The introduction of vision correction methods based solely on the use of the femtosecond laser(ReLEx® FLEX Refractive Lenticule Extraction – Femtosecond Lenticule Extraction; ReLEx® SMILE Refractive Lenticule Extraction – Small Incision Lenticule Extraction) opened a whole new chapter in corneal refractive surgery.
Methods of this type, or minimally invasive methods (in general surgery this includes laparoscopic methods) are called “keyhole methods.”
In the aforementioned methods, the change in the curvature of the cornea occurs as a result of stratification with a femtosecond laser of a specific part of the cornea, called the lens (lenticule), of a thickness and shape that depends on the type of visual defect. In the ReLEx® FLEX method, the lens is removed from the cornea after opening the corneal flap produced by the femtosecond laser. The ReLEx® SMILE method is one of the non-corneal methods – the corneal flap is not produced, and the lens is formed intrastromally by delaminating part of the cornea with the femtosecond laser. The lens is removed through a small (up to 4 mm) corneal incision. The painless extraction of this micro-lens (lenticule) through a pocket of several millimeters results in a change in the optical parameters of the eye, resulting in a permanent correction of the vision defect.
Micro-lens vision correction is characterized by much less invasiveness compared to other laser interventions, shorter procedure time, and relatively quick recovery – the very next day after the procedure, the patient can return to his daily duties.
The micro-lens vision correction procedure takes a few minutes and is performed on an outpatient basis, i.e. it does not require the patient to stay in the clinic.
A contraindication to laser vision correction is rapid progression of the defect within a year before the scheduled surgery. Also, people with cataracts, glaucoma, dry eye syndrome, tendencies to inflammatory eye diseases cannot undergo the procedure.
Micro-lens vision correction is a method of surgical treatment of refractive errors designed for people:
- Myopic ( from – 1.0 D to – 10.0 D)
- With astigmatism ( up to a maximum of – 5.0 D)
ReLEx® SMILE is performed more than 100 μm deep into the cornea. Initially, the VisuMax® femtosecond laser works deeper – the posterior refractive surface of the microlens is formed, which is responsible for the main power change. Later, slightly higher up, the anterior surface of the lenticule is prepared.
The ReLEx® SMILE procedure was first performed in 2007 by Walter Sekundo using ZEISS’ VisuMax® femtosecond laser, and became widely available in 2011 with the launch of ReLEx® SMILE (Carl Zeiss Meditec).
Advantages of the ReLEx® SMILE method
- This is a free method – inside the intact cornea, a so-called “free” method is created. lenticula (a thin section of the lens in the cornea). A minimally invasive incision is then made for the approach. The intraocular lens can then be removed through this small opening.
- The correction is performed exclusively with the Visumax femtosecond laser – the entire laser procedure (lens formation and incision) is done in one step, with the laser.
- The ReLEx® SMILE method can be used for high myopia, up to -10 diopters.
- No restrictions – after the procedure you can do all activities, rub your eyes, play sports, there is no danger of corneal flap displacement.
Disadvantages of the ReLEx® SMILE method
- There is no possibility of additional treatment with the same method – there is no possibility of correcting the result of the operation by repeating the ReLex SMILE method. Correction is possible with LASEK/PRK, femtoLASIK with thin corneal flap, CIRCLE methods.
- There is no possibility of using the so-called automatic static cyclorotation, important in the correction of astigmatism.
- No correction of hyperopia.
- No correction of higher-order aberrations, e.g., coma, spherical aberrations or correction of aberrations based on corneal topography (topo-guided).
