Mini-PRK for Myopia in Patients with Thin Corneas

Enhanced comfort with customised PRK technique. Dermot McGrath reports from the 2022 ESCRS Winter Meeting.

Anew minimally invasive customised myopic photorefractive keratectomy (PRK) technique delivers rapid visual rehabilitation and a more comfortable postoperative recovery when compared to traditional PRK and may offer an attractive alternative to either LASIK or SMILE for myopic corrections in appropriate patients, according to A John Kanellopoulos MD.

“This novel PRK technique may minimise pain and visual debilitation by accelerating re-epithelialization and early visual recovery. By using this approach, we make patients very happy because this is a very seamless procedure similar to LASIK or SMILE. It gives us another option for patients with thin corneas, as not every eye is made for a lamellar refractive procedure,” Dr Kanellopoulos told a Cornea Day session.

The mini-PRK procedure aims to essentially bypass some of the known disadvantages of traditional PRK, particularly in terms of visual recovery and postoperative comfort, Dr Kanellopoulos explained.

“The question is why we would consider doing PRK in a practice that we have advocated throughout the years as mainly focused on lamellar procedures? And the answer is that looking at the epithelial maps of patients where the corneal thickness is shallowing abruptly and living and practicing in a country where one out of 20 people has keratoconus, we need to have other options for these thinner corneas that are not suitable for LASIK or SMILE,” he said.

Dr Kanellopoulos’ prospective case series included 104 eyes of 52 patients who underwent PRK for bilateral myopia or myopic astigmatism. Epithelial removal was performed using the Epi Clear™ epikeratome (ORCA Surgical) using customised shape and diameter to denude a 6.5 mm to 7.0 mm disk from the central cornea.

“This is really the only key difference from the classic PRK protocol: We use the epikeratome to de-epithelialize the cornea, but only the diameter of the central cornea necessary for the ablation. We’re looking at a very small amount of corneal epithelium being removed, and the trick is to make sure to be able to see the shiny, polished surface of Bowman’s membrane, because otherwise, the surgeon may leave an island of epithelium behind that will interfere with the ablation. So, there is a little bit of a learning curve, and you cannot always obtain the exact deepithelialization you require,” Dr Kanellopoulos noted.

The results showed minimal postoperative pain and discomfort for most patients. All eyes were re-epithelialized by day four and all eyes

attained 20/25 immediately after the procedure and out to day four.

“The pain scores clearly showed the eyes that [received] the mini-PRK treatment greatly outperformed those [with] the epithelium removed [through] the transepithelial approach or alcohol de-epithelialization,” he said.

Visual recovery was also extremely rapid after mini-PRK treatment.

“All of the eyes were at least 20/25 when the patient walked out of the laser room after mini-PRK. And this is very different from traditional PRK, at least in my experience practicing all these years, where visual rehabilitation is much slower after surgery,” he said.

Dr Kanellopoulos concluded by saying this minimally invasive PRK approach offers clear advantages over traditional PRK and could provide a viable alternative to either SMILE or LASIK for select cases.

“The question is why we would consider doing PRK in a practice that we have advocated throughout the years as mainly focused on lamellar procedures?”

A John Kanellopoulos MD is Clinical Professor of Ophthalmology at New York University Medical School, USA, and Medical Director of LaserVision Clinical & Research Institute, Athens, Greece. ajk@brilliantvision.com

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