in omega-6 fatty acids, which promote inflammation.
  5. Uncontrolled hypertension and high cholesterol: Research by the National Eye Institute indicates that persons with hypertension are 1.5 times more likely to develop wet macular degeneration than persons without hypertension.
  6. Obesity: Being overweight doubles the risk of developing advanced macular degeneration.

The four risk factors we can't control:

  1. Advanced age: Although AMD may occur earlier, studies indicate that people over age 60 are at greater risk than those in younger age groups. For instance, a large study found that people in middle age have about a 2% risk of getting AMD, but this risk increased to nearly 30 percent in those over age 75.
  2. Race: Whites are much more likely to lose vision from age-related macular degeneration than are Blacks or African-Americans.
  3. A gene variant that regulates inflammation: While not all types of macular degeneration are hereditary, certain genes have been strongly associated with a person's risk of age-related macular degeneration, and genetic predisposition may account for half the cases of age-related macular degeneration in this country.
  4. Family history: Studies indicate that your chances of developing age-related macular degeneration are three to four times higher if you have a parent, child, or sibling with macular degeneration.

You can read more about risk factors for AMD and actions you can take at Risk Factors for Age-Related Macular Degeneration (AMD).

More about the Study from EMBO Molecular Medicine

Edited and excerpted from the study Abstract and Introduction, with the full article available online:

Age-related macular degeneration in its neovascular form (NV AMD) is the leading cause of vision loss among adults above the age of 60. Epidemiological data suggest that in men, overall abdominal obesity is the second most important environmental risk factor after smoking for progression to late-stage NV AMD.

To date, the mechanisms that underscore this observation remain ill-defined. Given the impact of high-fat diets on gut microbiota, we investigated whether commensal [i.e., a symbiotic relationship in which one species is benefited while the other is unaffected] microbes influence the evolution of AMD.

Using mouse models of NV AMD, microbiotal transplants, and other paradigms that modify the gut microbiome, we uncoupled weight gain from confounding factors and demonstrate that high-fat diets exacerbate choroidal neovascularization (CNV) by altering gut microbiota.

Gut dysbiosis [i.e., microbial imbalance] leads to heightened intestinal permeability and chronic low-grade inflammation characteristic of inflammaging [i.e., low-grade chronic systemic inflammation established during physiological aging] with elevated production of IL-6, IL-1ß, TNF-a, and VEGF-A that ultimately aggravate pathological angiogenesis.

Additional Macular Degeneration Information

Macular Degeneration
Medical Updates

Meet Joseph Fontenot, MD, CVLT: Be Informed and Proactive About Low Vision Services, Protect Yourself, and Always "Buyer Beware"

Dr. Joseph Fontenot head shot

Joseph Fontenot,

Dr. Joseph Fontenot is a medical doctor, Certified Low Vision Therapist, and Medical Director of Community Services for Vision Rehabilitation (CSVR), with offices in Alabama and Mississippi.

He is also the current Chair of the American Academy of Ophthalmology's Vision Rehabilitation Committee. In that role, he commissioned and led the production of There Is Something Else You Can Do, a newly-released six-minute video that emphasizes both the impact of vision loss on the individual and the responsibility of the ophthalmologist to refer to, or provide, appropriate vision rehabilitation services.

Dr. Fontenot has low vision himself, and understands the problems and needs of people with vision impairment. He began his career as a medical doctor almost 50 years ago. After working as a cardiologist for many years, he made the decision to transition into the low vision field as a result of his first-hand experience with vision loss, caused by macular degeneration.

"I became visually impaired at age 50, but I continued to work as a cardiologist for 14 years," Dr. Fontenot explains. "I could do that because I was able to access all of the low vision and access technology that I now try to make people aware of. When I was about to turn 65, I decided to go into this field. I realized that most people who have vision loss didn't know this technology was available, so I decided to start Community Services for Vision Rehabilitation (CSVR). Our mission is to provide help and assistance to those with low vision."

Maureen Duffy: Hello Dr. Fontenot. Thank you very much for speaking with us. To begin, how would you describe low vision for our readers? Is it more than a numerical definition?

Dr. Joseph Fontenot: Simply put, low vision is impaired vision that interferes with a person's normal everyday activities. It cannot be corrected by usual eye care or glasses or surgery. For instance, if a person has myopia (nearsightedness), they can go to the eye doctor who can provide a prescription for the proper glasses and they will be able to see well. That's not low vision; that's what's called a refractive error, which can be corrected. Or say the person has cataracts. They can go to the eye doctor, have cataract surgery, and then probably see well again after the surgery.

