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, which are photoreceptors responsible for color vision and high visual acuity.
The macula is yellow due to high concentrations of zeaxanthin and lutein – carotenoids that protect the area from ultraviolet light.
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.
In the early stages, patients seldom experience symptoms. As the disease progresses, however, they may experience:
Blurry or distorted vision
Reduced central vision
Decreased color brightness
Loss of color vision
Difficulty adapting to low light
Difficulty recognizing faces
The stages of AMD are determined by changes in the retina. As AMD progresses, two types of macular degeneration 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
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.