In my clinic, the question I hear most often from a patient on the verge of deciding on surgery is: "Will my prescription come back?" It is usually asked by someone who wants to be reassured one last time — and who, the more they searched the internet, the more they ran into answers that do not agree. Some pages say "it never comes back", others give no numbers at all and just say "it varies from person to person". I will do neither: I will share the numbers I have as they are, saying which question each one answers.
Let us first be clear: when we say "the prescription came back", one of three different things may actually be meant, and mixing these three up is what confuses patients most. The first is true regression arising within the cornea itself; the second is the progression of myopia itself, which had not yet stopped at the time of surgery; the third is presbyopia, which everyone experiences after 40 and which has nothing to do with surgery. Throughout this article I will treat these three separately.
Short answer: generally no, but you cannot say "never" either
Laser refractive surgery permanently changes the refractive power of the cornea; this change is made once on the operating table and the treated tissue does not return to its former state. But "the shape of the cornea is permanent" and "your eye's prescription will never change again" are not the same sentence — one is a physical fact, the other a promise. I do not make promises to my patients; I explain the data I have.
What laser does and does not do — the difference between reshaping and stopping
Laser reshapes the surface of the cornea so that light is focused correctly on the retina; it corrects myopic, hyperopic or astigmatic refractive error. But laser does not stop the eye from ageing, does not stop progressing myopia and does not prevent cataract that may develop later. The cornea is reshaped; the eye goes on living and ageing. If we do not establish this distinction from the start, we will read every natural change that comes later as "the operation failed" — which is usually not true.
As for the numbers: in a recent study looking at 12-month follow-up in 752 eyes, the regression rate was 18.2%.[1] In a PRK series looking at a much longer follow-up of eight to ten years, the rate was 22% — but in the same study 74% of patients stayed within ±0.25 dioptres of the target prescription.[2] I do not add these two rates up to produce a figure like "20% on average": one is a one-year follow-up, the other close to ten years; they use different methods and different thresholds.
What do 18.2% and 22% really measure?
There is a detail here that should not be overlooked: "regression" does not mean the slightest shift in the eye — it means a shift above a certain threshold. In the one-year study, regression was defined as "a myopic shift of at least 0.50 dioptres between month 3 and month 12".[1] So the 18.2% rate actually means "eyes that shifted by half a dioptre or more"; no change below that is included in the figure. In the eight-to-ten-year PRK series the threshold was set even lower (the spherical equivalent, i.e. the overall measure of your glasses prescription, becoming more myopic than −0.25 dioptres); despite this, the rate rose to 22% because of the longer follow-up.[2]
So how much of a shift actually occurs in eyes said to have "developed regression"? In the one-year study, the mean shift in eyes that developed regression was measured at between −0.37 and −0.46 dioptres (there is a small difference by sex).[1] That is just above the threshold (0.50 D), an amount small enough that most patients would not notice it on their own in daily life. The eight-to-ten-year series shows the same picture: despite the 22% regression rate, 74% of patients continued to stay within ±0.25 dioptres of the target.[2] In short: if you do not want to count a half-dioptre shift as "my prescription came back", the remaining picture is much more reassuring. I am not shrinking the numbers — 18.2% and 22% are real, measured rates — but reading them without knowing what they measure causes more anxiety than necessary.
There is no need to give up on surgery for fear that "the prescription will come back" — but I will not promise that "it never changes" either. The realistic expectation is this: the great majority of eyes remain completely stable; in some there is a shift of around half a dioptre, usually at a level that will not be noticed.
Why can the prescription come back?
Regression has several known triggers; knowing them lets us discuss in advance in whom the risk is somewhat higher.
The prescription not having fully settled before surgery
If myopia is still progressing — if the prescription has changed markedly in the past year — operating on that eye is risky timing. In such a case, the "increase" seen after surgery is not actually regression arising from the cornea, but the course of myopia that was already continuing. That is why I do not decide on surgery before the prescription is stable: the right time is not "the earliest date" but "the date the prescription has settled".
Having surgery at a very high prescription
Risk factors were also examined in the eight-to-ten-year PRK series: for every 1 dioptre increase in preoperative myopia, the likelihood of regression increases 1.4-fold; for every 1 micrometre increase in ablation depth (the amount of tissue treated by laser), the likelihood increases 1.05-fold. For every 1 millimetre increase in corneal diameter, however, the likelihood falls to 0.14-fold, i.e. it shows a protective effect.[2] In short: the higher the prescription, and the more deeply the cornea has been reshaped to correct it, the greater the likelihood of regression.
The individual healing response of corneal tissue
In a five-year comparison, thickening of the epithelial layer (the outermost cell layer of the cornea) in the central zone of the cornea relative to its periphery after FS-LASIK was more marked than after SMILE. The researchers think this uneven epithelial distribution may play a role in regression — but the same study also states that its effect on patients' subjective quality of vision was very small.[3] A separate study showed that in highly myopic eyes (over −8.00 dioptres), those that developed regression had lower corneal biomechanical resistance at months 3, 6 and 12[4] — that is, the tissue of some corneas responds somewhat more variably to the same operation. That is why preoperative topography and biomechanical measurements are so important.
