Abstract
Purpose: :
To evaluate the effects of corneal aberrations on the predicted visual quality of eyes implanted with ReZoom and ReSTOR multifocal intraocular lenses (MIOLs).
Methods: :
Corneal wave aberrations to the 5th order from 21 eyes of 21 pseudophakic patients were used to predict total visual performance (distance, intermediate and near) with the MIOLs. The corneal aberrations were combined with measured aberrations from the ReZoom (AMO) and ReSTOR (Alcon) MIOLs. The MIOLs were measured using a specially designed, high resolution Shack-Hartmann wavefront sensor (Nagy et al., ARVO 2007). The area under the through-focus visual Strehl optical transfer function (AVSOTF) for a 4.6 mm pupil was calculated to evaluate the retinal image quality through the focus range (0 - +3D) with each multifocal implant. Corneal aberrations of astigmatism, spherical aberration (SA) and coma were systematically eliminated form the calculations in order to investigate their contribution to overall retinal image quality.
Results: :
The mean (+ SD) age of the pseudophakic patients whose corneal aberrations was used in this study was age 71± 6.28 years. The average corneal total RMS , astigmatism RMS, coma RMS and SA RMS for the 21 eyes was 0.67 ± 0.29 .µm and 0.38 ± 0.16µm, 0.12 ± 0.06µm, and 0.1 ± 0.06 µm respectively. Adding all corneal aberrations and lens aberrations together resulted in a > 50% loss of retinal image quality for both multifocal lenses. After correcting for corneal astigmatism both the ReZoom and ReSTOR lenses showed a retinal image quality increase of almost 20%. When corneal astigmatism and corneal coma were corrected, retinal image quality improved 30% with both ReZoom and ReSTOR. Correcting for corneal spherical aberration had minimal effect for both multifocal lenses in this pseudophakic population which had minimal corneal spherical aberration.
Conclusions: :
In a pseudophakic population, corneal astigmatism and corneal coma, if uncorrected results in a 30 % reduction in retinal image quality when modeled with both ReZoom and ReSTOR multifocal IOL’S. Corneal aberrations and may have a strong influence on retinal image quality when combined with ReZoom and ReSTOR multifocal IOLs.
Keywords: cataract • intraocular lens • presbyopia