title: Corneal Higher-Order Aberrations of the Anterior Surface, Posterior Surface, and Total Cornea After SMILE, FS-LASIK, and FLEx Surgeries.
abstract: OBJECTIVE
  To investigate the corneal higher-order aberrations (HOAs) of the anterior surface, posterior surface, and total cornea after small incision lenticule extraction (SMILE) and compare the results using femtosecond laser-assisted in situ keratomileusis (FS-LASIK) and femtosecond laser lenticule extraction (FLEx).
  
  
  METHODS
  This study included 160 eyes in total; 73 eyes underwent SMILE, 52 eyes underwent FS-LASIK, and 35 eyes underwent FLEx surgery. Corneal HOAs of the anterior surface, posterior surface, and total cornea were evaluated using a Scheimpflug camera over 6-mm diameter preoperatively and 3 months postoperatively.
  
  
  RESULTS
  The anterior and total corneal HOAs significantly increased after SMILE, FS-LASIK, and FLEx surgeries, especially the spherical aberration and coma, whereas most posterior corneal HOAs remained unchanged. The SMILE procedure induced significantly lower anterior corneal and total corneal spherical aberration and third to eighth HOAs compared with FLEx surgery (P<0.01). FLEx surgery induced higher posterior corneal coma than SMILE (P=0.013) and FS-LASIK (P<0.001) surgeries.
  
  
  CONCLUSIONS
  SMILE, FS-LASIK, and FLEx surgeries mainly induced coma and spherical aberrations in the anterior surface and total cornea. The SMILE procedure induced less spherical aberration of the anterior cornea and total cornea than FLEx surgery. The posterior corneal spherical aberration significantly increased after FS-LASIK surgery. The SMILE procedure seems to have fewer effects on posterior corneal coma compared with the FLEx procedure.
authors.affiliation: Refractive Surgery Center, Tianjin Eye Hospital and Eye Institute, Tianjin Key Lab of Ophthalmology and Visual Science, Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China.
authors.forename: Wenjing
authors.initials: W
authors.lastname: Wu
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000328:Adult; D048988:Corneal Surgery, Laser / Q000379:methods*; D057108:Corneal Wavefront Aberration / Q000209:etiology / Q000473:pathology*; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000379:methods; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D009216:Myopia / Q000601:surgery*; D012189:Retrospective Studies; D055815:Young Adult