Macular degeneration is caused by a combination of aging, genetics, and environmental damage that gradually breaks down the central part of your retina. No single factor acts alone. Age is the strongest driver, but smoking, genetics, light exposure, and cardiovascular health all play significant roles in who develops the disease and how fast it progresses.
How the Retina Breaks Down
The macula, the small central zone of your retina responsible for sharp vision, depends on a thin layer of support cells called the retinal pigment epithelium (RPE). These cells sit on a membrane and act as a supply line, delivering oxygen and nutrients to the light-sensing photoreceptor cells above them. In macular degeneration, that supply line gets disrupted.
In the dry form, which accounts for roughly 80 to 90 percent of cases, fatty protein deposits called drusen accumulate between the RPE and the membrane beneath it. Small drusen are a normal part of aging and don’t affect vision. But as drusen grow larger, they physically block the flow of oxygen and nutrients to the photoreceptors. Over time, the RPE cells deteriorate, and the photoreceptors above them die off. This creates patches of cell death called geographic atrophy, which cause permanent blank spots in your central vision.
The wet form is less common but more aggressive. It develops when the body produces excessive amounts of a signaling protein called VEGF, which triggers abnormal blood vessels to grow up from beneath the retina into the macula. These new vessels are fragile and leak fluid and blood, which distorts and damages the photoreceptors rapidly. Without treatment, wet macular degeneration can destroy central vision within weeks or months. High levels of VEGF have been found directly in the abnormal vessel tissue removed from patients with wet AMD.
Age Is the Biggest Risk Factor
Macular degeneration prevalence rises steadily with each decade of life, with the highest rates in people 95 and older. The number of cases and the burden of disability peak in the 65 to 69 age group simply because that’s where the largest population volume sits, but the rate per person keeps climbing with age beyond that point. The disease is uncommon before age 50.
Aging contributes in several overlapping ways. Decades of light exposure generate cumulative oxidative damage. The RPE cells become less efficient at clearing waste. Bruch’s membrane thickens and becomes less permeable. And the immune system’s inflammatory responses become harder to regulate. None of these changes alone cause macular degeneration, but together they create the conditions for it.
Genetics and the Complement System
Two gene regions carry the strongest known genetic risk for AMD. The first is the Complement Factor H (CFH) gene, and the second is the Age-Related Maculopathy Susceptibility 2 (ARMS2) region. Variants in these genes can significantly raise your lifetime risk.
The CFH gene is particularly well understood. It produces a protein that helps regulate your complement system, a branch of the immune system that attacks damaged cells and foreign invaders. When CFH doesn’t work properly, complement activation goes into overdrive, causing chronic, low-grade inflammation in the retina. This inflammation accelerates drusen formation and RPE damage. Research suggests that ARMS2 variants may also contribute to complement system dysfunction, meaning both of the major genetic risk factors converge on the same inflammatory pathway.
Having these gene variants doesn’t guarantee you’ll develop AMD. But combined with environmental exposures like smoking or poor diet, they dramatically increase the odds. This is why the disease clusters in families but doesn’t follow a simple inheritance pattern.
Smoking Multiplies the Risk
Smokers are up to four times more likely to develop macular degeneration than nonsmokers, according to the FDA. That makes smoking the single largest modifiable risk factor for the disease.
Cigarette smoke damages the retina through multiple routes. It floods the body with free radicals, overwhelming the antioxidant defenses that protect RPE cells. It constricts blood vessels, reducing the already limited blood flow to the choroid (the vascular layer beneath the retina). And it promotes systemic inflammation, which compounds the immune dysregulation already happening in people with genetic susceptibility. The risk remains elevated for years after quitting, though it does gradually decline.
Blue Light and Oxidative Stress
Not all light is equally harmful to the retina. Research using precisely controlled light bands has identified blue-violet light in the 415 to 455 nanometer range as the most damaging wavelength for RPE cells. This narrow band generates the highest levels of reactive oxygen species (hydrogen peroxide and superoxide) and produces the most mitochondrial dysfunction in retinal cells.
