If your glasses prescription reads -8.00, -10.00, or higher, you've probably been told at some point that you're "not a candidate for LASIK." That's partially true โ but the full picture is more nuanced, and understanding where the limits actually lie helps you make a better decision about which procedure is right for your eyes.
Why LASIK Has a Prescription Limit
LASIK corrects your vision by removing corneal tissue with an excimer laser. Higher prescriptions require more tissue removal. The problem is that your cornea has a finite thickness (typically 500 to 560 microns), and there's a minimum safe thickness that must be preserved after surgery โ generally 250 to 300 microns of residual stromal bed โ to maintain structural integrity and prevent a complication called corneal ectasia (progressive thinning and bulging, similar to keratoconus).
For a typical cornea, this means LASIK can safely correct up to about -8 to -10 diopters of myopia. Some surgeons with extensive experience may push toward -12 in patients with unusually thick corneas, but this is the exception, not the rule โ and responsible surgeons err on the side of caution.
| Prescription Range | LASIK? | SMILE? | ICL? | Best Option |
|---|---|---|---|---|
| -1 to -6 diopters | โ Excellent | โ Excellent | โ (overkill) | LASIK or SMILE |
| -6 to -8 diopters | โ Good (if cornea allows) | โ Good | โ Excellent | Depends on corneal thickness |
| -8 to -10 diopters | โ ๏ธ Borderline | โ ๏ธ Upper limit | โ Ideal | ICL strongly preferred |
| -10 to -20 diopters | โ Not safe | โ Not available | โ Only option | ICL |
What Happens When Surgeons Push the Limits
Treating high prescriptions with LASIK beyond safe limits carries real risks. Corneal ectasia is the most serious โ the thinned cornea progressively weakens, vision deteriorates, and the patient may eventually need corneal crosslinking or, in severe cases, a corneal transplant. Higher corrections also produce larger optical zones that can exceed the treatment area of the laser, leading to higher-order aberrations (halos, starbursts, reduced contrast) and regression (the prescription partially returns over months to years).
ICL: The Solution for High Myopia
The Implantable Collamer Lens (ICL) was essentially designed for patients that LASIK can't safely treat. It corrects prescriptions from -3 to -20 diopters without removing any corneal tissue. For patients with -8 diopters and above, ICL actually delivers better visual quality than high-correction LASIK would โ sharper contrast, fewer aberrations, and no risk to corneal integrity.
In Colombia, ICL costs $2,000 to $3,500 per eye. For many high-myopia patients, this is less than the US cost of LASIK โ meaning the clinically superior procedure is also the more affordable one when performed in Colombia.
What About Partial LASIK + ICL?
In rare cases, a "bioptics" approach โ combining partial LASIK correction with ICL implantation โ may be discussed for extremely high prescriptions or complex refractive errors. This is uncommon and typically reserved for patients with unusual combinations of myopia, hyperopia, and astigmatism. It requires a surgeon experienced in both procedures and careful planning. If your surgeon suggests this approach, ask about their specific volume of bioptics cases and outcomes.
High Prescription? Let's Find Your Best Option
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