If you become pregnant after laser: temporary hormonal changes
What is meant here is a woman who has already had laser treatment becoming pregnant later. Laser treatment is not performed during pregnancy in any case; because the prescription fluctuates in this period, it is left until afterwards. But there is a question my previously operated patients often ask: why did my prescription shift during pregnancy or while breastfeeding? In a study following 100 women (53 of whom had previously had myopia laser) throughout pregnancy and up to six weeks after delivery, measurable changes in corneal thickness and curvature were found in the group that had previously had laser; these changes were associated with laser history and oestrogen levels.[5] However, the extent to which these changes return to their former state after delivery is not clear — so I do not give a definite rate. What I tell my patient is this: "let us wait a few months and decide once the prescription has truly settled."
The common denominator in this section is timing. If your prescription has not changed for the past year, it is not very high and your corneal measurements are suitable, you are already in a group with low regression risk.
This should not be confused with the eye ageing: presbyopia
Why near vision becomes harder in your 40s
Presbyopia is the reduction in the ability to focus at near distance as a result of the eye's lens losing its flexibility with age. It is an entirely natural process that everyone goes through — whether myopic, hyperopic or astigmatic, and whether or not you have had laser.
Does someone who has had laser also experience presbyopia? Yes, and it is not a failure of the operation
Laser corrects the refractive error of the cornea at the time of surgery; it does not touch the lens of the eye. Your lens naturally continues to stiffen over the years. So someone who has laser at 35 may have difficulty seeing near by the time they are 45 — this is not the operation "coming back", but the time having come for that person, too, for the presbyopia everyone will experience. I explain this distinction to my patients specifically, because when it is confused, people question their operation unfairly.
Monovision: an honest way to balance near and far
For those over 40 who want to see both far and near comfortably, monovision can be an option: the dominant eye is set for distance and the other eye is left slightly myopic for near; over time the brain learns to switch between the two. But I do not recommend it to everyone — people working in jobs sensitive to distance perception, or who rely heavily on depth perception, may find it hard to adapt. Before deciding, I usually suggest a trial period with contact lenses.
If you are approaching 40 and expect difficulty with near vision soon, let us discuss it before surgery — whether monovision is suitable or not, we decide the surgical plan then.
Does the choice of method change the risk of regression? (LASIK / SMILE / PRK)
Which method gives more stable results in which profile
In Türkiye in recent years, the most talked-about and searched-for method is SMILE — I also know this from conversations with patients. But "most talked about" and "most advantageous against regression" are not the same thing; the literature does not yet give a clear ranking on this point, and I will share this as it is.
| Method | Mean spherical shift in eyes that developed regression |
|---|---|
| SMILE | −0.66 D |
| LASIK | −0.48 D |
| PRK | −0.46 D |
2,781 eyes, 1-year follow-up.[6]
This difference needs to be read without exaggerating it: the difference between SMILE (−0.66 D) and LASIK (−0.48 D) is only 0.18 dioptres — an amount too small to be felt in daily life.
The study that gives this table (2,781 eyes, 1 year) finds SMILE to be the method showing more and larger regression than LASIK and PRK.[6] But another study with longer follow-up — 919 eyes, 1.5 years of follow-up — reports the exact opposite: it finds that SMILE showed the highest predictability and long-term stability, while trans-PRK was associated with more regression and a higher enhancement rate.[7]
Two serious studies give opposite results: the larger series puts SMILE behind, while the series with longer follow-up puts SMILE ahead. I suggest you treat any source that says "this one is best" with suspicion — the literature has not yet closed this question.
Regression is not the only decision criterion anyway. In SMILE, the fact that no flap is created on the corneal surface (unlike LASIK) is valuable in itself, an advantage independent of the regression debate. My approach in practice is this: I do not choose the method out of fear of regression, but according to individual characteristics such as the thickness of your cornea, the size of your prescription and your tendency to dry eye. In some corneal structures SMILE is more suitable, in some PRK is safer, and in some LASIK is the most balanced option — this is a decision that becomes clear at the measurement table, not a brand preference made in advance.
Would you like to compare LASIK, SMILE and PRK side by side?
Compare treatments (in Turkish) →What happens if the prescription really does come back?
Is a second laser correction (enhancement) always possible?
In a study examining retreatments with LASIK, PRK or ICL in 158 eyes, the complication rate was low (7.9%) and the efficacy/safety indices were around or above 1.0.[8] But saying "always possible" would not be right either. Here what comes into play is not a rate from the literature, but the things I look at in the examination: the remaining corneal tissue needs to be thick enough to be reshaped again, and dry eye needs to be under control. These limits are not the same for everyone; they are set by measurement. In some patients I recommend temporary use of glasses instead of an enhancement; this is not a failure, but a sensible choice.
