The Trans PKR (Trans-Epithelial PKR) is a recent improvement of PKR.
From a purely technological standpoint, it is not strictly speaking a revolutionary technique, but in practical terms and for patients, provided certain rules and indications are followed, it can become so and radically change our daily approach to refractive surgery.
To understand what Trans-PKR is, one must first know its predecessor: PKR.
Essentially, all refractive surgery operations can be divided into two families:
1- Surgeries involving the creation of a flap in the patient's cornea:
Classic Lasik Type (15 years of feedback): the flap is made with a microkeratome, a type of micro-surgical planer.
Or Femtolasik: the flap is created with a first laser called femtosecond (over 10 years of feedback).
In both cases, the difference lies only in the tool used to create the flap, but the Excimer laser that treats the visual defect (myopia, astigmatism…) is identical in all cases.
2- Surface Excimer Laser Procedures:
There is no flap, no cutting, but a very superficial peeling of the epithelium that is much less aggressive to the cornea.
The PKR is the oldest of the techniques (25 years) and is experiencing a resurgence of interest for various reasons:
There is no corneal flap, no cutting, resulting in significantly fewer serious complications, most of which are due to issues in creating the flap. Furthermore, the latest generation lasers produce less haze (scarring fog) and therefore allow for faster visual recovery than in the past.
Interestingly, and this can sometimes be difficult for patients to understand, although the PKR treatment is more superficial and less deep than in Lasik (since there is no cut flap in the cornea), it is more painful post-operatively, and visual rehabilitation takes longer.
The main drawback is therefore this post-operative pain (the operation itself is almost painless), but the pain begins an hour after and can last 24 to 48 hours. The pain is directly proportional to the degree of myopia treated: relatively mild for small myopias.
The healing phenomena (more or less significant haze) that can slow down or diminish the visual outcome have also been improved today by the new treatment profiles of the latest generation lasers. The placement of a therapeutic contact lens post-operatively and/or the use of Mitomycin eye drops can help mitigate post-operative discomfort and thus broaden the indications for PKR.
An important note: the laser that corrects the visual defect (myopia, astigmatism, hyperopia, or presbyopia) is the same as in Lasik; only the preparatory steps change depending on the techniques.
Let’s forget the other surface techniques like Lasek (lasek and not lasik), which is no longer offered today.
Let’s also set aside epilasik, which is also less practiced and is essentially a variant of PKR. The name “epilasik” can sometimes mislead patients into thinking they will benefit from a sort of Lasik, which is absolutely not the case; it is equivalent to a PKR but still has some convinced supporters today.
3- Now let's talk about the Trans-PKR:
In a "normal" PKR, the epithelium must be scraped or peeled superficially:
- This can be done mechanically with a spatula or with a small rotating brush,
- or with alcohol, which still involves some direct manipulation of the eye with surgical instruments and the prior placement of an eyelid retractor.
In the 90s, it had already been proposed to get rid of this epithelium by an initial burst of laser pulses called PTK prior to PKR, but this was quite difficult to systematize and little used in practice.
Trans PKR is a technique today validated by numerous international studies and offered exclusively on Amaris lasers marketed by the German firm Schwind.
It uses this principle of laser vaporization of the epithelium: it is therefore the same excimer laser that will vaporize the epithelium and resurface the corneal surface in one go to correct the visual defect, all without the slightest contact with the patient's eye.
The advantages compared to a classic PKR are clearly established and appreciable for the patient's comfort because while retaining the safety aspect of PKR, we will be able to significantly reduce the side effects (less pain and faster recovery).
Prices for TRANS PKR:
A partir de 2 200 euros avec option SmartPulse sur le laser Amaris 1050 RS.
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