title: Accuracy of toric intraocular lens implantation in cataract and refractive surgery.
abstract: OBJECTIVE
  To determine the accuracy of a commonly used 3-step procedure for toric pseudophakic and phakic intraocular lens (IOL) implantation.
  
  
  METHODS
  University Eye Clinic, Maastricht University Medical Centre, Maastricht, The Netherlands.
  
  
  METHODS
  Cohort study.
  
  
  METHODS
  In this analysis of toric IOL implantation, 6 preoperative images of the eye per patient and the surgery video were obtained using a digital imaging system. All 3 steps for toric IOL implantation were analyzed as follows: reference axis marking, alignment axis marking, and IOL alignment. In addition, vector analysis was used to calculate the errors in toric IOL alignment.
  
  
  RESULTS
  Forty eyes (26 pseudophakic, 14 phakic) were analyzed. The mean errors in reference axis marking, alignment axis marking, and toric IOL alignment were 2.4 degrees ± 0.8 (SD), 3.3 ± 2.0 degrees, and 2.6 ± 2.6 degrees, respectively. Together, these 3 errors led to a mean total error in toric IOL alignment of 4.9 ± 2.1 degrees. Subgroup analysis showed no significant difference in mean error between pseudophakic IOL and phakic toric IOL alignment (P=.501). Vector analysis showed a mean angle or error of -2 ± 8 degrees (pseudophakic IOLs) and 6 ± 14 degrees (phakic IOLs).
  
  
  CONCLUSIONS
  A commonly used 3-step ink-marker procedure to implant toric IOLs led to a mean error in IOL placement of approximately 5 degrees. The error was especially relevant in cases in which higher cylinder power IOLs were implanted. Orienting the toric IOL with great accuracy is necessary in all patients to achieve the best cylinder correction.
authors.affiliation: University Eye Clinic, Maastricht University Medical Centre, Maastricht, The Netherlands.
authors.forename: Nienke
authors.initials: N
authors.lastname: Visser
authors.forename: Tos T J M
authors.initials: TT
authors.lastname: Berendschot
authors.forename: Noël J C
authors.initials: NJ
authors.lastname: Bauer
authors.forename: Jessica
authors.initials: J
authors.lastname: Jurich
authors.forename: Oliver
authors.initials: O
authors.lastname: Kersting
authors.forename: Rudy M M A
authors.initials: RM
authors.lastname: Nuijts
mesh_terms: D000328:Adult; D001251:Astigmatism / Q000175:diagnosis; D002386:Cataract / Q000628:therapy; D015331:Cohort Studies; D003952:Diagnostic Imaging / Q000379:methods; D005260:Female; D006801:Humans; D019654:Lens Implantation, Intraocular / Q000379:methods*; D007910:Lenses, Intraocular; D008297:Male; D008433:Mathematics; D008875:Middle Aged; D054120:Phakic Intraocular Lenses; D011183:Postoperative Complications; D011446:Prospective Studies; D012029:Refraction, Ocular / Q000502:physiology; D054140:Refractive Surgical Procedures; D015203:Reproducibility of Results; D014741:Video Recording; D014792:Visual Acuity / Q000502:physiology