title: [A clinical study of actual corneal ablation depth in laser in situ keratomileusis].
abstract: OBJECTIVE
  To assess the predictability of corneal ablation depth in LASIK using NIDEK EC5000 excimer laser.
  
  
  METHODS
  Standard LASIK surgery was performed in 79 myopic patients with or without astigmatism with the NIDEK EC5000 excimer laser system.Ultrasonic corneal pachymetry was performed immediately after flap creation and after laser ablation during LASIK procedure,by which the actual corneal ablation depth was calculated.The values of actual and predicted ablation depth were compared.
  
  
  RESULTS
  The actual ablation depth was (92.32+/-29.86)μm, the predicted ablation depth was (74.16+/-25.95)μm.The differences between them(18.16+/-14.71)μm were statistically significant(p<0.001).Linear regression suggested that the actual ablation depth correlated closely with the predicted ablation depth(r=0.87,p<0.001).The regression model was Y=18.06+1.001X.The differences remained statistically significant and were independent of the levels of preoperative corneal keratometry,absolute preoperative spherical equivalent and the preoperative central cornea thickness.
  
  
  CONCLUSIONS
  The actual ablation depth was about(18.16+/-14.71)μm thicker than the predicted ablation depth in the NIDEK EC5000 excimer laser system. We may have to take into account this deviation in order to ensure sufficient thickness of residual stromal bed.
authors.affiliation: Department of Ophthalmology, Donggua n City People's Hospital, Dongguan 523018, China.
authors.forename: Guangbin
authors.initials: G
authors.lastname: Zhong
authors.forename: Bin
authors.initials: B
authors.lastname: Yang
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.forename: Guofu
authors.initials: G
authors.lastname: Huang
authors.forename: Xianming
authors.initials: X
authors.lastname: Jiang
authors.forename: Linyi
authors.initials: L
authors.lastname: Luo
mesh_terms: D001251:Astigmatism; D003315:Cornea; D003319:Corneal Stroma; D006801:Humans; D020731:Keratomileusis, Laser In Situ; D009216:Myopia / Q000601:surgery; D013524:Surgical Flaps