title: Femtosecond-Assisted LASIK Versus PRK: Comparison of 6-Month Visual Acuity and Quality Outcome for High Myopia.
abstract: OBJECTIVE
  To compare the results of femtosecond-assisted laser in situ keratomileusis (femto-LASIK) and photorefractive keratectomy with mitomycin C (PRK-MMC) for the correction of myopia more than 7.0 diopters (D).
  
  
  METHODS
  In this comparative nonrandomized trial, 60 eyes (30 eyes in each group) were enrolled. Patients were tested for uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent, ocular and corneal aberrations, and contrast sensitivity (CS) before surgery and at 3 and 6 months postoperatively.
  
  
  RESULTS
  Mean preoperative myopia was -8.65±1.51 and -8.04±1.70 D in the femto-LASIK and PRK-MMC groups, respectively (P=0.149). Intergroup differences in baseline indices were not statistically significant. At 6 months after surgery, UDVA showed an improving trend, but it was better in the femto-LASIK group (P=0.026). CDVA in the two groups remained similarly unchanged (P=0.170). For the femto-LASIK and PRK-MMC groups, the safety indices were 1.01±0.05 and 1.01±0.14 (P=0.949), respectively, and the efficacy indices were 0.99±0.07 and 0.93±0.22 (P=0.192), respectively. Comparing CS, only CS18 showed a significantly greater decrease in the femto-LASIK group compared with the PRK-MMC group (P=0.016). Intergroup differences were not statistically significant in other spatial frequencies. Changes in the ocular and corneal higher order aberrations were not statistically different between the two groups except ocular coma, which increased in the femto-LASIK group (P=0.041).
  
  
  CONCLUSIONS
  Femto-LASIK improves UDVA better than PRK-MMC in high myopia. However, because of increased coma, the quality of vision is reduced. In other words, visual acuity outcome is better with femto-LASIK and visual quality outcome is better with PRK-MMC.
authors.affiliation: Noor Ophthalmology Research Center (H.H., M.M.), Noor Eye Hospital, Tehran, Iran; Eye Research Center (R.G.), Tehran University of Medical Sciences, Tehran, Iran; and Department of Epidemiology and Biostatistics (S.A.), School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Hassan
authors.initials: H
authors.lastname: Hashemi
authors.forename: Mohammad
authors.initials: M
authors.lastname: Miraftab
authors.forename: Reza
authors.initials: R
authors.lastname: Ghaffari
authors.forename: Soheila
authors.initials: S
authors.lastname: Asgari
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D054018:Lasers, Excimer / Q000627:therapeutic use; D008297:Male; D016685:Mitomycin / Q000008:administration & dosage; D047728:Myopia, Degenerative / Q000503:physiopathology / Q000601:surgery*; D018903:Photorefractive Keratectomy / Q000379:methods*; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult
chemical_list: D016685:Mitomycin