A group of eye disorders affecting the central region of the retina (thus affecting the central field of vision) is referred to collectively as “macular degeneration”. Since people over 65 years of age serve as the prime target zone for this disease, it is also labeled as the “Age Related Macular Degeneration” or “AMD”/ “ARMD”. It happens to be the single biggest factor behind legal blindness in developed nations of the world. Since macula sustains irreversible damage at the hands of this disease, it leads to the loss of the sharp, fine-detail, straight-ahead vision, affecting its victims’ ability to perform activities like reading, writing, driving, recognizing faces and so forth.
This write-up is a compilation of 40 interesting facts about AMD, segregated into a host of relevant sections.
Global AMD Prevalence
Approximately 5% of the total global blindness is attributed to AMD. Estimates suggest that 196 million people around the globe will be affected by AMD in 2020, the number expected to rise to 288 million by 2040.
Age-related Macular Degeneration is the leading cause of severe vision loss in elderly persons in the developed world and accounts for one-third of all the cases of untreatable vision loss.
Middle-aged people (between the ages 50 – 59 years) have about a 2% risk of getting age related macular degeneration, while it increases to about 30% for people over 75 years of age.
AMD Prevalence In the United States of America
AMD affects approximately 11 million U.S citizens, with the number expected to double to about 22 million by 2050.
In the U.S., the prevalence of AMD is similar to that of all invasive cancers combined and more than double the prevalence of Alzheimer’s disease.
AMD Associated Health Costs Worldwide
Estimates suggest that the whole world bears about a total of US$343 billion as the health costs associated with visual impairment due to macular degeneration, US$225 billion of which is considered as direct health cost.
AMD Associated Health Costs in the U.S.
The direct healthcare costs borne by the US, Canada and Cuba collectively exceed US$98 billion.
Types of Age-related Macular Degeneration
Dry (Non-Neovascular) AMD
This type of macular degeneration makes up for about 90% of the total cases of AMD reported, also commonly known as “Non-neovascular AMD”. It leads to the thinning and aging of the macula, as a result of which small pieces of fat and protein, known as “drusen”, start to accumulate underneath the retina. In most cases, vision loss due to dry AMD takes place quite slowly, but it is still possible that it eventually progresses to a severe form, i.e. wet AMD. It is possible but quite rare for dry AMD to progress to the level of “legal blindness”.
Wet (Neovascular) AMD
Wet age related macular degeneration, also known as neovascular AMD, is held responsible for only about 10% of the total number of AMD cases reported. However, when it comes to the type of AMD responsible for the highest number of legal blindness cases, wet AMD far exceeds dry AMD. You can get more on the difference between wet and dry macular degeneration here.
There are some further rare variations of the disease as well, i.e. Geographical Macular Degeneration, Juvenile Macular Degeneration, Stargardt Disease, Best Disease and Juvenile Retinoschisis.
Stages of Age Related Macular Degeneration
The progression of AMD can be divided into three different stages:
Early stage AMD is not known for reflecting any noticeable signs of vision loss for most people. That is why eye doctors insist so strongly on having an eye exam on regular basis, especially if you fall among people bearing more than one risk factor of AMD. Experts can identify early stage age related macular degeneration by looking for medium-sized drusen (yellow colored waste deposits beneath the retina) in your eyes.
In most cases, some sort of vision loss shows up by this stage, but it is still highly unlikely to have some noticeable AMD symptoms. It is recommended to undergo a comprehensive eye exam from a specialized ophthalmologist/optometrist who will explore through the eye for changed pigmentation and/or larger drusen deposits in the retina.
As the name suggests, vision loss due to macular degeneration peaks at this stage, though not all cases of early AMD always progress to late AMD. According to National Eye Institute, 1 in every 20 people who have had early AMD in one eye (with the other eye remaining free of it) is susceptible to having advanced AMD after 10 years. Similarly, about 14% of those who have had early AMD in both eyes are likely to get AMD in one or both eyes 10 years later.
i) Dry AMD Symptoms
Dry AMD symptoms might not surface for up to 10 years after the disease’s onset; sometimes, even longer if only one eye is affected when dry AMD symptoms appear eventually, they may include:
Difficulty reading in low light conditions.
