Age-related macular degeneration (AMD) results from a slow buildup of fatty deposits beneath the retina that, over decades, starves the light-sensing cells responsible for your central vision. Globally, the number of people living with AMD more than doubled between 1990 and 2021, rising from about 3.6 million to over 8 million cases. The causes are a mix of unavoidable biology, inherited genetic risk, and controllable lifestyle factors, with smoking and age sitting at the top of the list.
How the Retina Breaks Down Over Time
The back of your eye contains a thin layer of support cells called the retinal pigment epithelium (RPE). These cells act like a recycling plant: they absorb waste from the light-sensing photoreceptors above them and pass nutrients up from the blood vessels below. The barrier between the RPE and those blood vessels is a thin membrane called Bruch’s membrane, and what happens to it over a lifetime is central to AMD.
Throughout adulthood, fatty particles accumulate inside Bruch’s membrane. The RPE naturally releases cholesterol-rich particles downward for disposal into the bloodstream, but as the membrane ages, those particles take longer to pass through and begin piling up. By age 70 and beyond, this process can create a distinct layer of tightly packed lipid material within the membrane itself. That layer makes the membrane increasingly waterproof in the wrong direction: nutrients from the blood supply struggle to reach the RPE, and waste products from the RPE can’t drain away efficiently.
This bottleneck leads to visible yellow deposits called drusen beneath the retina. Drusen physically push against RPE cells and further block the flow of nutrients. Over time, patches of RPE cells die off. Because the RPE is what keeps photoreceptors alive and nourished, those light-sensing cells die next. Research consistently shows that RPE loss comes first, followed by photoreceptor death. The result is a permanent blind spot in your central vision.
Dry AMD vs. Wet AMD
About 80% to 90% of AMD cases are the “dry” form, which progresses through the drusen-and-atrophy pathway described above. In its earliest stages, small drusen may cause no symptoms at all. As drusen grow larger and RPE cells begin to die in clusters, you may notice blurriness or a dim spot in the center of your vision. The advanced stage of dry AMD, called geographic atrophy, involves large areas of dead RPE and photoreceptors that produce a noticeable gap in central sight.
Wet AMD accounts for the remaining 10% to 20% of cases but causes the majority of severe vision loss. It develops when the tissue beneath the retina becomes starved of oxygen, often because the same lipid buildup and Bruch’s membrane changes have compromised blood flow. In response, the body ramps up production of a signaling protein that triggers new blood vessel growth. These emergency blood vessels sprout from the layer beneath the retina and push upward into it. The problem is that they’re fragile and leaky. Fluid and blood seep into the retina, distorting and destroying the delicate photoreceptor architecture. This protein also breaks down surrounding tissue to make room for the new vessels, which allows them to keep spreading. Wet AMD can cause rapid, dramatic vision loss over weeks or months, unlike the slower progression of dry AMD.
Genetic Risk Factors
Your genes play a major role in determining whether AMD develops. Two gene regions carry the greatest impact: the complement factor H (CFH) gene and the ARMS2 gene. CFH is involved in regulating your immune system’s complement pathway, a defense mechanism that tags damaged cells for destruction. When CFH doesn’t function properly, the complement system can mistakenly attack healthy retinal tissue, causing ongoing low-grade damage that accelerates drusen formation and RPE death.
People who carry high-risk variants in both CFH and ARMS2 face the steepest odds of progressing to advanced AMD. Those with high-risk CFH variants but no ARMS2 risk still face elevated risk, as do those with ARMS2 variants alone. The combination of both pushes risk highest. You can’t change your genetic profile, but knowing your family history of AMD helps gauge your personal risk level.
Smoking Is the Largest Controllable Risk
After age itself, smoking is the most consistent and well-documented risk factor for AMD. Current smokers face a two- to four-fold increase in risk compared to people who have never smoked, depending on the type of AMD. In one long-term study, current smokers had nearly four times the risk of developing late-stage AMD over a 10-year period. Smokers of 20 or more cigarettes per day roughly doubled their risk in both the Physicians’ Health Study and the Nurses’ Health Study.
