How Does LASIK Work?
LASIK, or laser-assisted in situ keratomileusis, is an outpatient procedure used to correct most common vision problems. Since the FDA approved LASIK in 1999, nearly 800,000 LASIK surgeries have been performed in the United States every year, making it one of the most common surgical procedures in the US.
LASIK is an exciting notion to patients who would like to reduce their dependence on glasses and contacts and can often be a good investment compared to the long-term cost of eyeglasses and contact lenses. LASIK has a success rate of over 90% at restoring vision to 20/20 or better.
But what exactly is LASIK? How does it work, and who is a good candidate for it? Your Arizona LASIK experts at Desert Vista Eye Specialists are here to clarify the LASIK process and explain exactly what the procedure treats, how it works, and delve into which patients can benefit the most from it.
What is LASIK?
LASIK is an outpatient surgical procedure designed to treat most common vision issues (known as refractive errors). It involves the usage of a specialized laser to reshape parts of the eye so that light can enter the eye better. There are two types of lasers that are typically used during the LASIK procedure:
- Excimer Lasers
- Femtosecond Lasers
Excimer lasers utilize UV light to vaporize tissues in the eye. These were the first lasers the FDA approved for LASIK in 1995 and are still used today.
Femtosecond lasers are primarily cutting lasers that are used to make an incision to get to the part of the cornea that needs to be reshaped. In traditional LASIK surgery, a femtosecond laser is used to make a small incision in the eye while an excimer laser is used to reshape the cornea.
In recent years, more and more surgeons have been moving to all-femtosecond LASIK. In this procedure, the femtosecond laser is used to both make an incision in the eye and reshape the cornea. LASIK using femtosecond lasers is more precise and can potentially produce better results.
What Does LASIK Treat?
LASIK treats what are known as refractive errors. Refractive errors occur when the shape of your cornea (the clear window at the front of your eye) is misshapen, causing light that enters the eye to refract in specific ways that prevents it from hitting the retina (the back part of the eye responsible for receiving vision signals) properly. This leads to objects appearing blurry, or halos to appear around lights in the case of astigmatism.
LASIK can effectively treat the following refractive errors:
Myopia, more commonly known as nearsightedness, in which the eye’s abnormal elongated shape causes light that enters the eye to come to a point focusing on an area in front of the retina, causing distant objects to appear blurry.
Hyperopia, or farsightedness, in which the eye’s oblong shape causes light that enters the eye to focus on a point behind the retina, causing closer objects to appear blurry.
Astigmatism in which an irregularly shaped cornea scatters light as it enters the eye, making it focus unevenly on the retina and causing blurry vision.
What Happens During a LASIK Procedure?
The LASIK surgery itself involves using lasers to reshape the surface of your cornea. The reshaping process is unique to each individual as it wholly depends on what refractive errors you have and what the surface of your cornea currently looks like. The procedure shaves off pieces of cornea tissue to shape it so that light has an easier time of entering the eye and focusing directly on the retina, producing sharper vision.
At the beginning of the procedure, numbing drops will be placed on your eyes. Then a specialized eyelid speculum will be inserted to keep your eyes open during the procedure. A suction ring will also be placed over your eye, which might dim your vision. This helps to keep your eye in the proper spot for the procedure.
There are two main phases to the surgery:
- Creation of the Corneal Flap
- Reshaping the Cornea
Creating the Corneal Flap
Most LASIK procedures involve creating what is known as a corneal flap. For all-laser LASIK, a femtosecond laser is used to make a precise incision in the cornea. Your LASIK surgeon will then fold the flap back, exposing the inner portion of the cornea that needs to be reshaped.
Reshaping the Cornea
Once the corneal flap has been pulled back, your surgeon can access the part of the eye they need to in order to improve your vision. Using either a femtosecond or excimer laser, your surgeon will carefully remove pieces of your cornea to effectively reshape its surface.
During this phase, you’ll be asked to focus on a light while your surgeon works. Rather than working in a continuous stream like a laser pointer, the lasers used in LASIK emit pulses, slowly removing corneal tissue bit by bit to ensure accuracy. Your eye is carefully monitored during this portion and is measured 500 times a second to ensure even the tiniest movements are accounted for.
There is a failsafe built into the laser to stop it should your eye move too much outside of the position it needs to be in for surgery.
After the cornea is reshaped, your surgeon will fold the corneal flap back over your eye. No stitches are usually required and your cornea will begin healing instantly.
What Happens Immediately After LASIK Surgery?
The LASIK procedure itself typically only takes between 15 and 30 minutes to complete, and you can go home right afterwards. However, you will need someone to drive you to and from your appointment as you won’t be able to drive for the first day after surgery. You’ll be given eye drops, anti-biotic eye drops, and ocular steroids to help deal with pain, swelling, and to avoid infection. Your doctor will also give you eye shields to wear to stop you from touching your eyes. Because no stitches are involved, it’s important you don’t touch or rub your eyes to allow the corneal flap to properly heal.
You may have a gritty or dry sensation in your eyes immediately after surgery, or they might be excessively watery. This is perfectly normal and should go away with the next day or so. Most patients begin to see improved vision within 24 hours of getting LASIK. Over the next few days, patients often report significant improvements to vision.
How Long Does It Take to Recover from LASIK?
While you’ll notice a significant improvement in vision in the few days after surgery, it can take a few months for your eyes to fully recover.
The day of surgery, we usually recommend going home and resting for a few hours to allow your eyes time to heal. Do not shower for the first 24 hours after surgery and avoid makeup, lotions, or face creams as these can get in the eyes and cause problems during recovery. If you go outside, you need to wear sunglasses until the third day after surgery.
Avoid strenuous exercise and swimming for the first four to six weeks after your procedure.
Will LASIK Permanently Correct My Vision?
LASIK reshapes your cornea, permanently removing the refractive errors you were experiencing before. Most people have 20/20 vision or better after the procedure, and those that don’t usually have 20/40 vision or better. It’s possible you may still need slight vision correction like glasses or contacts after the surgery, depending on how bad your refractive error was prior to surgery.
It’s also important to understand that the eye changes as we age. Around 40 years of age, most people begin developing what’s known as presbyopia. This condition makes it harder for you to see things up close. In many cases, patients will require reading glasses at some point, even if they have had LASIK surgery.
Who Can Get LASIK Surgery?
While LASIK is a common procedure, not everyone will qualify for it.
When we evaluate candidates for surgery, we typically look for a few things. First, the patient must be 18 years or older. Second, the patient must have had a stable prescription for at least a year. This means your vision can’t have changed drastically in the last year. Thirdly, we require patients to have enough corneal thickness that corneal flaps can be created. If the cornea is too thin, the procedure may not work properly and the risks are increased. Finally, we look for patients that have generally healthy eyes (i.e. no glaucoma, macular degeneration, diabetic eye conditions, infections, etc.).
If you meet these criteria, you might be a good candidate for LASIK eye surgery. Take our online candidacy test to find out if you’d be a good fit for the procedure.
However, the only way to know for sure is to get a LASIK consultation so one of our LASIK surgeons can properly evaluate your eyes.