How Does LASIK Work?

Christian explains the process and risks of LASIK surgery, from preoperative exams, to lasers in your eyes.

Learn more about your ad-choices at https://www.iheartpodcastnetwork.com

See omnystudio.com/listener for privacy information.

Episode Transcript

Speaker 1 (00:02):
Welcome to brain stuff from How Stuff Works. Hi, I'm
Christian Sager, and welcome to brain stuff. When was the
last time you got to use an eyelid speculum? You
know those small metal prongs that push your eyelids open
clockwork orange style. WELLEMI drugs. I hope the answer is never.

(00:23):
But if you have been subject to one of these
uncomfortable devices, it's probably because you've had corrective surgery to
your vision. See. Our corneas are like windows that allow
light to pass through our retinas where it's converted into
electrical signals to our brain. If you have eyesight problems,
it's usually because your eye can't focus an image onto

(00:43):
your retina. For centuries, we've relied on external lenses like
glasses or contacts for correction, But with modern technology, surgeons
can actually alter the shape of the eye itself, using
lasers to change its focal point. The most popular technique
is called LASIC, which stands for laser assisted in Puto

(01:04):
karatma lusis. It's very effective at treating several visual problems,
especially near sightedness. Before any reputable eye doctor performs LASIC,
they're going to give you a thorough preoperative eye exam.
They'll measure your current prescription and manually check the surface
of your cornea with a dye called flu or a cane.
Other tests map your corneas topography and measure the exact

(01:28):
diameter of your pupil. To qualify for LASIC, you'll need
to meet a certain range of vision, corneal thickness, and
pupil size. It's also risky if you're pregnant, have severe
heart problems, certain diseases, or take some types of drugs.
Once you've passed preopp assessment, you come back for the
actual LASIC process, conducted by both the surgeon and a

(01:50):
technician operating the laser machine. They'll put a topical anesthetic
in your eyes to numb any discomfort, and that's good
because the next step is to eye open your eyes
with special tape and that good old eyelid speculum. Then
they'll calibrate the laser and mark your cornea for alignment
using a suction ring with an extremely precise surgical blade

(02:11):
called a micro kera tom, the surgeon cuts a flap
in your cornia and folds it back. You'll be asked
to focus on a red light which isn't the laser
but helps center your eye. Now it's laser time. A
laser mixing reactive gases like chlorine and fluorine with inert
gases like argon, crypton, and xenon, produces a tightly focused

(02:33):
beam of ultraviolet light that vaporizes a microscopic portion of
the cornea. This is a cool laser that doesn't heat
the surrounding air or surface. Instead, it breaks down the
molecular bonds of organic materials. The beam itself is microscopic,
less than a nanometer wide. The surgeon reshapes the cornea
by controlling the size, position, and number of laser pulses applied. Surprisingly,

(02:58):
this only takes a few seconds. When it's finished, your
corneal flap is replaced with a small antibiotic added. The
cornea heels and rebonds, immediately naturally sealing itself. Again. Taking
into account the time for both eyes, the entire procedure
is usually done in only fifteen to thirty minutes. After

(03:18):
the operation, they'll give you these cool eye shields that
prevents you from touching your eyes but let you see
enough to get around. You'll wear them for the rest
of the day and sleep in a mask that night.
Of course, someone has to drive you home, and once
you get there, you'll need to apply rewedding drops, antibiotic drops,
and possibly a moisturizing gel inside your bottom eyelid. The

(03:39):
ophthalmologist will follow up the next day on a recurring
basis for about a year. Now you're probably asking, but Christian,
couldn't there be side effects when a doctor shoots a
laser into my eye? Well, yeah, of course there could.
Most commonly, eyes can be under corrected, overcorrected, or get
a small wrinkle when the corneal flap is replaced paste

(04:00):
that causes a blur. For the most part, these are
easily fixed with a second procedure. Sometimes a surgeon won't
even recommend further refining, since many recipients of lasik never
achieve normal vision, but do reduce their corrective prescriptions significantly.
Other rarer side effects can include halos around lights, light sensitivity,

(04:23):
and double vision. I'd be lying if I said there
wasn't a chance of partial or complete blindness, but it
is minuscule compared to the success rate. This is especially
true if you're seeing a reputable doctor. Keep in mind,
there are so many unscrupulous practitioners out there that the
f d A actually had to issue a stern warning
about dodgy sales pitches underplaying the risks of lasik. But

(04:47):
twenty five years after it was invented by Golem payment,
lasic is safer than ever before. There's other types of
eye surgery to including radial car atautomy, automated lamellar keratoplast see,
and photo refractive care atatomy. All of them, however, involved
slicing up your cornea to some degree. Check out the

(05:12):
brainstuff channel on YouTube, and for more on this and
thousands of other topics, visit how stuff works dot com