Age-related macular degeneration (AMD) is the leading cause of blindness among older Americans. However, new treatments have dramatically changed the course of this disease over the last 10 years, making AMD more manageable than ever before. The key to saving your sight is early detection combined with treatments based on modern medicine.
It’s believed that more than 11 million people in the U.S. have some form of AMD, and that number is expected to be 22 million by 2050, doubling the number of patients affected.
Macular degeneration is caused by deterioration of the central portion of the retina, known as the macula. The retina is the inside of the back layer of the eye, which receives and records the images entering the eye. The macula, specifically, is designed to focus central vision, and is what makes being able to read, recognize faces and colors, drive a car, and see fine details possible.
The macula collects highly detailed images from the center of the field of vision and transmits them through the optic nerve to the brain, where they are interpreted as sight. If cells in the macula start to deteriorate, these images are not received correctly, and the transmitted information to the brain is also faulty.
Cause of AMD
In its earliest stages, macular degeneration doesn’t cause any symptoms. However, it can still be identified during a thorough ophthalmological examination. Areas of deterioration show up as small yellow deposits (drusen) that appear in the layer of cells directly behind the retina.
While drusen can be found even in healthy eyes as people age, numerous drusen typically lead to a diagnosis of AMD. The number and size of the drusen are measured, and a grade is applied that signifies the stage of the disease.
In the early stage, drusen are few in number, small, and don’t have significant pigmentation. The patient usually has no vision loss. In the intermediate stage, the drusen have multiplied, become larger, are more deeply pigmented, and may be causing slight vision disturbances like wavy or blurred vision. Advanced AMD can mean partial to total loss of central vision.
Types of AMD
There are two forms of macular degeneration. The most common type is dry, which occurs slowly over time, as the light-sensitive cells of the macula break down. Dry macular degeneration accounts for around 90% of diagnosed cases.
Dry macular degeneration can have early, intermediate and advanced stages. However, sometimes the dry form abruptly turns into what is known as wet macular degeneration, either from the early stage or the intermediate stage. The wet form is always considered to be advanced; it only accounts for 10% of cases but causes 90% of legal blindness from AMD.
Early Detection of AMD
Macular degeneration is a leading cause of vision loss in Americans who are 60 years of age and older, and advanced age-related macular degeneration is a leading cause of visual impairment and irreversible blindness across the globe.
Since early stages of AMD typically don’t cause symptoms, waiting to have an eye exam until vision disturbances appear can increase the risk of AMD progression to the point of irreversible vision loss.
The risk of getting advanced age-related macular degeneration is around 2% for people between the ages of 50 and 59, but rises sharply to 30% for those over the age of 75. Between 1-3% of people with small drusen start to experience vision problems within the first five years of diagnosis. Among those with larger drusen, 50% experience late-stage vision loss within five years.
Are You at Risk for AMD?
Anyone can develop AMD, but your risk goes up if you have one or more risk factors for the disease. Risk factors for AMD include:
- Being 50 or older
- Smoking (doubles risk)
- Eating a diet high in saturated fat
- High blood pressure/hypertension
- Familial history of AMD
Annual vision exams are the best way to help identify early AMD. Your doctor can perform a vision acuity test to check for central vision loss or use an Amsler grid to see if you are having wavy or blurry spots in your peripheral range, both signs of possible AMD.
They can also conduct pupil dilation to allow a close-up examination of your retinas, or fluorescein angiography to look for signs of wet AMD by injecting dye into a vein in your arm and watching to see if dye leaks from blood vessels in the retina.
Finding AMD before it causes symptoms is the best-case scenario, as it allows for treatment to be pursued as soon as possible, holding off the progression of the disease and preventing vision loss for as long as possible.
Treatment for dry AMD is targeted at slowing the progression of the disease. The most effective form of treatment currently available is vitamin and antioxidant combinations known as AREDS or AREDS2 formulations. Taking AREDS or AREDS2 supplements can reduce the risk of progression from intermediate to advanced AMD by about 25%.
Those who have risk factors but don’t yet have drusen in the size or number for a diagnosis of AMD can take the following steps:
- Stop smoking
- Eat a healthy diet
- Treat high blood pressure/hypertension
- Get annual vision care exams from an ophthalmologist
Treatment for wet AMD is more invasive, as this is considered an advanced form of the disease and carries a much higher risk of partial or total central vision loss. There are several treatment options, the most common of which are injectable vascular endothelial growth factor blockers, commonly called anti-VEFG drugs:
- Beovu® (brolucizumab)
- Eylea™ (aflibercept)
- Lucentis® (ranibizumab)
- Macugen® (pegaptanib)
- Avastin™ (bevacizumab)
Photodynamic therapy can also be used to help control the abnormal blood vessel growth and bleeding in the macula. Other potential treatments are in research and testing phases, including other types of injectables, gene therapy, implantable chips to stimulate vision, and retinal cell transplants.
The Cost of AMD
It is estimated that the global cost of visual impairment due to AMD is $343 billion, including $255 billion in direct health care (DHC) costs, with $98 billion in DHC costs in the US, Canada, and Cuba (WHO subregion AMR-A) alone.
In addition to these costs is the impact on patients suffering from AMD, who may become unable to work, drive, or enjoy quality of life due to vision loss or complete blindness. Individual health care costs also go up exponentially for patients whose AMD has resulted in blindness or severe visual impairment.
To avoid incurring such costs and protect vision, those aged 50 and older should pay particular attention to making and keeping appointments for annual eye exams with an ophthalmologist. Lack of access to quality eye health care is a significant contributor to the prevalence of blindness from AMD. To learn more about how we support the entire continuum of eye health, visit Versant Health.