title: Comparison of Higher Order Aberrations after Wavefront-guided LASIK and PRK: One Year Follow-Up Results.
abstract: OBJECTIVE
  To evaluate the changes and predictability of higher order aberrations (HOAs) after personalized laserin situkeratomileusis (LASIK) and personalized photorefractive keratectomy (PRK) for simple myopia and compound myopic astigmatism.
  
  
  METHODS
  In this prospective cross-sectional study, 100 eyes were included. A total of 50 eyes underwent personalized LASIK and 50 eyes underwent personalized PRK. Preoperative and postoperative wavefront data were compared between the two groups. The influential factors and predictability of HOAs were also assessed.
  
  
  RESULTS
  Total HOA increased in the amount of 0.01 ± 0.14 μm for the 5 mm pupil (P= 0.55) and 0.08 ± 0.22 μm for the 6 mm pupil (P= 0.02) after PRK; however after LASIK the corresponding values for the 5 and 6 mm pupil sizes were 0.05 ± 0.12 and 0.15 ± 0.18 μm, respectively (P< 0. 001). Mean changes were not significantly different between the PRK and LASIK groups for both 5 and 6 mm pupil sizes (P= 0.21 andP= 0.13, respectively). Spherical aberration increased following LASIK more than following PRK (P< 0.001). Changes in the root mean square (RMS) of total HOA had a statistically significant negative correlation (P< 0.001) with its preoperative value. HOA and spherical aberration reduced in majority of eyes when the preoperative spherical equivalent refraction was low.
  
  
  CONCLUSIONS
  For the 6mm pupil size, the total HOA increased following both personalized PRK and LASIK with no significant difference between the two groups. Change of the total HOA RMS was influenced by the preoperative values. The known influencing factors could predict nearly 50% of the changes in total HOA.
authors.affiliation: Poostchi Eye Research Center, Department of Ophthalmology, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Seyed Hamid Reza
authors.initials: SH
authors.lastname: Jahadi Hosseini
authors.affiliation: Poostchi Eye Research Center, Department of Ophthalmology, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Seyed Mohammad Bagher
authors.initials: SM
authors.lastname: Abtahi
authors.affiliation: Poostchi Eye Research Center, Department of Ophthalmology, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Khalili
keywords: High Order Aberration; Laser in situ keratomileusis; Personalized; Photorefractive Keratectomy; Spherical Aberration; Wavefront-guided