Vision Correction & Laser Eye Surgery (LASIK)
Laser eye surgery is an umbrella term for several eye surgeries used to correct refractive errors (i.e., how your eye focuses light). The most common types of laser eye surgery include LASIK, PRK, LASEK and EpiLASIK.
Each of the four laser eye surgery procedures below uses the same special laser, called an “excimer” laser, to reshape the cornea. This is what corrects vision. But laser eye surgery can vary in the specifics of the procedure, the recovery time, which surgical instruments are used and your patient candidacy. You might be a better candidate for PRK, for instance, than for LASIK.
Dr. Elhosn will be able to determine from a comprehensive, laser-eye-surgery-specific eye exam which procedure is best for you. His recommendation will follow which procedure he thinks will give you the best possible outcome. Most patients for these laser eye surgeries achieve 20/20 or better vision.
Laser in Situ Keratomileusis
LASIK is the most common laser eye surgery. LASIK starts with the creation of a thin flap in the cornea. Your surgeon uses a blade or a laser to make this flap. The laser is considered more desirable by some doctors because of its advantages, such as fewer complications; however, all-laser LASIK costs a bit more than LASIK that uses a blade. Once the flap is created, the excimer laser is used to reshape the cornea, which corrects the refractive error.
PRK is the second most common type of laser eye surgery. PRK starts with the removal of a portion of the epithelial tissue. There is therefore no need for flap creation, and the removed tissue grows back. Some patients prefer PRK because they don’t want a corneal flap, and some patients are better candidates for PRK eye surgery than for LASIK (for instance, people with thin corneas). Once the epithelium is removed, a laser is used to reshape the cornea. The laser is the same (i.e., excimer) as the one used in LASIK. The PRK recovery period is a bit longer than that of LASIK. However, PRK is becoming more popular given the lower risk of the procedure and the better visual outcomes. Dr. Elhosn will explain the pros and cons of each procedure with you at the time of consultation.
Laser Epithelial Keratomileusis
LASEK is similar to LASIK and PRK, but it starts with the application of alcohol to the corneal epithelium. This loosens the outermost corneal cells and allows the surgeon to move them out of the way, without removing them, for the laser procedure. After reshaping the stroma, the surgeon can replace the sheet of epithelial cells and put a contact lens to let it heal.
Who gets laser eye surgery?
Laser eye surgery is recommended for people aged 18 or older. Before age 18, the eye might still be changing. Even after age 18, the eye might change. It’s important to have a record of stable vision for at least a year before having laser eye surgery. Dr. Elhosn requires two years of stable vision. Additional criteria must be met to be a candidate for laser eye surgery.
Only a trained professional can determine your candidacy for laser eye surgery and recommend the best procedure for you. For more information, see “Am I a LASIK Candidate?”
LASIK candidates exist in droves, though few people take the time to get a consultation. In fact, millions of people wish to reduce their dependence on eye glasses or contacts, but few take the plunge.
The first step is learning if you’re a LASIK candidate.
Am I a LASIK Candidate?
If you’re thinking about LASIK, here are a few questions that can help you know if you might be a good laser eye surgery candidate.
What Happens at a Laser Eye Surgery Consultation?
The first step in having laser eye surgery is not, sadly, picking out non-prescription sunglasses. It’s scheduling an evaluation, also called a consultation, during which Dr. Elhosn evaluates your candidacy for laser eye surgery, such as LASIK. After a thorough discussion and a non-invasive eye exam, Dr. Elhosn will be able to determine if laser eye surgery is right for you. He can then recommend the best procedure, such as LASIK or PRK, based on your eye exam results.
What to do before your laser eye surgery consultation
Dr. Elhosn will likely tell you to stop using contact lenses in the days or weeks leading up to your evaluation. Contact lenses distort the shape of the cornea, and Dr. Elhosn will want your cornea to have returned to its natural shape by the day of your laser eye surgery consultation.
What your provider does at your laser eye surgery consultation
On that day, you and Dr. Elhosn will go to a private room where he will ask about your use of eye glasses and contacts, the reasons you want LASIK, and your expectations after the procedure is performed. Some patients hope laser eye surgery will leave them totally independent from eye glasses and contacts, but this isn’t realistic. Most adults will need reading glasses by a certain age, for instance.
Good laser eye surgery candidates have realistic goals for laser eye surgery, such as reducing the need for eye glasses and contact lenses or enjoying a more active lifestyle. Patients with unrealistic expectations are not good candidates.
Dr. Elhosn will also want to know about your health history. General health conditions, such as diabetes or an autoimmune disease, and ocular health conditions, such as dry eyes or ocular herpes, can affect whether or not you are a candidate for laser eye surgery and how you will recover after the procedure.
Some medications, such as common migraine pills, can also affect healing. These and other lifestyle factors—including playing contact sports or consuming alcohol and drugs—can also influence candidacy. Dr. Elhosn might ask about any of these things to better understand your candidacy for laser eye surgery.
The comprehensive laser eye surgery exam
A typical laser eye surgery consultation continues with a very comprehensive eye exam. This exam will include tests you might recognize, such as pupil dilation and prescription measurement. But Dr. Elhosn will also use some tests that are specific to the world of laser vision correction. He will measure your cornea in detail, including its thickness, curvature and topography. He might perform a tear-film test to check for dry eyes. Each test will be explained before it is performed, and all of them are painless.
What you learn at the laser eye surgery consultation
Once the eye exam is finished, you and Dr. Elhosn will discuss the results and your candidacy for laser eye surgery. Patients who are good candidates for eye surgery will get a chance to ask questions about the procedure the doctor believes is best for their eyes. LASIK and PRK are the two most commonly recommended laser vision correction procedures.