When we talk about low vision, though, what we're talking about is impaired vision that cannot be corrected by simply having the proper glasses or by having some medication or surgery. Low vision is anything that impairs the person's function. Say, for instance, a person uses a computer at work. If they have low vision, they might have great difficulty doing certain work-related computer tasks. It's going to interfere with their function and they might lose their job. Say they can't drive a car; that certainly, in almost any country in the world now, impairs your ability to get a job and get around to many places independently. When we're talking about vision that impairs your everyday function, that is low vision.

With low vision, you could also have contrast sensitivity loss. Contrast sensitivity is the ability to tell objects apart which are similar in shape or color, such as a blue napkin on a table that's a lighter shade of blue. If you lose that ability, you're going to have trouble doing all sorts of visual tasks. You could also have loss of color perception.

You could have visual field defects, or "tunnel vision," which you can get with glaucoma, retinitis pigmentosa, or a stroke. A normal visual field is around 150-160 degrees. The world around us is 360 degrees, so if your visual field is smaller than 20 degrees, that is a very small window on the world.

You could also have a scotoma, which is a central blind spot or central visual field loss, which you can get with macular degeneration or diabetic eye disease.

But numerical measurements, meaning those that define "legal blindness," are necessary, because you do have to have some kind of objective measurement, and not just a subjective statement saying "Vision impairs my function." You need it for many purposes, including disability benefits and tax exemptions. But legal blindness is not a functional low vision definition and doesn't tell you very much about what a person can and can't see.

[Editor's note: You can learn more about the definitions of legal blindness, including visual acuity and visual field measurements, at Visual Acuity and Low Vision, A Functional Definition of Low Vision, and Low Vision vs. Legal Blindness on the VisionAware website.]

MD: What you're saying, then, is that it's important to look for an eye doctor who specializes in, and understands, low vision.

JF: Yes. Anyone who has impaired vision should see a low vision specialist. Usually the low vision specialist works in a low vision rehabilitation clinic or practice and you would be examined there. They can determine how severe your vision loss is, what your contrast sensitivity is, and whether you have blind spots or field defects.

The low vision specialist also asks you a lot of questions about your own particular goals and needs. For example, a person who is transitioning from high school to college has a different set of needs from those of a retired person. It's a matter of determining your own capabilities and goals and then determining what would be helpful to you in achieving those goals – what sort of training, what kinds of aids and devices would help you get there? That's what visual rehabilitation is about: helping a person achieve the goals they want or need to do.

MD: What is the best way to find a good low vision specialist?

JF: The best way to do it, I think, is to ask your own eye doctor, who should know what low vision services are available in your area. They should also know about the ethical standards of those clinics and the type of services they provide. You could also give your doctor information about the new video There Is Something Else You Can Do, which was created specifically to help eye doctors understand and locate low vision services.

You should look for a clinic of the highest quality. Generally speaking, the best quality low vision clinics would be at, near, or affiliated with a university or medical school. If you have one of those in your area, you should probably go to that. An alternative would be a non-profit clinic located in an organization that is serves the needs of blind and visually impaired persons.

[Editor's note: You can use the VisionAware Directory of Services and the American Foundation for the Blind VisionConnect™ App to locate a clinic or an organization that provides these services in your area.]

You should also ask if the clinic has a comprehensive program that offers more than simply walking in, having an eye examination, being sold a magnifier, and then walking out. It should be an organization that provides a full range of vision rehabilitation services. You don't want to be restricted to just one device or service. If you encounter any organization or clinic that is trying to get you to buy only one type of low vision device, that's probably not the best place for you to go.

It's also important to find out ahead of time if you can return a low vision device if it doesn't work out for you. Most reputable clinics will offer a trial period that can be as short as 1-2 weeks or as long as 30 days. This allows you to try out the low vision device in your own home. If the device doesn't work for you, you want to have the option to return it. Some items might not fit into this category, such as less expensive devices or prescription glasses, but for any expensive device, you should make sure that you can return it within a reasonable amount of time.

MD: Some low vision practices ask prospective patients to call ahead for a pre-appointment discussion. Is it a good idea to do this before going to an appointment?

JF: If a clinic offers to have a telephone consultation by an eye doctor prior to your appointment, that's usually a telltale sign that it might not be a clinic you want to go to – particularly if they say you'll have to pay a certain amount of money up front that is above and beyond your normal insurance co-pay.

