title: Effect of effective lens position on cylinder power of toric intraocular lenses.
abstract: OBJECTIVE
  To evaluate the effects of effective lens position (ELP) on the corneal plane effective cylinder power of toric intraocular lenses (IOLs).
  
  
  METHODS
  Retrospective cross-sectional study.
  
  
  METHODS
  Ninety-four eyes from 78 patients who underwent uncomplicated phacoemulsification with implantation of an AcrySof toric IOL (1.50- to 3.00-D cylinder).
  
  
  METHODS
  The amount of corneal plane effective cylinder power of toric IOLs given by the manufacturer (target-induced astigmatism vector [TIA]) was compared with the postoperatively achieved cylindrical correction (surgically induced astigmatism vector [SIA]). The theoretical corneal plane cylinder power of toric IOLs was calculated according to ELP and corneal power using a refractive vergence formula.
  
  
  RESULTS
  The TIA (1.59 ± 0.43 D) was significantly smaller than the SIA (1.78 ± 0.65 D; p < 0.001). The difference between the magnitudes of SIA and TIA demonstrated a significant negative correlation with ELP (r = -0.219 and p = 0.034). The theoretical corneal plane cylinder power of toric IOLs demonstrated a decreasing trend as the ELP and corneal power increased. The range of changes in corneal plane effective cylinder power according to ELP and corneal power was greater in toric IOLs with high toricity.
  
  
  CONCLUSIONS
  The cylinder power of AcrySof toric IOLs should be adjusted according to ELP. For eyes with small ELP, the cylinder power should be reduced, and for eyes with large ELP, the cylinder power should be increased. The amount of reducing or increasing cylinder power of toric IOLs should be increased as the toricity increases.
authors: Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea.
authors: Youngsub
authors: Y
authors: Eom
authors: Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea.
authors: Su-Yeon
authors: SY
authors: Kang
authors: Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea.
authors: Jong Suk
authors: JS
authors: Song
authors: Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea.
authors: Yong Yeon
authors: YY
authors: Kim
authors: Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea. Electronic address: hyomkim@kumc.or.kr.
authors: Hyo Myung
authors: HM
authors: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001251:Astigmatism / Q000503:physiopathology / Q000628:therapy; D003315:Cornea / Q000502:physiology*; D063171:Corneal Pachymetry; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular; D008297:Male; D008875:Middle Aged; D018918:Phacoemulsification; D011474:Prosthesis Design; D019591:Pseudophakia / Q000503:physiopathology*; D012029:Refraction, Ocular / Q000502:physiology*; D012189:Retrospective Studies; D055815:Young Adult