title: Time course of optical quality and intraocular scattering after refractive lenticule extraction.
abstract: OBJECTIVE
  To assess the time course of optical quality and intraocular scattering in relation to visual acuity after femtosecond lenticule extraction (FLEx) for the correction of myopia.
  
  
  METHODS
  This study evaluated 36 eyes of 36 patients with spherical equivalents of -4.38±1.53 D [mean ± standard deviation] who underwent FLEx. Before surgery, and 1 week and 1, 3 and 6 months after surgery, we assessed the modulation transfer function (MTF) cutoff frequency, Strehl ratio, objective scattering index (OSI), and OQAS values (OVs), using a double-pass instrument. We also investigated the relationship of the OSI with corrected distance visual acuity (CDVA) preoperatively and postoperatively.
  
  
  RESULTS
  The mean changes in MTF cutoff frequency, Strehl ratio, OSI, OV100%, OV20%, and OV9% preoperatively and 6 months postoperatively were -5.51 ± 15.01, -0.03 ± 0.07, 0.35 ± 0.83, -0.17 ± 0.48, -0.14 ± 0.38, and -0.09 ± 0.22, respectively. We found no significant preoperative correlation between the OSI and logMAR CDVA (Spearman rank correlation coefficient r = 0.068, p = 0.69), and modest, but significant correlations 1 week and 1, 3, and 6 months postoperatively (r = 0.572, r = 0.562, r = 0.542, r = 0.540, p<0.001, respectively).
  
  
  CONCLUSIONS
  FLEx induced a transient decrease in optical quality in association with an increase in intraocular scattering in the early postoperative period, possibly due to mild interface haze formation, but gradually recovered with time. It is suggested that this transient degradation in optical quality related to an increase in the intraocular scattering may result in a slight delay of CDVA recovery in the early postoperative period.
authors.affiliation: Department of Ophthalmology, University of Kitasato School of Medicine, Kanagawa, Japan.
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
mesh_terms: D000328:Adult; D003710:Demography; D005260:Female; D006801:Humans; D007908:Lens, Crystalline / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000503:physiopathology / Q000601:surgery; D012029:Refraction, Ocular; D012542:Scattering, Radiation; D013997:Time Factors; D055815:Young Adult