title: First eye prediction error improves second eye refractive outcome results in 2129 patients after bilateral sequential cataract surgery.
abstract: OBJECTIVE
  To define theoretical correction factors for second-eye intraocular lens (IOL) power adjustment based on first eye refractive prediction error (PE).
  
  
  METHODS
  Database study.
  
  
  METHODS
  We included 2129 patients who underwent bilateral sequential phacoemulsification cataract surgery with the same IOL model.
  
  
  METHODS
  Retrospectively calculated PEs (Hoffer Q, Holladay 1, SRK/T) were analyzed for association between paired eyes, examining the effect of interocular differences in axial length (AL) and corneal power. A range of correction factors (CF) derived from the first eye PE were applied to the second eye PE using optimized and non-optimized IOL constants (IOLCs).
  
  
  METHODS
  Second eye mean absolute error (MAE).
  
  
  RESULTS
  Prediction errors of paired eyes were correlated. Interocular corneal power differences exceeding 0.60 diopters (D) were associated with a weaker correlation but interocular AL differences did not affect the correlation. When a 50% CF was applied to second eyes of patients with a first eye PE between ±0.50 and ±1.50 D, it improved refractive outcomes from 30%, 56%, and 92% to 42%, 75%, and 96% within ±0.25 D, ±0.50 D and ±1.00 D, respectively, and reduced the MAE from 0.49 to 0.37 D (P<0.0001). For first eye PE below ±0.50 D, a 50% CF reduced the MAE from 0.32 to 0.30 D (P<0.00001). A 50% CF also reduces second eye MAE for eyes with nonoptimized IOLCs.
  
  
  CONCLUSIONS
  A 50% CF reduces second eye PE when either first eye optimized PE is within ±1.50 D or when nonoptimized IOLCs are used. The correlation is weaker when interocular corneal power differences are >0.60 D.
authors.affiliation: Academic Unit of Ophthalmology, University of Bristol, Bristol Eye Hospital, Lower Maudlin Street, Bristol, United Kingdom. topetros@yahoo.com
authors.forename: Petros
authors.initials: P
authors.lastname: Aristodemou
authors.forename: Nathaniel E
authors.initials: NE
authors.lastname: Knox Cartwright
authors.forename: John M
authors.initials: JM
authors.lastname: Sparrow
authors.forename: Robert L
authors.initials: RL
authors.lastname: Johnston
mesh_terms: D003951:Diagnostic Errors; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular; D008962:Models, Theoretical; D018918:Phacoemulsification; D011446:Prospective Studies; D012029:Refraction, Ocular / Q000502:physiology*; D012030:Refractive Errors / Q000175:diagnosis*; D014792:Visual Acuity / Q000502:physiology*