title: Comparison of visual acuity, higher-order aberrations and corneal asphericity after refractive lenticule extraction and wavefront-guided laser-assisted in situ keratomileusis for myopia.
abstract: OBJECTIVE
  To compare postoperative visual acuity, higher-order aberrations (HOAs) and corneal asphericity after femtosecond lenticule extraction (FLEx) and after wavefront-guided laser-assisted in situ keratomileusis (wfg-LASIK) in myopic eyes.
  
  
  METHODS
  We examined 43 eyes of 23 patients undergoing FLEx and 34 eyes of 19 patients undergoing wfg-LASIK to correct myopia. Ocular HOAs were measured by Hartmann-Shack aberrometry and corneal asphericity was measured by a rotating Scheimpflug imaging system before and 3 months after surgery.
  
  
  RESULTS
  There was no statistically significant difference in uncorrected (p=0.66 Mann-Whitney U-test) or corrected distance visual acuity (p=0.14) after two surgical procedures. For a 6-mm pupil, the changes in fourth-order aberrations after FLEx were statistically significantly less than those after wfg-LASIK (p<0.001). On the other hand, there were no statistically significant differences in the changes in third-order aberrations (p=0.24) and total HOAs (p=0.13). Similar results were obtained for a 4-mm pupil. The positive changes in the Q value after FLEx were statistically significantly less than those after wfg-LASIK (p=0.001).
  
  
  CONCLUSIONS
  In myopic eyes, FLEx induces significantly fewer ocular fourth-order aberrations than wfg-LASIK, possibly because it causes less oblation in the corneal shape, but there was no statistically significant difference in visual acuity or in the induction of third-order aberrations and total HOAs. It is suggested that FLEx is essentially equivalent to wfg-LASIK in terms of visual acuity and total HOA induction, although the characteristics of HOA induction are different.
authors.affiliation: Department of Ophthalmology, University of Kitasato School of Medicine, Sagamihara, Kanagawa, Japan. kamiyak-tky@umin.ac.jp
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Kamiya
authors.forename: Kimiya
authors.initials: K
authors.lastname: Shimizu
authors.forename: Akihito
authors.initials: A
authors.lastname: Igarashi
authors.forename: Hidenaga
authors.initials: H
authors.lastname: Kobashi
authors.forename: Mari
authors.initials: M
authors.lastname: Komatsu
mesh_terms: D057128:Aberrometry; D000293:Adolescent; D000328:Adult; D003315:Cornea / Q000473:pathology* / Q000601:surgery; D057108:Corneal Wavefront Aberration / Q000503:physiopathology / Q000517:prevention & control*; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ; D054018:Lasers, Excimer / Q000627:therapeutic use*; D028022:Low-Level Light Therapy; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D011184:Postoperative Period; D012189:Retrospective Studies; D013524:Surgical Flaps; D014792:Visual Acuity / Q000502:physiology*; D055815:Young Adult