The procedure is performed under topical anesthesia with the application of special drops. The surgeon then cuts the cornea with specialized equipment called a microkeratome, creating a flap that is lifted. The patient then undergoes the laser treatment prescribed for each patient. The patient's sick leave lasts only 24 to 48 hours.

Another alternative is to not create a corneal flap, but instead perform the treatment by applying the laser directly to the cornea, without making any cuts.

This technique is called Trans-PRK. It has the advantage of being technically simpler for both the surgeon and the patient, and it can be used on thinner corneas. On the other hand, Trans-PRK requires more recovery time, and vision is blurred for about 10 days.  

To be a candidate for refractive surgery, the patient must be at least 18 years old, have refractive stability of the defect for at least 1 year, undergo an exam called corneal topography which must be normal, and have reasonable postoperative expectations.

The great advantage of using lasers to correct visual defects is their maximum precision. Excimer laser surgery can be of two types:

LASIK: In addition to the Excimer Laser, an automated scalpel (microkeratome) is used to lift a layer of the cornea approximately 130 microns thick, allowing the laser to be applied within the thickness of the cornea.

Surface ablation: The first superficial layer of the cornea is scraped and the laser is applied directly to the surface.

It is reserved for cases where the cornea is very thin and cannot be cut with the microkeratome. The laser literally evaporates corneal tissue, thereby reshaping the shape of the cornea, making it flatter in cases of myopia and more curved in cases of hyperopia.

In the hands of an excellent surgeon, with the most advanced technology, adequate experience, and compliance with all requirements, it is highly safe. However, like any other surgery, it carries inherent risks. These include infection, inflammation, and corneal scarring, among others. Fortunately, the likelihood of these risks occurring is very low, but if they do occur, they can leave visual aftereffects.

The best candidate for this procedure is anyone who is dissatisfied with their glasses or contact lenses and wants to stop depending on them. Some of the requirements to be a good candidate for laser surgery are:

• Over 18 years old.
• The refractive error must be stable.
• The eye must not have any disease that would impair its function. Therefore, the absence of glaucoma, keratoconus, and other ocular diseases must be confirmed.
• Corneal thickness must be adequate (greater than 500 microns). To determine these characteristics, specialized examinations such as corneal topography and pachymetry are essential.
• When refractive errors are greater than approximately 8 diopters and 5 diopters of hyperopia or astigmatism, it is very difficult to achieve adequate correction with laser surgery, and the recommended option is surgery to place a permanent intraocular lens.

Additionally, in patients over 50 years of age, this type of excimer laser surgery is generally not ideal, and another, slightly more complex type of operation may be required, called phacoemulsification plus intraocular lens implantation for refractive purposes.

Local anesthesia is used for the procedure, so the patient remains awake during the treatment. However, since their eyes are anesthetized, there is no pain and, in general, only minimal discomfort.

Laser correction of distance vision is long-term. When patients reach the age of 50 or 60, they are at normal risk of developing another vision-affecting disease: cataracts. In a small percentage of cases (less than 5%), the defects may progress or regress, but generally at levels well below the initial defect.

Regarding near vision (reading and other near vision activities), it is very important to understand that, due to the onset of presbyopia, every patient who undergoes surgery on both eyes for distance vision will require reading glasses after the age of 40.

The first thing you should do is attend a specialized optometry and ophthalmology consultation. Detailed examinations will be performed to determine if you are a good candidate for laser surgery and to rule out any medical conditions that might prevent the procedure.

If you are a good candidate, the ophthalmologist will give you instructions and recommendations you should consider before the procedure to ensure its quality.

Finally, your surgery is scheduled for the nearest date or the day you consider most convenient.

If you wear soft contact lenses, you should discontinue use before undergoing pre-surgery examinations: one week if they are soft and two weeks if they are rigid.

Basic Care

• The patient may notice some additional fatigue or difficulty focusing, and sometimes a feeling of dizziness. All of this is normal during the initial period.
• During the first three months it is essential not to rub your eyes and avoid any possibility of hitting them (do not practice contact sports)
• Physical exertion in itself does not pose any problems; the patient can practice aerobics, lift weights, etc., a few days after surgery.
• It is recommended to avoid entering swimming pools, the sea or Turkish baths for 3 weeks (due to the risk of contamination) and not to wear eye makeup for two weeks.
• Whenever riding a motorcycle or bicycle, it is essential to wear appropriate protective eyewear to prevent foreign bodies from entering the eye.
• It is advisable to protect yourself from the sun with dark glasses.
• It is very important to apply all the drops according to the instructions.