Lasting correction of myopia, astigmatism and hyperopia with laser treatment in Paris, with Dr Gozlan.
LASIK is the gold-standard technique for laser myopia surgery. Painless, fast and micrometrically precise, it provides a lasting correction of myopia and astigmatism — as well as hyperopia — freeing the vast majority of patients from glasses and contact lenses. Dr Gozlan, an ophthalmic surgeon holding a University Diploma in Refractive Surgery and Phacoemulsification (University of Toulouse), explains in detail the principle, technologies, indications, procedure steps, postoperative course, results, risks and cost of this surgery.
LASIK (Laser-Assisted in Situ Keratomileusis) is a refractive surgery that reshapes the cornea — the transparent lens at the front of the eye — to correct a visual defect. The principle relies on two complementary lasers : a femtosecond laser first creates a thin corneal flap, then an excimer laser sculpts the underlying cornea with micron-level precision. The flap is then repositioned without sutures : it adheres naturally within a few minutes. The procedure takes approximately fifteen minutes for both eyes and is performed on an outpatient basis.
By modifying the curvature of the cornea, the surgery shifts the focal point of light so that it falls exactly on the retina : the image becomes sharp again without optical correction. Performed since the mid-1990s, LASIK is now one of the most widely performed and extensively studied procedures in the world, with several decades of follow-up and millions of eyes treated.
Myopia is the most common reason for laser myopia surgery. In the myopic eye, which is too long or too convergent, the image is formed in front of the retina : distance vision is blurred while near vision remains clear. To correct myopia, the excimer laser flattens the centre of the cornea, reducing its optical power and shifting the focal point back onto the retina.
LASIK corrects low, moderate and high myopia, generally up to approximately -8 to -10 dioptres, provided corneal thickness is sufficient. Beyond this range, or when the cornea is too thin, other options are considered (phakic implant such as ICL). Laser correction of myopia is stable and permanent : once the cornea has been reshaped, myopia does not recur. However, it does not prevent presbyopia, which naturally develops around age 45, nor does it eliminate the need for possible retinal monitoring in highly myopic patients.
Astigmatism is very often associated with myopia ; LASIK corrects it during the same procedure. The astigmatic eye has a cornea that is not spherical but toric (oval-shaped, like a rugby ball) : light is not focused at a single point, resulting in distorted and doubled vision at all distances. To correct astigmatism, the excimer laser applies an asymmetric ablation that regularises the two meridians of the cornea and restores a spherical shape.
LASIK treats myopic, hyperopic and mixed astigmatism, most often up to approximately 5 dioptres of cylinder. Precision is further enhanced by customised treatments guided by aberrometry (wavefront) or corneal topography, which finely map the irregularities specific to each eye. This is one of the great advantages of laser surgery : a tailored correction of astigmatism, axis by axis, impossible to achieve as precisely with spectacles.
LASIK also corrects hyperopia, most often up to approximately +4 dioptres. In the hyperopic eye, which is too short, the image is formed behind the retina : vision is tiring, especially at near distances. Here, the laser steepens the periphery of the cornea to increase its power and bring the focal point forward onto the retina. Correction of hyperopia requires a slightly broader ablation ; its indication and stability are assessed during the preoperative evaluation.
The term LASIK encompasses several technological variants. Femto-LASIK (or "all-laser") refers to the modern technique in which the flap is created using a femtosecond laser, without a mechanical blade : it is the safest, most reproducible, and most precise approach. SMILE is a related technique, without a flap, in which a thin corneal lenticule is extracted through a micro-incision ; it is reserved for certain cases of myopia and astigmatism. PRK, on the other hand, acts on the surface without cutting a flap.
Regardless of the technique, the outcome is optimized through several refinements :
The procedure is intended for patients bothered by a refractive error whose vision has been stable for at least one year. To be a candidate for LASIK, the following criteria must be met :
When the cornea is too thin or irregular, surface PRK is often preferable. Only the preoperative assessment can confirm that LASIK is the safest technique for your eyes.
No procedure is performed without a thorough pre-operative assessment. This painless examination lasts approximately one hour and is entirely critical to ensuring a safe outcome. It includes :
Important : contact lenses must be removed several days (soft lenses) to several weeks (rigid lenses) before the assessment, as they temporarily distort the cornea and compromise measurement accuracy.