Recognition of people’s faces getting difficult.
Vision getting blurry while trying to read written or printed texts.
Visual function recovery getting slow after bright light exposure.
Colors appearing faded.
Vision getting hazier and less defined.
ii) Wet AMD Symptoms
According to National Eye Institute:
Wet AMD can display all of the symptoms listed above for dry AMD as well as the following:
- Metamorphopsia – the phenomenon of straight lines appearing wavy or crooked.
- Central Scotoma – Central vision getting a blind spot, which can grow bigger if left untreated.
Appearance and growth of Wet AMD symptoms are much rapid compared to those of Dry AMD symptoms.
Among those with early AMD in one eye, where the other eye is not affected, around 1 in 20 will have advanced AMD after 10 years.
Around 14 % of people with early AMD in both eyes will have late AMD in one or both eyes after 10 years.
Macular Degeneration Risk Factors
Major macular degeneration risk factors include:
Smoking: According to research, smokers are two to three times more likely to develop age related macular degeneration compared to their nonsmoking peers.
Dietary intake has been known to affect the progression of AMD for a long time. For example, a diet loaded with highly processed and packaged food devoid of fresh vegetables can contribute to the rapid progression of age related macular degeneration.
Obesity: Studies reveal that the risk of developing advanced AMD is doubled when you are obese.
Hypertension: According to studies conducted by the National Eye Institute (NEI), the probability of developing wet AMD increases by 1.5 times in people suffering from hypertension.
Sunlight Exposure: Though lacking inconclusive evidence, long term sunlight exposure is believed to contribute to the progression of AMD due to the harmful effects of UV (ultraviolet) light on the retina.
Above mentioned risk factors for AMD are considered to be controllable, while the risk factors for age related macular degeneration beyond our control are listed below:
Age: Age, without any doubt, can be considered as the greatest risk factor for AMD. Although macular degeneration might strike someone during middle age, people over 75 years of age are the likeliest to be victims of AMD, in fact 30% more than people below 60 years
Gender: Yes, gender is also believed to play a part beyond our control in age related macular degeneration, females having a higher likelihood of becoming the victims.
Iris Color: Eye color, courtesy to the color of pigments within the iris, also matters in determining your chances of developing age related macular degeneration, i.e. people with light-colored eyes are more probable to become victims of dry AMD.
Genetics and Family History: Heredity doesn’t account for all types of macular degeneration, but scientists have been able to identify certain genes capable of determining a person’s risk of developing AMD. Similarly, a person with a parent, siblings or other close family members is three to four times more likely to be affected with AMD. You can learn more about genetic eye diseases here.
Treatment and Prevention
There is no known cure for AMD as yet, but there are certain treatments that can help slow down the advancement of the disease. Some effective options include:
If diagnosed with wet AMD, having laser surgery at an early stage might help slow the degeneration down or even stop further vision loss, but in most cases, it is often very hard to tell if the surgery will do more harm than good.
This is a treatment based on anti VEGF drugs. These are injected into the affected eye via a thin needle to reduce the abnormal growth of blood vessels underneath the retina. These drugs also slow down the leakage of fluids into the macula, offering a significant help in dealing with wet AMD.
Eye supplements can help with Dry AMD. Your ophthalmologist will tell you what vitamins or minerals are recommended for your particular case of dry AMD, but these are found to be generally helpful.
- Vitamin C (500 mg)
- Vitamin E (400 IU)
- Lutein (10 mg)
- Zeaxanthin (2 mg)
- Zinc (80 mg)
- Copper (2 mg)
Low Vision Aids
Technology in the health sector is advancing particularly fast. Various low vision aids can help with macular degeneration, one of them is IrisVision – a vision-enhancing device comprised of a Samsung Gear VR headset and a smartphone. It has superlative features like IrisBubble, which lets you see clearly without blind spots or missing visual detail, also offering adjustable brightness settings, clinical adjustments and so much more.
To conclude, prevention is always better than cure. So, make sure you take really good care of your eyes and resort to appropriate medical assistance as soon as possible rather than delaying unnecessarily. And for a comprehensive understanding of age-related macular degeneration, you can click here.