When you think about contact lenses, you probably don’t picture wearing a bowl of water on your head, but strangely enough, that’s how they began. In his 1508 “Codex of the Eye”, Italian inventor Leonardo da Vinci speculated that submerging the head in a bowl of water could alter vision. He even created a glass lens with a funnel on one side so that water could be poured into it, but the device was impractical (and probably looked pretty ridiculous). In 1636, after reviewing Leonardo’s work, French scientist René Descartes proposed another idea: placing a glass tube filled with liquid in direct contact with the cornea. In case you were wondering, this is the reason they’re called “contact” lenses—because they make direct contact with the surface of the eye. Descartes’ invention worked somewhat to enhance vision; however, using it made blinking impossible. Improvements in the design of contact lenses would not be seen again for nearly two centuries.
A sight for sore eyes
In 1801, English scientist Thomas Young made a basic pair of contact lenses based on Descartes’ idea. He changed Descartes’ contact lens design by reducing the size of the glass tube to ¼ inch and then using wax to stick the water-filled lenses to his eyeballs. Don’t judge Mr. Young for gluing glass to his eyes—he was also the first to accurately describe astigmatism, greatly advancing the field of eye care. However, Young’s device was not practical, nor was it able to correct vision problems. In fact, the idea of using contact lenses to correct the refraction errors that cause nearsightedness, farsightedness, and astigmatism wasn’t suggested until 1845. English physicist Sir John Herschel was the first to hypothesize that taking a mold of the cornea might produce lenses that could correct vision. However, without the necessary technology, Herschel was unable to test his hypothesis, and his theory remained mere speculation until nearly 100 years later.
The technology improves
The early 1880s were a revolutionary period for contact lenses. New glass production, cutting, and shaping technologies made thin lenses possible for the first time. Designs for glass contact lenses that fit in the eye, allowing the wearer to blink, were independently invented by three men: Dr. Adolf Fick, Eugene Cult, and Louis J. Girard. Credit for the discovery usually goes to Dr. Fick, a Swiss physician who wrote a treatise entitled “A Contact Spectacle,” in which he described the first contact lens with refractive power for visual improvement. The first physical example of the lens was made by artificial eye-maker F. A. Mueller in 1887. These types of contact lenses were called scleral lenses, and they covered the entire eye, not just the cornea. They were slightly convex, allowing room for tears or a dextrose solution—the liquid that creates the refractive power to correct vision—to fill the eye much like Da Vinci’s bowl of water. In 1888, Dr. Fick constructed and fitted the first successful contact lens. However, there were two major issues with Fick’s contacts: the lenses were made from heavy blown glass and were 18–21mm in diameter. The weight alone made them uncomfortable to wear, but worse, the glass lenses covered the entire exposed eye. Unlike other bodily organs, which are oxygenated by the blood, the eyes get their oxygen directly from the air. So covering your eyeballs with glass shields is, essentially, suffocating them. Scleral lens wearers experienced excruciating eye pain after a few hours of use. Nonetheless, glass scleral lenses were the main form of contact lenses for the next 60 years.
The eyes have it
By the late 1920s, technological advances in both anesthesiology and materials finally allowed Sir John Herschel’s ideas about creating molds of the cornea to be tested. In 1929, Dr. Dallos and Istvan Komàromy of Hungary perfected a method of making molds from living eyes, proving Herschel’s theories. For the first time, it was possible to create contact lenses that conformed to the actual shape of the eye. And in the 1930’s, new plastics made it possible to produce lightweight, transparent contact lenses. Unbreakable, scratch-resistant, malleable, and easy to manufacture plastic revolutionized the contact lens industry, making glass lenses quickly become obsolete. But even though the new lenses were plastic, they were still scleral lenses, covering the entire eye and only wearable for a few hours at a time.
In 1948, an English optical technician named Kevin Touhy was sanding down a plastic lens when the part that covered the white of the eye fell off. Rather than start over, he decided to try the smaller lens. He smoothed the edges and popped it in his eye, delighted to discover that the lens still worked and stayed in place, even when blinking. This happy accident was the birth of the corneal lens, the type most commonly used today. The discovery allowed wearers to leave their contacts in longer, as the eyes could breathe somewhat better and the corneal lenses were more comfortable than scleral lenses. After Touhy’s invention became public, a number of other changes were rapidly introduced to these types of lenses. In 1950, George Butterfield came up with the idea of a curved, rather than flat, corneal lens design. Later in the 1950s, Frank Dickenson, Wilhelm Sohnjes, and John Neil created thinner lenses, of about 0.20 millimeters. Even thinner lenses, of about 0.10 millimeters, were introduced in the early ‘60s. However, even with all these improvements, corneal lenses still hindered oxygen flow to the eyes and couldn’t be worn for long periods or overnight.
That was soon to change, beginning in 1958. At that time, Czechoslovakian chemist Otto Wichterle was developing a new type of plastic, called hydrogel, that was soft and pliable when wet, yet could be shaped and molded. An optometrist named Dr. Robert Morrison, of Pennsylvania, became aware of Wichterle’s work and recognized its potential for contact lenses. Wichterle released his patents for worldwide use, and a manufacturing facility for hydrogel soft lenses was set up in Dr. Morrison’s lab. In 1960, Bausch and Lomb was granted access to the hydrogel and took the material to new levels, including creating a refined casting technique that produced consistent lens surfaces, as well as a process for mass production. Ciba Vision’s introduction of silicone hydrogels in 1998 offered extremely high oxygen permeability. Both hard and soft contact lenses continued to improve over the next 25 years, especially in terms of oxygen permeability, to allow the eyes to breathe.
A review in contact lens history
Today’s best contact lenses are breathable, durable, and comfortable, and scientists continue the quest for new lens improvements. Having advanced the technology of contact lenses from sticking your head in a bowl of water to near-invisible flexible discs of silicone, vision enhancements of the future will surely be something to see.