Quitting helps, but not immediately. Data from the Rotterdam Study showed that the elevated risk of wet AMD persisted for up to 20 years after a person stopped smoking. Former smokers still carried about three times the risk of geographic atrophy compared to people who never smoked. The message is straightforward: the sooner you quit, the better, but the damage to Bruch’s membrane and the retinal blood supply takes a very long time to resolve.
Cardiovascular Health and Shared Pathways
AMD and cardiovascular disease share several underlying mechanisms. The lipid deposition process in Bruch’s membrane mirrors what happens inside artery walls during atherosclerosis. Both conditions involve fat accumulation, inflammatory responses, and complement system activation. Risk factors common to both include obesity, lack of physical exercise, elevated inflammatory markers, and certain genetic variants related to cholesterol metabolism.
The exact relationship between high blood pressure, cholesterol levels, and AMD is still being refined. Some studies find that the same high-density lipoprotein cholesterol (HDL) detected at higher levels in AMD patients may actually protect against coronary heart disease, creating a complex picture. What is clear is that the overall metabolic health of your blood vessels matters for your eyes, not just your heart.
Blue Light and Sunlight Exposure
Despite widespread marketing of blue-light-blocking glasses and screen filters, there is currently no evidence that normal screen use or LED lighting damages the human retina or contributes to AMD. Large studies comparing blue-light-filtering lens implants to standard lenses after cataract surgery found no difference in AMD rates, even after 10 years of follow-up in a study of over 186,000 patients.
The relationship between cumulative sunlight exposure and AMD is more nuanced. Some studies have flagged sunlight as a potential risk factor, with blue wavelengths carrying the most energy and therefore the greatest theoretical capacity for retinal damage. But results across human studies are conflicting, partly because it’s nearly impossible to separate the effects of blue light from ultraviolet radiation in real-world sun exposure. Your retina does have a built-in defense: macular pigments made of lutein and zeaxanthin that filter blue light naturally. Higher dietary intake of these pigments is associated with lower AMD risk.
The AREDS2 Nutritional Formula
The most rigorously tested nutritional intervention for AMD comes from the Age-Related Eye Disease Studies, funded by the National Eye Institute. The current recommended formula, known as AREDS2, was shown to slow progression from intermediate to advanced AMD. It contains 500 mg of vitamin C, 400 IU of vitamin E, 80 mg of zinc, 2 mg of copper (added to prevent zinc-related copper deficiency), 10 mg of lutein, and 2 mg of zeaxanthin.
The original formula included beta-carotene, but the AREDS2 trial found that swapping it out for lutein and zeaxanthin actually reduced the risk of advanced AMD further. This matters especially for current or former smokers, since beta-carotene supplementation is linked to increased lung cancer risk in that group. A lower zinc dose of 25 mg performed comparably to the 80 mg dose in the trial, though 80 mg remains the standard in most commercial formulas. These supplements are intended for people who already have intermediate AMD in one or both eyes. They don’t prevent AMD from developing in the first place.
How AMD Is Spotted Early
In its earliest stages, AMD often produces no noticeable symptoms. Small drusen are typically found during a routine dilated eye exam. As the disease progresses, you may notice that straight lines appear wavy or bent, a distortion called metamorphopsia. Some people develop a dim or blank spot near the center of their vision.
The Amsler grid is a simple checkerboard-pattern tool used to monitor for these changes at home. You look at the center dot with one eye at a time. If the grid lines appear wavy, broken, or missing in any area, that suggests new distortion or a blind spot that warrants prompt evaluation. The grid is particularly useful for catching the transition from dry to wet AMD, where early treatment can preserve significantly more vision. An FDA-approved home monitoring device called ForeseeHome uses similar principles with greater sensitivity for people at high risk of conversion to wet AMD.
The practical takeaway is that AMD develops through a chain of events that starts decades before symptoms appear. Fat accumulates in Bruch’s membrane, waste removal slows down, drusen form, the RPE deteriorates, and photoreceptors follow. Genetics load the gun, aging pulls the trigger, and smoking accelerates the entire process. The factors you can control, including not smoking, maintaining cardiovascular fitness, eating lutein-rich foods like leafy greens, and getting regular eye exams, represent your best tools for slowing or catching the disease before it takes central vision.