In 1940, a Royal Airforce pilot  named Gordon “Mouse” Cleaver was battling with a German fighter plane when his aircraft was hit by cannon fire.

The canopy of his plane shattered in battle, and he had no choice but to flip upside down, fall  out, and parachute to safety. This left shards of the plane's  canopy embedded in his face and eyes, which is why fighter pilots usually wear  protective goggles during their flights.

In his rush to get ready that morning, Cleaver had forgotten to bring  his protective goggles with him. Now getting shrapnel in your eyes isn’t great, but there was a silver lining to all this. This incident not only changed the  course of Gordon Cleaver's life, but it led to the treatment for a  devastating disease that he didn’t even have. [Intro music] When Cleaver took to the sky in 1940, he was flying one of the most legendary  fighter planes of World War II called a Hawker Hurricane.

When you think of a fighter plane, you  probably think of a frame like this And then you might imagine an armored  glass canopy for the pilot to see out of. But it turns out, glass is actually NOT a  great material for things that need to fly. Glass canopies are heavy,  stiff, and when they break, they shatter into thousands of tiny  pieces that get in literally everything.

Which is why, beginning around World War II, aircraft designers started using acrylic. Acrylic is the common name for  Poly-methyl Metha-crylate or PMMA. This is a synthetic plastic that  engineers can mold into different shapes.

It’s also known by its brand names  Plexiglas in the US, and Perspex in the UK. Acrylic was perfect to replace  the glass in fighter planes because it’s lightweight and flexible. A lighter plane gets better fuel efficiency, while a more flexible plane  is better at absorbing stress.

The biggest advantage though, is how it shatters. When an acrylic canopy breaks, it does so in larger, more blunt fragments, instead of the thousands of tiny shards. And, that’s MUCH easier to remove  from the bodies of injured soldiers.

When Cleaver had all that shrapnel in his eyes, that shrapnel was shards of acrylic. And, he had to undergo more than a dozen surgeries to remove it. The surgeons never were able to get all of it out.

Normally, having something  permanently stuck in your eye would cause constant pain or inflammation. But Cleaver’s doctor, named Harold Ridley, noticed something unusual. The acrylic in his eye didn’t  seem to be causing any of that.

There was no noticeable inflammatory reaction. Not only that, but Cleaver  still had pretty good vision for the severity of his injury, despite having shards of a  foreign material in his eye. That gave Dr.

Ridley an idea. This is your eye. It sits inside your orbit, the protective bony socket in your skull, and it’s also surrounded and  controlled by six extra-ocular muscles.

That’s what allows us to move our eyes around. Then there’s your cornea, your iris, the lens, and finally your retina, which  converts all the information from the rest of the eye into electrical  signals that go to your optic nerve. The way these all work together is  that when light enters your eye, it gets focused through the  dome shape of your cornea.

The iris has muscles to  constrict or dilate your pupil, controlling the light as it passes through to  reach the lens, retina, and the optic nerve. This ability to change focus is one of  the most important functions of your eyes. Think about how you have to  refocus the lens on a camera or microscope every time you change the zoom.

This is happening in your eye … the lens and the cornea work  together to serve this function. Your cornea does most of the heavy lifting, but your lens can literally  change shape to change your focus. This is what allows us to see things  that are close up, or really far away, and our lens does this so fast we  don’t even realize it’s happening.

Unfortunately, a lot of us will one  day develop something called cataracts, which is when the lens of your  eye becomes cloudy over time. Over half of Americans that live  to age 80 will get cataracts. It causes blurred vision, brightness  sensitivity, seeing colors less vividly, and a whole host of other symptoms.

Cataracts are the leading  cause of blindness globally, and for a long time, we really  didn’t have a good way to treat them. We tried, though. Back in 500BCE, doctors tried  a method called couching.

This comes from a french word that means  “to put to bed” or “to lay it down” because that’s what they were essentially  trying to do with the cataract. The way they tried to accomplish  this was by taking a sharp needle, shoving it in the patient's eyes, and  physically pushing the fully formed cataract, and the rest of the lens with it,  to the side of the eye socket. This meant that it wasn’t  blocking light from the retina and messing up their vision anymore.

But it also meant the lens couldn’t  serve any of its normal functions because it’s in the side of their eye. You’re not really supposed to have  a lens at the side of your eye, and, shockingly, people didn’t react  well to having part of their eye shoved aside with a giant needle. Having a part of the eye where it didn’t belong, combined with the lack of  disinfected needles at the time, almost always resulted in infections, and eventually blindness  after the procedure was done.

Another technique we tried was called extraction, and it's just what it sounds like. They cut a large incision in your  cornea and extracted the lens. This was a VAST improvement over  just shoving it to the side, but it still came with a lot of risks, right?

The wounds didn’t heal very well, sometimes pieces of lens were left behind,  and infection was still a pretty big problem. Then came phaco-emulsification... In this procedure, they STILL  inserted a needle into your eye, but then ultrasonic waves broke up the lens  into tiny pieces and those got sucked out.

Can we stop putting needles in people’s eyes? The smaller incision for this approach, plus improved infection control  by the 60s when it came around, made removing a cloudy lens much safer. There was still one issue though … you were left without a lens.

Which brings us back to Dr. Ridley’s idea. When he saw how well Cleaver’s eye  responded to the acrylic in it, Ridley thought he might be able to use  that material to replace parts of the eye when they’re damaged.

He tried replacing the bad lens  that people with cataracts have with a piece of acrylic in the exact  same shape as the original lens. This is called the intraocular lens, or IOL, and it works something like this: A surgeon makes tiny incisions  near the edge of your cornea, and inserts an instrument to break  the lens into smaller pieces. Sometimes the lens will be softened with a laser to make it easier to remove.

Once that’s complete, a new,  flexible artificial lens made of acrylic is inserted in its place. When they were first invented, IOLs were actually considered pretty controversial because eye doctors only ever really  took things OUT of people's eyes, they weren’t supposed to put things in. Plus, Ridley didn’t follow the standard protocol for testing this medical advancement  on animals before putting it in people.

This led to some pretty avoidable complications with the early version of the implants. But as the technology improved, IOLs became standard for treating cataracts. An IOL is able to focus light  before it comes into your retina pretty similarly to how your natural lens would, and you can even get customized ones!

Some IOLs now have blue light filters, UV filters, or they can help fix astigmatism. Today, 20 million cataract surgeries  using IOLS are performed every year. And in 1987, Gordon Cleaver himself  was diagnosed with cataracts.

He got an IOL, and regained his vision. All thanks to the surgery inspired  by him forgetting his goggles all those decades ago. [ OUTRO ]