All these surface techniques ultimately achieve the same visual result as the techniques with a Lasik or femtolasik cut after a few weeks or even a few months. This is quite understandable, as in all cases, the excimer laser that treats the visual defect is the same; the only difference is the approach used to apply it: either on the surface or under a corneal flap.
La PKR
First technique with Excimer laser used in the world:
Photorefractive Keratectomy (PRK) consists of flattening the center of the cornea in myopic patients and the periphery of the cornea in hyperopic patients by directly applying the Excimer laser to the surface of the cornea, without previously cutting a corneal flap.
Initially, a simple abrasion of the superficial layer of the cornea (the epithelium) is performed, either through mechanical abrasion or by applying alcohol.
At the end of the procedure, for high myopia, a mitomycin-based eye drop can be applied, and often a therapeutic contact lens is used for a duration of 1 to 4 days in continuous wear.
This is a proven method with long-term results that are exactly comparable to those of Lasik after a few months.
It is also known that the procedure is 99.9% free from the risk of ectasia (serious postoperative corneal deformation), which is why, in the presence of even minor thickness or shape abnormalities of the cornea, PRK or another surface technique is preferred over Lasik.
It has two major disadvantages: postoperative pain lasting 2 to 3 days and a slower visual recovery (1 to 2 weeks), sometimes complicated by a more or less persistent "haze" (scarring fog).
Disadvantages
– The short-term comfort of PRK is significantly worse than that of Lasik. In comparative studies, more than 90% of patients prefer Lasik to PRK.
– The pain induced by PRK is real and lasts on average 3 days. It requires pain relief treatment, but the effect is often only partial.
Each individual has a personal sensitivity threshold, and some tolerate PRK quite well, while others do not.
The recovery time for vision is longer than for Lasik.
Vision improves over the first few weeks but with fluctuations.
Visual acuity begins to stabilize with a feeling of slight blur, which gradually dissipates during the first month. Returning to professional activities is possible as early as the third day.
Wearing tinted glasses (sunglasses) is recommended in cases of strong light exposure.
By the third month, vision will be similar to that achievable with Lasik.
Serious complications from PRK are extremely rare. It is, therefore, a very safe technique.
La PKR (PhotoKératectomie Réfractive) et la TransPKR (Transépithéliale PKR) sont deux techniques de chirurgie réfractive utilisées pour corriger des défauts visuels comme la myopie, l’astigmatisme, et dans certains cas, l’hypermétropie. Bien que similaires dans leur objectif, elles diffèrent dans leur approche chirurgicale, leur confort post-opératoire, et leur processus de guérison. Comparons-les pour mieux comprendre leurs avantages respectifs.
LASEK:
This is another surface technique in which the epithelium is detached with alcohol and repositioned at the end of the procedure, which can, inconsistently, accelerate healing. It is now very rarely practiced.
Of all the surface techniques, we prefer Trans-PKR since we have experienced it, as it combines the advantages of PKR while minimizing the disadvantages.
Good evening
except that there is no contact with the laser. What is the difference between trans-PCR and PRK?
Thank you
Hello,
With the Trans-PKR technique, the same excimer laser vaporises the epithelium and resurfaces the corneal surface in a single step to correct the visual defect.
Trans-PKR is the only 100% laser technique, with no contact whatsoever with the patient's eye. It combines all the safety advantages of PRK, of which it is an improvement, with less pain and faster results than traditional PRK.
Sincerely,
Dr Marc Chemla