What is the macula?
The macula is an oval area in the central portion of the retina. In the center of the macula, the fovea contains most of the eye’s six million cones, photoreceptors responsible for color vision and high visual acuity. The macula is yellow due to the high concentration of zeaxanthin and lutein, carotenoids that protect the area from ultraviolet light.
What causes macular degeneration?
Macular degeneration, or age-related macular degeneration (AMD), develops when cells in the macula deteriorate, impacting vision.
Among the earliest signs of AMD are drusen, yellow deposits of lipids that naturally develop in the retina. They don’t always cause problems, but when the drusen are soft and large, they accumulate and may interfere with the macula’s ability to obtain nutrients and eliminate waste. As a result, they increase the risk for AMD. Drusen are visible during an eye examination.
What are the stages of AMD?
The stages of AMD are determined by changes in the retina. As AMD progresses, two types may be diagnosed:
Non-exudative or dry macular degeneration
More than 90% of patients diagnosed with AMD have this type, which progresses slowly over many years. Drusen and cellular atrophy or thinning are present, leading to the gradual loss of central vision.
Exudative or wet macular degeneration
About 10-20% of patients with dry AMD progress to wet AMD. This stage begins when abnormal blood vessels develop in the choroid, a process called neovascularization.
The choroid is a layer behind the retina responsible for nourishing retinal cells. As new blood vessels form, they can extend into the subretinal space, causing bleeding and swelling, which leads to retinal damage, detachment, and blindness.
What are the symptoms of macular degeneration?
In the early stages, patients seldom experience symptoms. As the disease progresses, however, patients may experience:
- Blurry or distorted vision
- Reduced central vision
- Decreased color brightness
- Loss of color vision
- Difficulty adapting to low light
- Difficulty recognizing faces
How is macular degeneration treated?
Treatment depends on the stage of the disease. While there aren’t any FDA-approved treatments currently available for dry AMD, supplementation with zinc and antioxidants may slow its progression.
Treatment for wet AMD focuses on stopping abnormal blood vessel growth using photodynamic therapy or anti-vascular endothelial growth factor (anti-VEGF) medications to inhibit neovascularization.
The best way to delay the progression of macular degeneration is with regular comprehensive eye exams that identify the problem while it’s in the early, dry stage.
