LASIK is a surgery that is about 20 years old. Because it was approved by the Food and Drug Administration (FDA) as recently as 1998, there is limited information on its long-term harms through longitudinal studies.
While the procedure is generally considered very safe, there are some reports to consumer information bureaus and government agencies that side effects can last longer than expected.
It is important to understand the potential risks of this elective vision-improving procedure before deciding if you want to pursue it yourself. It is also important to know that the reports of side effects are often several years old, and advances in LASIK technology have greatly improved outcomes for the millions of people who have undergone this procedure.
If you are concerned about LASIK, due to other vision problems you have or your greater medical history, consult with more than one optometrist, ophthalmologist, or eye surgeon before deciding on the best choice for you.
A 2016 study in the Journal of Cataract & Refractive Surgery found that LASIK has a 96% patient satisfaction rate. The latest research indicates that LASIK has a 99% success rate in achieving 20/40 vision or better, and a 90% success rate in achieving 20/20 vision or better.
Is LASIK Safe?
LASIK is an eye surgery designed to correct your vision so you no longer need corrective eyewear, like glasses or contact lenses. The procedure is clinically called laser-assisted in-situ keratomileusis, a type of refractive surgery that uses a cutting laser to reshape the cornea so light refracts properly to the retina at the back of the eye. This reshaping of the cornea can treat nearsightedness, farsightedness, and astigmatism.
The procedure was first approved for the public by the Food and Drug Administration (FDA) in 1998. Long-term data is not readily available, but there is data on short-term results. For most people, LASIK is a safe, successful procedure that corrects vision for at least several years.
LASIK does not work for everyone, and in some instances, it can fail. There are associated risks to the procedure since it is surgery, and there are potential side effects that remain after the surgery. However, advances in the technology over the past several decades have allowed for fewer side effects and a greater overall success rate.
Success Rates for LASIK and Associated Risks
While LASIK is a safe and successful procedure for many — as of June 2018, about 9.5 million Americans have undergone the surgery — it is not foolproof. Different studies have found variances in overall success rates as well as the occurrence of negative side effects.
According to a recent FDA clinical trial, as many as half of people who undergo LASIK experience at least temporary vision aberrations, disturbances, or changes after undergoing the procedure the first time, although they had otherwise healthy eyes before the procedure. A third developed chronic dry eyes, past the healing stage from the surgery; a third also had trouble driving at night or performing tasks close to their eyes due to vision trouble; 40 percent were sensitive to light; and about 20 percent reported painful or sore eyes.
Because the eyes change with age, many people experience vision regression after surgery and will require corrective wear again.
A team at Ohio State University analyzed data that had been sent to the FDA from LASIK system manufacturers involving 4,500 patients in 2007. Of those patients, most achieved between 20/20 and 20/40 vision within six months after their procedure, but about 20 percent reported dry eyes. About the same percentage reported worsening glares, halos, and trouble with driving at night.
A new clinical trial, conducted by the FDA in partnership with the National Eye Institute and the Navy Refractive Surgery Center and published in 2017, reported that many who did not have pre-existing dry eyes or visual aberrations were at a risk of developing these temporarily after LASIK. Of the 574 participants, 28 percent reported dry eyes after surgery; 45 percent reported new visual aberrations persisting three months after the surgery; 50 to 60 percent reported that glares, halos, and double vision were common; and 5 percent reported glares, halos, and double vision that they considered “extreme” or “very bothersome.” In addition, 41 percent of patients reported some visual aberration persisting six months after the surgery; 1 in 50, or about 2 percent, reported having a lot of trouble performing regular tasks due to persistent vision problems; and a quarter experienced mild to severe dry eyes for six months after LASIK.
Complications Associated with LASIK Eye Surgery
There are several potential complications associated with LASIK surgery, although they are considered unlikely.
- Dry eyes: Many people experience dry eyes for the first six months after the surgery, which can reduce the quality of vision. This is caused by a temporary decrease in tear production in the tear ducts, so you may receive prescription eye drops to mitigate the sensation. If this side effect lasts longer than six months, there may be damage from the laser procedure. This is considered a common short-term side effect. Consumer Reports lists it occurring more than 10 percent of the time.
- Irritation, inflammation, and night-vision issues: The severity of these issues is usually reported as mild. They are reported to occur between 1 and 10 percent of the time within the first four weeks following LASIK based on data from the American Journal of Ophthalmology and a study by Consumer Reports.
- Glare, halos, or double vision: After LASIK, most people experience a few weeks of difficulty seeing at night. They may experience glares or halos around lights, or struggle with double vision. Problems seeing in dim light or darkness may be permanently reduced due to how the cornea is reshaped. Continuing to experience double vision or glare effects around lights is an abnormal side effect after a few weeks. This problem occurs more than 10 percent of the time.
- Undercorrections: This is a common side effect among people who are nearsighted due to the laser not removing enough tissue from around the cornea. This could necessitate another LASIK procedure within a year to remove more tissue. In the meantime, you may still need corrective wear like glasses. According to the American Academy of Ophthalmology (AAO), about 10.5 percent of U.S. LASIK patients require retreatment.
