People with blue eyes appear to be at elevated risk of developing macular degeneration, perhaps because more light can penetrate their eyes.

Caucasians are at the greatest risk of developing macular degeneration

A 2016 analysis across ethnic groups found, among other things, that white participants had the highest incidence of the disease, followed by Chinese, Hispanic, and Black participants. This study did not answer why that may be the case.

Age-related macular degeneration is the primary cause of blindness in older Americans.

Wet macular degeneration affects 10%-15% of those with macular degeneration

This form of molecular degeneration refers to when excess blood vessels form in the back of the eye and damage the macula. If someone with this condition looks at straight lines, they will typically appear wavy or crooked.

Melanin and light scattering contribute to different eye colors

Brown eyes have high melanin, while blue eyes have low melanin. Multiple genes contribute to eye color, which can change over time due to melanin buildup. Hazel eyes can shift color depending on ambient light.

As deposits build up under the eye, the retina bends with macular degeneration

The retina bends due to the accumulation of proteins and other materials beneath it. That's considered the milder "dry" form of macular degeneration. Another form, called "wet" macular degeneration, is caused by abnormal blood vessels leaking fluid into the eye, which can rapidly affect central vision.

Vitamins can slow macular degeneration

Research published in 2022 affirmed that vitamin formulations containing vitamins C and E, copper, zinc, lutein, and zeaxanthin—but no beta carotene—can enhance eye health and slow the progression of macular degeneration.

US macular degeneration burden is based on statistical modeling and Medicare claims

Prevalence estimates for age-related macular degeneration in the US are usually based on the Vision and Eye Health Surveillance System. Disease numbers are generated using Bayesian meta-regression (a type of statistical modeling), which pulls together information from multiple sources, including Medicare claims.

Targeting cholesterol metabolism may help address macular degeneration.

Vision experts generally don't recommend blue-light-blocking glasses because there's no scientific evidence that the light from computer screens damages eyes.

The macula is a small area in the center of the retina

This part of the eye—roughly the bullseye of the back of the eye—is responsible for processing the central vision of the eye. Degradation of the macula, formally called macular degeneration, leads to symptoms including blurred vision, the need for brighter lighting, and difficulty recognizing faces. The condition doesn't affect peripheral vision, but if you lose central vision, you can still be considered blind.

Lack of Vitamin D seems to be one major factor fueling MS risk

Researchers believe that a combination of factors can elevate MS risk, including a lack of vitamin D exposure in different locales, genetic history, cigarette smoke exposure, and Epstein-Barr virus infection.

World health experts expect more than 240 million global cases of AMD in 2030

The World Health Organization estimated in 2019 that by 2020 there would be roughly 195.6 million cases of age-related macular degeneration and projected that the number would continue to grow. (Some users may experience a paywall.)

Drusen are bumps under the retina that distort the vision of most macular degeneration patients

These yellow deposits are made up of proteins and lipids and come in a variety of sizes. They're common in people aged 50 and older, but amassing many of them is often a symptom of age-related macular degeneration—the most prevalent type of macular degeneration.

Cigarette smoke exposure boosts MS risk by up to 55%, though smokeless tobacco doesn't

The components of the smoke itself are associated with these significantly increased risks, so it's something beyond nicotine itself that drives that risk. What's more, smoking also increases the risk of developing antibodies to MS-treating drugs.

There are more than 1,400 listed clinical trials for macular degeneration

The US database of clinical trials listed more than 1,400 macular degeneration trials in early 2026. That doesn't mean every trial is recruiting, but it does indicate there is significant interest in this medical condition.

MS risk is shaped by geography, not just genes

Latitude—and related vitamin D exposure—seems to affect MS risk. People who migrate from a high-risk MS latitude (like northern Europe or the northern US) to a lower-risk latitude (like tropical areas) before age 15 tend to adopt the lower risk of their new country—suggesting there's a critical window for environmental exposure.

Photodynamic therapy is one current treatment for age-related macular degeneration.

Watch patient stories describing life with macular degeneration

This video series features patients discussing their experiences with the disorder, family members describing caregiving, and other insights about the disease.

Stroke risk doubles each decade after age 55

While age is the greatest risk factor, genetics, diet, and overall health play a prominent role in determining individual stroke risk. Prevention focuses heavily on modifiable risk factors. High blood pressure is the single most important controllable risk factor, contributing to both types of stroke.

In a first, eye prosthesis has restored sight to macular generation patients

In a clinical trial, 27 of 32 participants with advanced macular degeneration regained enough vision to read books, food labels, and subway signs about a year after receiving a prosthetic retina device. This is the first device to restore functional vision to patients with incurable vision loss, though in this case they can only see in black and white, with no shades in between.

Changes in vision or eye pain can be early MS symptoms

This occurs due to myelin degradation around the optic nerve, impairing its ability to transmit visual information to the brain. Individuals may especially experience eye symptoms after exercising or taking a hot shower because boosted body temperatures slow down nerve function in nerves already damaged by MS.

Because the retina lacks pain receptors, during a solar eclipse, those watching without protective eyewear may suffer from permanent damage without realizing it.

Multiple genes are associated with Alzheimer's risk, but one particularly well-known disease-associated gene is apolipoprotein E (APOE), which typically encodes a protein that helps carry cholesterol and other fats in the bloodstream.

See the global blindness burden by cause and continent.

