Optical aberrations of intraocular lenses measured in vivo and in vitro

Abstract

Corneal and ocular aberrations were measured in a group of eyes before and after cataract surgery with spherical intraocular lens (IOL) implantation by use of well-tested techniques developed in our laboratory. By subtraction of corneal from total aberration maps, we also estimated the optical quality of the intraocular lens in vivo. We found that aberrations in pseudophakic eyes are not significantly different from aberrations in eyes before cataract surgery or from previously reported aberrations in healthy eyes of the same age. However, aberrations in pseudophakic eyes are significantly higher than in young eyes. We found a slight increase of corneal aberrations after surgery. The aberrations of the IOL and the lack of balance of the corneal spherical aberrations by the spherical aberrations of the intraocular lens also degraded the optical quality in pseudophakic eyes. We also measured the aberrations of the IOL in vitro, using an eye cell model, and simulated the aberrations of the IOL on the basis of the IOL's physical parameters. We found a good agreement among in vivo, in vitro, and simulated measures of spherical aberration: Unlike the spherical aberration of the young crystalline lens, which tends to be negative, the spherical aberration of the IOL is positive and increases with lens power. Computer simulations and in vitro measurements show that tilts and decentrations might be contributors to the increased third-order aberrations in vivo in comparison with in vitro measurements.

Correlation of higher-order wavefront aberrations with visual function in pseudophakic eyes

“…It has been shown that ocular higher-order aberration in pseudophakic eyes is comparable with that in phakic eyes of subjects of the same age. [11][12][13] This is because standard IOLs have a positive spherical aberration, and thus add to the total ocular aberration.…”

Through-focus response of multifocal intraocular lenses evaluated with a spatial light modulator

“…The performance of these lenses has been reported in numerous studies performed both in vivo and in vitro showing that decentration and tilt are two frequent and important factors affecting vision to be taken into account in cataract surgery (see For example [1][2][3][4] and the references therein). To assess the optical quality of MIOLs several experimental setups were designed in which the Point Spread Function (PSF) and/or the Modulation Transfer Function (MTF), measured for the distance and the near foci, are the essential merit functions.…”

“…On the other hand the response of a MIOL to misalignments, such as tilt and decentration is a crucial issue for assessing its optical performance [6][7][8] and the tolerance to these factors is included in the battery of tests contained in the ISO 11979:2006 standard [9]. The influence of misalignments of monofocal intraocular lenses has been tested with different techniques such as using Purkinje images [10,11], Scheimpflug photography [11,12] and ray tracing [3,8,13]. However, these techniques are not easily adapted to assess the performance of decentered MIOLs.…”

Aberration-correcting effect of ThinOptX IOL

“…Aberrometry has been applied recently to evaluate visual quality after cataract or refractive surgery. [8][9][10][11] Most reports related to high-order aberrations of an IOL-implanted eye measure whole-eye aberration, and yet measurements are affected by front corneal aberration, which may disrupt on-target evaluation of the IOL. We measured, compared, and evaluated whole-eye, corneal, and internal spherical aberrations of ThinOptX IOL-and Acrysof IOL-implanted eyes.…”