title: Changes in corneal astigmatism among patients with visually significant cataract.
abstract: OBJECTIVE
  To determine the prevalence of corneal astigmatism, changes in astigmatism, and biometry measurements with age and to correlate fellow eye measurements of patients undergoing cataract surgery.
  
  
  METHODS
  Prospective, observational study.
  
  
  METHODS
  3498 eyes of 1814 patients undergoing cataract surgery.
  
  
  METHODS
  Setting was a single center teaching hospital. Preoperative biometry data measured by partial coherence interferometry (IOLMaster; Carl Zeiss Meditec, Jena, Germany) were collected and analyzed.
  
  
  RESULTS
  Mean age of the cohort was 74.52 ± 10.23 years. Mean corneal astigmatism was 1.04 ± 0.78 D OD and 1.04 ± 0.79 D OS. About 19.7% and 4.9% of eyes had corneal astigmatism greater than 1.5 and 2.5 D, respectively. The prevalence of against-the-rule astigmatism significantly increased with age bilaterally. Paired fellow eye analysis found a positive correlation for corneal astigmatism, axial length, anterior chamber depth, and white-to-white distance (p < 0.001). About 33.33% of right eyes with corneal astigmatism greater than 2.5 D had more than 2.5 D of astigmatism in the fellow eye. This is in comparison with only 1.5% of right eyes with corneal astigmatism of less than 1.5 D having corneal astigmatism greater than 2.5 D in the fellow eye.
  
  
  CONCLUSIONS
  Patients with high corneal astigmatism in 1 eye are more likely to have significant astigmatism in the fellow eye. This may necessitate the need for bilateral toric intraocular lens (IOL) implantation during cataract surgery. Against-the-rule astigmatism should be treated more aggressively during cataract surgery, because this is likely to worsen with age. Such information is useful when calculating toric IOL power at the time of surgery.
authors.affiliation: Department of Ophthalmology, University Hospital Ayr, Ayr.
authors.forename: Douglas A M
authors.initials: DA
authors.lastname: Lyall
authors.affiliation: Department of Ophthalmology, University Hospital Ayr, Ayr; Faculty of Medicine, University of Glasgow, Glasgow, United Kingdom. Electronic address: sathish.srinivasan@gmail.com.
authors.forename: Sathish
authors.initials: S
authors.lastname: Srinivasan
authors.affiliation: Department of Ophthalmology, University Hospital Ayr, Ayr.
authors.forename: Jia
authors.initials: J
authors.lastname: Ng
authors.affiliation: Department of Ophthalmology, University Hospital Ayr, Ayr.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Kerr
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D001251:Astigmatism / Q000453:epidemiology / Q000503:physiopathology*; D001699:Biometry; D002386:Cataract / Q000453:epidemiology / Q000503:physiopathology*; D002387:Cataract Extraction / Q000706:statistics & numerical data; D003315:Cornea / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007368:Interferometry; D019654:Lens Implantation, Intraocular; D008027:Light; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D017678:Sex Distribution; D055815:Young Adult