The primary causes of macular degeneration

Age-related macular degeneration (AMD) develops when cells in the macula—the part of your retina that handles sharp central vision—break down over time. The exact mechanism is not fully understood, but the damage involves a combination of aging, genetics, and environmental factors working together. In most cases, no single cause explains why one person develops AMD and another does not.

The macula contains millions of light-sensitive cells called photoreceptors. As you age, waste products accumulate in and around these cells. In AMD, the eye's natural cleanup system becomes less efficient, and harmful proteins and lipids build up in layers beneath the retina. This buildup damages the supporting cells that keep photoreceptors alive, eventually leading to vision loss in the center of your visual field.

Key Takeaways

  • Age is the strongest risk factor for macular degeneration; the condition is rare before age 50 and becomes more common after 60.
  • Genetics play a significant role—having a parent or sibling with AMD roughly doubles your risk, and certain genetic variants increase susceptibility substantially.
  • Smoking is the most modifiable risk factor; smokers develop AMD earlier and more severely than non-smokers, and quitting can reduce progression.
  • High blood pressure, obesity, and a diet low in antioxidants and omega-3 fatty acids contribute to AMD development and progression.
  • The two forms of AMD—dry and wet—develop through different mechanisms, though both involve damage to the macula.

How age increases your risk

Age is the strongest predictor of macular degeneration. The condition is uncommon in people under 50, but prevalence rises sharply after age 60. By age 75, roughly one in four people show signs of AMD, though not all experience vision loss severe enough to notice.

The aging process itself damages the structures that support retinal health. The retinal pigment epithelium—a layer of cells that nourishes photoreceptors and removes waste—becomes less efficient with time. Blood vessels that feed the retina become stiffer and less able to deliver oxygen and nutrients. These changes happen to everyone, but the rate and severity vary widely based on genetics and lifestyle.

Genetic factors that increase susceptibility

If a parent or sibling has macular degeneration, your risk roughly doubles compared to someone with no family history. Researchers have identified at least 34 genetic variants associated with AMD, though most people with the condition carry only a few of them.

The strongest genetic links involve genes that control inflammation and immune response in the eye. One variant in the CFH gene (which regulates a protein involved in immune regulation) is present in roughly half of all AMD cases. Another in the ARMS2 gene affects how cells in the retina handle stress. Having these variants does not mean you will develop AMD, but it makes the condition more likely if other risk factors are present.

Genetic testing for AMD risk is available but not routine. It may be useful if you have a strong family history and want to know whether aggressive lifestyle changes could reduce your risk, though no genetic test can predict with certainty whether you will develop the condition.

Smoking and its direct impact on the macula

Smoking is the most significant modifiable risk factor for macular degeneration. People who smoke are two to four times more likely to develop AMD than non-smokers, and they typically develop it 5 to 10 years earlier. The risk remains elevated for years after quitting, but it does decline over time.

Smoking damages the macula through multiple pathways. Cigarette smoke contains oxidative compounds that generate harmful free radicals in the retina, overwhelming the eye's natural antioxidant defenses. Smoking also increases inflammation throughout the body and in the eye specifically, accelerates the buildup of drusen (the waste deposits under the retina), and reduces blood flow to the retina. Former smokers who quit show slower progression of existing AMD compared to those who continue smoking.

Cardiovascular and metabolic risk factors

High blood pressure, high cholesterol, obesity, and diabetes all increase the risk of macular degeneration, likely through shared mechanisms of vascular damage and inflammation. People with uncontrolled hypertension are roughly 1.5 times more likely to develop AMD. Obesity increases risk by roughly 50 percent, and diabetes roughly doubles it.

These conditions damage the small blood vessels that supply the retina and promote chronic inflammation—a state where immune cells remain activated and release damaging chemicals. Maintaining healthy blood pressure, cholesterol, and weight through diet and exercise reduces AMD risk. Some research suggests that controlling these factors may slow progression in people who already have the condition, though the evidence is stronger for prevention than for treatment of existing disease.

Diet, antioxidants, and nutritional factors

A diet low in antioxidants and omega-3 fatty acids increases AMD risk. The macula is metabolically active and generates large amounts of free radicals during normal function. Antioxidants like lutein, zeaxanthin, vitamin C, vitamin E, and zinc help neutralize these free radicals and protect retinal cells.

People who eat more leafy greens, fish, nuts, and colorful vegetables have lower AMD risk than those whose diets are high in refined carbohydrates and processed foods. The Age-Related Eye Disease Study (AREDS) and its follow-up (AREDS2) found that specific combinations of antioxidants and minerals slowed progression in people with intermediate or advanced AMD, though they did not prevent the condition from developing in healthy people.

Differences between dry and wet macular degeneration causes

Dry AMD, which accounts for roughly 85 percent of cases, develops when the retinal pigment epithelium gradually fails and photoreceptors die from lack of support. Drusen accumulate, the macula thins, and central vision slowly declines. The underlying cause involves aging, genetics, and inflammation, but the process is gradual and does not involve bleeding.

Wet AMD, the more aggressive form, occurs when abnormal blood vessels grow beneath the retina in response to the damage caused by dry AMD. These fragile new vessels leak fluid and blood, causing rapid damage to the macula and sudden vision loss. Wet AMD develops in roughly 10 to 15 percent of people with dry AMD, though the risk is higher in those with certain genetic variants and in smokers. The trigger for abnormal vessel growth involves signaling molecules called vascular endothelial growth factor (VEGF), which the eye produces in response to oxygen deprivation and inflammation.

Frequently Asked Questions

Can macular degeneration skip a generation in families?

Yes. AMD involves multiple genes, and inheritance patterns are complex. You can carry genetic risk factors without developing the condition yourself, and your children may inherit those same factors. Family history increases risk, but it does not determine outcome.

Does sun exposure cause macular degeneration?

The evidence is mixed. Some research suggests that cumulative ultraviolet exposure increases AMD risk, while other studies find no clear link. Wearing sunglasses with UV protection is reasonable for eye health generally, but sun exposure is not considered a major AMD risk factor the way smoking and age are.

Can you develop macular degeneration in only one eye?

Yes, though it is less common. AMD typically affects both eyes, but one eye may develop it years before the other, or one eye may progress faster. The underlying risk factors are the same in both eyes, but the timing and severity can differ.

Does macular degeneration run in families if only one parent has it?

Having one parent with AMD increases your risk compared to the general population, but not as much as having two affected parents. Your risk also depends on which genetic variants you inherited and your own lifestyle factors like smoking and diet.

Is macular degeneration preventable if you have the genetic risk?

Genetics load the gun, but lifestyle pulls the trigger. People with high genetic risk can still delay or reduce AMD severity by not smoking, maintaining healthy blood pressure and weight, eating a diet rich in antioxidants, and exercising regularly. Prevention is not may provide, but modifiable factors matter even when genetics are unfavorable.