LASIK is performed on an outpatient basis in six steps. You remain awake, lying comfortably ; the procedure on both eyes takes approximately fifteen minutes.
One of the major advantages of LASIK is the speed of recovery. In the hours following the procedure, a gritty sensation, tearing, and light sensitivity are normal. Vision clears by the same evening and becomes sharp by the next day :
You should avoid rubbing your eyes, exposure to dust, swimming, and contact sports for one to two weeks, and protect your eyes from sunlight.
LASIK ranks among the most effective surgeries in modern medicine. A landmark meta-analysis of nearly 68 000 eyes found 99.5 % of eyes achieving an uncorrected acuity of at least 20/40, approximately 91 % (90.8 %) achieving 20/20 without correction, and a rate of loss of two lines of acuity below 1 % (Sandoval et al., J Cataract Refract Surg, 2016). Compared with PRK, LASIK offers a faster recovery and less pain, with an equivalent outcome at one year (Cochrane review, Shortt et al.). The result is stable and permanent; an enhancement remains possible in rare cases.
LASIK is a safe procedure, proven across millions of cases, but like any surgical intervention it carries risks, most often minor and transient:
Adherence to contraindications and the quality of the preoperative assessment reduce these risks to a minimum.
LASIK is not performed in the presence of: keratoconus or an excessively thin cornea, unstable refraction, pregnancy or breastfeeding, severe dry eye, certain corneal or autoimmune diseases, and in patients under 18 years of age. In several of these situations, PRK or a phakic implant may be offered.
LASIK and PRK correct the same refractive errors — myopia, astigmatism, hyperopia — with the same excimer laser, but differ in their approach. With its flap, LASIK offers recovery within 24–48 h and excellent immediate comfort. PRK, which works on the surface without a flap, is preferred for thin corneas, contact-sport athletes, and certain high-exposure professions. In the long term, both techniques deliver equivalent results.
Refractive surgery is not covered by the French national health insurance (Assurance Maladie) as it is considered an elective procedure. However, many supplementary health insurance plans (mutuelles) offer a "refractive surgery" package covering all or part of the procedure ; it is advisable to check your coverage. The cost depends on the technique and the correction required ; a clear and detailed quote is provided during the preoperative consultation, with no obligation.
No. The eye is anaesthetised with drops: during the procedure you feel no pain, at most slight pressure. In the following hours, a gritty sensation and tearing are common but temporary.
LASIK corrects myopia up to approximately −8 to −10 diopters, provided the cornea is sufficiently thick. Low and moderate myopia are the ideal indications; beyond that, a phakic implant (ICL) may be offered.
Yes, and with great precision. Astigmatism, often associated with myopia, is corrected at the same time through asymmetric ablation guided by topography or aberrometry, up to approximately 5 diopters of cylinder.
Very quickly: most patients see clearly by the next day and resume normal activities within 24 to 48 hours. Vision fully stabilises within a few weeks.
Yes, the laser correction of myopia and astigmatism is stable and permanent. However, the procedure does not prevent presbyopia (around age 45); an enhancement is possible in rare cases.
Yes. LASIK is performed on both eyes during the same session, which lasts about fifteen minutes in total. This is a comfort advantage over PRK.
Femto-LASIK is the modern form of LASIK: the corneal flap is created with a femtosecond laser rather than a mechanical blade, making it the safest and most reproducible approach. The subsequent step (excimer laser reshaping) is identical.
The majority of patients report no lasting discomfort. Halos or glare at night may occur in the first few weeks and then subside. Pupil diameter measurement during the assessment helps limit this risk.
An eye-tracking system re-centres the laser beam in real time on the eye's micro-movements, hundreds of times per second. In the event of a sudden movement, the laser stops automatically and resumes once the eye is re-centred.
Office work can be resumed within 1 to 2 days. Non-contact sports are possible after about one week, and swimming and contact sports after two to three weeks.
LASIK is performed from age 18, once refraction has been stable for at least one year. There is no strict upper age limit, but after 45 presbyopia is factored into the treatment strategy.
No, refractive surgery is not covered by the French national health insurance (Assurance Maladie). However, many supplementary insurance plans offer a dedicated allowance covering all or part of the procedure.
Dr Gozlan, holder of the University Diploma in Refractive Surgery and Phacoemulsification, assesses your LASIK eligibility during a comprehensive evaluation and determines with you the technique best suited to your eyes.
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