Photorefractive keratectomy (PRK) was introduced more than 25 years ago as a corneal refractive surgical technique using the Excimer laser. The advent of laser-assisted in situ keratomileusis (LASIK) led to a decline in the popularity of PRK. Nevertheless, there is a recognition that surface ablation has several potential advantages with regard to preserving corneal biomechanical integrity and avoiding intraoperative and late flap-related complications.
The purpose of this study is to evaluate postoperative pain, corneal epithelial healing, development of corneal haze, refractive outcomes, and corneal aberrations in a novel one-step, modified keratectomy (PRK), termed All-surface laser ablation (ASLA), compared to conventional, transepithelial photorefractive alcohol-assisted PRK.
In the study, 60 eyes of 30 myopic patients were prospectively recruited to a randomized fellow eye study. Patients underwent conventional alcohol-assisted PRK in one eye (control group) and ASLA-modified transepithelial PRK in the other (30 eyes in each treatment arm).
The results of the study are as follows. At 3 days after surgery, the average pain score was 64% lower in the ASLA group (P , 0.0005). At this point, 96% of ASLA eyes had no epithelial defect, whereas 43% in the alcohol-assisted group did not achieve complete epithelial healing, and required replacement of bandage contact lens. The haze level was consistently lower in the ASLA group at all time points from 1 to 6 months.
This study shows that the ASLA technique may have a future role in refractive surgery, due to the fact that it offers faster epithelial healing, lower pain scores, and significantly less haze formation.
This article gives a good comparison of alcohol-assisted PRK against the modified ALSA technique stated here, which is the same as the TransPRK that is possible by the SCHWIND Amaris Excimer lasers. Definitely worth a read for people who are interested in the development of TransPRK from conventional PRK and after the development of LASIK and Epi-LASIK. It does also mention about the past form of TransPRK which was conducted using 2 steps. Do take some time to study this article to help you better understand TransPRK.