What is AMD?
Age-related macular degeneration (AMD) is the leading cause of vision loss among people age 50 and older.1 It is a chronic, progressive disease that causes the central part of your vision—the part used for reading, seeing people’s faces, and driving—to deteriorate slowly. AMD affects more than 9 million Americans, including 1 in 8 over age 60.2 Unfortunately, nearly 80 percent of people with AMD have substantial, irreversible vision loss at the time of their first treatment.
AMD affects the macula, the central part of the retina of the eye that controls visual acuity and gives us clear, detailed vision. In most people, AMD causes slow, gradual changes in vision over many years. In some cases, AMD progresses more rapidly and causes severe vision loss in just a few months.
AMD Risk Factors and Symptoms
One of the earliest symptoms of AMD is poor or deteriorating night vision, often presented as difficulty reading in dim light or driving at night. As the disease progresses, symptoms may also include distortion of straight lines or dark and blurry central vision. However, these symptoms are often overlooked or appear after vision loss has occurred. Therefore, it is important to have your rod intercept (RI) measured with the AdaptDx if you’re exhibiting night vision problems and/or you have multiple risk factors:
- Age 50 or older
- Family history of AMD
- Caucasian (white)
- Smoker or past smoker
- Being overweight
- Heart disease, high blood pressure or high cholesterol
Detecting Age-related Macular Degeneration
Identifying AMD early allows patients to work with their eye doctor to take action before significant vision loss has occurred. Putting a care plan in place at the earliest possible time will preserve as much vision as possible over a longer duration. Family Focus is among the first in the country to offer patients a new test to detect AMD in its earliest stages, before irreversible damage to the retina has occurred. The new diagnostic aid, AdaptDx, offers a simple, noninvasive test measure of dark adaptation, the earliest symptom and biomarker for AMD.4 An automatically generated measure called the Rod intercept (RI) – the time in minutes it takes for dark adaptation to occur – can indicate presence of the disease at least three years before it becomes clinically evident.
The AdaptDx test lasts less than 10 minutes and can easily fit into a comprehensive eye examination. Akin to visual field tests for glaucoma, this test of retinal function complements the structural imaging and photography of the retina for a more robust evaluation of retinal health.
Dry and Wet AMD
There are two forms of macular degeneration: dry (non-neovascular or atrophic) AMD and wet (neovascular or exudative) AMD. More common than the wet form, dry AMD affects about 80 to 90 percent of individuals diagnosed with AMD. Dry AMD is an early stage of the disease that can last five years or longer. It is associated with a thinning of the macula and fatty deposits under the retina called drusen. In most cases, normal daylight vision is unaffected so individuals are not aware they have AMD. However, even though people usually blame it on other causes, dry AMD impacts their dark adaptation (or “night vision”) in a telltale fashion.
In 10 to 20 percent of individuals, dry AMD progresses to the wet form of the disease in which new blood vessels, growing beneath the retina, leak blood and fluid that cause permanent damage to light-sensitive retinal cells. These cells die off, causing central vision blurriness and blind spots.
The transition from dry to wet AMD can happen rapidly, and if it is left untreated can lead to legal blindness in as little as six months. Management of wet AMD with anti-VEGF injections is well understood and once initiated usually helps to stop or slow further vision loss. However, it is limited in its ability to reverse damage already done.
While there is no cure for dry AMD yet, progression of the disease may be slowed with diet and lifestyle changes, and in some cases, with specific high-dose vitamin and mineral supplements.
The Age-Related Eye Disease Studies (AREDS and AREDS2) conducted by the National Eye Institute showed that daily intake of certain high-dose vitamins and minerals can slow progression of the disease.
Current treatments for wet AMD, including anti-VEGF injections, photodynamic therapy, or laser surgery, are all aimed at stopping abnormal blood vessel growth. Drug therapy works by inhibiting a protein called vascular endothelial growth factor (VEGF), which stimulates the growth of new blood vessels. These anti-VEGF drugs slow or prevent additional vision loss, and may even improve vision to some extent. Several agents with different mechanisms of action or that target different disease pathways are currently under investigation and may expand the options available to treat AMD.
The AdaptDx is the first and only diagnostic aid for the subclinical detection and management of age-related macular degeneration (AMD), the leading cause of adult blindness. The AdaptDx enables eye care professionals to detect AMD several years before physical changes to the retina are visible and allows them to monitor disease progression. This facilitates proactive treatment at each stage of this chronic disease to eliminate preventable blindness. Backed by more than 20 years of proven clinical research, the AdaptDx is an easy-to-use functional test that accurately measures dark adaptation, a key biomarker of AMD. The AdaptDx is made in the USA by MacuLogix, Inc. Visit www.MacuLogix.com for additional information.
Dr. Joseph Rich, (573) 446-1600, [email protected]