Montefiore Einstein offers the following content courtesy of the National Library of Medicine.
What Is LASIK?
Laser-assisted in-situ keratomileusis (LASIK) is laser eye surgery that permanently changes the shape of the cornea (the clear covering on the front of the eye). It is done to improve vision and reduce a person’s need for glasses or contact lenses.
For clear vision, the eye’s cornea and lens must bend (refract) light rays properly. This allows images to be focused on the retina. Otherwise, the images will be blurry. This blurriness is referred to as a “refractive error.” It is caused by a mismatch between the shape of the cornea (curvature) and the length of the eye.
LASIK uses an excimer laser (an ultraviolet laser) to remove a thin layer of corneal tissue. At Montefiore Einstein, are one of only a handful of academic medical centers in the nation to own the WaveLight® FS200 femtosecond laser and Allegretto Wave Eye-Q Excimer Laser System technologies. This gives the cornea a new shape so that light rays are focused clearly on the retina. LASIK causes the cornea to be thinner. LASIK is an outpatient surgical procedure. It takes 10 to 15 minutes to perform for each eye.
The only anesthetic used is eye drops that numb the surface of your eye. The procedure is done when you are awake, but you will get medicine to help you relax. LASIK may be done on one or both eyes during the same session.
The procedure is performed by creating a flap of corneal tissue and peeling it back, so that the corneal tissue can be reshaped by the excimer laser. A hinge on the flap prevents it from being completely separated from the cornea.
Initially, a special automated knife (a microkeratome) was used to cut the flap to perform LASIK. Now, a more common and safer method is to use a different type of laser (femtosecond) to create the corneal flap.
The amount of corneal tissue the excimer laser will remove is calculated ahead of time. The surgeon will calculate this based on several factors, including:
- A wavefront test, which measures how light travels through your eye
- The shape of your cornea surface
- Your glasses or contact lens prescription
Once the reshaping is done, the surgeon replaces and secures the flap. No stitches are needed. The cornea will naturally hold the flap in place.
Why LASIK Is Performed
LASIK is done on people who use glasses or contact lenses because of nearsightedness (myopia), and is used to correct farsightedness and also astigmatism.
The U.S. Food and Drug Administration (FDA) and American Academy of Ophthalmology (AAO) have developed these guidelines for determining LASIK candidates.
- You should be at least 18 years old (21 in some cases, depending on the laser used). This is because vision may continue to change in people younger than 18. A rare exception is a child with one very nearsighted eye and one normal eye. Using LASIK to correct a very nearsighted eye may prevent amblyopia (lazy eye).
- Your eyes must be healthy and your prescription stable. If you are nearsighted, you should postpone LASIK until your condition has stabilized. Nearsightedness may continue to increase in some people until their mid to late 20s.
- Your prescription must be within the range that can be corrected with LASIK.
- You should be in good general health. LASIK may not be recommended for people with diabetes, rheumatoid arthritis, lupus, glaucoma, herpes infections of the eye or cataracts. You should discuss this with your surgeon.
Other recommendations:
- Make sure you have realistic expectations from the surgery.
- Weigh the risks and rewards. If you're happy wearing contact lenses or glasses, you may not want to have the surgery.
For people with age-related presbyopia, LASIK cannot correct vision so that one eye can see at both distance and near. However, LASIK can be done to allow one eye to see near and the other to see far. This is called "monovision." If you can adjust to this correction, it may eliminate or reduce your need for reading glasses. In some instances, surgery on only one eye is required.
LASIK Risks
You should not have this procedure if you are pregnant or breastfeeding, because these conditions can affect eye measurements. You should not have this procedure if you take certain prescription drugs, such as Accutane, Cordarone, Imitrex or oral prednisone.
Risks may include:
- Corneal infection
- Corneal scarring or permanent problems with the cornea’s shape, making it impossible to wear contact lenses
- Decrease in contrast sensitivity, even with 20/20 vision, objects may appear fuzzy or gray
- Dry eyes
- Glare or halos
- Light sensitivity
- Night driving problems
- Patches of red or pink in the white of the eye (broken blood vessels, usually temporary)
- Reduced vision or permanent vision loss
- Scratchiness
What to Expect at Your Procedure
Before the Procedure
A complete eye exam will be done before surgery to make sure your eyes are healthy. Other tests will be done to measure the curvature of the cornea, the size of the pupils in light and dark, the eyes’ refractive error and the thickness of the cornea (to make sure you will have enough corneal tissue left after surgery). You will sign a consent form before the procedure. This form confirms that you know the procedure’s risks, benefits, alternative options and possible complications.
After the Procedure
Following the surgery:
- You may have burning, itching or a feeling that something is in your eye. This feeling doesn’t last for more than six hours in most cases.
- An eye shield or patch will be placed over your eye to protect the flap. It will also help prevent rubbing or pressure on your eye until it has had enough time to heal (usually overnight).
- It is very important NOT to rub your eye after LASIK, so that the flap does not dislodge or move.
- For the first 6 hours, keep your eyes closed as much as possible.
- The surgeon may prescribe mild pain medicine and a sedative.
- Vision is often blurry or hazy the day of surgery, but blurriness will improve by the next day.
Call your eye surgeon right away if you have severe pain or any of the symptoms get worse before your scheduled follow-up appointment (24 to 48 hours after surgery).
At the first visit after the surgery, the eye shield will be removed and the surgeon will examine your eye and test your vision. You will receive eye drops to help prevent infection and inflammation.
Do not drive until your vision has improved enough to safely do so. Other things to avoid include:
- Contact sports
- Hot tubs and whirlpools
- Swimming
- Use of lotions, creams and eye makeup for two to four weeks after surgery
Your eye surgeon will give you specific instructions.
Prognosis
Most people’s vision will stabilize in a few days after surgery, but for some people, it may take up to three to six months. A small number of people may need to have another surgery because the vision is over- or under-corrected. Although a second surgery may improve distance vision, it may not relieve other symptoms, such as glare, halos or problems with night driving. These are common complaints following LASIK surgery, especially when an older method is used. These problems should go away by six months after the surgery in most cases. However, a small number of people may continue to have problems with glare. Even after a second surgery, a few people may still need to wear contact lenses or glasses.
If your distance vision has been corrected with LASIK, it is likely that you will still need reading glasses at around age 45. LASIK has been performed in the United States since 1996. Most people seem to have stable and lasting vision improvement.