18 Mar Drusen Not Associated with Macular Degeneration
Updated by Mike Rosco, MD on 3/10/23 at 9:10 PM
Drusen are associated with age-related macular degeneration (ARMD) but are not diagnostic of the disease. Too many feel that these “spots” are indicative of ARMD, but they can, and often are, normal.
What Are These White Lesions?
Drusen are white spots, or lesions, seen within the layers of the retina. There are two types; hard and soft. The differences between the two are somewhat subtle.
Hard drusen are small and well defined with sharp borders. A poppy or sesame seed are examples of objects with sharp margins. “Hard” can be associated with macular degeneration, usually the dry (and most common) form.
Soft drusen are larger and have fluffier borders – think of the borders of a cotton ball. “Soft” can be normal, but are usually seen more often with exudative, or wet, ARMD (the less common, more harmful form).
Drusen, by definition, can be found anywhere in the retina. When they are located outside the macula, they are usually of no consequence and not related to any disease. I am usually concerned when they are located within the macula.
I have found that most non-retina people (i.e. doctors) are afraid to mention this; that drusen away from the macula are of little consequence and, if anything, can just be a family trait.
Other “Findings” of Macular Degeneration
“Findings” are the features or physical characteristics of a disease. These are the things we look for as evidence of disease.
Signs of ARMD include atrophy and/or increased retinal pigmentation, retinal swelling, and blood. There may be fibrosis (scar tissue) which is an indication of prior choroidal neovascularization. Many doctors will term anything abnormal in the macula as “scars.” This is incorrect.
In addition to physical findings, symptoms of ARMD are important to explore. Symptoms of ARMD are ways you describe changes in your vision.
Making the Diagnosis of Macular Degeneration
Ophthalmologists evaluate both the physical findings and the patient’s symptoms to make the diagnosis of macular degeneration. Though there are exceptions, it occurs predominantly in patients over the age of 50-55 years old.
Having just drusen, for example, but no change in vision or other signs of the disease, probably does NOT signify macular degeneration. It may, however, be a sign of early disease and careful monitoring may be prudent.
Many times macular degeneration is diagnosed based solely upon the physical findings, but unless there is any evidence of decreased vision, I’d hold off on making the diagnosis.
Best Test for Diagnosis
If there is any doubt about the diagnosis of macular degeneration, the single best test, in my opinion, is a fluorescein angiogram. This test can show any damage to the macula (the part of the retina responsible for central vision) that can not be seen by the usual methods. More subtle damage can be detected in this manner.
Unassociated drusen will not show any macular damage on fluorescein angiogram.
What Does This Mean? This means there are far fewer patients that actually have the disease than are diagnosed. In other words, there are instances where ARMD shouldn’t really be diagnosed. However, many docs feel that it is safer to give the diagnosis for liability reasons.
I don’t agree with this.
If there is any question about the presence or absence of macular degeneration, I would encourage you to ask your doctor about ordering a fluorescein angiogram.