- Overcorrections: This problem involves removing too much tissue from the eye. It can be a harder problem to fix than an undercorrection.
- Astigmatism: This can be a side effect even in people who have not previously had astigmatism, or a shape change in their eye. Removing tissue from the cornea unevenly can lead to the eye changing shape.
- Inaccurate measurement or screening for glaucoma: Consumer Reports notes this mistake occurs more than 10 percent of the time, and it can increase the risk associated with undergoing LASIK. This underscores why it’s essential to choose an experienced surgeon.
- Reduced vision with age: In people whose eyes are constantly changing, LASIK will not permanently improve vision. With farsightedness in particular, vision will get worse with age.
- Flap problems or abnormal healing: During the procedure, a flap of tissue on the front of the eye is pulled back so the laser can more easily access the cornea. If this is not conducted properly, the flap removal can lead to excess tears or an infection in the eye, which may occur less than 1 percent of the time after the procedure. During healing, the epithelium (outermost corneal tissue layer) can grow abnormally. Problems that develop due to abnormal tissue healing occur between 1 and 10 percent of the time.
- Vision changes: If the procedure does not work, vision can get worse, and you may see less clearly than before. Damage to the optic nerve is reported less than 1 percent of the time.
- Vision loss: At worst, you may experience vision loss due to problems with the laser, tissue healing, or other aspects of the surgery. Disabling vision loss may occur less than 1 percent of the time.
Some of this damage may be caused by accidentally cutting tiny nerves in the cornea when the laser is introduced to remove some of the tissue. LASIK also thins the cornea, making it weaker, and can permanently alter the shape of the eye. People who experience vision problems after LASIK may not be able to have these issues or damage fixed.
However, there are some conditions that increase the risks of vision problems after LASIK.
- Autoimmune conditions like rheumatoid arthritis
- A suppressed immune system due to medications or a chronic condition like HIV
- Pre-existing, persistent dry eyes
- Hormonal changes, including pregnancy, breastfeeding, hormonal medications, or age
- Pre-existing eye disorders or diseases like herpes simplex, uveitis, keratitis, cataracts, glaucoma, lid disorders, or eye injuries
It is important to properly screen potential patients for these conditions, so they do not suffer long-lasting or permanent side effects. If you are concerned that you have any of these conditions, seek a second opinion from another ophthalmologist or eye surgeon before proceeding with LASIK.
Technology Improvements Help LASIK Become More Successful
Although there have been complications associated with LASIK, those are becoming less common as technology improves and the surgery becomes more effective and safe. An analysis of more recent LASIK data submitted to the FDA and published in 2017 found that vision problems may persist for weeks or months, but for the majority of LASIK patients, they eventually resolved.
In the new data of about 350 patients, about 20 percent of people still reported at least mild trouble driving at night. Glares were reported by 20 percent, and halos were also reported by 20 percent of patients. Mild dryness roughly doubled to about 40 percent of patients reporting this chronic side effect.
Technological Advancements in LASIK
Updates to the instruments used during surgery, including laser focus, instrument precision, and even material quality, have all helped to improve LASIK over the past 20 years. Better training and better tools make LASIK easier for the surgeon, which improves healing and outcomes for you, the patient. LASIK is now one of the safest and most common vision correction procedures.
Technological advancements that have helped improve the safety and successful outcomes of LASIK include:
- Introduction of the femtosecond laser. Use of the femtosecond laser means that a blade is no longer required for the procedure, and blade-related complications during surgery are no longer a concern. Additionally, a much thinner flap on the cornea can be made with the laser, allowing for a quicker and easier recovery.
- Wavefront laser technology. This type of laser technology allows for corrections of errors on the cornea that glasses and contact lenses can’t fix, resulting in even better vision than when patients wore their glasses.
- Topography-guided laser vision correction. With this form of laser vision correction, tens of thousands of data points on the eye are collected before treatment, analyzed, and sent to an excimer laser in order to perform highly individualized corneal corrections.
No surgery, including minor outpatient surgeries, is without risk, but these are being mitigated as LASIK becomes better and more popular.
LASIK Eye Surgery: Overview. (December 30, 2017). Mayo Clinic.
Journal of Cataract & Refractive Surgery, Vol. 42, Issue 8, August 2016, Pages 1224-1234
Medical Devices: LASIK: What Are the Risks and How Can I Find the Right Doctor for Me? (August 8, 2018). U.S. Food and Drug Administration (FDA).
Blurred Vision, Burning Eyes: This Is a LASIK Success? (June 11, 2018). The New York Times.
Outcomes of LASIK for Myopia with FDA-Approved Lasers. (April 26, 2007). Cornea.
LASIK Eye Surgery: Will You Really Get Rid of Your Glasses? (February 2013). Consumer Reports.
LASIK – Laser Eye Surgery. (December 12, 2015). American Academy of Ophthalmology (AAO).
Advances in Technologies for Laser-Assisted In Situ Keratomileusis (LASIK) Surgery. (January 9, 2014). Expert Review of Medical Devices.