title: Rotational stability of the AcrySof SA60TT toric intraocular lenses: a cohort study.
abstract: BACKGROUND
  To evaluate the rotational stability of the three types of AcrySof SA60TT toric intraocular lenses (Alcon, Switzerland) in cataract surgery after the first postoperative week.
  
  
  METHODS
  A retrospective study of 44 eyes in 33 patients. All patients underwent similar uncomplicated phacoemulsification cataract surgery. Seven eyes with corneal astigmatism of less than 1.5 D were implanted with the AcrySof SA60T3 intraocular lens. Seventeen eyes with astigmatism between 1.5 D and 2.25 D received the SA60T4 intraocular lens, and 20 eyes with more than 2.25 D of corneal astigmatism received the SA60T5 intraocular lens. Intraoperatively, the axis of the toric lens was aligned to the steepest axis of the corneal astigmatism. Main outcome measure was the postoperative position of the lens, assessed at 1 week and 3 months, using a specially designed angle measuring eyepiece for the slit lamp.
  
  
  RESULTS
  There was no significant difference in the rotational stability of the three types of toric intraocular lenses. Overall, the postoperative rotation was within 5 degrees in 95% and within 2 degrees in 68% of eyes. The mean absolute rotation was 2.2 +/- 2.2 degrees. No lens showed more than 9 degrees of rotation, and no lens required secondary repositioning. There was no trend for either clockwise or anti-clockwise rotation. The surgical procedure did not change the corneal astigmatism.
  
  
  CONCLUSIONS
  Once placed to it's position, each of the three types of the AcrySof SA60TT toric intraocular lenses demonstrate rotational stability in the capsular bag.
authors.affiliation: Moorfields Eye Hospital NHS Foundation Trust, 162 City Road, London, EC1V 2PD, UK. b.zuberbuehler@zubisoft.ch
authors.forename: Bruno
authors.initials: B
authors.lastname: Zuberbuhler
authors.forename: Theo
authors.initials: T
authors.lastname: Signer
authors.forename: Richard
authors.initials: R
authors.lastname: Gale
authors.forename: Eduard
authors.initials: E
authors.lastname: Haefliger
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001251:Astigmatism / Q000209:etiology / Q000601:surgery; D002387:Cataract Extraction / Q000009:adverse effects; D015331:Cohort Studies; D006801:Humans; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular / Q000145:classification* / Q000592:standards*; D008875:Middle Aged; D011184:Postoperative Period; D011474:Prosthesis Design; D012189:Retrospective Studies; D012399:Rotation; D013997:Time Factors