LIghter-colored eyes have heightened risks for macular degeneration

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

Around 20 million Americans suffer from macular degeneration, and it's the leading cause of blindness in older Americans. Risk factors for age-related macular degeneration include aging, genetics, smoking, hypertension, obesity, and diet.

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.

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.

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.

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.

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.

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.

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.

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.

Tetrachromacy allows humans to observe 10 times the normal amount of colors

Resulting from a mutation on the X chromosome, the rare genetic condition causes individuals to possess an additional type of photoreceptor cell, typically sensitive to the orange range, located between the standard red and green cones. This enables the perception of approximately 100 million colors.

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...

The resurgence of Black lung disease in coal miners

Black lung disease is a preventable condition long associated with coal miners who regularly breathe in toxic coal dust. Simple workplace safety procedures make the disease entirely preventable, but cases are rising. Due to lax enforcement of rules, miners in Central Appalachia are increasingly diagnosed with cases stemming from silica dust inhalation.

Beyond burns, fireworks can harm respiratory, auditory, and visual health

While mishandling fireworks can cause severe burns and loss of appendages, there are also risks for viewers of displays. Released particulate matter can cause the surrounding air to resemble wildfire smoke, and the explosions can cause hearing loss and damage to the corneas.

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.

Early menopause, occurring before age 45, can be triggered by certain risk factors

Some potential causes of early menopause include autoimmune disorders, chemotherapy, smoking, and certain surgeries that cause the body to produce lower levels of estrogen and progesterone.

Modern media exposure may impact whether people dream in color or black and white

A 1942 study found that 70.7% of college sophomores rarely saw colors in their dreams, while a similar survey in 2003 showed that only 20% reported the same. The prevalence of color television and films may make color dreams or the recollection of color features easier to remember.

Breaking eye contact during a toast is supposedly bad luck

Superstitious types throughout Europe claim that toast participants must maintain eye contact for the duration of the toast. Failing to do so results in seven years of bad luck. Others are more specific, saying it will result in seven years of bad sex.

Airborne microplastics may influence cloud formation and climate

Microplastics are increasingly found in the atmosphere and may affect the climate by reflecting or absorbing sunlight based on their pigmentation. Like mineral dust, they may become cloud seeders and alter regional precipitation patterns as they become more abundant.

Larger animals like giraffes, elephants, and blue whales have developed a unique defense against cancer, a phenomenon known as Peto's Paradox

Mental health experts caution against youth sports betting

People in their early 20s represent the fastest-growing group of sports gamblers. That fact concerns mental health professionals, who warn that early exposure to gaming primes children’s brains to seek digital rewards.

Visit these 'blue zones,' where people live the longest

Blue zones, a term coined in 2004 by National Geographic Fellow Dan Buettner, are regions in the world where people live the longest and healthiest lives. Researchers have identified a few key aspects defining the culture of these areas—physical activity, diet, purpose-driven lives, and more. Explore the top five blue zones from across the world here.

Large animals like giraffes and elephants have evolved unique cancer defenses

One may expect the larger an animal is, the more likely it is to develop cancer—simply because there are more cells and more chances for a dangerous mutation. However, some large animals show cancer rates almost 10 times lower than humans—a phenomenon known as Peto's Paradox.

A nuclear reactor's characteristic blue light is produced from superluminal particles

When light travels through water, its effective speed is 25% lower than its speed in a vacuum. Just as sound waves bunch up and produce a sonic boom when objects move faster than the speed of sound, particles moving faster than this reduced speed generate a shock wave of light, visible as a blue hue.

Studies suggest when you sleep is as important as how much you get, and syncing with your circadian rhythms may lead to less fatigue and improved long-term health outcomes

Tattoos remain visible on your skin thanks to immune cells called macrophages

Alzheimer's can lead to brain shrinkage, with an average of around 2% of volume reduction per year

Firework or sparkler burns, even if they cover a relatively small area of skin, can significantly affect our range of motion.

Fear or disgust related to clusters of holes and cracks, called trypophobia, may stem from evolutionary processes to help us avoid pathogens.

When caught in the mouths of cardinal fish, seed shrimp release glowing, bioluminescent chemicals, which alert predators of the cardinal fish, prompting the shrimp's ejection.

An investigation suggests a Scottish island became awash in forever chemicals via seafoam and seaspray—raising questions about what that means for the safety of other coastal areas.

Power lines are dotted with large, brightly colored balls to improve the visibility of these thin wires to helicopters and small planes and help prevent potential crashes.

Radioactive elements can introduce software errors because the ionizing radiation they produce can detach electrons from atoms, and computer code relies on the distribution of electrons.

Bone marrow (soft tissue found inside certain bones) generates roughly 500 billion new blood cells each day

Dirty lightning is a thunderstorm created from friction between rising and falling flows of ash and smoke during volcanic eruptions.

Explore the known asteroids, comets, and spacecraft involved in asteroid studies within our solar system with 'Eyes on Asteroids,' a 3D visualization from NASA.

Telehealth demand for GLP-1s for weight loss is booming as consumers seek easier access.

Poison ivy is in the same family as mangoes, cashews, and pistachios—and they all produce oily urushiol in their raw, unprocessed state—but they are typically prepared in ways to avoid causing human discomfort.

US housing costs have risen by roughly 175% between 1991 and 2026—but a growing number of Gen Zers are becoming homeowners anyway. In 2025, 4% of homebuyers were Gen Z, up from 3% the year before.

Watch the cumbersome, but necessary, precautions healthcare workers must take to care for and protect themselves while caring for Ebola patients.

Dorothy's famous entrance into Oz in 'The Wizard of Oz' relied on analog tricks, including a body double and sepia-toned paint, as much as it did on technology

After 25 people used virtual reality headsets to practice flying with virtual wings—flapping their arms—their visual cortex responded to the wings almost as if they were real arms, treating them as body parts.

In 1939, baseball star Lou Gehrig delivered his inspirational 'Luckiest Man' speech after retiring due to the health condition that now bears his name.

See 33 images that became central to huge scandals, including a young Charles and Camilla, Michael Jackson's baby on a hotel balcony, and Hugh Grant's mugshot.

Gerrymandering works through two techniques: cracking opposing voters across districts to dilute their power, and packing them into a few to waste their votes in lopsided majorities.

A Yale student wrote a profound essay about the consulting industry's influence on elite college students that was published in a book of her writing after she died in a post-graduation car accident.

Budweiser stores yeast derived from the original 1800s strain in a secret bunker, which only the Head of Yeast Management can access—not even the CEO

The word 'jazz' evolved from 'jasm,' 19th-century American slang for 'energy'