One theory claims the retinae of SAD patients may fail to adjust to less light in winter

Most people’s eyes become more sensitive to light in the winter months, but some do not. This failure to adjust causes ripple effects on those individuals’ biological clocks. This Ted-ED video provides a clear, brief, narrative explanation of the condition in six minutes.

Why are kids increasingly diagnosed with myopia?

According to the World Health Organization, 40% of the world will have myopia—nearsightedness—by 2030. This NPR podcast episode details why people are being diagnosed with myopia at increasingly younger ages. Early onset myopia can lead to...

Diabetes has downstream effects on the heart, eyes, kidneys, and more

High blood sugar levels in untreated diabetes roughen artery walls, increasing plaque buildup, heart disease, and high blood pressure risk. High levels also cause acid to build up in the bloodstream, potentially making the brain swell, the lungs fill with fluid, and the heart to beat arrhythmically—all fatal complications.

Why your favorite color is probably blue

From a young age, we are primed to choose a favorite color, but strangely as we grow up, our preference often changes—and it’s largely due to influences outside our control.

New eye implant clinical trial recruiting in 2026

University of Southern California researchers have launched a phase 2b clinical trial of a stem cell implant designed to restore vision in people with advanced dry macular degeneration. Patients will be randomized to receive the stem cell implant or a simulated procedure and placebo implant. This type of larger, second-stage clinical trial is designed to confirm efficacy and dosing and to look for side effects. It's one of the stages that precedes the US Food & Drug Administration approval of a device.

The design of a psychiatric ward in Norway aims to integrate more circadian rhythm-friendly lights as part of its treatment protocols for conditions including psychosis, severe depression, and more.

Alzheimer's disease is the leading cause of dementia and risks rise after age 65

Read this primer about Alzheimer's disease and learn what factors increase the risk of this form of dementia, including genetics, being a woman, and health conditions, including high blood pressure.

Ultraprocessed foods are linked with a 58% elevated risk of developing dementia.

Even if you have some ASD-linked gene variations you may not develop ASD

Individual environment and life experiences affect how genes perform in the body, potentially adding methyl groups to DNA that affect their function and turning genes on and off—which may heighten or reduce disease risk.

Jaundice, which can make the skin and eyes appear yellow, is a buildup of bilirubin, a waste product that forms when old red blood cells break down.

Usher Syndrome, a rare genetic disorder, causes progressive hearing and vision loss, and people with the condition sometimes eventually become deaf and blind.

Sitting 10+ hours per day increases dementia risk

People who sit for at least 10 hours per day are more likely to develop dementia, according to a study published in 2023. This article details the study on the murky relationship between brain health and prolonged sitting. This study involved...

Risk factors linked with ASD include older parents, preterm births, and toxic prenatal exposures

Though researchers agree that there is a strong genetic component to ASD development, certain environmental factors heighten that risk, with studies suggesting older parents, premature birth, maternal obesity, and air pollution exposure in utero all elevate risks of ASD development. There is no connection between receiving vaccines and ASD development.

Alzheimer's in the United States is most prevalent in the South and the East.

Eclipse glasses protect the eyes from overexposure to the sun's ultraviolet, blue, and infrared light, as a person's instinct to look away from the sun is diminished when it's partly blocked.

Medical experts warn that completing genetic testing for Alzheimer's can be fraught, in part because there's a shortage of genetic counselors to help navigate the findings and their potential implications.

Here's why genetically identical sisters can have different colored eyes

The sequence of DNA that we inherit from our parents encodes directions for making our cells and giving us specific traits. Identical twins have the same DNA sequence, so how can one twin end up with a genetic disorder while the other twin does not? Robin Ball explains how the secret lies in X chromosome inactivation.

Eczema appears to heighten the risk of developing shingles.

Some data links schizophrenia to older paternal age and birth complications

Yet both associations are not yet considered firm enough to definitively be causative. Schizophrenia is a multi-causal syndrome and a mixture of factors, including genetics, are widely believed to be behind its development.

Musicians are 57% more likely to have tinnitus compared to the general public

Musicians have four times the risk of developing hearing loss, and their risk of developing tinnitus is increased by more than half.

Many cancers arise from genetic mutations inherited from your parents

These mutations may happen in response to environmental or lifestyle factors, or may be passed down through family members. Genetic testing can be important in catching certain family cancers early and ensuring patients receive the right treatment for their disease.

Some men may be at elevated risk of inheriting tinnitus

A 2017 Swedish Twin Registry study suggests that bilateral tinnitus—when tinnitus occurs in both ears instead of just one—appears to be heritable, at least in men.

One decibel of hearing loss increases tinnitus risk by 6% for older people

That's according to an analysis of more than 18,000 people published in BMC Medicine in 2023. The tinnitus risk is not just limited to older people: The research also concluded that one decibel of hearing loss increases the risk of developing tinnitus among young adults by 3 percent.

Reindeers are the only known mammals whose eyes change color with the seasons, going from golden yellow in the summer to deep blue in the winter.

Dozens of US research projects focus on the zebrafish's ability to grow new retina cells

The small, striped minnow can repair its optic nerve in just under a week. Scientists are interested in hacking its regenerative capacity to grow new retina cells to treat human eye disorders, including macular degeneration. In 2020, the US National Eye Institute had nearly 80 projects focused on zebrafish.

The additive effects of smoking, diabetes, and poor diet are the biggest risk factors for developing pancreatic cancer.