title: Optical quality and intraocular scattering after femtosecond laser small incision lenticule extraction.
abstract: OBJECTIVE
  To investigate objective optical quality and changes in light scatter after femtosecond laser small incision lenticule extraction (SMILE) for moderate to high myopia correction.
  
  
  METHODS
  Prospective clinical study of 66 eyes of 66 patients (23 males, 43 females) with a mean age of 28.67 ± 6.62 years, mean spherical refraction of -6.06 ± 1.57 diopters, and mean cylindrical refraction of -0.68 ± 0.46 diopters. Every patient had a 3-month follow-up after a standard SMILE procedure. An optical quality analysis system was used to measure modulation transfer function cutoff frequency (MTFcutoff), Strehl2D ratio, and objective scatter index (OSI).
  
  
  RESULTS
  At 3 months postoperatively, mean spherical equivalent was 0.03 ± 0.24 diopters and corrected distance visual acuities of all patients were equal to or better than preoperative values, with a mean safety index of 1.12 ± 0.17 (range: 0.80 to 1.50) and mean efficacy index of 1.18 ± 0.21 (range: 0.80 to 1.50). Mean OSI increased from 0.75 preoperatively to 1.09 at 20 days postoperatively (P < .05), and gradually declined to 0.94 at 40 days and 0.82 at 3 months postoperatively (P > .05). MTFcutoff and Strehl2D ratio did not change significantly compared with preoperative values (P > .05). Multiple linear regression analysis revealed that preoperative OSI was significantly correlated with optical quality at 3 months. Patients with less preoperative OSI tended to acquire higher MTFcutoff (b = -8.61) and lower OSI (b = 0.65) (P < .05).
  
  
  CONCLUSIONS
  SMILE had little impact on retinal image quality after myopia correction. Postoperative OSI showed a temporary increase and then returned to normal.
authors.forename: Huamao
authors.initials: H
authors.lastname: Miao
authors.forename: Li
authors.initials: L
authors.lastname: He
authors.forename: Yang
authors.initials: Y
authors.lastname: Shen
authors.forename: Meiyan
authors.initials: M
authors.lastname: Li
authors.forename: Yongfu
authors.initials: Y
authors.lastname: Yu
authors.forename: Xingtao
authors.initials: X
authors.lastname: Zhou
mesh_terms: D000293:Adolescent; D000328:Adult; D003319:Corneal Stroma / Q000503:physiopathology / Q000601:surgery*; D048988:Corneal Surgery, Laser / Q000379:methods*; D005260:Female; D006801:Humans; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008027:Light; D008297:Male; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D011446:Prospective Studies; D012029:Refraction, Ocular / Q000502:physiology*; D012542:Scattering, Radiation; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult