LASIK, SMILE or ICL: Which Method Fits Your Prescription?

You do not choose the method — your measurements do

Almost everyone arrives with a method already in mind, usually the one a friend had or the one they saw advertised. It rarely survives the examination. Vision correction is a matching problem: the surgeon fits a technique to your prescription, your corneal thickness and the shape of your cornea, and a clinic that promises you a specific method before measuring any of that is guessing. This page sets out which prescriptions each method actually covers, what rules a method out, and what you can work out for yourself before you travel.

1. The numbers on your prescription, and what they mean here

Three figures matter. Sphere (SPH) is the strength of the correction — negative for myopia, positive for hyperopia. Cylinder (CYL) is astigmatism. Axis says where the astigmatism sits. A prescription like −4.50 −1.25 x 180 is a moderate myopia with mild astigmatism, and sits comfortably inside the range of several methods. One like −13.00 does not, and no amount of shopping around will change that.

A fourth figure is not on your optician's paper and is the one that most often decides the outcome: corneal thickness, measured in micrometres by pachymetry. It is measured in the clinic, not at the optician.

2. What each method covers

• LASIK and femto-LASIK. Myopia to roughly −8 or −10 D, astigmatism to about −5 D, hyperopia to about +4 D. Needs a cornea thick enough that enough tissue remains under the flap — in practice this is the limit that rules LASIK out most often. Fastest recovery of all the laser methods. LASIK details.
• SMILE. A similar myopia range, to roughly −10 D, with astigmatism to about −5 D. No flap, a small incision, more of the cornea's structure left intact and less post-operative dryness — which is why it is preferred for thinner corneas, for patients who already have dry eyes, and for contact sports. Not generally used for hyperopia. SMILE details · SMILE vs LASIK compared.
• PRK and surface ablation. The option when the cornea is thin but the prescription is low. No flap at all; recovery is slower and more uncomfortable in the first days, with the same end result.
• ICL, the implantable lens. Myopia from about −3 all the way to −18 or −20 D, and astigmatism with a toric version. Nothing is removed from the cornea, so a thin cornea is no obstacle; instead the eye needs enough depth in the anterior chamber and a healthy endothelial cell count. It is also the only reversible option — the lens can be taken out. ICL details · What ICL costs in Turkey.
• Lens replacement. From the mid-forties on, when the eye's own lens is stiffening or a cataract is forming, replacing the lens does the job that laser cannot. Cataract and lens surgery.

3. What rules laser out entirely

Keratoconus, or a topography that merely suggests it. Laser thins the cornea further, so in a cornea that is already weakening it is contraindicated. The treatment that comes first is cross-linking — see keratoconus treatment options and costs.

A prescription that is still moving. Surgeons want at least twelve months of stability, with no more than about half a diopter of change in the last year. Under 18 almost always means waiting.

Pregnancy and breastfeeding. Hormones shift the refraction; the operation is postponed rather than refused.

Untreated severe dry eye, active eye inflammation, uncontrolled diabetes, some autoimmune conditions. Several of these are a question of sequence, not a permanent no — dry eye in particular is often treated first and the surgery done afterwards. More on dry eye and laser surgery.

And a limitation that is not a contraindication but surprises people: laser corrects the optics of the eye, not the brain's use of it. If one eye has been amblyopic since childhood, correction will not restore its vision — why a lazy eye is a different problem.

4. The four measurements a real recommendation rests on

Corneal thickness (pachymetry), corneal shape (topography and tomography, which is what detects early keratoconus), pupil diameter in the dark, which affects night vision after treatment, and the tear film. A fifth for lens candidates: anterior chamber depth and endothelial cell count. Every one of these is measured on the day, and together they take an hour or two. This examination is the product you are buying first, and at our partner hospitals it starts from $150.

5. What you can find out before you fly

Send a photo of your prescription with your age and how long your vision has been stable. From that, our partner ophthalmologists can usually say which methods are plausible and which are already out, and issue an individual proforma within a working day. It is not a diagnosis and it does not replace the examination, but it is enough to know whether you are planning a three-day LASIK trip or a week for an ICL — and enough to avoid booking a flight for an operation you were never a candidate for. Send your prescription.

6. If the answer is no

It happens, and hearing it early is the good outcome. Depending on the reason, the alternative may be an ICL instead of laser, cross-linking before anything else, a lens replacement rather than a corneal procedure, or simply better-fitted glasses or lenses. What comes next if you are turned down goes through each case.

Frequently asked questions

I have −7 with astigmatism. Which method?
Probably LASIK or SMILE, and corneal thickness decides between them. At −7 you are inside the laser range but close enough to the edge that the measurement genuinely matters.

I have −12. Is laser possible?
Generally not. That is ICL territory, and the result at that prescription is usually better with a lens than it would have been with laser even if laser were possible.

Can both eyes be done on the same day?
Yes, that is the standard for laser and for ICL, and it is why prices are quoted for both eyes.

Will I still need reading glasses?
If you are over about 45, very likely — distance correction does not prevent presbyopia. Surgeons discuss monovision or a presbyopia-correcting lens for exactly this.

How long does the result last?
The correction is permanent, but the eye keeps ageing. Most people are stable for decades; a small number need an enhancement later.

Related: What vision correction costs in Turkey · LASIK recovery · SMILE recovery · ICL recovery · Partner hospitals

This page is general information, not medical advice. The ranges above are typical and vary by platform and by surgeon; suitability is determined individually by a licensed doctor after examination.