title: Effects of ablation depth and repair time on the corneal elastic modulus after laser in situ keratomileusis.
abstract: BACKGROUND
  The biomechanical properties of the cornea should be taken into account in the refractive procedure in order to perform refractive surgery more accurately. The effects of the ablation depth and repair time on the elastic modulus of the rabbit cornea after laser in situ keratomileusis (LASIK) are still unclear.
  
  
  METHODS
  In this study, LASIK was performed on New Zealand rabbits with different ablation depth (only typical LASIK flaps were created; residual stroma bed was 50 or 30% of the whole cornea thickness respectively). The animals without any treatment were served as normal controls. The corneal thickness was measured by ultrasonic pachymetry before animals were humanly killed after 7 or 28 days post-operatively. The corneal elastic modulus was measured by uniaxial tensile testing. A mathematical procedure considering the actual geometrics of the cornea was created to analyze the corneal elastic modulus.
  
  
  RESULTS
  There were no obvious differences among all groups in the elastic modulus on after 7 days post-operatively. However, after 28th days post-operatively, there was a significant increase in the elastic modulus with 50 and 30% residual stroma bed; only the elastic modulus of the cornea with 30% residual stroma bed was significantly higher than that of 7 days.
  
  
  CONCLUSIONS
  Changes in elastic modulus after LASIK suggest that this biomechanical effect may correlate with the ablation depth and repair time.
authors.affiliation: Collage of Mechanics, Taiyuan University of Technology, Yingze west street 79, Taiyuan, 030024, People's Republic of China.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Wang
authors.affiliation: Collage of Mechanics, Taiyuan University of Technology, Yingze west street 79, Taiyuan, 030024, People's Republic of China. lixiaona@tyut.edu.cn.
authors.forename: Xiaona
authors.initials: X
authors.lastname: Li
authors.affiliation: Collage of Mechanics, Taiyuan University of Technology, Yingze west street 79, Taiyuan, 030024, People's Republic of China. chenweiyi@tyut.edu.cn.
authors.forename: Weiyi
authors.initials: W
authors.lastname: Chen
authors.affiliation: Department of Excimer Laser, Shanxi Eye Hospital, Fudong street 100, Taiyuan, 030002, People's Republic of China.
authors.forename: Rui
authors.initials: R
authors.lastname: He
authors.affiliation: Collage of Mechanics, Taiyuan University of Technology, Yingze west street 79, Taiyuan, 030024, People's Republic of China.
authors.forename: Zhipeng
authors.initials: Z
authors.lastname: Gao
authors.affiliation: Collage of Mechanics, Taiyuan University of Technology, Yingze west street 79, Taiyuan, 030024, People's Republic of China.
authors.forename: Pengfei
authors.initials: P
authors.lastname: Feng
mesh_terms: D000818:Animals; D003198:Computer Simulation; D003315:Cornea / Q000503:physiopathology* / Q000601:surgery*; D063171:Corneal Pachymetry / Q000379:methods; D055119:Elastic Modulus; D054459:Elasticity Imaging Techniques / Q000379:methods; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D008954:Models, Biological; D011817:Rabbits; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D016896:Treatment Outcome; D014945:Wound Healing / Q000502:physiology*
keywords: Ablation depth; Cornea; Elastic modulus; LASIK; Repair