title: Effect of astigmatism on visual acuity in eyes with a diffractive multifocal intraocular lens.
abstract: OBJECTIVE
  To examine the effect of astigmatism on visual acuity at various distances in eyes with a diffractive multifocal intraocular lens (IOL).
  
  
  METHODS
  Hayashi Eye Hospital, Fukuoka, Japan.
  
  
  METHODS
  In this study, eyes had implantation of a diffractive multifocal IOL with a +3.00 diopter (D) addition (add) (AcrySof ReSTOR SN6AD1), a diffractive multifocal IOL with a +4.00 D add (AcrySof ReSTOR SN6AD3), or a monofocal IOL (AcrySof SN60WF). Astigmatism was simulated by adding cylindrical lenses of various diopters (0.00, 0.50, 1.00, 1.50, 2.00), after which distance-corrected acuity was measured at various distances.
  
  
  RESULTS
  At most distances, the mean visual acuity in the multifocal IOL groups decreased in proportion to the added astigmatism. With astigmatism of 0.00 D and 0.50 D, distance-corrected near visual acuity (DCNVA) in the +4.00 D group and distance-corrected intermediate visual acuity (DCIVA) and DCNVA in the +3.00 D group were significantly better than in the monofocal group; the corrected distance visual acuity (CDVA) was similar. The DCNVA with astigmatism of 1.00 D was better in 2 multifocal groups; however, with astigmatism of 1.50 D and 2.00 D, the CDVA and DCIVA at 0.5m in the multifocal groups were significantly worse than in the monofocal group, although the DCNVA was similar. With astigmatism of 1.00 D or greater, the mean CDVA and DCNVA in the multifocal groups reached useful levels (20/40).
  
  
  CONCLUSIONS
  The presence of astigmatism in eyes with a diffractive multifocal IOL compromised all distance visual acuities, suggesting the need to correct astigmatism of greater than 1.00 D.
  
  
  BACKGROUND
  No author has a financial or proprietary interest in any material or method mentioned.
authors.affiliation: Hayashi Eye Hospital, Japan. hayashi-ken@hayashi.or.jp
authors.forename: Ken
authors.initials: K
authors.lastname: Hayashi
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Manabe
authors.forename: Motoaki
authors.initials: M
authors.lastname: Yoshida
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Hayashi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001251:Astigmatism / Q000503:physiopathology*; D019923:Capsulorhexis; D005260:Female; D006801:Humans; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular; D008297:Male; D008875:Middle Aged; D018918:Phacoemulsification; D011446:Prospective Studies; D011474:Prosthesis Design; D019591:Pseudophakia / Q000503:physiopathology*; D014792:Visual Acuity / Q000502:physiology*