title: Surgically induced astigmatism after phacoemulsification with and without correction for posture-related ocular cyclotorsion: randomized controlled study.
abstract: OBJECTIVE
  To report the impact of posture-related ocular cyclotorsion on one surgeon's surgically induced astigmatism (SIA) results and the variance in SIA.
  
  
  METHODS
  Institute of Eye Surgery, Whitfield Clinic, Waterford, Ireland.
  
  
  METHODS
  This prospective randomized controlled study included eyes that had phacoemulsification with intraocular lens implantation. Eyes were randomly assigned to have (intervention group) or not have (control group) correction for posture-related ocular cyclotorsion. In the intervention group, the clear corneal incision was placed precisely at the 120-degree meridian with instruments designed to correct posture-related ocular cyclotorsion. In the control group, the surgeon endeavored to place the incision at the 120-degree meridian, but without markings.
  
  
  RESULTS
  The intervention group comprised 41 eyes and the control group, 61 eyes. The mean absolute SIA was 0.74 diopters (D) in the intervention group and 0.78 D in the control group; the difference between groups was not statistically significant (P>.5, unpaired 2-tailed Student t test). The variance in SIA was 0.29 D(2) and 0.31 D(2), respectively; the difference between groups was not statistically significant (P>.5, unpaired F test).
  
  
  CONCLUSIONS
  Attempts to correct for posture-related ocular cyclotorsion did not influence SIA or its variance in a single-surgeon series. These results should be interpreted with full appreciation of the limitations of currently available techniques to correct for posture-related ocular cyclotorsion in the clinical setting.
authors.affiliation: Department of Ophthalmology, Waterford Regional Hospital, the Institute of Eye Surgery, Whitfield Clinic, Suite 14, Whitfield Clinic, Cork Road, Waterford, Ireland. iandooley@eustace.net
authors.forename: Ian
authors.initials: I
authors.lastname: Dooley
authors.forename: Sofia
authors.initials: S
authors.lastname: Charalampidou
authors.forename: Arhsed
authors.initials: A
authors.lastname: Malik
authors.forename: Greta
authors.initials: G
authors.lastname: Ormonde
authors.forename: James
authors.initials: J
authors.lastname: Loughman
authors.forename: Laura
authors.initials: L
authors.lastname: Molloy
authors.forename: Stephen
authors.initials: S
authors.lastname: Beatty
mesh_terms: D000368:Aged; D001251:Astigmatism / Q000209:etiology* / Q000503:physiopathology; D015350:Contrast Sensitivity / Q000502:physiology; D019781:Corneal Topography; D005260:Female; D006801:Humans; D019654:Lens Implantation, Intraocular; D008297:Male; D018918:Phacoemulsification / Q000009:adverse effects*; D011187:Posture; D011446:Prospective Studies; D014102:Torsion Abnormality / Q000209:etiology / Q000601:surgery*; D014792:Visual Acuity / Q000502:physiology