Aspheric photorefractive keratectomy for myopia and myopic astigmatism with the SCHWIND AMARIS laser: 2 years postoperative outcomes

PurposeTo evaluate mid-term refractive outcomes and higher order aberrations of aspheric PRK for low, moderate and high myopia and myopic astigmatism with the AMARIS excimer laser system (SCHWIND eye-tech-solutions GmbH, Kleinostheim, Germany).MethodsThis prospective longitudinal study evaluated 80 eyes of 40 subjects who underwent aspheric PRK. Manifest refractive spherical equivalent (MRSE) of up to −10.00 diopters (D) at the spectacle plane with cylinder up to 3.25 was treated. Refractive outcomes and corneal wavefront data (6mm pupil to the 7th Zernike order) were evaluated out to 2 years postoperatively. Statistical significance was indicated by P<0.05.ResultsThe mean manifest spherical equivalent refraction (MRSE) was −4.77±2.45 (range, −10.00D to −0.75D) preoperatively and −0.12±0.35D (range, −1.87D to +0.75D) postoperatively (P<0.0001). Postoperatively, 91% (73/80) of eyes had an MRSE within ±0.50D of the attempted. No eyes lost one or more lines of corrected distance visual acuity (CDVA) and CDVA increased by one or more lines in 26% (21/80) of eyes. Corneal trefoil and corneal higher order aberration root mean square did not statistically change postoperatively compared to preoperatively (P>0.05, both cases). There was a statistical increase in postoperative coma (+0.12μm) and spherical aberration (+0.14μm) compared to preoperatively (P<0.001, both cases).ConclusionAspheric PRK provides excellent visual and refractive outcomes with induction in individual corneal aberrations but not overall corneal aberrations