Unfortunately, there are some clinics and organizations that are not working for the best interests of the patient. They will try and push expensive glasses or devices that they can make quite a nice profit from. And be careful when clinics state that their one device is going to solve all of your problems. It's probably not going to work and almost certainly it's going to be very expensive.

MD: Prospective patients should also know what a true comprehensive low vision examination includes. Can you tell us more about the different components of a low vision exam?

JF: The first thing to know is that it's different from a standard eye exam by a regular eye doctor. There are no drops put in the eyes to dilate the pupil, so the person won't have to wear dark glasses after the examination.

I start the examination by doing a history to find out when the person first started having symptoms. When did they first notice that their vision was not good? Then I'll ask when they stopped doing certain activities. When did you stop driving? When were you not able to read small print, like newsprint? When did you start having trouble using your computer? We try to reach people as early as possible and ask these questions to get a history of the events and steps occurring in the person's vision loss.

And there are three additional questions we always ask. The first is about depression, the second is about macular degeneration, and the third is about Charles Bonnet syndrome.

Depression: We ask the patient about their mood and also observe if they are exhibiting any signs of depression or anxiety. Depression is very common in people who have lost their vision. Losing your vision is a life-changing event. It is similar to loss of a spouse or child and it is very common for people to become depressed. Sometimes they will work through this depression, but sometimes they do not, and it will take some time to get over the loss of vision. We believe that helping the person function better will prevent most of the depression that can, and frequently does, occur because of vision loss.

Macular degeneration: If a patient has typical macular degeneration, we always say, "Do you know it's very unlikely you'll become totally blind?" Usually, the patient will say, "No, I was worried about that. I thought I was going to go blind." We then tell the patient, "If all you have is macular degeneration, it's extremely rare that you would ever go totally blind. Your central vision likely will get worse, but it's very rare to get to the point where you'll be blind.

Most patients are very relieved to hear this and some say, "My doctor didn't tell me that." Nowadays, however, many more say "My doctor did tell me that," which is good – good for the patient and good for the doctor. However, you can't say that to someone with glaucoma or diabetic eye disease or retinitis pigmentosa. But since a majority of people in the United States who have vision loss have macular degeneration, it's something that should be done.

Charles Bonnet syndrome: Many low vision specialists also ask about Charles Bonnet syndrome (CBS) and routinely ask the patient whether they have the visual hallucinations associated with it. We reassure them that this is a normal event that, by some estimates, affects 20-30% of adults with vision loss.

[Editor's note: Charles Bonnet syndrome (CBS) is a condition that causes vivid, complex, recurring visual hallucinations, usually in older adults with later-life vision loss. The visual hallucinations associated with CBS can range from animated, colorful, dreamlike images to less complex visions of people, animals, vehicles, houses, and similar everyday images. You can learn more about CBS at Charles Bonnet Syndrome: Why Am I Having These Visual Hallucinations? on the VisionAware website.]

Dr. Joseph Fontenot administering a low vision visual acuity test

Dr. Fontenot administering the
ETDRS visual acuity chart

After we ask questions and get a history, then we'll do a visual acuity test. For this test, we do not use a standard letter chart. Everybody knows there's an E up top and there's only one letter there, so it's not good for evaluating people who have significant vision loss. We use a different chart, called the ETDRS chart, which stands for the Early Treatment of Diabetic Retinopathy Study.

In addition to the visual acuity test, which gives us a numerical measurement, such as 20/40 or 20/200, we routinely do several other tests.

One is a reading test, with the person reading a chart that contains sentences of different size print, going from very large to very small. This gives us information about near vision and the person's reading ability.

We also routinely test contrast sensitivity and color perception and do a visual field test, which tells us if the person has blind spots or other visual field-related difficulties. These problems may not be obvious from doing simple visual acuity testing.

After doing all these tests, we have a very good idea of what the patient is actually seeing, and a good idea of what the patient needs to be able to see better.

[Editor's note: You can learn more about the components of a comprehensive low vision examination, including an eye health evaluation; the Amsler grid test for macular degeneration; visual field testing; tests for color perception and contrast sensitivity; a lighting evaluation; and examples of specialized low vision eye charts at Components of the Low Vision Examination on the VisionAware website.]

MD: Many people say they just want "a pair of glasses" to help them see "like they used to" before they had low vision. However, people might not understand that they may need more than one device to carry out different everyday tasks. Can you talk about that?

