title: Corneal astigmatism analysis for toric intraocular lens implantation: precise measurements for perfect correction.
abstract: OBJECTIVE
  Corneal astigmatism is a common refractive error observed in a significant percentage of cataract patients. Accurate measurements of the preexisting corneal astigmatism are essential in order to achieve the desired refractive outcome after toric intraocular lens (IOL) implantation. This article presents a comprehensive review of recent published literatures on methods for measuring preoperative corneal astigmatism for toric IOL implantation.
  
  
  RESULTS
  A variety of instruments has been introduced and used to measure the magnitude and meridian of corneal astigmatism during preoperative assessments of cataract patients. Instruments that consider both the anterior and posterior corneal surfaces as critical factors for measuring total corneal astigmatism are expected to provide better accuracy. Although these instruments facilitate improved evaluations of corneal astigmatism and have helped minimize postoperative residual astigmatism, a perfect method to analyze preoperative corneal astigmatism has not yet been established.
  
  
  CONCLUSIONS
  Perfect correction of astigmatism after toric IOL implantation by using accurate corneal astigmatism values is the goal of this surgical procedure. To achieve this, correct and precise measurements of corneal astigmatism to determine the magnitude and meridian should be obtained.
authors.affiliation: aThe Institute of Vision Research, Department of Ophthalmology, Corneal Dystrophy Research Institute bSeverance Biomedical Science Institute, Brain Korea 21 Plus Project for Medical Science, Yonsei University College of Medicine, Seoul, South Korea *Hun Lee and Tae-im Kim contributed equally to the writing of this article.
authors.forename: Hun
authors.initials: H
authors.lastname: Lee
authors.forename: Tae-Im
authors.initials: TI
authors.lastname: Kim
authors.forename: Eung Kweon
authors.initials: EK
authors.lastname: Kim
mesh_terms: D001251:Astigmatism / Q000175:diagnosis* / Q000601:surgery; D003316:Corneal Diseases / Q000175:diagnosis* / Q000601:surgery; D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation; D006801:Humans; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular; D018918:Phacoemulsification; D014792:Visual Acuity