See the evolution of vision, from cells that could only detect the intensity and direction of light to the human eyeball.

When focusing on an object, muscles change the shape of the lens, which refracts incoming light such that it focuses at the retina. If the cornea is unable to bend light correctly, lenses or contact lenses can provide supplemental refraction to ensure a focused image is produced.

Several companies are attempting to create brain-computer interfaces that skip over retinas and optic nerves to allow visual input to go straight to the brain, potentially restoring some sight to the blind. Clinical trial findings suggest restored sight is sparse and manifests differently than a sighted person might expect, appearing as specks of "light" clusters called phosphenes to help differentiate one's surroundings.

Scientists have created lenses that use nanoparticles to convert infrared light into visible light, allowing human eyes to observe previously invisible parts of the electromagnetic spectrum. This technology may help colorblind individuals by converting colors they cannot see into wavelengths they can.

An estimated two-thirds of the world's adults use a form of prescription glasses or contacts, proof spectacles were a godsend when they were invented in 1286 CE. But what did people do before that? Different tools were used for distinct vision problems, but some would use magnifying lenses, clear emeralds, and more. Watch this video for a historical explanation.

Specialized photoreceptor cells in the retina called cones each possess photopigments that activate when exposed to three ranges of visible light. Other forms of electromagnetic radiation outside the activation range do not generate signals for processing in the brain, thereby limiting average human vision to approximately 10 million colors.

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.

Since CRISPR was revealed as a gene editing tool in 2012, it has been on an accelerated track to real-world applications. Among other clinical demonstrations, doctors have now injected a CRISPR treatment directly into eye cells, helping vision-impaired patients see shapes and colors again.

While some animals are sensitive to many forms of light, humans possess receptors that are sensitive to red, green, and blue wavelengths. These receptors send signals to the brain, which are processed and mixed to produce the array of colors we observe, including magenta, pink, and "supercolors" that lack a corresponding natural wavelength in the visible spectrum.

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.

What if the thing that restored your vision… was your own tooth? That’s exactly what happened to Brent Chapman. After 20 years without sight, a bizarre surgery using his tooth as a lens restored his vision.

Just as Earth's atmosphere allows the sun's visible light to pass through while blocking other harmful radiation, telescope mirrors and other optics can only reflect, absorb, or transmit certain types of light. Detectors also utilize semiconducting materials that react to specific energies of light, thereby preventing a one-telescope-fits-all solution.

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.

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.

The human brain has developed cognitive shortcuts to help us navigate in a world where our visual senses are constantly bombarded of information. But these shortcuts can also be exploited, tricking the brain into telling us something is happening when it really isn't. This short video unpacks the neuroscience behind some of the most common (but perplexing) optical illusions.

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 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.

After a University of Michigan engineering student suffered retinal burns from an ultrashort pulse laser, researchers realized it could be used to reshape the cornea and improve a person's vision with greater precision than a scalpel and earlier laser technologies. Agencies, including the National Science Foundation, the National Institutes of Health, and the Department of Energy, provided funding to develop and commercialize the procedure.

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.

The eyes really are the windows to the soul.

All forms of electromagnetic radiation, from radio waves to gamma rays, travel at the speed of light in a vacuum, but their wavelengths decrease as their frequencies increase. The light-sensitive nerve cells in the human eye are sensitive to a narrow range of values, which we observe as the spectrum of visible light.

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.

The human body depends on information from the five sensory organs—the eyes, ears, nose, tongue, and skin—to react to the world around it. Each of these organs, in its own way, relies on complex circuitry to send signals back to the central nervous system.

Before surgery, a patient’s vision needs are incorporated with measurements and mapping of their eye’s surface to identify corrections to refractive errors. This ensures light entering the eye correctly focuses onto the retina to produce a clear image.

Eyes have long been said to be the window to the soul. In this article, a psychologist and pupillometrist explores research demonstrating pupils as a window into the mind. Pupils tell us how intensely someone is exerting mental effort, or even reveal what a person is imagining. Read this article for insight into the field of pupillometry and how it can offer insights into our psyches.

Clinicians must screen for symptoms of eye and vision damage in leprosy patients, including loss of sensation, reduced blink reflex, and inability to close or keep the eyes closed.

Paleontologists analyzed the fossilized eye and ear structures of 16 theropods, finding that some had owl-like hearing and huge pupils. These characteristics are consistent with modern-day nocturnal species, including nightjars and geckos.

Invisibility is an oft-coveted superpower that many creatures throughout the animal kingdom have evolved to mimic through transparent camouflage. This article explores the science of this seemingly magical ability. The two critical ingredients in...

Despite seeming like a rare ability in land animals and unseen in plants, bioluminescence has evolved at least 29 times across marine species, indicating its necessity for survival where hiding spots are rare and highlighting how environments provide evolutionary pressure.

Colorblind artist Neil Harbisson was born into a world of grey. In 2004, he had a chip installed connected to an external color frequency sensor. Once the sensor "reads" a color, it sends a signal to the chip and plays an associated sound both in and outside Harbisson's head.

From Galileo’s crude spyglass to the James Webb Space Telescope, each technological leap has expanded our observational reach and redefined philosophical and moral conceptions of our place in the universe. Identifying signs of life through the study of exoplanet atmospheres would represent the next great revolution.

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.

After analyzing fossils, genetic data, and statistical methods, scientists believe octocorals were the first organisms to evolve light-producing abilities. As a result of independent evolution across at least 94 species, this phenomenon is connected to a diverse range of behaviors.

When you close your eyes, do you see static or colorful patterns or an "intrinsic grey" known as Eigengrau in German? This variation of our internal experiences is just the tip of the iceberg, one that scientists are increasingly studying and...

Near-infrared luciferase systems allow researchers to image and analyze cellular activity in living animals because they penetrate tissue more deeply than visible light. This provides a means of studying gene expression and protein interactions without harming the animals.

Camouflage—nature's master game of hide-and-seek—is more complex than simply how things look. The disguising process required millions of years of evolution that have programmed how our brains take shortcuts. Watch this video to see examples of camouflage and understand how we process it.

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.