title: Effect of biometric characteristics on biomechanical properties of the cornea in cataract patient.
abstract: OBJECTIVE
  To determine the impact of biometric characteristics on the biomechanical properties of the human cornea using the ocular response analyzer (ORA) and standard comprehensive ophthalmic examinations before and after standard phacoemulsification.
  
  
  METHODS
  This study comprised 54 eyes with cataract with significant lens opacification in stages I or II that underwent phacoemulsification (2.8 mm incision). Corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann-correlated intraocular pressure (IOPg), and corneal-compensated intraocular pressure (IOPcc) were measured by ORA preoperatively and at 1mo postoperatively. Biometric characteristics were derived from corneal topography [TMS-5, anterior equivalent (EQTMS) and cylindric (CYLTMS) power], corneal tomography [Casia, anterior and posterior equivalent (EQaCASIC, EQpCASIA) and cylindric (CYLaCASIA, CYLpCASIA) power], keratometry [IOLMaster, anterior equivalent (EQIOL) and cylindric (CYLIOL) power] and autorefractor [anterior equivalent (EQAR)]. Results from ORA were analyzed and correlated with those from all other examinations taken at the same time point.
  
  
  RESULTS
  Preoperatively, CH correlated with EQpCASIA and CYLpCASIA only (P=0.001, P=0.002). Postoperatively, IOPg and IOPcc correlated with all equivalent powers (EQTMS, EQIOL, EQAR, EQaCASIA and EQpCASIA) (P=0.001, P=0.007, P=0.001, P=0.015, P=0.03 for IOPg and P<0.001, P=0.003, P<0.001, P=0.009, P=0.014 for IOPcc). CH correlated postoperatively with EQaCASIA and EQpCASIC only (P=0.021, P=0.022).
  
  
  CONCLUSIONS
  Biometric characteristics may significantly affect biomechanical properties of the cornea in terms of CH, IOPcc and IOPg before, but even more after cataract surgery.
authors.affiliation: Department of Ophthalmology, Saarland University Medical Center, Homburg Saar 66424, Germany; Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai 200011, China.
authors.forename: Xue-Fei
authors.initials: XF
authors.lastname: Song
authors.affiliation: Experimental Ophthalmology, Saarland University, Homburg Saar 66424, Germany.
authors.forename: Achim
authors.initials: A
authors.lastname: Langenbucher
authors.affiliation: Department of Ophthalmology, Saarland University Medical Center, Homburg Saar 66424, Germany.
authors.forename: Zisis
authors.initials: Z
authors.lastname: Gatzioufas
authors.affiliation: Department of Ophthalmology, Saarland University Medical Center, Homburg Saar 66424, Germany.
authors.forename: Berthold
authors.initials: B
authors.lastname: Seitz
authors.affiliation: Department of Ophthalmology, Saarland University Medical Center, Homburg Saar 66424, Germany.
authors.forename: Moatasem
authors.initials: M
authors.lastname: El-Husseiny
keywords: biomechanical properties; biometric characteristics; cataract surgery; corneal tomography; correlation analysis; ocular response analyzer