PRK – Photo Refractive Keratectomy
Photo refractive keratectomy (PRK) is a type of laser eye surgery designed to correct vision problems like nearsightedness, farsightedness and astigmatism. PRK came before another laser procedure called laser-assisted-in-situ keratomileusis (LASIK), but PRK is still performed frequently and regularly today. LASIK has the same overall effect as PRK—it is just a slightly different way to correct vision. Both surgeries work by changing the shape of the cornea.
PRK vs LASIK – What are the differences?
In LASIK, an eye surgeon makes an incision (with either a laser or a blade) in the cornea to create a flap of tissue. The flap of tissue is lifted so the laser can be applied to reshape the inner layers of the cornea. The computer-controlled surgical laser carefully reshapes the layers of the cornea to repair imperfections in curvature that lead to distorted vision. The corneal flap is then put back in place and heals over the reshaped part of the cornea in a few days.
In PRK, the eye surgeon does not create a flap of corneal tissue. Instead, the outer layer of the cornea is removed to expose an area for a laser to reshape. This makes PRK a better choice for people whose eyes meet certain criteria, such as having thin corneas or chronically dry eyes.
The most significant differences between PRK and LASIK are the initial discomfort and the speed of visual recovery. Recovery from PRK takes a little longer than from LASIK because the outer layer of the cornea needs time to heal.
During this recovery time, a PRK patient is given prescription eye drops (antibiotic and anti-inflammatory drops) to promote healing and to reduce discomfort after eye surgery. The drops are normally prescribed for several months following surgery. PRK patients can expect it to take one to three days for the discomfort, blurring and other post-surgical effects to subside, and it will take up to six months for vision to reach absolute peak acuity and clarity.
LASIK recovery is much faster. The discomfort following LASIK surgery is usually mild and short term. While most patients report seeing normally within several hours after the procedure, their vision continues to improve gradually for several months before reaching peak quality.
Both surgeries are safe and effective and carry a very high rate of patient satisfaction. Choosing between PRK and LASIK is a decision best made in consultation with a trained eye doctor who specializes in laser eye surgery. The good news is that history has shown that whichever you choose, you’re likely to be very pleased with the outcome.
Oftentimes when LASIK isn’t a good option for someone, PRK is a suitable alternative. Developed in the mid-1980s, PRK carries many of the benefits, risks and price ranges as other laser eye surgeries.
Photorefractive kerectomy remains a common eye surgery today, especially for people who have thin or irregular corneas or who have additional conditions that reduce their candidacy for other types of vision correction.
PRK is what eye surgeons (ophthalmologists) call an “ablative” procedure. This means the surgeons ablate, or remove, tissue from the eye. (LASIK is also an ablative procedure; however, LASIK is both an ablative and incisional procedure, meaning it involves tissue removal and also tissue cutting. PRK does not involve cutting.)
PRK has two basic steps:
Step 1: Removal of outer corneal layer (called the “epithelial layers”). This will grow back.
Step 2: Laser reshaping of cornea’s middle layer (called the “stroma”). This corrects vision.
Step 1: Removal of epithelial layers
Removal of the cornea’s outer layers can happen three ways for PRK. Which way your surgeon uses will depend on his preference. The goal of any of these three ways is to expose the stroma, a middle layer of your cornea, which the laser needs to reach to correct vision.
He can soak the outer layers with a weak alcohol solution to softens tissue, thus enabling the surgeon to remove it.
He can remove the outer layers mechanically with a variety of surgical instruments, such as a sponge or a brush.
Finally, he can remove the outer layers by a laser, the same one that corrects vision.
Step 2: Laser vision correction
Once the epithelial layers are removed, the surgeon can then use a laser, called an “excimer” laser, to reshape your cornea. This laser has traditionally been able to correct nearsightedness, farsightedness and astigmatism. However recent technologic advancements have enabled surgeons to further customize the vision correction through WaveFront mapping, a technology found in the Hubble telescope! Custom WaveFront PRK can cost a few hundred dollars more than traditional ones, but most doctors favor customization for the added safety and the chance it will improve vision beyond what even glasses and contacts could.
(To learn more about customized laser vision correction, click here.)
How is PRK different from LASIK?
Recall that in PRK the outer layers get removed and grow back later. In LASIK, your surgeon won’t remove the outer layers. However, instead he will create a flap in the cornea stroma. Lifting this flap provides the same service as the first step of PRK: The surgeon can now reach the stroma to perform laser vision correction.
What are the benefits of PRK?
PRK offers some benefits other eye surgeries, including LASIK, do not. A big benefit is the elimination of flap complications, since there’s no flap created. No flap equals no flap complications, in other words. PRK also leaves the eye in a stronger and more stable condition than other eye surgeries, such as RK or AK.
Finally, this is an attractive laser eye surgery for some people who aren’t good LASIK candidates. This might include people with thin or irregular corneas or who prefer not to have a flap created.
What are drawbacks of PRK?
PRK can have a slower visual recovery than LASIK. PRK might require weeks for full recovery to functional vision, for instance, whereas LASIK takes days to functional vision. During the first several days of PRK recovery, patients tend to feel varying levels of discomfort (e.g., burning and watery eyes), too, and they can have fluctuating vision as epithelial tissue regrows.
What results can I expect from PRK?
LASIK and PRK are surgical procedures and therefore have risks. Results from laser eye surgery vary, but most people who get laser vision correction do achieve 20/20 vision. Some do not. PRK and LASIK have been shown in clinical studies to get similar results. (Most of these studies are based on at least one year after patients’ surgery dates, because by that time, both groups of patients have achieved their full visual acuity based on their procedures.)