title: Comparison of 120- and 140-μm SMILE Cap Thickness Results in Eyes With Thick Corneas.
abstract: OBJECTIVE
  To evaluate clinical outcomes after small incision lenticule extraction (SMILE) with different cap thicknesses in thick corneas.
  
  
  METHODS
  Forty patients with central corneal thickness of more than 560 μm were recruited in this prospective, randomized, masked, paired-eye study. Patients were randomized to receive SMILE with a 120-μm cap thickness in 1 eye and 140-μm cap thickness in the other. Uncorrected and corrected distance visual acuity (CDVA), contrast sensitivity (CS), higher-order aberrations (HOAs), and morphologic modifications of corneal architecture were measured during the 3-month follow-up period.
  
  
  RESULTS
  Postoperative refractive outcomes, visual outcomes, CS, and the changes in HOAs were similar between both groups. The persistence of brightly reflective particles in the corneal interface layer was 1388.6 ± 219.5/mm in eyes with 120-μm cap thickness and 54.7 ± 8.6/mm in eyes with 140-μm cap thickness (P < 0.001). The hyperreflectivity line at the interface layer almost disappeared in all eyes with 140-μm cap thickness, and it still persisted in 43% of the fellow eyes at 3 months postoperatively. The anterior surfaces of lenticules in the 140-μm cap thickness group exhibited more smoothness than in the 120-μm cap thickness group.
  
  
  CONCLUSIONS
  There was a lower level corneal wound-healing response after SMILE with a 140-μm cap thickness than with a 120-μm cap thickness, although the thickness of cap creation did not affect visual outcomes by 3 months postoperatively.
authors.affiliation: Refractive Surgery Center, State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
authors.forename: Manli
authors.initials: M
authors.lastname: Liu
authors.forename: Yugui
authors.initials: Y
authors.lastname: Zhou
authors.forename: Xianghua
authors.initials: X
authors.lastname: Wu
authors.forename: Tiantian
authors.initials: T
authors.lastname: Ye
authors.forename: Quan
authors.initials: Q
authors.lastname: Liu
mesh_terms: D000293:Adolescent; D000328:Adult; D001251:Astigmatism / Q000503:physiopathology / Q000601:surgery*; D015350:Contrast Sensitivity / Q000502:physiology; D003315:Cornea / Q000473:pathology*; D003319:Corneal Stroma / Q000601:surgery*; D048988:Corneal Surgery, Laser / Q000379:methods*; D057108:Corneal Wavefront Aberration / Q000503:physiopathology; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008866:Microsurgery / Q000379:methods; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D009929:Organ Size; D011446:Prospective Studies; D014792:Visual Acuity / Q000502:physiology; D014945:Wound Healing / Q000502:physiology; D055815:Young Adult