Efficacy and safety of transepithelial photorefractive keratectomy

Abstract

Transepithelial photorefractive keratectomy (PRK) was introduced to prevent complications from conventional PRK and femtosecond laser-assisted laser in situ keratomileusis (LASIK). In the 2-step platform, phototherapeutic keratectomy is followed by PRK. It did not show notable safety or efficacy superiorities over conventional PRK. In the conventional single-step transepithelial PRK, ablation of epithelium and stroma occurs in a single continuous session by an Amaris laser. It showed better comparative safety results. Reverse single-step transepithelial PRK and the platform using smart-pulse technology were recent improvements in the single-step Amaris laser. They provide a smoother postablative stromal bed counter. In the refined single-step platform, a modified nomogram is used for determination of ablation parameters, along with modifications in postablative measures. It yielded better comparative results in hyperopia. Controlled trials comparing reverse, smart-pulse technology-equipped, or refined platforms of single-step transepithelial PRK with other modern laser-assisted methods could provide more robust evidence on the topic. Some key elements with significant roles in post-transepithelial PRK outcomes are discussed.

Real-world Comparison of StreamLightTM trans-PRK and Conventional PRK With Regard to Refractive Outcome, Wound Healing, Pain Intensity and Visual Recovery Time

“…In mean, the pain score of tPRK patients was 5.4, only half as high as the PRK patients' pain score of 10.8. This is in line with the results from other clinical studies on tPRK, indicating that postoperative pain after tPRK is lower compared to conventional PRK [10,11,13].…”

Corneal biomechanical properties after SMILE versus FLEX, LASIK, LASEK, or PRK: a systematic review and meta-analysis

“…After epithelial removal, an excimer laser is used to remodel the cornea [3]. The most frequent complication of PRK is postoperative pain [4]. Soon after the development of PRK, laser-assisted in situ keratomileusis (LASIK), which was approved by FDA in 1998, [5] replaced PRK and has been the predominant refractive surgery worldwide since the 1990s [6–8].…”

Fellow eye comparison between alcohol-assisted and single-step transepithelial photorefractive keratectomy: late mid-term outcomes

“…Consequently, both techniques can be considered effective and safe for the correction of moderate myopic and astigmatic errors. Recently, Adib-Moghaddam et al published a complete review on single-step TransPRK, and their conclusions are similar [ 26 ].…”

“…Laser epithelial debridement previous to ablation of the stroma has been used from early 1990, but the technique was not popularized because it was a two-step procedure and, in addition, either the laser de-epithelization was not complete and a supplementary mechanical removal of the remnant epithelium was needed or the surgeon had to use various subtle signs (such as the dissipation of the autofluorescence of the epithelium) to determine when epithelial ablation was complete [ 5 - 10 ]. It was not until 2009 that a system was developed to perform epithelial and stromal ablation in one step in a predictable manner (Schwind Amaris, Schwind eye-tech-solutions GmbH, Kleinostheim, Germany) and this approach has been reported to have similar refractive results as PRK and possibly some advantages like less post-operative pain, less epithelial erosion-related symptoms, shorter epithelial closure time and in some studies less corneal haze [ 11 - 26 ]. The purpose of the present study was to evaluate the outcomes, comparing alcohol-assisted PRK and single step TransPRK techniques, considering refractive results, aberrometry, contrast sensitivity test, Objective Scatter Index (OSI, measured by AcuTarget®, Visiometrics SL, Cerdanyola del Vallès, Spain) and tear film stability assessed by serial measurements of OSI with a late mid-term follow-up time (minimum 30 months and a mean of 35.2 +/ - 5.0 months) using a contralateral (fellow eye) approach.…”