There are many myths out there regarding the permanence of LASIK eye surgery. We will try to debunk these myths, but at the same time give you absolutely essential knowledge on LASIK surgery, its effectiveness, its safety, and most importantly how long it is likely to last. As a general rule though, modern LASIK is permanent vision correction and you can expect far longer than 10 years of great vision.
Why do people think LASIK doesn’t last?
Much of this has to do with the original LASIK eye surgery that was being performed in the 1990s. It’s hard to believe but LASIK is an established procedure that has now been performed for 25 years. Just as cars, cell phones, and computers have come along way so too has LASIK vision surgery.
LASIK improves your existing vision by either flattening the central cornea in the case of myopic LASIK for nearsightedness or by steepening the central cornea for hyperopic LASIK to treat farsightedness. In the case of nearsightedness, which accounts for 85% of LASIK procedures, the eye has too much power. This is why people with poor distance vision from myopia wear glasses or contact lenses with negative power. The eye has too much power and LASIK decreases that power by removing a minimal amount of central corneal tissue. LASIK lasers cannot add tissue to the eye; they can only remove tissue. So, for farsighted treatments, our LASIK lasers remove tissue in a donut shape peripherally and barely touch the center of the cornea. This removal of tissue causes the center of the cornea to steepen and gives the eye more power. This idea is key to understand how this technology works and how modern LASIK platforms have improved to make LASIK last a very long time.
The original LASIK lasers performed what is now referred to as “conventional ablations” and these were very effective, but they had small optical zones and did not include something called a “blend zone.” Modern LASIK has completely moved away from these small optical zones because we found out the body didn’t like them, and a phenomenon known as regression would occur. This regression would not make eye surgery completely ineffective but a small return of myopia was sometimes seen. Regression is a loss of effect and it was happening because the body was trying to smooth out something that it felt didn’t belong (ie a central flattening of the cornea.) Thus, LASIK surgeons and laser manufacturers moved to larger optical zones that blended into the surrounding tissue so the body didn’t feel there was anything it needed to smooth out. For comparison, 1990s LASIK could have a 5.0-5.5mm optical zone with no blend zone. In today’s modern LASIK, nearly all treatments have a 6.5mm optical zone that blends all the way out to 8 or 9mm (our cornea is about 12mm in diameter) which makes LASIK last and not regress. Dr. Swanic had his LASIK performed about 10 years ago in 2010 and he still has the exact same 20/20 vision today as he did back then.
How long does LASIK last for farsightedness?
The short answer is that farsighted LASIK lasts just as long but it takes us a bit longer to get to our intended effect. As we discussed earlier farsighted LASIK is a very different procedure in which peripheral corneal tissue is removed which forces the central cornea to steepen. There is a limit to how much farsightedness we can treat with LASIK. Generally, LASIK lasers only allow us to program them to a correction of about 6 diopters for farsightedness. The good news is that corrections over 6 diopters of farsightedness are quite rare. It can be difficult to make corrections over about 3 diopters to be stable long term. Still, most patients seeking farsighted LASIK consultations actually have under 3 diopters of farsightedness in their glasses or contact lenses.
As we mentioned before, regression of the effect of LASIK is now very rare with nearsighted treatments with modern lasers with blend zones. More importantly, if I program my laser to correct -6.00D of nearsightedness the effect will be immediate and the next day the vision will be close to 20/20. Farsighted LASIK is programmed as positive treatments so if I program +3.00D the next day the patient is typically overcorrected. This overcorrection is intentional by both the surgeon and the laser to help keep your vision good long term. The issue is that all farsighted treatments have some level of regression over the first few months to even a year so if we don’t overcorrect in the short term we will end up undercorrected in the long term.
How long does LASIK last for astigmatism?
LASIK surgery is very stable for astigmatism and you can expect to have very long term correction with modern LASIK platforms. Our Visx iDesign 2.0 system is FDA approved to correct up to 5 diopters of astigmatism and we have had excellent results on patients with high astigmatism. The iDesign procedure actually captures a custom wavefront of your eye in our office which is transferred to the laser days prior to your treatment. On the day of your treatment, the laser gets this wavefront precisely aligned to your eye based on tiny iris details that are unique to your eye. This technology is called “iris registration” and it helps us achieve high astigmatism corrections both safely and consistently.
What is a LASIK enhancement?
LASIK is a very safe and effective surgical procedure, but even the best and most modern LASIK lasers will occasionally have an occasional undercorrection or overcorrection. This varies based on the level of correction that was attempted. For instance, the incidence may be 1% on a correction of -2.00 but that can increase to 5-6% on a correction of -6.00. If this occurs we perform a procedure called a LASIK enhancement to improve the vision. This does not mean that the LASIK “didn’t last” because we usually know that enhancement will be necessary within the first month after the initial procedure. LASIK enhancements are typically performed about 3 months after the initial procedure to ensure the eye is stable and that the procedure is necessary.
Does Presbyopia affect how long LASIK lasts?
Presbyopia as a process is not completely understood but is thought to be due to a loss of elasticity of the natural lens of the eye. This leads to a loss of near vision at about the age of 40. The loss of near vision slowly progresses and by the age of 45 presbyopia often causes people to need reading glasses.
Presbyopia can make it seem like LASIK has worn off because the near vision has declined. However, the procedure is still working and the distance vision remains very good as this process occurs. Patients who have had LASIK previously can consider what Dr. Swanic refers to as “blended vision” on one eye to help regain some near vision and not be dependent on reading glasses. In blended vision our staff will determine which eye your body prefers to sight distance objects, we call this the dominant eye. We then do not treat this eye, but instead provide a hyperopic, or farsighted, treatment to the other non-dominant eye to boost near vision. We call this “blended vision” because we don’t overcorrect this eye like was sometimes seen in what people refer to as “monovision.”
As an example, Dr. Swanic has perfect vision in both eyes from his nearsighted LASIK procedure. As he ages his near vision will inevitably decline. He knows that his left eye is his dominant eye that his body prefers to target distance objects. He plans to see a LASIK surgeon to correct his right, non-dominant, eye to improve his near vision so that he doesn’t need reading glasses for all tasks. He will likely get some reading glasses for certain activities that require very fine vision and ease the strain of having one eye doing a majority of the near work.
Does a cataract affect how long LASIK lasts?
A cataract is a natural hardening of the lens inside of our eye. LASIK is a procedure that works on the cornea or outside of the eye. If you have LASIK surgery, it will not prevent a cataract. A separate surgery will be necessary to remove the clouded lens. Cataracts typically don’t affect vision until after age 60. Because LASIK surgery is a procedure performed outside of the eye it is not good for treating a cataract that occurs inside of the eye. Cataract surgery, which Dr. Swanic also performs, removes this hardened and cloudy lens and restores sight to the eye. When a cataract develops it will make a prior LASIK procedure no longer effective, but again it is not that the LASIK has worn off, it is simply that a different process is occurring. Fortunately, we have excellent treatment options to correct cataracts.
Want to know more about LASIK? Read the next article in our LASIK series: What Happens if I Blink During LASIK?