Ophtalmology

The refractive surgery is a method of surgery techniques aiming to erase refractive errors such as nearsightedness (myopia),farsightedness (hyperopia), astigmatism and presbyopia. These techniques include procedures that can be executed reshaping the cornea (laser surgery) and those based upon intraocular lenses implantation (intraocular surgery).

PRK (SURFACE ABLATION)

PRK has been used for over 30 years as a refractive surgery technique common and stable representing still  a great opportunity for those patients which cannot be treated with other more recent laser techniques.

It is recommended in case of myopia, astigmatism and mild hyperopia, furthermore it can suit to those patients presenting thin corneas or particular corneal anomalies.

PRK is an effective technique using both laser and excimer to reshape the cornea curvature and correct the refraction error.

It is performed removing the epithelium  (the cornea surface part) and applying the laser on the cornea stroma to reshape the curvature. Furthermore, this technique offers extraordinary accuracy great stability and reproducibility.

Main stages can be sum up as following:

1. PREPARATION: topical anesthetic drops are placed in the eye
2. ABLATION: corneal epithelium is removed using a micro brush
3. REFRACTIVE ERROR CORRECTION:  the excimer laser performs on the corneal curvature with variable intensity according to the visual impairment
4. CONTACT LENS: a protective contact lens is applied over the laser reshaped cornea to stimulate the epithelial regeneration.

Although this technique is particularly recommended on those eyes presenting a thin cornea and mild visual impairments, its disadvantage is that of creating a temporary wound on the eye surface. For this reason a protective contact lens is applied. The initial post-surgery is more annoying compared to the Lasik technique equivalent requiring sometimes a slowest recovery of a couple of days.

LASIK

The Lasik technique reshapes the cornea in order to correct refraction errors  such as nearsightedness (myopia), farsightedness (hyperopia), astigmatism and presbyopia thanks to the excimer laser.

Compared with PRK,  this technique requires a first eye preparation stage; a thin circular “flap” is created in the corneal surface to allow the laser treatment to be performed below the flap created. The flap can be created either using a mechanical surgical tool called microkeratome or using a femtosecond laser.

Lasik technique Pros are a faster healing and a significant reduction od disturbs related to the post-operative. In fact, the patient can restart his daily routine the day after the surgery.

Lasik Cons compared to the surface ablation are the possibility of a trauma provoking a dislocation of the flap and a dry-eye persistent condition.

Main Lasik stages can be sum up as following:

1. PREPARATION: topical anesthetic drops are placed in the eye
2. FLAP CREATION:  the microkeratome creates the corneal flap to allow the laser treatment to be performed below  (corneal stroma )
3. VISUAL IMPAIRMENT CORRECTION:  the excimer laser performs on the corneal curvature with variable intensity according to the visual impairment to be treated.
4. FLAP RELOCATION: the last stage is to lay the flap back in place, no stitches are required, allowing the tissue to heal naturally.