What did people do before eyeglasses were invented?

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.

Scientists create contact lenses that give you infrared vision

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.

Corrective vision technologies rely on the bending of light waves

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.

The origin of LASIK eye surgery, from a lab incident to federal funding and widespread use

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.

When did people start making and using glass?

This article details the search for the ancient origins of glass, a now-common item through which archaeologists can spot histories of trade and innovation. Bronze Age glass was made from crushed quartz instead of sand, and artisans could color glass with materials such as cobalt. These trace metallic add-ons have given scientists a vital clue into the origins of glass, which is currently debated as either Egypt or the Near East.

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

Credit for inventing the laser was fought over for nearly three decades

Although Theodore Maiman built the first working laser in 1960, Gordon Gould coined the term earlier. Charles Townes and Arthur Schawlow of Bell Labs filed a patent after Gould came up with the idea and name, but before Gould filed his patent.

Plastic's history began with an inventor seeking a $10,000 prize offer

In 1869, the first synthetic polymer—celluloid—was created as a substitute for ivory in billiard balls. It became the historical catalyst for the eventual manufacturing of plastics everywhere as an alternative to the depletion of other natural resources, including tortoiseshell and horns.

The first 3D printing patent was filed in 1967

Wyn Swainson, an English literature graduate student, filed a patent in Denmark for a system that scans an object and uses the scanning data to rebuild it using lasers that harden light-sensitive plastic. However, he never developed a working prototype. The idea originated from wanting to produce recreations of sculptures.

Why surgeons implant teeth into eyes

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.

Watch a time-lapse of 3D printing two pairs of eyeglasses by layering plastic filament.

Experience a century of America's healthcare advances with this medical visualization, tracing a sampling of healthcare innovations from head to toe.

The unexpected origin story of the snow globe

In 1900, a Vienna tradesman named Erwin Perzy I was attempting to invent an inexpensive way to improve light amplification in hospital operating rooms. After experimenting with a glass globe filled with water, the idea for the snow globe struck. Industrious as well as inventive, Perzy eventually turned his idea into a successful business. Read the full article to learn how the invention grew to become recognized globally.

Using brain implants to restore vision

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.

View a timeline of 3D printing technology through 2019

The first working 3D printing device was invented in 1983 and utilized stereolithography, a process in which a laser triggers a chemical reaction that hardens liquid resin. Powder-based laser sintering technology was patented in 1987, with metal-based powders first being used for 3D printing in 1997.

Photography was invented by a romantic artist

The invention of photography changed the landscape of art forever. The first photographs were created by Louis-Jacques-Mandé Daguerre, a romantic era printmaker, by using light and chemistry to expand upon images produced by the earlier camera obscura.

A collective effort from multiple scientists and inventors led to the light bulb

While Thomas Edison's thin carbon filament design made light bulbs commercially viable, prior contributions, such as Joseph Swan's development of the first successful incandescent filament electric lamp, made its eventual invention possible.

See how cataracts—a leading cause of vision loss globally—form and how sound waves are often used to help remove them.

A brief history of augmented reality (w/photos and videos)

Different sources trace the history of augmented reality back to the beginning of the 20th century,. The term augmented reality however was coined by Thomas P. Caudell in the '80s.

The first glasshouse was constructed in 1931

The Maison de Verre in Paris was built to house a doctor's office on the ground level and an apartment upstairs. Unlike the typical model that would follow, this glass house exposed very little of the home's interior.

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.

Cell theory originated from microscopic observations of cork and dental plaque

In the mid-1600s, Robert Hooke identified compartment-like structures—which he called cells—in cork, and Anton van Leeuwenhoek discovered bacteria in samples of his dental scrapings. Almost 200 years later, Matthias Schleiden and Theodor Schwann showed that plants and animals, respectively, are composed of cells, proving that cells are the foundation of all living things.

LSD was discovered accidentally after its inventor touched his face and hallucinated.

Restoring vision in impaired patients via CRISPR

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.

Visualize the 5,000-year history of consumer credit in one infographic

Consumer loans for agriculture were likely first used around 3500 BCE, but modern consumer credit took many more centuries to be established. England's credit reporting system, for instance, dates back to the early 1800s when a group of English tailors began swapping information about customers who failed to settle their debts.

How billiard balls catalyzed the 'Plastics Century'

For centuries, billiard balls were made of ivory from elephant tusks. But when excessive hunting caused elephant populations to decline, they began to look for alternatives: celluloid, which would become known as the first plastic.

LSD (better known as acid) was created in 1938 by Swiss chemist Dr. Albert Hofmann

Lysergic acid diethylamide, better known as LSD or acid, was first developed synthetically in 1938 by Swiss chemist Dr. Albert Hofmann. It's since become a linchpin for an entire aesthetic, fueled a counterculture movement, and is being studied for potential therapeutic uses.

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 world's first webcam was invented in the early 1990s by scientists at Cambridge Computer Laboratory to monitor a coffee pot for researchers working in different labs on various floors.

The first successful IVF pregnancy was in the United Kingdom in 1978

Gynecologist Patrick Steptoe and his collaborator Robert Edwards, a biologist, attempted to fertilize a human egg cell in a petri dish 101 times before finally succeeding. This resulted in the birth of Louise Brown—at the time referred to as a "test tube" baby—in 1978, who was born into the spotlight.

Rune Elmqvist forwent practicing medicine to invent the first inkjet printer

The Mingograph recorded real-time physiological signals from a patient's electrocardiogram, helping doctors diagnose heart and brain conditions. Eight years later, in 1958, Elmqvist worked with cardiac surgeon Åke Senning to develop the first fully implantable pacemaker.

Most custom earmolds for in-ear hearing aids are made using 3D printing

The technology has also been utilized for behind-the-ear and receiver-in-canal hearing aids, allowing for the creation of structures tailored to the patient's anatomy for enhanced effectiveness. 3D printing has also been used to print retinal eye cells and custom eyeglass frames.

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

The first identification of Alzheimer's was made in 1906.

736,900 cochlear implants had been implanted by 2020 worldwide

In the United States, roughly 118,100 devices had been implanted in adults by that point and 65,000 in children. These estimated figures come from the US Food and Drug Administration, which first approved cochlear implants for adults experiencing hearing loss in the mid-1980s, and collected reports from cochlear implant manufacturers approved for the US market.

According to the Greek historian Herodotus, the first person to successfully predict a solar eclipse was the Greek philosopher Thales of Miletus in 585 BCE, with the resulting celestial event ending a half-decade-long war.