The macula is the central portion of the retina responsible for sharp, detailed central vision, allowing us to perform tasks like reading and recognizing faces. As people age, the macula can undergo changes. Receiving a diagnosis that mentions the presence of “drusen” can be concerning because these deposits are closely associated with Age-Related Macular Degeneration (AMD). While drusen are common in older adults, their size, number, and characteristics determine whether they represent normal aging or signify the onset of AMD.
What Are Drusen Deposits
Drusen are small, yellowish deposits found beneath the retina, accumulating between the retinal pigment epithelium (RPE) layer and Bruch’s membrane. These deposits are extracellular material composed of lipids and proteins, which are waste products from the retina’s intense metabolic activity. Their presence suggests a breakdown in the eye’s natural waste removal system, a process that becomes less effective with age. A few scattered, small drusen are common in people over the age of 50 and are often considered a normal sign of aging. However, when these deposits grow larger or become numerous, they can interfere with RPE cells and disrupt the delivery of nutrients to the photoreceptor cells responsible for vision.
The Diagnostic Relationship Between Drusen and Macular Degeneration
The mere presence of drusen does not automatically equal a diagnosis of Age-Related Macular Degeneration. The diagnostic distinction relies heavily on the size and quantity of the deposits observed during a dilated eye examination. Small drusen, defined as less than 63 micrometers in diameter, are prevalent and do not increase the risk for significant vision loss. They are considered an age-related change with no associated clinical risk.
A diagnosis of Early AMD is made when multiple small drusen or a few medium-sized drusen (63 to 125 micrometers) are present in the macula. The diagnosis progresses to Intermediate AMD when at least one large druse (125 micrometers or more) is detected, or when extensive medium drusen are found. The presence of pigmentary changes, such as areas of hyper- or hypo-pigmentation alongside drusen, also serves as a definitive marker for AMD.
Classifying Risk and Tracking Progression
Ophthalmologists use a standardized classification system based on drusen characteristics to stage the disease and determine the risk of progression to advanced vision loss. This staging is important because it informs the patient’s monitoring schedule and potential intervention strategies. For instance, the presence of large drusen in both eyes significantly increases the five-year risk of progressing to the advanced stage.
The advanced stage is categorized into two distinct forms: dry and wet. Advanced dry AMD, or geographic atrophy, involves the progressive degeneration and death of the retinal pigment epithelium and underlying photoreceptor cells, leading to blind spots in central vision. Advanced wet AMD, or neovascular AMD, occurs when drusen-damaged tissue triggers the abnormal growth of fragile new blood vessels beneath the retina. These vessels leak fluid and blood, causing rapid and severe central vision loss. Regular monitoring, which may include the use of an Amsler grid at home to detect visual distortions, is recommended to track any changes in vision.
Patient Management and Lifestyle Adjustments
For individuals diagnosed with Intermediate AMD, or Advanced AMD in only one eye, specific nutritional supplementation is proven to slow the disease’s progression. The Age-Related Eye Disease Study 2 (AREDS2) formulation is a high-dose combination of antioxidants and minerals that can reduce the risk of progressing to advanced AMD by about 25% over five years. This formula includes:
- Vitamin C
- Vitamin E
- Zinc
- Copper
- Lutein
- Zeaxanthin
This supplement regimen is not recommended for those with only small drusen or Early AMD, as the benefits do not outweigh potential side effects in lower-risk stages. Smoking cessation is a primary lifestyle intervention, as smoking drastically increases the risk of developing and progressing to advanced AMD. Additionally, wearing sunglasses that block ultraviolet (UV) and blue light protects the macula from damaging radiation, supporting the overall health of the retinal structures.