title: Conventional Versus Inverted Side-cut Flaps for Femtosecond Laser-Assisted LASIK: Laboratory and Clinical Evaluation.
abstract: OBJECTIVE
  To study the differences in early corneal cellular events and biomechanical properties after femtosecond laser-assisted LASIK performed using conventional or inverted side-cut angles.
  
  
  METHODS
  In the laboratory study, left eyes of 24 rabbits underwent LASIK flap creation with a 70° or 115° side-cut. The contralateral eyes served as controls. The corneas were harvested 24 hours postoperatively. In the clinical study, 2 eyes of each patient (n = 29) were randomized to corneal flap creation with 70° or 115° side-cut angles during LASIK. The Ocular Response Analyzer (ORA; Reichert Ophthalmic Instruments, Depew, NY) was used to assess biomechanical properties of the cornea.
  
  
  RESULTS
  In rabbit eyes, epithelial ingrowth was observed more frequently in flaps with 70° side cuts compared to flaps with 115° side-cuts. Corneas with 70° side-cuts showed significantly increased apoptotic cells compared to 115° side-cuts in the central (P = .001) and peripheral (P = .004) regions. Fifty-eight eyes of 29 patients were included in the clinical study. An overall reduction in Goldmann-correlated intraocular pressure, corneal-compensated intraocular pressure, corneal resistance factor, corneal hysteresis measurements, p1 area, p2 area, and p1 area 1 and p2 area 1 was noted 37 ± 2 months after surgery (P < .001). No significant difference was observed in the change of any of these parameters between both groups (P ≥ .146).
  
  
  CONCLUSIONS
  Significant differences in wound healing were observed in rabbit corneas that underwent LASIK with conventional or inverted side-cuts. Variation in flap side-cut angles did not alter the long-term biomechanical properties measured with the ORA in patients after LASIK. [J Refract Surg. 2017;33(2):96-103.].
authors.forename: Vishal
authors.initials: V
authors.lastname: Jhanji
authors.forename: Tommy C Y
authors.initials: TC
authors.lastname: Chan
authors.forename: Wai Ying
authors.initials: WY
authors.lastname: Li
authors.forename: Rayne R
authors.initials: RR
authors.lastname: Lim
authors.forename: Marco C Y
authors.initials: MC
authors.lastname: Yu
authors.forename: Kasin
authors.initials: K
authors.lastname: Law
authors.forename: Peng
authors.initials: P
authors.lastname: Yi
authors.forename: Yolanda W Y
authors.initials: YW
authors.lastname: Yip
authors.forename: Yumeng
authors.initials: Y
authors.lastname: Wang
authors.forename: Tsz Kin
authors.initials: TK
authors.lastname: Ng
authors.forename: Shyam S
authors.initials: SS
authors.lastname: Chaurasia
authors.forename: Rajiv R
authors.initials: RR
authors.lastname: Mohan
mesh_terms: D000328:Adult; D000818:Animals; D017209:Apoptosis; D001696:Biomechanical Phenomena; D039481:CD11b Antigen / Q000378:metabolism; D060527:Corneal Keratocytes / Q000473:pathology; D003319:Corneal Stroma / Q000601:surgery*; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D020287:In Situ Nick-End Labeling; D007429:Intraocular Pressure / Q000502:physiology; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D019394:Ki-67 Antigen / Q000378:metabolism; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000378:metabolism / Q000503:physiopathology / Q000601:surgery*; D011817:Rabbits; D013524:Surgical Flaps; D014792:Visual Acuity / Q000502:physiology; D014945:Wound Healing / Q000502:physiology*; D055815:Young Adult
chemical_list: D039481:CD11b Antigen; D019394:Ki-67 Antigen