JF: A comprehensive low vision clinic offers many alternative forms of vision enhancement. Most people who go to a low vision clinic do so because they have an idea that all they need is a "better pair of glasses" and so they very commonly come in and say "Doc, all I want is a pair of glasses that I'll be able to see with."

But unfortunately, standard glasses only work up to a certain point and although stronger glasses are available, they might not be adequate for all the needs of a person who has truly significant vision loss.

Stronger glasses have some disadvantages. They are more difficult to use than normal glasses, they require a much closer viewing distance, and they are harder to focus. They do require some practice and experience in using them. And there are often much better alternatives than simply stronger glasses.

All low vision clinics offer stronger glasses and sometimes these glasses are the best alternative. But the person needs to understand that a very strong pair of glasses is not easy to use and they're not necessarily going to help the person to sit back and read a long novel comfortably. Stronger glasses might be good for "spot reading" or "spot viewing" where you just need to, say, look at a thermostat or read a medication label.

MD: What you're saying, then, is that a person doesn't always need to spend $1,000-$3,000 for a custom-made pair of strong glasses.

JF: That's right. There may be better alternatives to stronger glasses. There are different kinds of magnifiers, both with and without built-in lights. There are electronic magnifiers, which are like video cameras that project an enlarged image onto a monitor screen. And there are more alternatives, too, such as audio output devices and braille output devices.

Smart phones and tablets have recently become very useful for people with low vision. They have many built-in accessibility features and many apps designed specifically for users who have low vision.

A fully-stocked low vision rehabilitation clinic will have easily a thousand different items available to achieve the result the patient wants and needs. It's usually not a matter of only "getting a better pair of glasses."

Proper lighting is also very important. People who have loss of contrast sensitivity will invariably need more light. The type of light they need is usually more "white," instead of "blue-ish" or "yellow-ish." Whiter light maximizes the contrast between different colors and different shades of color.

MD: What about paying for low vision devices? They can be very expensive.

JF: At Community Services for Vision Rehabilitation, we serve people with any eye condition, of any age, and with or without insurance coverage. Generally speaking, though, low vision devices are not covered by insurance or Medicare. I've been doing this for almost 15 years now, and I've had just one patient who actually got their insurance company to pay for a device. He was the most persistent man I've ever known. I think they finally paid for something just to get him off their backs, but it took him years.

Some devices, particularly electronic magnifiers and magnifying systems, are expensive, but there are plenty of low-cost devices that are available, too. For example, a person who has macular degeneration and a visual acuity of 20/200 would probably be able to read normal-sized print with a hand-held magnifier that costs $60-$70, or an electronic magnifying device for $150 that connects to a standard television screen.

You can also buy used equipment. And we let people lease equipment from us. If a patient wants to try an electronic video magnifier, or CCTV, we let them take it home for a month or two. We can give them a used one, let them pay $10-$20 a month, let them try it out at home, and if they don't like it they can bring it back.

Remember that it's a matter of your own needs and choices – not just what is being offered to you. Aids and devices have become much more sophisticated and are actually less expensive than they were 20-30 years ago. There is much greater variety now, in terms of both capability and expense.

I always recommend going to a reputable, comprehensive low vision clinic that has a full array of optical and electronic devices. As I always say to my patients, it's a matter of "buyer beware." Be an informed and proactive consumer.

MD: Dr. Fontenot, I've very much enjoyed talking with you. We thank you for your support of VisionAware and your longstanding commitment to blind and visually persons everywhere.

More Helpful Information

Diabetes and diabetic retinopathy
Low Vision
Macular Degeneration
Personal Reflections
Retinitis Pigmentosa
Stroke or Brain Trauma

Have Diabetes? Education, Guidance, and Support Are Essential

The American Diabetes Association celebrates American Diabetes Awareness every November and this year the theme is #This is Diabetes. The 2016 campaign seeks to showcase real-life stories of the 29 million Americans managing the day-to-day triumphs and challenges of diabetes to raise awareness and to create a sense of urgency about this public health concern. Their mission is to empower, educate, and support people living with diabetes in order to improve health outcomes and quality of life.

american diabetes association 2016 poster with wording #this is diabetes share your story

Did You Know These Facts About Diabetes?

