Making the Case for PRK

Back to the surface with trans-PRK approach. Dermot McGrath reports

Although LASIK or SMILE procedures remain the principal focus of most refractive surgery practices, there is still a viable place for surface ablations using the latest laser platforms, according to Alexandre Denoyer MD.

“I have been performing more and more surface ablations in my practice and I believe there are some compelling arguments to justify it in terms of safety and patient satisfaction,” Prof Denoyer said at the online annual meeting of the French Implant and Refractive Surgery Association (SAFIR).

Prof Denoyer, head of department of anterior eye surgery at University Hospital of Reims, France, noted surface treatments respect the biomechanical integrity of the cornea, unlike LASIK or lenticule extraction procedures.

“The sub‐basal nerve fibres are not affected by a surface procedure, and we know that the nerve re-composition in LASIK is not always total even if there is a reorganisation of the corneal nerve bundles in the months after surgery,” he said.

Problems of haze, often highlighted as one of the main reasons why PRK fell out of favour, are far less of an issue with the optimised surface ablation profiles used by today’s laser platforms, added Prof Denoyer.

Several excimer laser platforms now propose trans-PRK software options including SmartSurf (Schwind Amaris), TransEpi PRK (Bausch + Lomb Technolas), cTen (iVis Technologies) and Streamlight (Alcon Wavelight).

The basic concept is to employ an all-laser “no touch” surgery with trans-PRK, explained Alexandre Denoyer.

“It is one procedure with three key steps: an epithelial photoablation, a stromal photoablation, and a complementary photoablation for 'smoothing' the corneal surface. It’s a totally non-contact surgery in the sense that no instruments are used apart from the laser, and it has been shown that the healing with trans-PRK is even faster than after a standard surface ablation procedure,” he said.

In terms of outcomes, Prof Denoyer said that the results have been shown to be equivalent to traditional PRK treatments or LASIK and SMILE.

“For mild or moderate myopia with or without astigmatism the results are comparable to LASIK and SMILE. For hyperopia and severe astigmatism, there is a widespread perception that LASIK will perform better,” he said.

Another compelling reason to use trans-PRK is the issue of retreatments after LASIK or SMILE: “The efficacy of surface ablation retreatments is another advantage as it gives the same results as re-lifting the flap in LASIK without the risk of epithelial ingrowth which has been shown to be as high as 13% after flap re-lift,” he said.

Prof Denoyer added that further studies are needed to determine if postoperative pain is less than with traditional PRK. Issues of transient haze may still occur with trans-PRK due to laser heating the corneal surface when ablating the epithelial layer, but the effect can be attenuated by ensuring a brief pause between the epithelial ablation and the stromal ablation to allow the surface to cool, he concluded. adenoyer@chu-reims.fr – alexandredenoyer.com

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