title: Fellow-eye comparison of 2 aspheric microincision intraocular lenses and effect of asphericity on visual performance.
abstract: OBJECTIVE
  To evaluate visual performance and aberrations with aspheric and spherically neutral microincision intraocular lenses (IOLs) and assess the influence of asphericity on visual performance, wavefront aberration, and depth of focus.
  
  
  METHODS
  St. Thomas' Hospital, London, United Kingdom.
  
  
  METHODS
  Clinical trial and cohort study.
  
  
  METHODS
  In the first study, patients with bilateral cataract were randomized to receive an aspheric Acri.Smart 36A IOL or a spherically neutral Akreos MI60 IOL in the first eye. The other IOL was implanted in the second eye within 3 weeks. Assessments at 3 months were 100% and 9% corrected distance visual acuity (CDVA) and distance-corrected near visual acuity (DCNVA). Aberrations and depth of focus were computed using iTrace software. In the second study, data from the other published study was combined to assess the visual performance, aberration, and depth of focus in groups of spherical, spherically neutral, and negatively aspheric (asphericity -0.17 μm) IOLs.
  
  
  RESULTS
  In part 1, there was no difference in 100% or 9% CDVA, DCNVA, or depth of focus between the 2 microincision IOLs. Total spherical aberration was lower with the aspheric IOL. In part 2, the CDVA and DCNVA were not different between the spherical (n = 44), spherically neutral (n = 32), or aspheric (n = 76) IOLs. Total spherical (P<.01) and vertical coma aberrations decreased with increasing IOL asphericity (P<.01). Depth of focus (4.0 mm pupil) also decreased with increasing asphericity and was significant between the spherical IOL and aspheric IOLs. The DCNVA did not differ between groups.
  
  
  CONCLUSIONS
  Asphericity of IOLs did not affect distance visual acuity. The difference in depth of focus was significant only between negatively aspheric and spherical IOLs. Asphericity differences up to 20 μm did not influence depth of focus.
authors.affiliation: Department of Ophthalmology, St. Thomas' Hospital, London, United Kingdom. mayank_nanavaty@hotmail.com
authors.forename: Mayank A
authors.initials: MA
authors.lastname: Nanavaty
authors.forename: David J
authors.initials: DJ
authors.lastname: Spalton
authors.forename: Kavita B
authors.initials: KB
authors.lastname: Gala
mesh_terms: D000368:Aged; D015331:Cohort Studies; D057108:Corneal Wavefront Aberration / Q000503:physiopathology; D003867:Depth Perception / Q000502:physiology*; D006801:Humans; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular; D008866:Microsurgery; D018918:Phacoemulsification; D011446:Prospective Studies; D019591:Pseudophakia / Q000503:physiopathology*; D014792:Visual Acuity / Q000502:physiology*