00:00In 1948, Spanish ophthalmologist Jose Ignacio Barraquer-Monell
00:12was fed up with glasses.
00:14He wanted a solution for blurry vision that fixed the eye itself,
00:19without relying on external aids.
00:22But the surgery he eventually devised was not for the faint of heart.
00:26Barraquer began by slicing off the front of a patient's cornea
00:31and dunking it in liquid nitrogen.
00:34Using a miniature lathe, he ground the frozen cornea
00:38into the precise shape necessary to focus the patient's vision.
00:42Then he thawed the disc and sewed it back on.
00:46Barraquer called this procedure keratomileusis,
00:50from the Greek words for carving and cornea.
00:54And though it might sound grisly, his technique produced reliable results.
00:59So, how did Barraquer's surgery work?
01:03Keratomileusis corrects what are called refractive errors,
01:08imperfections in the way the eye focuses incoming light.
01:12Ideally, the cornea and lens work together to focus light
01:16on the surface of the retina.
01:18Several kinds of refractive errors can impair this delicate system.
01:23In people with myopia, or short-sightedness,
01:26a steep cornea focuses light just short of the retina.
01:31Those with hyperopia, or far-sightedness, have the opposite problem.
01:36Light is focused too far beyond the retina.
01:39And in people with astigmatism, the cornea has two different curvatures,
01:44which focus light at two distances and produce blurry vision.
01:49Even those with perfect vision will eventually suffer from presbyopia,
01:53or aging eyes.
01:55As the proteins in the lens age, they slowly increase its size.
02:01By an adult's mid-40s, the lens is too large to easily change shape and shift focus.
02:08Glasses and contact lenses bend light to compensate for these refractive errors.
02:14But, as Barraquer's procedure shows,
02:17we can also alter the shape of the cornea itself,
02:21moving the focal point backwards, forwards, or pulling a divided image together.
02:28And thankfully, modern eye surgeons can sculpt the cornea with far less invasive tools.
02:35In corrective laser eye surgery, surgeons rely on eczema lasers.
02:40These tools are accurate enough to etch words into a human hair.
02:46To safely accomplish these ultra-fine incisions,
02:50they use a technique called photoablation.
02:53This allows the lasers to essentially evaporate organic tissue
02:57without overheating surrounding eye tissue.
03:00So how does laser eye surgery actually work?
03:04The first step is to separate a thin layer from the front of the cornea.
03:08This can be done with either a flat, wide blade or a femtosecond laser
03:14that produces millions of tiny plasma bubbles
03:17to create a plane beneath the corneal surface.
03:21Surgeons then lift the flap to expose the inside of the cornea.
03:25Guided by the refractive error and the shape of the cornea,
03:29the eczema laser robotically sculpts the exposed corneal bed
03:33into the correct shape.
03:35This process usually takes less than 30 seconds for each eye.
03:40Finally, the flap is closed,
03:42and its edges reseal themselves in just a few hours.
03:46Because the lasering is done on the eyeball itself,
03:49it's described as in-situ or on-site.
03:53Its complete name is laser in-situ keratomyelusis,
03:57but you probably know it as LASIK.
04:00Essentially, this technique carves a patient's contact lens prescription
04:05onto their cornea.
04:07Like any surgical procedure, LASIK comes with certain risks.
04:10Some patients experience slightly blurred vision that can't be corrected by glasses.
04:15But the technique is currently about as likely to damage your eyes
04:19as wearing daily disposable contact lenses for one year.
04:23Today, a technique called SMILE enables surgeons to sculpt the cornea
04:28through even smaller incisions, further reducing recovery time.
04:32And lasers aren't just correcting the three types of refractive errors.
04:36This technology can also restore aging eyes.
04:40In a technique called laser-blended vision,
04:43surgeons adjust one eye to be slightly better at distance vision
04:47and the other to be better at close-range vision.
04:50The difference between the two eyes is small enough
04:53that most patients can merge their vision,
04:56allowing both eyes to work together at all distances.
05:00Advances in laser technology continue to make vision correction surgery
05:04more effective and accessible.
05:07One day soon, Baraker's vision of a world without glasses may finally come true.
05:30Use the tranquillum.
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