The macula is the central portion of your retina responsible for the sharp, central vision needed for reading or driving. It is where retinal photoreceptors are most densely packed, and is the most metabolically-active portion of the eye.
Age-related macular degeneration (ARMD or AMD), is a gradual deterioration of the macula. Macular degeneration mainly affects central vision, causing decreased vision directly ahead. It is the leading cause of decreased vision among Americans age 65 and older. In fact, 25% of all Americans over the age of 75 have macular degeneration.
Wet and Dry Forms of Macular Degeneration
The early stage of macular degeneration is referred to as the “dry” (non-neovascular) form. About 85 percent of AMD patients are diagnosed with dry AMD. The “wet” (neovascular) form of macular degeneration usually leads to more serious vision loss.
Dry AMD results from the gradual aging and thinning of macular cells. Yellowish spots known as drusen begin to accumulate in and around the macula. It is believed these spots are deposits of waste-products from deteriorating cells. The drusen may block nutrients and oxygen from reaching the photoreceptors of the macula, leading to further deterioration.
Gradual central vision loss may occur with dry macular degeneration but usually is not nearly as severe as wet AMD symptoms. However, even dry AMD can slowly progress to late-stage geographic atrophy (gradual degradation of retinal cells that also leads to significant vision loss) over a period of years.
In about 10 percent of cases, dry AMD progresses to the more advanced and damaging wet (neovascular or exudative) form of the eye disease. New blood vessels grow beneath the retina, trying to get more nutrients and oxygen to the macula. Unfortunately, these new vessels tend to leak blood and fluid, causing more harm than good. This leakage causes permanent damage to light-sensitive retinal cells, which die off leaving blind spots in central vision.
Macular Degeneration Symptoms and Signs
Age-related macular degeneration usually produces a slow, painless decrease in vision, although in some cases vision loss may be sudden. Early signs of AMD include darker areas in your central vision or blurry or distorted vision.
At Frontier Eye Care, we utilize technology that can detect early signs of macular degeneration before symptoms occur. If we detect early signs of AMD (such as drusen deposits) during your retinal eye exam, we will then scan your maculas with “optical coherence tomography” (OCT). The OCT scan takes just a couple of minutes. OCT is an optical scan, and is completely painless. But it can give us information similar to an ultrasound or MRI to see beneath your maculas and rule out early signs of wet macular degeneration.
PHOTO OF OCT. CAPTION: If Dr. Hodgson detects early signs of ARM, such as a defect in your central vision, he may perform a scan of your macula called optical coherence tomography (OCT). This test can help rule out swelling or bleeding of the macula if your AMD has progressed to the wet form.
What Causes Macular Degeneration?
Though macular degeneration is associated with aging, research suggests there also is a genetic component to the disease, and it seems to run in families. Deteriorating, oxygen-starved cells within the retina likely trigger neovascularization (abnormal blood vessel growth) which can lead to damage in wet AMD. Neovascularization is activated by a protein called vascular endothelial growth factor (VEGF).
Who Gets Age-Related Macular Degeneration?
Besides affecting older populations, AMD occurs more frequently among Caucasians and females in particular. The disease also can result as a side effect of some drugs, such as hydroxychloroquine.
Irrefutable evidence indicates that smoking cigarettes is the greatest controllable risk factor for macular degeneration. In fact, just living with a smoker will double your risk for AMD. Other risk factors for macular degeneration include having a family member with AMD, high blood pressure, and obesity. High levels of dietary fat, especially saturated fats and trans fats, may also contribute to the development of AMD.
Treatment of Macular Degeneration
There is no outright cure for age-related macular degeneration, but some treatments may delay its progression or even improve vision. Treatments for macular degeneration depend on whether the disease is in the early, dry form or in the more advanced, wet form.
No FDA-approved treatments exist for dry macular degeneration. However, major studies by the National Eye Institute called the “Age-Related Eye Disease Studies” (AREDS and AREDS 2) have shown that certain anti-oxidant vitamins may help slow progression of dry macular degeneration, and make it less likely to progress to the wet form. Ask us which AREDS multivitamins are right for you.
If we determine you have wet AMD, we will refer you to a retinal specialist for treatment. Most likely, you will be treated with one of the newer anti-VEGF drugs. These drugs block the vascular endothelial growth factor (VEGF) that triggers the abnormal blood vessel growth. Sometimes, these drugs not only stop the progression of AMD, but can actually improve your vision.
At Frontier Eye Care, your eye health and the future of your vision is our greatest concern. An annual comprehensive eye exam will help ensure that we detect early signs of macular degeneration, and preserve your vision to the greatest extent possible.
Call Frontier Eye Care at (307) 472-2020 if you have questions about macular degeneration or to schedule your next eye exam, especially if you are concerened about macular degeneration or have a family history.