title: Comparison of the Astigmatic Power of Toric Intraocular Lenses Using Three Toric Calculators.
abstract: OBJECTIVE
  To compare the astigmatic power of toric intraocular lenses (IOLs) obtained from the AcrySof, TECNIS, and iTrace toric calculator in patients with preoperative with-the-rule (WTR) or against-the-rule (ATR) corneal astigmatism.
  
  
  METHODS
  Fifty eyes with cataract and corneal astigmatism greater than 0.75 diopters were enrolled in each group (WTR and ATR). Keratometric values were measured using autokeratometry, an IOLMaster, and an iTrace, which incorporated corneal topography and ray-tracing aberrometry. Based on measured keratometric values, the astigmatic power of each toric IOL was calculated using three toric calculators.
  
  
  RESULTS
  Bland-Altman plots showed good agreement between six pairwise corneal astigmatism values in both groups. The TECNIS calculator tended to suggest a higher astigmatic power of the toric IOL than the AcrySof calculator. With the higher astigmatism and keratometric values from the IOLMaster, in both groups, calculations from the AcrySof and TECNIS calculators resulted in higher calculated astigmatic powers than those from same calculators with autokeratometry-measured values, demonstrating good agreement. With the higher calculated astigmatic power values, the values from the iTrace toric calculator using keratometric values obtained from iTrace ray tracing wavefront aberrometry or iTrace simulated keratometry showed fair to moderate agreement with those from the other calculator-keratometry pairs in both groups.
  
  
  CONCLUSIONS
  To achieve the best refractive outcome after toric IOL implantation, understanding the differences in keratometric values between instruments and in calculated astigmatic power among toric calculator programs is necessary. Moreover, systemic analysis of each toric calculator in conjunction with postoperative data is required.
authors.affiliation: The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Hyun Ju
authors.initials: HJ
authors.lastname: Park
authors.affiliation: The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea.; Department of Ophthalmology, International St. Mary's Hospital, Catholic Kwandong University College of Medicine, Incheon, Korea.
authors.forename: Hun
authors.initials: H
authors.lastname: Lee
authors.affiliation: The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Young Jae
authors.initials: YJ
authors.lastname: Woo
authors.affiliation: The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea.; Cornea Dystrophy Research Institute, Department of Ophthalmology, Severance Biomedical Science Institute, and Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Eung Kweon
authors.initials: EK
authors.lastname: Kim
authors.affiliation: The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Kyoung Yul
authors.initials: KY
authors.lastname: Seo
authors.affiliation: Biostatistics Collaboration Unit, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Ha Yan
authors.initials: HY
authors.lastname: Kim
authors.affiliation: The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea. tikim@yuhs.ac.
authors.forename: Tae-im
authors.initials: TI
authors.lastname: Kim
mesh_terms: D057128:Aberrometry; D000368:Aged; D000369:Aged, 80 and over; D001251:Astigmatism / Q000503:physiopathology / Q000601:surgery; D002386:Cataract; D003315:Cornea / Q000601:surgery; D019781:Corneal Topography; D005123:Eye; D005260:Female; D006801:Humans; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular; D008297:Male; D008875:Middle Aged; D018918:Phacoemulsification / Q000379:methods*; D011184:Postoperative Period; D012029:Refraction, Ocular / Q000502:physiology*; D014792:Visual Acuity / Q000502:physiology
keywords: Astigmatic power; corneal astigmatism; keratometry; toric IOL; toric calculator