How does laser eye surgery work? – Dan Reinstein

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

100 thoughts on “How does laser eye surgery work? – Dan Reinstein

  1. Imagine the collapse of eyeglasses market/production if all people are able to afford the procedure…


  2. I'll stick with my glasses thank you. I look like a potato without them. And that would definitely increase tear production.

  3. I had ortho-k for a decade. It's basically retainers for your eyes. Recently stopped because I want to do LASIK asap. I hate having my astigmatism back. It's extremely severe and basically impossible to correct with glasses which are cheaper than contacts. I can't wait to get LASIK done and be done with it

  4. There are so many different ways to have eyesurgery. I myself had TransPKR, this method doesn't involve slicing the cornea. This is a way newer method and way les inconvenient for the patient.

  5. I'm telling you people, in some other universe, TED-Ed videos are helping people get straight As in their exams!
    Thank you TED-Ed!! 🧡

  6. The animation is just EYE LIGHTNING😁

    Edit: The way of showcasing children to let us understand what MYOPIA , HYPERMETROPIA or ASTIGMATISM works is just EYE – SOOTHING

  7. "One day soon, Barraquer's vision of a world without glasses may finally come true"

    Well excuse me but like a lot of people I don't have thousands of dollars to put in Lasik

  8. How can someone at 1920-30ish had an idea of cutting cornea, polishing it, and put it back again

    edit : they use brilliant

  9. ok i'm confused. about 20 minutes ago i thought about my bad eyesight and how glasses didn't even work for me because there was this weird blurry patch on the ground. i went to yt to get my mind off of it, and this video was the first one i saw. near the end i started tearing up a bit because i was all "aw dude i don't want my eye sliced off" and then the voiceover guy went "did you know that you're crying right now?"

  10. I have been wearing glasses for the past 12 years of my life and im planning on having a lasik and this helps me very much. I am also trying out contact lenses. I am planning on having the surgery in 2020. Wish me luck❤

  11. I love my cornea, These techniques may be very safe but once cornea gets damaged, in the future if any problems occur I guess it won't repair itself. I prefer to use glasses

  12. I myself had laser operation 3.5 months ago. And it took my eyes aproximately 2 months to be healed and become clear fine enough for me. But I feel my eyes now are a little bit light sensitive now. I see light clouds around the light sources more often than I used to see. I hope it decreases by time. And now the only thing I got concerned about this is how would the light coming from the screen of such devices as phones, televisions or computers affect my eyes as of now, and how can I protect my eyes from them?

  13. I bet the original surgery was super terrifying…but I wonder what people saw through the eye that had the cornea removed

  14. So basically this guy just got sick of seeing people with glasses so he plucked out his patients cornea and dumped it in liquid nitrogen then stick it back in. Damn history's messed up.

  15. I have heard that laser eye surgery couldn't fix farsightedness and that if you fix your nearsightedness you can then end up with old age farsightedness which can't be corrected. Is this just old news and new methods have now been developed? Or can you still only correct your vision once and then your eye is in a state where it is too difficult to fix old age farsightedness if it develops?

  16. " One day soon, Barraquer's vision of a world without glasses may finally come true. "

    "Places sunglasses on his eyes"

  17. Blurriness that can't be corrected by glasses??? Why not???? That slight risk sounds like such a nightmare that alone it is deterring me from going through with the surgery

  18. When people ask me where I see myself in 2 months I reply "I don't have 2020 vision" yea i cant see without my glasses

  19. This video was extremely hard to watch; I get so squeamish when it comes to eye stuff.
    But the content was so good so I was conflicted. Man I had to take small pauses to get through this LOL

  20. I've wanted to get LASIK for decades now and everytime I go they tell me my eyes are too bad to do the procedure on. 🙁

  21. I was having a great time until I heard "Did you know you're crying right now?" Now I'm contemplating like Spongebob at the diner

  22. A decade or so ago I was at a computer security (the industry I work in) conference, it just so happened at the same time there was a laser eye surgery conference in town at the same time. around two-thirds of the experts for that conference wore glasses, that told me all I needed to know about the procedure.

  23. Recently Lasix was discovered to have some pretty awful ramifications for a percentage of lasix users, even to the point where doctors that previously approved the procedure stated they regret giving it FDA clearance.

    Some people are attributing it to doctors performing lasix on patients who weren’t good candidates, thus having negative outcomes.

    Do your own research people, you can’t replace your eyes so be weary and get multiple lasix doctors opinions on whether you’re a good candidate or not if you want to do it.

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