Comparisons between conventional, transepithelial PRK inconclusive
ATHENS, Greece — Review and meta-analysis of the current literature show that transepithelial PRK leads to faster healing of the epithelium and maybe less pain, but it is not clear whether visual outcomes are better as compared with conventional PRK.
“Comparisons are inconclusive because of inconsistencies in the use of MMC and postoperative medications because the length of follow-up varies and the nomograms vary,” Dan Epstein, MD, PhD, said at the European Society of Cataract and Refractive Surgeons Winter Meeting. “Overall, the message is confusing and somewhat contradictory.”
Transepithelial PRK evolved from a double-step to a single-step procedure in which epithelial thickness has become part of the nomogram for ablation. Nomograms were modified several times, and in this respect, transepithelial PRK is still a work in progress.
“The procedure now used shows superiority to conventional PRK when it comes to safety indexes and postoperative complications, but data on efficacy vary considerably and on the whole long-term efficacy seems comparable,” Epstein said.
Advantages that the literature consistently confirms are the shorter operation time and epithelial healing time.
“The average is 2.5 days as compared with the 3.7 days of conventional PRK, quite remarkable. All eyes achieve complete re-epithelialization by day 3,” Epstein said.
Haze is also less likely because transepithelial ablation leads to less keratocyte loss, a lower inflammatory response and a smoother bed contour.
Patients report lower degrees of pain, but this parameter is difficult to evaluate because of the varying postoperative medication regimens.
“Predictability seems excellent, but for all refractive procedures there are such enormous ranges in UDVA results, from 50% to 95%, that we are quite unable to say which is best,” Epstein said. – by Michela Cimberle
Epstein D. The transepithelial approach: a re-birth of PRK. Presented at: ESCRS Winter Meeting; Feb. 15-17, 2019; Athens, Greece.
Disclosure: Epstein reports no relevant financial disclosures.