title: Evaluation of actual retinal images produced by misaligned aspheric intraocular lenses in a model eye.
abstract: OBJECTIVE
  To examine the effect of misalignment (decentration and tilt) of intraocular lenses (IOLs) on retinal image quality using a water-immersed model eye with corneal spherical aberration adjusted to the values found in normal human eyes (spherical aberration 0.25 μm; pupil diameter 6 mm).
  
  
  METHODS
  Three types of IOL holders were prepared. The first was without decentration or tilt, the second had a decentration of 0.5 mm, and the third had a tilt of 5.0°. One spherical IOL and three aspherical IOLs, each with a power of +20 D, were set in the holders and their optical properties (wave front aberration, defocused modulation transfer function, defocused point spread function, and Landolt ring simulations) were compared.
  
  
  RESULTS
  Coma aberrations generated by misaligned IOLs were related to the spherical aberration corrective power of the IOLs. Landolt ring simulations show that the depth of focus increased as spherical aberration increased and that the retinal image quality was degraded by increases in coma aberration.
  
  
  CONCLUSIONS
  Coma aberration was generated by IOLs with a large degree of spherical aberration correction, leading to reduced retinal image quality when the IOL was misaligned. This suggests that, in a clinical setting, the quality of vision might be improved by reducing the degree of coma aberration using IOLs that retain, or minimally correct, spherical aberration.
authors.affiliation: Department of Applied Visual Science, Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Fujikado
authors.affiliation: Research and Development Department of Topcon Corporation, Tokyo, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Saika
keywords: coma aberration; decentration; misalignment; spherical aberration; tilt