The damage is dramatically worse when a waste product called A2E has accumulated in RPE cells, which happens naturally with age. In lab studies, RPE cells loaded with A2E and exposed to light at 420 nanometers produced up to 10 times more hydrogen peroxide than cells kept in the dark. The oxidative stress also depleted the cells’ natural antioxidant enzymes, making them progressively more vulnerable to further damage. This is why researchers have suggested that filtering blue-violet light may be particularly important for people who already have early AMD.
Sunlight is the primary source of blue-violet light exposure over a lifetime, though screens and LED lighting contribute smaller amounts. The eye’s natural lens filters some of this light, which is one reason AMD risk increases after cataract surgery removes that natural filter.
Cardiovascular Health and Shared Pathways
Macular degeneration and cardiovascular disease share several underlying mechanisms: atherosclerosis, chronic inflammation, and VEGF activity. A large meta-analysis of longitudinal studies found that AMD is a potential risk factor for cardiovascular disease, with the strongest association being between late-stage AMD and stroke. The link to stroke was stronger than the link to coronary heart disease, and hemorrhagic stroke showed a particularly tight association.
This connection runs in both directions. The same processes that stiffen and narrow arteries throughout the body also affect the tiny vessels feeding the retina. High blood pressure, obesity, high cholesterol, and physical inactivity all contribute to the vascular environment that allows AMD to develop and progress. Treating these conditions won’t reverse existing macular degeneration, but managing them is part of slowing its course.
Who Gets It Most Often
Race and ethnicity influence AMD rates, though the reasons involve a mix of genetics, pigmentation, and possibly environmental differences. White Americans have the highest prevalence of both dry AMD (5.4%) and wet AMD (0.84%). Asian Americans have nearly comparable rates of dry AMD (5.04%) but lower rates of the wet form (0.49%). Latino and Black Americans have the lowest overall rates, with Black Americans showing the lowest prevalence for both types (3.62% dry, 0.47% wet).
Interestingly, the differences shift with age. At age 60, Asian Americans actually had a 28% higher risk of developing dry AMD compared to white Americans, though this gap disappeared by age 80. Latinos showed a 28% higher risk of wet AMD at age 60 relative to whites, but that difference also faded with age. These patterns suggest that the timing and type of AMD vary across populations, not just the overall likelihood.
Nutrients That Affect Progression
The landmark AREDS2 study, conducted by the National Eye Institute, identified a specific combination of nutrients that reduced the risk of intermediate AMD progressing to the advanced stage by about 25%. The formula includes 500 mg of vitamin C, 400 IU of vitamin E, 80 mg of zinc, 2 mg of copper (to prevent zinc-related copper deficiency), 10 mg of lutein, and 2 mg of zeaxanthin.
Lutein and zeaxanthin are the two nutrients most specific to the retina. They concentrate in the macula and act as a natural blue-light filter and antioxidant shield, directly counteracting the oxidative mechanisms that drive AMD. The AREDS2 formula replaced beta-carotene from the original study because beta-carotene increased lung cancer risk in smokers. These supplements are widely available over the counter and are recommended for people with intermediate AMD or advanced AMD in one eye. They don’t prevent AMD from developing in the first place, and they don’t restore vision already lost.
How the Stages Progress
AMD is classified into stages based on the size of drusen deposits and whether pigment changes or advanced damage are present. Normal aging involves only tiny drusen (63 micrometers or smaller) with no pigment abnormalities. Early AMD means medium-sized drusen (between 63 and 125 micrometers) have appeared. Intermediate AMD involves large drusen (over 125 micrometers) or pigmentary changes in the retina. Late AMD is defined by either geographic atrophy (advanced dry) or abnormal blood vessel growth (wet).
Most people with early AMD never progress to late AMD. The transition from intermediate to late AMD is where the greatest risk of vision loss occurs, and it’s the stage where the AREDS2 supplements have their proven benefit. Progression can take years or decades in the dry form, while the wet form can develop suddenly at any stage.