  • The diabetes rates are a growing public health crisis affecting our diverse communities. Type 2 diabetes accounts for about 90% to 95% of all diagnosed cases of diabetes and Type 2 diabetes is more common in African Americans, Latinos, Native Americans and Asian Americans/Pacific Islanders, and older adults.
  • The health and economic costs for diabetes are enormous. People with diabetes can have health care costs that are 2.3 times higher than someone without diabetes.
  • People with diabetes are more likely to have high blood pressure and high cholesterol, risk factors for heart attacks and strokes.
  • People with diabetes are at major risk of vision loss and the risk increases the longer a person has diabetes. Between 40 and 45 percent of Americans diagnosed with diabetes have some stage of diabetic retinopathy, damage to the small blood vessels in the retina that can result in vision loss (NEI).

Living with diabetes is hard work and can be overwhelming. It requires careful attention to diet, exercise, blood sugars, and medications. Significant lifestyles changes often need to be made and sustained over time. Research suggests that only about 14% of patients with diabetes are able to maintain adequate control of their blood sugar, blood pressure and cholesterol levels through self-management.

American Diabetes Association picture of blood glucose meters with wording: this is crunching numbers, this is diabetes

People need education and guidance to live successfully with diabetes. And research shows they also need support from family, friends and the community. This kind of support improves their ability to apply knowledge and sustain behavior changes for better diabetes management. This means better blood sugar control and fewer complications of this devastating disease. The result of successful lifestyle modifications is a longer and healthier life for someone with diabetes.

What Ten Things Can Family and Friends Do to Help?

Supporting someone you know with diabetes can make a big difference and empower them to achieve their health goals. The Center for Disease Control (CDC) in their feature "Friends, Family and Diabetes" suggests you support your loved one in the following ways:

  1. Learn about diabetes. Find out why and when blood sugar should be checked, how to recognize and handle highs and lows, what lifestyle changes are needed, and where to go for information and help. Chronically high blood sugar from diabetes is associated with damage to the tiny blood vessels in the retina, leading to diabetic retinopathy.

  2. Know diabetes is individual. Each person who has diabetes is different, and their treatment plan needs to be customized to their specific needs. It may be very different from that of other people you know with diabetes. You should ask your friend or relative how you can help, and then listen to what they say. They may want reminders and assistance (or may not), and that can change over time.

  3. Go to appointments if it's OK with your relative or friend. You could learn more about how diabetes affects them and how you can be the most helpful.

  4. Give them time in the daily schedule so they can manage their diabetes—check blood sugar, make healthy food, take a walk.

  5. Avoid blame. People with diabetes are often overweight, but being overweight is just one of several factors that can lead to diabetes. And blood sugar levels can be hard to control even with a healthy diet and regular physical activity. Diabetes is complicated!

  6. Step back. You may share the same toothpaste, but your family member may not want to share everything about managing diabetes with you. The same goes for a friend with diabetes.

  7. Accept the ups and downs. Moods can change with blood sugar levels, from happy to sad to irritable. It might just be the diabetes talking, but ask your friend or relative to tell their health care team if they feel sad on most days—it could be depression.

  8. Be encouraging. Tell them you know how hard they're trying. Remind them of their successes. Point out how proud you are of their progress.

  9. Walk the talk. Follow the same healthy food and fitness plan as your loved one; it's good for your health, too. Lifestyle changes become habits more easily when you do them together.

  10. Know the lows. Hypoglycemia (low blood sugar) can be serious and needs to be treated immediately. Symptoms vary, so be sure to know your friend's or relative's specific signs, which could include:

  • Shakiness
  • Nervousness or anxiety
  • Sweating, chills, or clamminess
  • Irritability or impatience
  • Dizziness and difficulty concentrating
  • Hunger or nausea
  • Blurred vision
  • Weakness or fatigue
  • Anger, stubbornness, or sadness

If your family member or friend has hypoglycemia several times a week, suggest that he or she talk with his or her health care team to see if the treatment plan needs to be adjusted.

Offer to help them connect with other people who share their experience. Online resources such as the American Association of Diabetes Educators' Diabetes Online Community or in-person diabetes support groups are good ways to get started. Sharing the burden of diabetes with your loved one is a great way to say you care about them. Support them on their journey to control their disease so the disease does not control them. You are an essential part of their team!

Resources on VisionAware

Diabetes Articles

Diabetes Guides

En Espanol: Introduccion a la Diabetes y La Diabetes y La Perdida de Vision

Sources of Information

Centers for Disease Control and Prevention. National Diabetes Statistics Report: Estimates of Diabetes and Its Burden in the United States, 2014. Atlanta, GA: U.S. Department of Health and Human Services; 2014.

CDC Diabetes Family and Friends

Facts About Diabetic Retinopathy

Diabetes and diabetic retinopathy

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