En español | You can't see them. They don't block your vision. But if you're over 60, there's a good chance that you have some drusen — that's German for rocks — deposited in your eyeballs.
Though they're generally benign, these small yellow spots on the retina are worth watching because, in some cases, they can lead to another condition that can very much impair your vision: age-related macular degeneration (AMD), the leading cause of blindness for Americans over age 65.
What are drusen?
As their name implies, drusen are debris. The cells in your retina (like the cells throughout your body) create waste, which is normally mopped up by your immune system. When your immune cells can't keep up, that waste can build up and create these spots on the retina.
"I call them the age spots of the eyes,” says Carl Awh, M.D., an ophthalmologist and president of the American Society of Retina Specialists (ASRS). “They're one of those things that can occur over time, though it's also not uncommon to see them in younger people's eyes. Some people are probably more genetically susceptible to them."
A few drusen are normal and are not a sign of disease, Awh says. “Most people don't have drusen that are big enough, widespread enough or in a location in the eye that presents any risk to vision."
Drusen become troublesome only when they start growing in size or number or developing in a problematic location. Specifically, if you develop too many drusen, if they get too large or if they develop beneath the macula — the bull's-eye focal point of the retina that processes sharp, clear, straight-ahead vision — you're at risk for developing dry AMD. This type of AMD accounts for 85 to 90 percent of macular degeneration, as opposed to the wet form, which arises when blood vessels grow under the retina and leak.
That's why if you're 65 or older, it's important to get your eyes checked every year or two, as recommended by the American Academy of Ophthalmology (AAO). An exam can catch early risk factors for AMD, which is a sight-threating condition, Awh says.
Screening for drusen
To check for drusen, your eye doctor will dilate your pupils and examine your eyes through an ophthalmoscope, a device that allows an ophthalmologist to see the retina and other areas at the back of the eye.
"Your doctor might also scan your retina using an optical coherence tomography (OCT) scan,” Awh says. OCT uses light waves to take detailed cross-section images of your retina and the tissues beneath it.
If you have drusen that may be problematic, your doctor will check for symptoms of macular degeneration using an Amsler grid, which looks like a graph paper with dark lines forming a grid. Early signs of macular degeneration can include wavy, broken or distorted lines, or blurred or missing patches on the grid.
Though there is no treatment for drusen, you can take steps to slow the progression of the AMD that's associated with them, Awh says. “Once someone has macular degeneration, we educate and have them monitor their vision at home daily and report if there are any changes. We also examine them at regular intervals, depending on the severity.”
Studies show that you may also be able to slow the progression of dry AMD by taking a blend of eye-protective supplements: vitamins, minerals and antioxidants, specifically those used in the large Age-Related Eye Disease Studies (AREDS) — major clinical trials sponsored by the National Eye Institute:
- Vitamin C (400 mg)
- Vitamin E (400 IU)
- Lutein (10 mg)
- Zeaxanthin (2 mg)
- Zinc (80 mg)
- Copper (2 mg)
But don't go out and buy these supplements, which are branded as AREDS2 and are available over the counter, without consulting your doctor, Awh cautions. Recent research shows that, for a few people, they may do more harm than good. “Though these supplements are appropriate for the average patient with AMD, I have been part of recent investigations that have found that they can increase the risk of getting worse for a small percentage of people,” he says. “We can determine that risk through genetic testing."
What you can and should do, whether you have drusen and AMD or not: Don't smoke, and eat vision-protecting foods such as dark leafy greens, yellow fruits and vegetables, fish and a balanced, nutrient-rich diet, which has been shown to be beneficial for people with AMD, according to the AAO.
The Cholesterol Connection
Cholesterol is a component of drusen, and there are similar risk factors between hardening of the arteries (atherosclerosis) and AMD. That's caused some researchers to question whether the same drugs that can protect against cholesterol buildup in the arteries, like statins, can reduce the presence of drusen in the eyes. Turns out, they can. In a 2016 study, researchers gave 23 adults with AMD and many large drusen high doses (80 mg) of atorvastatin daily for 12 months. At the end of the study, 10 of the participants had fewer and smaller drusen and better visual acuity. None of them had progressed to advanced AMD.
"More research needs to be done,” says Carl Awh, M.D., president of the American Society of Retina Specialists, “but that does imply there's a link."