For a lot of us, contact lenses are an everyday item. There doesn’t seem to be much to think about, it’s a small, clear disc that you wear for most the day and sometimes even the night. With lenses now both extremely comfortable and effective at correcting vision it can be easy to forget that a lot of trial and error had to take place before they became the way we know them now.
Skip through time...
The first and most basic concept of a contact lens came from the great Italian inventor Leonardo da Vinci. When considering how to correct the refractive errors that cause poor eyesight, da Vinci produced sketches proposing a possible solution. He demonstrated how seeing through the bottom of a glass bowl filled with water could help rectify the issue. While dunking your face in a bowl of water is a clearly impractical way of doing things, his method does acknowledge the necessity of the lens making contact with your eye!
French philosopher René Descartes further developed this concept in an essay where he discussed the effects of using a test tube filled with water to achieve a similar result to da Vinci. Descartes also pointed to how the water only needed to touch the cornea, rather than the whole eye, to correct vision. His idea of using a test tube over an entire bowl of water was simpler than da Vinci had suggested, although still not quite a perfectly practical solution.
Scientist Thomas Young put Descartes’ ideas into practice by creating a pair of lenses using his proposed technique. He reduced the length of the tubes to create a lens about a quarter of the size and used wax to glue the tubes to his eyes. Unsurprisingly, this didn’t seem to catch on as an eyewear trend!
Another British scientist, John Herschel, had an idea closer to the contact lenses we have today. He conceived of making moulds of the human eye then using these moulds to design the front of corrective lenses for individuals with vision problems.
His idea was made reality later that century. It’s disputed who was the first to make the first glass contact lens, with both an F.A Mueller and Adolf E. Fick cited as inventors. Either way, both their prototypes were both made of glass and would cover the entire front surface of the eye.
While useful for correcting vision, these lenses created obvious issues. As they were made of glass they felt considerably heavy on the eye, particularly after a few hours. The lenses covered the whole surface of the eye so when the wearer blinked, oxygen-carrying moisture was prevented from reaching the eye. Take into account the fact that thick glass isn’t particularly permeable in the first place, and that makes for one uncomfortable and potentially dangerous contact lens.
American optometrist William Feinbloom developed a contact lens that combined glass and plastic. A glass portion covered the cornea while a plastic surrounding sat on the white of the eye (sclera). This wasn’t just a lighter lens with more oxygen permeability, but the plastic was also more compatible with the natural tissues of the eye than glass, meaning that lens was overall more comfortable.
Kevin Touhy took lens design to the next stage with a design that only covered the cornea of the eye, leaving the sclera free to breathe naturally. These lenses were small and made of a non-porous plastic called Polymethyl Metharylate. They moved during blinking, which meant that more oxygen could reach the eye and that the lens could be worn for longer without causing irritation.
This more comfortable lens helped to increase the general popularity of contact lenses in the 1950s and 60s and, as their popularity grew, the technology used to make them became more advanced.
The link between vision correction and water hadn’t been forgotten amongst all these developments and Czech chemist Otto Wichterle made a massive breakthrough in creating the first hydrogel lenses. Along with his colleague, Drahoslav Lim, they created a material that absorbed up to 40% of water, which was also transparent and could be moulded into a comfortable lens shape. Using his son’s toy building kit at home, Wichterle produced the first four hydrogel lenses.
As manufacturing technology became more sophisticated, the lenses got thinner and by the end of the 60s had got to the stage when they were a mere 0.10mm thick. In the early 1970s, Bausch & Lomb released the first commercial soft hydrogel lenses, their SofLens. Multifocal lenses and Toric lenses aimed at presbyopia and astigmatism sufferers became available later in the decade.
The 80s saw the general release of daily disposable lenses, which marked a significant change for how people saw contact lenses. They became more convenient and hygienic, but also more appealing to other markets. Glasses wearers who wouldn’t normally wear contacts now had an option if they wanted to wear contacts for special occasions or sports.
The 80s also enjoyed such advancements in the materials used for contact lenses that certain lenses became available for extended wear. Contact lenses had now become so light, high in water content and permeable by oxygen that they could even be worn by some people as they slept. This marked a significant shift from the days of heavy, glass lenses that covered the entire eye.
In the late 90s and early 2000s, silicone hydrogel became the material of choice for most contact lens manufacturers. These let up to five times more oxygen through to the eye, which helps to keep your eyes feeling fresh and comfortable for longer than ever before. They absorb even more water than hydrogel lenses meaning that they are very pliable so they fit your eyes easily. Disposable silicone hydrogel lenses became available towards the end of the first decade of lenses, providing a super comfortable, convenient and hygienic choice for lens wearers.
Contact lens technology has continued to advance with new materials such as senofilcon C now available. This new material absorbs even more water helping to keep your eyes feeling healthy hydrated and healthy. There has even been talk of smart contact lenses, although these seem some way off from being truly ready for public consumption. With the constant strive for improvement in contact lens wear, who knows what will come next?