Speaker 1: Welcome to brain stuff from How Stuff Works. Hi, I'm
Speaker 1: Christian Sager, and welcome to brain stuff. When was the
Speaker 1: last time you got to use an eyelid speculum? You
Speaker 1: know those small metal prongs that push your eyelids open
Speaker 1: clockwork orange style. WELLEMI drugs. I hope the answer is never.
Speaker 1: But if you have been subject to one of these
Speaker 1: uncomfortable devices, it's probably because you've had corrective surgery to
Speaker 1: your vision. See. Our corneas are like windows that allow
Speaker 1: light to pass through our retinas where it's converted into
Speaker 1: electrical signals to our brain. If you have eyesight problems,
Speaker 1: it's usually because your eye can't focus an image onto
Speaker 1: your retina. For centuries, we've relied on external lenses like
Speaker 1: glasses or contacts for correction, But with modern technology, surgeons
Speaker 1: can actually alter the shape of the eye itself, using
Speaker 1: lasers to change its focal point. The most popular technique
Speaker 1: is called LASIC, which stands for laser assisted in Puto
Speaker 1: karatma lusis. It's very effective at treating several visual problems,
Speaker 1: especially near sightedness. Before any reputable eye doctor performs LASIC,
Speaker 1: they're going to give you a thorough preoperative eye exam.
Speaker 1: They'll measure your current prescription and manually check the surface
Speaker 1: of your cornea with a dye called flu or a cane.
Speaker 1: Other tests map your corneas topography and measure the exact
Speaker 1: diameter of your pupil. To qualify for LASIC, you'll need
Speaker 1: to meet a certain range of vision, corneal thickness, and
Speaker 1: pupil size. It's also risky if you're pregnant, have severe
Speaker 1: heart problems, certain diseases, or take some types of drugs.
Speaker 1: Once you've passed preopp assessment, you come back for the
Speaker 1: actual LASIC process, conducted by both the surgeon and a
Speaker 1: technician operating the laser machine. They'll put a topical anesthetic
Speaker 1: in your eyes to numb any discomfort, and that's good
Speaker 1: because the next step is to eye open your eyes
Speaker 1: with special tape and that good old eyelid speculum. Then
Speaker 1: they'll calibrate the laser and mark your cornea for alignment
Speaker 1: using a suction ring with an extremely precise surgical blade
Speaker 1: called a micro kera tom, the surgeon cuts a flap
Speaker 1: in your cornia and folds it back. You'll be asked
Speaker 1: to focus on a red light which isn't the laser
Speaker 1: but helps center your eye. Now it's laser time. A
Speaker 1: laser mixing reactive gases like chlorine and fluorine with inert
Speaker 1: gases like argon, crypton, and xenon, produces a tightly focused
Speaker 1: beam of ultraviolet light that vaporizes a microscopic portion of
Speaker 1: the cornea. This is a cool laser that doesn't heat
Speaker 1: the surrounding air or surface. Instead, it breaks down the
Speaker 1: molecular bonds of organic materials. The beam itself is microscopic,
Speaker 1: less than a nanometer wide. The surgeon reshapes the cornea
Speaker 1: by controlling the size, position, and number of laser pulses applied. Surprisingly,
Speaker 1: this only takes a few seconds. When it's finished, your
Speaker 1: corneal flap is replaced with a small antibiotic added. The
Speaker 1: cornea heels and rebonds, immediately naturally sealing itself. Again. Taking
Speaker 1: into account the time for both eyes, the entire procedure
Speaker 1: is usually done in only fifteen to thirty minutes. After
Speaker 1: the operation, they'll give you these cool eye shields that
Speaker 1: prevents you from touching your eyes but let you see
Speaker 1: enough to get around. You'll wear them for the rest
Speaker 1: of the day and sleep in a mask that night.
Speaker 1: Of course, someone has to drive you home, and once
Speaker 1: you get there, you'll need to apply rewedding drops, antibiotic drops,
Speaker 1: and possibly a moisturizing gel inside your bottom eyelid. The
Speaker 1: ophthalmologist will follow up the next day on a recurring
Speaker 1: basis for about a year. Now you're probably asking, but Christian,
Speaker 1: couldn't there be side effects when a doctor shoots a
Speaker 1: laser into my eye? Well, yeah, of course there could.
Speaker 1: Most commonly, eyes can be under corrected, overcorrected, or get
Speaker 1: a small wrinkle when the corneal flap is replaced paste
Speaker 1: that causes a blur. For the most part, these are
Speaker 1: easily fixed with a second procedure. Sometimes a surgeon won't
Speaker 1: even recommend further refining, since many recipients of lasik never
Speaker 1: achieve normal vision, but do reduce their corrective prescriptions significantly.
Speaker 1: Other rarer side effects can include halos around lights, light sensitivity,
Speaker 1: and double vision. I'd be lying if I said there
Speaker 1: wasn't a chance of partial or complete blindness, but it
Speaker 1: is minuscule compared to the success rate. This is especially
Speaker 1: true if you're seeing a reputable doctor. Keep in mind,
Speaker 1: there are so many unscrupulous practitioners out there that the
Speaker 1: f d A actually had to issue a stern warning
Speaker 1: about dodgy sales pitches underplaying the risks of lasik. But
Speaker 1: twenty five years after it was invented by Golem payment,
Speaker 1: lasic is safer than ever before. There's other types of
Speaker 1: eye surgery to including radial car atautomy, automated lamellar keratoplast see,
Speaker 1: and photo refractive care atatomy. All of them, however, involved
Speaker 1: slicing up your cornea to some degree. Check out the
Speaker 1: brainstuff channel on YouTube, and for more on this and
Speaker 1: thousands of other topics, visit how stuff works dot com