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.

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