High Refractive Error and Laser – In Brief
- Indicative laser limits: myopia up to approximately -10 D, hyperopia up to approximately +4 D, astigmatism up to approximately 5–6 D – always provided the cornea is sufficiently thick and regular.
- Above these limits, a phakic lens (ICL) is safer, correcting myopia up to -20 D without corneal intervention.
- After the age of 45, with a high refractive error and early presbyopia, refractive lens exchange is considered.
- The method is determined by a qualification examination: topography and corneal thickness, stability of the refractive error, and retinal condition – see qualification for the procedure.
If you have a really significant refractive error, you probably know this scenario: you hear in another clinic that “you don’t qualify.” What do you feel? Frustration! Is such a high refractive error really a lifelong sentence to glasses? Although classic LASIK laser has its limitations, our modern refractive surgery is not deterred by this at all. At Swisslaser, we don’t stand still; we search. We want to find an ideal and safe solution for everyone, even for you. We will now explain where the limit for traditional laser ends and what fantastic alternatives we have up our sleeve so you can finally see perfectly.
What will you learn from the text below?
- When is a refractive error considered too high for classic correction? The safety limit for lasers is myopia above -10 diopters or hyperopia above +5 diopters.
- What truly limits the possibility of performing a LASIK procedure? It’s simple: the higher the refractive error, the more cornea we remove, which is why its thickness is crucial.
- Does astigmatism exclude me from laser correction? No, although irregular or very high astigmatism (above 3 diopters) can be a challenge, we handle it very well.
- What method is the best alternative to LASIK for a thin cornea? An option is ReLEx® SMILE (the “keyhole” method), which minimally interferes with the cornea and corrects refractive errors up to -10 D.
- What if I don’t qualify for any laser method? Then we resort to traditional surgery, which means implanting intraocular lenses or exchanging them.
High Refractive Errors: When Does Laser Correction Have a Limit?
Classification of refractive errors: How do we define myopia, hyperopia, and astigmatism?
Before we get to the limits, let’s see how we classify the refractive errors we deal with:
| Defect | Small | Medium | Large / High |
| Myopia | up to $-3 D$ | from $-3 D$ to $-6 D$ | Above $-6 D$ |
| Hyperopia | up to $+2.5 D$ | from $+2.5 D$ to $+6.0 D$ | Above $+6.0 D$ |
| Astigmatism | up to $1$ cyl. diopter | up to $2$ cyl. diopters | Above $3$ cyl. diopters |
We always start with a super-accurate examination so that we can precisely assess your individual case.
Limits of possibilities: When is a refractive error a contraindication for laser surgery? (+5 D, -10 D)
Medicine operates according to safety principles, which is why laser has its limits. We consider traditional correction contraindicated when myopia exceeds -10 diopters or hyperopia is above +5 diopters. Does this mean you have to give up? Absolutely not!
Traditional LASIK: Why Do We Sometimes Say “No”?
Secrets of the LASIK method: What does the flap cutting technique involve?
In the LASIK method, we do this: first, the surgeon cuts an ultra-thin flap (our flap), gently moves it aside, and only then does the excimer laser reshape the inner part of the cornea, correcting the refractive error. Afterwards, we close the flap, and the eye heals quickly.
Corneal thickness: A key limit for high refractive errors
What often stands in our way with high refractive errors is corneal thickness. You need to know: the higher the refractive error, the more corneal tissue we remove. And your cornea must be thick enough to be stable and safe after correction! Many people with a high refractive error simply have a cornea that is too thin for safe LASIK.
Correction problems: Challenges of irregular astigmatism
Another challenge is irregular astigmatism. Although we correct routine cases in a flash, an irregular shape can make it difficult for the laser to perfectly remove the refractive error.
Modern Alternatives: ReLEx® SMILE and Traditional Surgery
The “keyhole” method: How ReLEx® SMILE bypasses the corneal flap problem?
Heard “no” for LASIK? Don’t give up! We present ReLEx® SMILE – it’s a cosmic leap in technology! We call it the “keyhole” method because we don’t create a flap. Instead, we remove corneal tissue through a tiny incision. Because we minimally interfere with the structure, the cornea remains more stable, and healing is super quick.
Dr. Victor Derhartunian emphasizes: “ReLEx® SMILE is our tool that has changed the rules of the game for high myopia. It allows us to safely correct refractive errors up to -10 diopters, especially in those patients whose cornea was too thin for LASIK. Corneal stability after SMILE is our priority.”
Scope of SMILE application: When is the minimally invasive method the best solution? (up to -10 D)
SMILE is for you if you have myopia from -0.5 to -10 diopters or astigmatism up to -5.0 diopters. This is minimal invasion and maximum safety.
When laser is not enough: Options for traditional surgery (Phakic lenses and lens exchange)
And what if your refractive error is truly enormous (e.g., -15 D)? Then we move on to traditional surgery. These are equally effective and safe methods that fix the problem from within: we implant intraocular lenses (phakic) or perform refractive lens exchange.
FAQ – Frequently Asked Questions
1. Can irregular astigmatism be corrected at all?
Yes, of course. Sometimes we use specialized lasers for this, and in more difficult cases, toric lenses work great.
2. What is a phakic lens?
Think of it as a permanent contact lens that we implant into the eye. It is placed just in front of your natural lens.
3. Can the refractive error return after correction?
This happens very rarely and mainly concerns people with exceptionally high refractive errors. That’s why at Swisslaser, we qualify you only when we are sure that the refractive error is already stable.
4. After intraocular lens implantation, do I see sharply at every range?
It depends on which lens we implant! You can choose one that will provide you with sharpness for one, two, or even all distances (trifocal lens).
5. Is SMILE more expensive than LASIK?
Costs vary, but remember that SMILE is the latest and least invasive technology. Always view it as an investment in your quality of life.
6. How many diopters is a high refractive error?
Conventionally, high myopia starts from -6 D, high hyperopia from +4 to +5 D, and high astigmatism above 2–3 D. From the perspective of the procedure, however, not only the number of diopters matters, but also the thickness and shape of the cornea and the stability of the refractive error.
7. Up to what refractive error can laser vision correction be performed?
Approximately, laser corrects myopia up to about -10 D, hyperopia up to about +4 D, and astigmatism up to about 5–6 D, always provided the cornea is sufficiently thick. Above these limits, a phakic lens (ICL) is safer, and after the age of 45, refractive lens exchange is often performed.
8. What disqualifies one from laser vision correction?
Too thin or irregular cornea (keratoconus), unstable refractive error (change above 0.5 D per year), active eye diseases (untreated dry eye, uncontrolled glaucoma, cataracts), pregnancy and breastfeeding, and certain general diseases. Most of these contraindications do not close the path to a phakic lens.
9. Can the refractive error return after laser correction?
The effect is permanent because the laser permanently changes the shape of the cornea. With high refractive errors, a slight regression occurs somewhat more often, which is why we only operate on stabilized refractive errors, and for borderline corneas, we choose ICL. Natural changes after the age of 45 (presbyopia) are a separate process.
