title: Comparison of techniques for corneal power assessment after myopic LASIK without the use of preoperative data.
abstract: To compare the accuracy of different corneal power assessment techniques that do not require preoperative information with the clinical history method.
  
  
  
  This retrospective study analyzed 50 eyes of 50 patients using 3-month postoperative data. Net corneal powers were obtained with each of the following methods: Maloney, Wang, Sonego-Krone, Srivannaboon, Shammas, Orbscan flat axis, and Gaussian optics formula with Orbscan. Results were compared to the clinical history method using paired sample t test, Bland-Altman plots, and linear regression.
  
  
  
  Both the Gaussian optics formula and Wang method were not significantly different from the clinical history method. The Sonego-Krone method significantly underestimated the corneal power, whereas the Maloney, Srivannaboon, Shammas, and Orbscan flat axis methods significantly overestimated the corneal power.
  
  
  
  The Gaussian optics formula and Wang method yielded comparable results with the clinical history method for assessing corneal power. The Gaussian optics formula produced the smallest standard deviation.
authors.affiliation: Department of Ophthalmology and Visual Sciences, Chinese University of Hong Kong, Hong Kong Eye Hospital, Kowloon, Hong Kong. artcheng@netvigator.com
authors.forename: Arthur C K
authors.initials: AC
authors.lastname: Cheng
authors.forename: Srinivas S K
authors.initials: SS
authors.lastname: Rao
authors.forename: Silvania
authors.initials: S
authors.lastname: Lau
authors.forename: Amy
authors.initials: A
authors.lastname: Wong
authors.forename: Dennis S C
authors.initials: DS
authors.lastname: Lam
mesh_terms: D000328:Adult; D001699:Biometry / Q000379:methods; D003315:Cornea / Q000502:physiology*; D003941:Diagnostic Techniques, Ophthalmological; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D054018:Lasers, Excimer; D009216:Myopia / Q000601:surgery*; D012029:Refraction, Ocular / Q000502:physiology*; D012189:Retrospective Studies