Related article: ICL surgery: who is a candidate and who is not?
Why small changes usually do not affect daily life
The scenario my patients worry about most is: "I was −5.00; will 1.00 come back?" No. The average amount that comes back in eyes that develop regression ranges between −0.46 and −0.66 dioptres depending on the method.[6] So even if regression develops in a −5.00 D patient, the expected picture is around half a dioptre, not 1.00 D — vision without glasses is largely preserved.
If regression develops, we measure first and then decide: if it is a small shift, an additional procedure is usually not needed; if it is a marked shift, enhancement options are discussed together with their safety profile.
How can you assess your own risk?
The risk factors I have described so far — the size of the prescription, how long it has been stable, corneal measurements, age — combine with different weights in different people. Rather than explaining this one by one, we have prepared the interactive assessment tool on our site; with a few questions it assesses your age, the change in your prescription over the past year and your presbyopia scenario after 40.
How great is this risk for your eye? Find out with the free suitability assessment.
Start the suitability test (in Turkish) →Frequently asked questions
I cannot say a definite "never" — in the great majority the result remains permanent, but in some eyes a small shift that usually does not affect daily life can be seen. At one-year follow-up this rate was measured at 18.2%, and in an eight-to-ten-year PRK series at 22%; in the same series 74% of patients continued to stay within ±0.25 D of the target.
Regression usually appears within the first year after surgery (between months 3 and 12), but in eight-to-ten-year follow-ups small shifts are also seen in some patients. A separate study of retreated patients reported that the more time had passed since the first operation, the greater the shift tended to be.
Yes, it is. Laser corrects the cornea but does not touch the lens of the eye; the lens naturally loses its flexibility with age. This does not mean the operation failed — everyone who has not had laser goes through the same process.
Probably not for distance, but you may need reading glasses at near (books, phone) because of presbyopia — this is a natural process that happens to everyone. Options such as monovision can reduce this need, but are not suitable for everyone.
The literature is not clear on this. A study of 2,781 eyes finds SMILE to be the method showing more regression than LASIK and PRK, while another study of 919 eyes with longer follow-up reports SMILE as the method with the highest predictability and stability. Moreover, the SMILE-LASIK difference in the first study is only 0.18 dioptres — a clinically small amount. The choice of method should be determined by the thickness of your cornea and the size of your prescription rather than by these conflicting data.
Usually yes. In the retreatment study of 158 eyes, the complication rate was low (7.9%) and the results were safe. But the remaining corneal tissue needs to be thick enough; in some patients glasses or lenses are recommended instead of an enhancement.
Let us first be clear: laser treatment is not performed during pregnancy; this question applies to patients who have already had the operation. During pregnancy and breastfeeding, hormonal changes can cause measurable, temporary changes in corneal thickness and curvature; one study showed this in women who had previously had laser. But the extent to which these changes fully return to their former state after delivery is not clear, so I cannot give a definite rate. My advice to my patients: wait a few months and decide once the prescription has truly settled.
No. A small regression is a predictable possibility that can arise from known causes such as a high preoperative prescription or the individual response of corneal tissue. Presbyopia is a separate process that comes with age and has nothing to do with the operation. Neither means "the operation failed".
References
- Ma et al. "Gender differences in myopic regression, corneal haze, and ectasia after corneal refractive surgery: a retrospective cohort study." Clinical and Experimental Optometry, 2026. PMID 42702085
- Mohaghegh et al. "8-to-10-Year Follow-Up Results of Photorefractive Keratectomy and Risk Factors for Myopia Regression." Beyoglu Eye Journal, 2025. PMID 40630851
- Li et al. "Study of corneal and retinal thicknesses at five years after FS-LASIK and SMILE for myopia." BMC Ophthalmology, 2024. PMID 39237938
- Shao et al. "Changes in Corneal Biomechanics and Epithelial Thickness in High Myopia Over -8.00D with/without Myopic Regression After FS-LASIK." Clinical Ophthalmology, 2026. PMID 41924206
- Shao H et al. "Impact of myopic laser surgery and pregnancy-related hormonal fluctuations on corneal biomechanics." American Journal of Translational Research, 2025. PMID 41268241
- Manion et al. "Preoperative Risk Factors of Keratometry, Myopia, Astigmatism, Age, and Sex for Myopic Regression After LASIK, PRK, and SMILE." Cornea, 2025. PMID 40199570
- Aljaberi et al. "Comparative clinical outcomes of SMILE, femtosecond LASIK, and transepithelial PRK: a multicenter Iraqi study." Frontiers in Ophthalmology, 2026. PMID 42058504
- Ang et al. "Retreatment using LASIK, PRK, or ICL for myopic regression after corneal laser refractive surgery." BMC Ophthalmology, 2026. PMID 42260445
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