title: Arcuate keratotomy to treat corneal astigmatism after cataract surgery: a prospective evaluation of predictability and effectiveness.
abstract: OBJECTIVE
  Although several nomograms are available for the incisional keratotomy to correct naturally occurring astigmatism, astigmatic keratotomy in eyes after cataract surgery has not been well analyzed. The predictability and effectiveness of arcuate keratotomy in pseudophakic eyes were studied.
  
  
  METHODS
  A prospective, multicenter study.
  
  
  METHODS
  One hundred four eyes of 86 patients with residual corneal astigmatism of 1.5 diopters (D) or more after cataract surgery were examined.
  
  
  METHODS
  Arcuate keratotomy was performed in nine centers by nine surgeons.
  
  
  METHODS
  The amount of astigmatic correction was calculated using the vector analysis of preoperative and 6-month postoperative refractive cylinder results.
  
  
  RESULTS
  Multiple regression analysis showed that optical zone size, number of incisions, and incision length had significant correlations with the amount of astigmatic correction. The regression equation was expressed as effects = (-0.643 x optical zone size) + (0.998 x incision number) + (0.057 x incision length) + 2.356. The parameter of predictability (r2: 35%) was lower than that reported for congenital astigmatism (48 to approximately 56%). A new nomogram was derived based on the multiple regression equation.
  
  
  CONCLUSIONS
  Astigmatic keratotomy in pseudophakic eyes is less predictable than that in eyes with idiopathic astigmatism, but the procedure is sufficiently effective in reducing the residual astigmatism after cataract surgery. Individual nomograms are necessary for astigmatic keratotomy in eyes with naturally occurring and postsurgical astigmatism.
authors.affiliation: Department of Ophthalmology, University of Tokyo School of Medicine, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Oshika
authors.forename: J
authors.initials: J
authors.lastname: Shimazaki
authors.forename: F
authors.initials: F
authors.lastname: Yoshitomi
authors.forename: K
authors.initials: K
authors.lastname: Oki
authors.forename: I
authors.initials: I
authors.lastname: Sakabe
authors.forename: S
authors.initials: S
authors.lastname: Matsuda
authors.forename: T
authors.initials: T
authors.lastname: Shiwa
authors.forename: M
authors.initials: M
authors.lastname: Fukuyama
authors.forename: Y
authors.initials: Y
authors.lastname: Hara
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001251:Astigmatism / Q000209:etiology / Q000601:surgery*; D002387:Cataract Extraction / Q000009:adverse effects*; D003315:Cornea / Q000601:surgery*; D005260:Female; D006801:Humans; D007646:Keratotomy, Radial; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D019591:Pseudophakia / Q000150:complications; D012044:Regression Analysis; D016896:Treatment Outcome