How Does Macular Degeneration Lead to Blindness?
The easy answer? It doesn’t. According to the National Federation for the Blind, nearly 7% of adults over age 65 fit the definition of “visually impaired.” A great many of those cases stem from macular degeneration, which currently impacts 10 million people who either have the condition or are at severe risk of contracting it. For patients over 55 years of age, macular degeneration is the leading cause of severe vision loss.
The macula is the region of the retina most responsive to light stimuli, providing precise focus for sharp, close vision. It’s the part of your eye that functions when you do things like read an analog clock from across a room, sew a button on a shirt, or read a book up close. Damage or deterioration to the macula inhibits this type of vision, while leaving lateral and peripheral vision untouched.
For this reason, people with severe macular degeneration are still generally able to navigate their way around a room and take care of themselves; however, they may need assistance for fine-motor tasks that require precise or up-close vision.
Macular degeneration presents in two different ways: dry and wet. The dry variety is more common by far and is generally less severe; it occurs when protein and fat deposits called “drusen” accumulate within the macula and interfere with its ability to efficiently process visual stimuli. This interference is gradual and generally not severe and may take years to even become noticeable.
Wet macular degeneration is much less common, accounting for approximately 10% of all cases of macular degeneration. However, it is also much more severe, involving the rapid proliferation of unnecessary blood vessels which hemorrhage into the macula—thus the “wet”designation. In addition to increased severity, wet macular degeneration also develops much more rapidly, quickly inhibiting the patient’s vision in a very noticeable manner.
Dry macular degeneration currently has no known effective treatment capable of either slowing the disease’s progression or repairing lost vision. Wet macular degeneration has a variety of treatments, from periodic eye injections to laser treatments, all of which are designed to slow proliferation of unwanted vessels or prevent leakage from those vessels once they exist.
If you have noticed the symptoms of macular degeneration—distortion, wavy lines, difficulty seeing with precision, or a “donut hole” in the center of your vision—schedule an appointment with your doctor quickly to confirm or rule out macular degeneration as a potential cause. But know this...macular degeneration will never lead to total blindness. Although vision may be impaired, you will still have some vision! Please let us know about your experience with macular degeneration below.
Dr. Jenna Zigler