Single-step transepithelial versus alcohol-assisted photorefractive keratectomy in the treatment of high myopia: a comparative evaluation over 12 months.

Background/aims: To evaluate refractive outcomes of single-step transepithelial photorefractive keratectomy (TransPRK) versus alcohol-assisted PRK (EtOH-PRK) for the correction of high myopia.

Methods: This was a retrospective non-randomised comparative study conducted at the American University of Beirut Medical Center, Beirut, Lebanon. Eyes with myopia (spherical equivalent (SE) larger than -6.00 D) that had undergone EtOH-PRK treatment combined with mitomycin C and TransPRK (SE: -7.53±0.90 D and -7.24±0.77 D, p=0.062), using the Schwind Amaris excimer laser, were included. 59 eyes (37 patients) that had single-step TransPRK were compared with 59 eyes (36 patients) that had EtOH-PRK. Visual and refractive outcomes, including analysis of astigmatism, and corneal higher order aberrations (HOAs) at 6.0 mm optical zone, were compared for 12 months postoperatively.

Results: Baseline characteristics were similar between the two groups (p>0.05). The SE deviation from target (SEDT) at 1 week, 1, 3, 6 and 12 months follow-up visits were similar between groups (p=0.428). At 12 months, 81.3% and 73.3% of eyes that had undergone TransPRK and EtOH-PRK, respectively, were between ±0.50 D SEDT (p=0.381). Mean cylinder power was 0.33±0.26 D versus 0.41±0.30 D at 12 months follow-up (p=0.140). The mean success index was 0.50±0.50 for the TransPRK group and 0.49±0.52 for the EtOH-PRK group (p=0.939), while the absolute mean angle of error was 7.81°±61.98° vs 13.12°±71.86° (p=0.667), respectively. The change in total, spherical and comatic corneal HOAs were similar in both groups at 12 months (p>0.05). Haze was similar between both groups; two eyes had +1 haze at 12 months in the TransPRK group versus zero eyes among the EtOH-PRK group (p=0.154).

Conclusions: Single-step TransPRK for high myopia with or without astigmatism appears to yield similar visual, refractive and safety results as EtOH-PRK.