by
Mamisoa Andriantafika
Living without glasses or contact lenses is now possible for a great number of patients, but not with just any technique, nor at just any age. Eligibility for refractive surgery depends on a set of criteria: your age, the prescription of each eye, the thickness of your cornea and… your lifestyle. In this article, we review these criteria, then offer you an interactive simulator to get a first personalised orientation.
No data is stored or transmitted by the simulator: everything is computed in your browser. And of course, only a complete preoperative work-up can confirm a surgical indication.
Femto-LASIK is the reference technique: a corneal flap is cut with a femtosecond laser, then the excimer laser reshapes the cornea to correct myopia and astigmatism. Recovery is fast, within 2 to 3 days. Discover our Wavelight EX500 laser platform.
PRK (surface laser) corrects the same defects without cutting a flap: the epithelium is removed and grows back within a few days. It is preferred for thinner corneas or contact sports, at the cost of a slightly longer recovery.
The ICL is a lens implanted between the iris and the crystalline lens, without touching the cornea. It is the solution of choice for high myopia, and it is reversible.
Finally, lens surgery (PRELEX, or clear lens exchange) replaces the crystalline lens with an implant, as in cataract surgery. It corrects both distance vision and presbyopia, and is mainly intended for patients over 55.
Laser on the cornea, implant in front of the crystalline lens or lens replacement: each technique has its ideal patient profile.
Between 25 and 35, all lights are green: stable refraction and presbyopia still far away.
Before 25, it is often too early to operate: myopia is still changing and stability is the priority. The rule is a prescription unchanged for at least two years before considering surgery.
Between 25 and 35, this is the ideal window for refractive surgery: the refraction is stable and presbyopia far enough away to fully enjoy, for many years, corrected vision at distance and near.
Between 35 and 45, presbyopia is approaching. Depending on your activities, a small compromise can be discussed: mini-monovision, where one eye is slightly tuned for near, preserves functional near vision at the expense of perfect distance vision. This compromise suits office work well, much less a taxi driver who drives at night.
Between 45 and 55, with presbyopia established, we enter a « grey » age: it becomes difficult to compensate both distance and near vision. We hesitate to replace the still-transparent crystalline lens of a young presbyope; a multifocal ICL may possibly be discussed, knowing that in the medium term it will have to be removed to replace the lens when cataract appears.
After 55, the logic reverses: lens surgery (PRELEX) often becomes the best option, correcting distance and near in a single procedure. It also definitively prevents cataract, since the natural lens is replaced by an implant.
Myopia is the laser's favourite ground: up to about −8 D, Femto-LASIK or PRK give excellent results, provided the cornea is thick enough. Beyond that, the laser would have to remove too much tissue: the ICL becomes the reference for high myopia.
Strong hyperopes (beyond +3 D), on the other hand, are poor candidates for Femto-LASIK: the peripheral ablation profile required does not give good visual quality. And the implant alternative is often closed: in hyperopes, the anterior chamber is narrow and the ICL is frequently too large to be placed there safely.
The same caution applies to high astigmatism, beyond 3.5 D: the laser corrects these high cylinders poorly. If the astigmatism is regular, which only corneal topography can confirm, a toric ICL can be an option.
High hyperopia or astigmatism beyond 3.5 D: the laser is probably not the right answer.
Every corrected dioptre consumes corneal tissue: pachymetry sets the laser's limit.
Pachymetry measures the thickness of the cornea, on average around 540 µm. The laser « sculpts » the correction into this tissue: the stronger the correction, the more it consumes. To preserve the strength of the cornea, the surgeon must guarantee a sufficient residual posterior wall after the flap cut and the ablation.
A thin cornea does not rule out everything: it first excludes LASIK (which « spends » the thickness of the flap), while PRK, more tissue-sparing, sometimes remains possible. Otherwise, the ICL, which does not touch the cornea, takes over.
During the work-up, pachymetry is always coupled with corneal topography, essential to detect early keratoconus, a formal contraindication to laser.
With the same prescription, two patients may call for different strategies. Contact sports (boxing, martial arts, rugby) do not rule out LASIK: once healed, the flap holds up well. They do however contraindicate the ICL implant: under the effect of a blow, the implant can knock against the crystalline lens and damage it. Depending on the correction, PRK may be preferred. Remember that with high myopia, the retina is more fragile: violent contact sports such as boxing are discouraged anyway. Professional or night driving demands maximal distance vision and tolerates monovision and multifocal optics poorly: a full distance correction is better, even if it means wearing reading glasses.
Conversely, office work, on screen, at intermediate distance, accommodates a mini-monovision very well, extending reading comfort as presbyopia approaches.
This is the whole purpose of the preoperative consultation: crossing your optical profile with your daily life to choose not « the best technique » in absolute terms, but the best technique for you.
Office worker or taxi driver: with the same prescription, the right strategy is not the same.
Answer the 5 questions below: the simulator crosses your age, your prescription eye by eye, the stability of your refraction, your activities and your pachymetry if you know it, then ranks the four techniques according to your profile.
The simulator orients; only the preoperative work-up decides.
This simulator provides general guidance, not medical advice. Other specific parameters come into play, such as dry eye, corneal topography, anterior chamber depth, pupil size or retinal status. They will be assessed during the preoperative examination: cycloplegic refraction, topography and pachymetry, biometry and dilated fundus examination.
It is this complete work-up, performed by your ophthalmologist in Brussels, that confirms eligibility, chooses the technique and sets the optical strategy: full correction, monovision or implant.
