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.

A 1974 Science News article proclaimed that within a decade, light therapy would be on par with traditional drugs.

See photos of ultraviolet light therapy, widely administered in the early 1900s, particularly among children with skin diseases, tuberculosis, rickets, and more.

Certain visible light therapies, when applied at specific intensities, can be used to treat skin conditions, including acne.

This 1440 Original video dives into what the science says about phototherapy and its various potential applications.

Red light therapy—a treatment harnessing a specific form of energy that penetrates the top layers of skin—is marketed for skincare and wellness, but has its roots in NASA plant growth research.

High-powered red light therapy—delivered directly to nerve fibers via a fiber optic needle—has been used in recent experimental research to suppress pain.

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

Breaking down sunlight and why the sun appears yellow despite emitting green light the most

The first newborn screen for diseases was developed in 1961.

Blood color differs across the animal kingdom, with some animals producing blood that appears green (a group of lizards in New Guinea) or blue (horseshoe crabs).

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.

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

Bright light therapy involves basking in 10,000 lux of light for 30 minutes each morning

Blacklights can illuminate certain biological materials, including blood, teeth, and fingernails, because they contain fluorophores—molecules that visibly glow immediately after exposure to higher-energy light.

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

Eight years after receiving an eyeball tattoo, a patient's swim in the Mediterranean set off rare complications that caused pigment clumping and cornea issues.

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

Light therapy was widely used as a medical treatment for various maladies in the early 1900s before it was replaced by antibiotics.

Water is naturally tinted with a slight blue, but sediments and organics can alter its color

Imagining if humans could perform photosynthesis and how it would change our anatomy

Secondary complications from measles in children range across the whole body.

Touch helps newborns regulate stress, gain weight, and feel less pain

In 2026, the US FDA approved a light-activated gel combined with red light therapy as a nonsurgical treatment option for the most common type of skin cancer.

Gene therapy, a hope of the Human Genome Project, has successfully treated a baby born with a rare urea cycle disorder that causes toxic ammonia level buildup.

View a gallery of biofluorescent animals, which contain cells that emit various colors when exposed to ultraviolet light.

A planned clinical trial to treat a rare lysosomal storage disorder in utero has buoyed hopes of providing prenatal gene therapies, but it was still awaiting FDA approval to begin enrolling patients as of May 2026.

NASA began investigating the healing properties of red light therapy in the 1980s, when researchers studying how LED lights could aid in photosynthesis noticed that their hands seemed to heal faster than normal under the lights.

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

Melanin and light scattering contribute to different eye colors

Vitamin A does not cure measles, but it helps reduce the symptoms

Virtually all plants are biofluorescent because their photosynthesis is powered by chlorophyll, a pigment that glows red as a way to get rid of excess energy when exposed to ultraviolet light.

How to repair a baby’s broken heart

Hippocratic doctors treated severe mental illness with the poisonous plant hellebore

In 2023, the FDA approved gene therapy for sickle cell disease, enabling one-time infusion bespoke treatments that use a patient's own stem cells to effectively cure a painful condition that disproportionately affects people of African American descent.

Western babies often lack a gut microbe common elsewhere.

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.

Watch how doctors examine leprosy patients for signs of vision impairment

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

The chlorophyll in plants captures energy in the form of red and blue light

Tennis balls are yellow, partly thanks to a suggestion by British naturalist and broadcaster Sir David Attenborough.

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

How personalized gene-editing saved a baby's life

Bioluminescent reaction enzymes are often used in biomedical research

View a gallery of plants made to shine using ultraviolet-induced visible fluorescence photography, in which organisms re-emit the ultraviolet light they are exposed to in vibrant, glowing colors.

Starting with red, colorful objects will appear to lose their colors the deeper they are submerged because water scatters light, reducing the amount available to reflect off objects and be observed.

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

The weakest form of light that is dangerous to humans is ultraviolet

Study shows singing to babies improves their well-being

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

In the early 20th century, 'baby cages' were popular among parents who believed that putting their children in the cold would build their immunity to minor illnesses.