Tuesday, July 18, 2017


Contact lenses have a remarkable history that goes back more than 500 years.

In 1508, Leonardo da Vinci is often credited with the first conception of the idea of contact lenses, in Codex Of The Eye, Manual D. , where he explained a means of manipulating the corneal power of eye by either submerging the entire head in a bowl of water or by wearing a water-filled glass hemisphere over the eye.

Actually he wasn't really talking about correcting vision at that point, but the idea behind the contact lens at its most basic came from manipulating the cornea's power.

in 1636, René Descartes conceptualized a similar idea where a hollow glass tube filled with water placed directly against the cornea, with the protruding end being shaped in order to correct vision. The only drawback of the idea was that it made blinking of eyes  completely impossible.

Basically, there were a lot of crazy ideas thrown down on paper before anyone attempted to actually follow them through to their sharp conclusion, be it vision or pain.

In 1845, Sir John Herschel published two new ideas in the Encyclopedia Metropolitana. The first was for a spherical capsule of glass filled with animal jelly, while the second was a mould of the cornea that could be impressed on a transparent medium. While there's no evidence that these ideas were ever tested or not.

 In 1887, German glassblower F. E. Muller developed the first eye covering that could be both seen through, as well as tolerated.

But until this point in time, any relatively comfortable device that could be placed on the eye made vision more difficult, or impossible, and any device that improved vision was unbearably uncomfortable.

In 1888,  when German ophthalmologist Adolph Fick started forcing fitted blown-glass shells into the eyes of bunnies, the technology's first live test subjects. Fick's design was aimed at helping patients with Keratoconus, a problem that renders the cornea cone-shaped. The glass shells were meant to push the eye flatter, not to improve, say, near sightedness.

His lenses were made from heavy blown glass, and were roughly two centimeters in diameter.

But these lenses were much more comfortable than previous attempts because of the filling of the empty space between cornea/callosity and glass with a dextrose solution. Although this was a huge step forward in lens technology but still they were rather large, inconvenient, and could only be worn for a few hours at a time.

At the same time, German medical student August Muller was experimenting with glass discs aimed at improving vision-his own, actually. His 1889 thesis recounts that although he could get the lenses fit on his eyes, violent pain kicked in about a half an hour after insertion. But with the short-lived fix, his myopia improved.

Those lenses were not the small, light things we have today. That was a kind of  big glass sheets—about twice the size of current disposables covering even the whites of the eyes. The shape exacerbated problem number two. Glass was the wrong material. Eyes need to breathe. Every other tissue in the body is delivered oxygen via red blood cells but the cornea sucks in oxygen directly from the atmosphere. "Glass is impermeable to oxygen. If the oxygen doesn't get to the eye, the cornea starts to swell," explains Nathan Efron, professor of optometry at Australia's Queensland University of Technology.

 It wasn't until 1948, when optical technician Kevin Tuohy realized by accident that contacts didn't have to cover the whites of the eyes at all. While Tuohy was lathing the lens, a recently invented transparent plastic, the part supposed to cover the whites of the eyes dropped off. This left him thinking. So he polished down the disk's edges and tried the slimmer model himself. To his surprise, it actually stayed put—even after blinking.

This increased comfort allowed to  be worn up to sixteen hours a day, where as previous lenses could only be worn for 3-4 hours at a time. As manufacturing technology improved into the 1960s, and lens designs became more sophisticated, Plexiglas corneal lenses became the first contacts to have mass appeal. 

The early research into soft lenses was done by Czech chemists Otto Wichterle and Drahoslav Lím, which began in 1959. Several years later, in 1965, the National Patent Development Corporation in the United States purchased the rights to produce the lenses, but sublicensed them to Bausch & Lomb.

Gradually, over the next 25 years, the polymers from which soft lenses are manufactured improved from time to time again. Increases in oxygen permeability and wetability, made them more comfortable, and decreases in manufacturing costs made them literally disposable. In fact, disposable soft contact lenses were first conceived by British optometrist Rishi Agarwal in by 1972.

So over and all Next time you pop in your lenses, give a little silent thanks to their inventors that the material is soft and your eyes are in tact. 

This wonderfully engineered tool for clear vision, invisible to both wearer and admirer is today used by 120 million people around the world.

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