Effect of decentration and tilt on the image quality of aspheric intraocular lens designs in a model eye

Eppig, Timo; Scholz, Katja; Löffler, André; Messner, A.; Langenbucher, Achim

doi:10.1016/j.jcrs.2009.01.034

Cited by 153 publications

(145 citation statements)

References 49 publications

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“…Posterior corneal changes after EK affect its parallelism with the anterior corneal surface. 139 These changes include tilt and decentration, which have both been reported to increase whole-eye HOAs in the context of intraocular lenses, 16,35 and increased corneal thickness. 139 Disruption of parallelism may reduce the compensatory ability of the posterior cornea, exaggerating the effects of anterior corneal irregularity and increasing whole eye HOAs, 54,77,139 and negatively impacting the modulation transfer function.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Determinants of visual quality after endothelial keratoplasty

Turnbull

Tsatsos

Hossain

et al. 2016

Survey of Ophthalmology

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Endothelial keratoplasty is now favored over full-thickness penetrating keratoplasty for corneal decompensation secondary to endothelial dysfunction. Although endothelial keratoplasty has evolved as surgeons strive to improve outcomes, fewer patients than expected achieve best corrected visual acuity of 20/20 despite healthy grafts and no ocular comorbidities. Reasons for this remain unclear, with theories including anterior stromal changes, differences in graft thickness and regularity, induced high order aberrations, and the nature of the graft-host interface. Newer iterations of endothelial keratoplasty such as thin manual DSEK, ultrathin DSAEK, and DMEK have achieved rates of 20/20 acuity of approximately 50%, comparable to modern cataract surgery , and it may be that a ceiling exists, particularly in the older age group of patients. Establishing the relative contribution of the factors that determine visual quality following endothelial keratoplasty will help drive further innovation, optimising visual and patient-reported outcomes while improving surgical efficacy and safety.

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Section: Accepted Manuscriptmentioning

confidence: 99%

Determinants of visual quality after endothelial keratoplasty

Turnbull

Tsatsos

Hossain

et al. 2016

Survey of Ophthalmology

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“…We simulated postoperative wavefront aberrations of eyes through the use of spherical IOLs in which there were no preoperative problems or intraoperative/postoperative complications (e.g., clinically detectable tilt or decentration of IOL) which could offset the possible benefits of an aspheric IOL [3,4,22,23]. In a previous pilot study (not published), we measured HOAs of IOLs using an optical bench, and found that the HOAs of the AR40e IOL was almost zero.…”

Section: Discussionmentioning

confidence: 99%

“…[1,2] Nowadays, the implantation of an aspheric intraocular lens (IOL) has become popular after cataract surgery, as well as wavefront correction in refractive surgery [3,4]. Theoretically, an aspheric IOL should improve retinal image quality by compensating corneal spherical aberration (SA), which is the major cause of decreasing image quality and is usually positive in eyes with cataracts [4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Simulation of the Through-Focus Modulation Transfer Functions According to the Change of Spherical Aberration in Pseudophakic Eyes

Kim

Yoon

et al. 2015

Journal of the Optical Society of Korea

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To evaluate the effects of spherical aberration (SA) correction on optical quality in pseudophakic eyes, we simulated the optical quality of the human eye by computation of the modulation transfer function (MTF). We reviewed the medical records of patients who underwent cataract surgery in Asan Medical Center, retrospectively. A Zywave aberrometer was used to measure optical aberrations at 1-12 postoperative months in patients with AR40e intraocular lens implants. The MTF was calculated for a 5 mm pupil from measured wavefront aberrations. The area under the MTF curve (aMTF) was analyzed and the maximal aMTF was calculated while changing the SA (-0.2 ~ +0.2 µm) and the defocus (-2.0 ~ +2.0 D). Sixty-four eyes in 51 patients were examined. The maximal aMTF was 6.61 ± 2.16 at a defocus of -0.25 ± 0.66 D with innate SA, and 7.64 ± 2.63 at a defocus of 0.08 ± 0.53 D when the SA was 0 (full correction of SA). With full SA correction, the aMTF increased in 47 eyes (73.4%; Group 1) and decreased in 17 eyes (26.6%; Group 2). There were statistically significant differences in Z(3, -1) (vertical coma; P = 0.01) and Z(4, 4) (tetrafoil; P = 0.04) between the groups. The maximal aMTF was obtained at an SA of +0.01 µm in Group 1 and an SA of +0.13 µm in Group 2. Optical quality can be improved by full correction of SA in most pseudophakic eyes. However, residual SA might provide benefits in eyes with significant radially asymmetric aberrations.

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“…In contrast to an aspheric IOL with negative SA designed to offset the positive SA of the average cornea, the so-called aberration-free IOL has no SA [22]. The latter has proved to be more resistant to decentration and tilt than the former, and still provides better image quality than spherical IOLs [23], [24]. Between the aberration-compensating and the aberration-free IOLs, a variety of aspheric lenses with intermediate SA values are currently available for clinical practice.…”

Section: High Order Aberration Compensationmentioning

confidence: 99%

New trends in intraocular lens imaging

2011

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As a result of modern technological advances, cataract surgery can be seen as not only a rehabilitative operation, but a customized procedure to compensate for important sources of image degradation in the visual system of a patient, such as defocus and some aberrations. With the development of new materials, instruments and surgical techniques in ophthalmology, great progress has been achieved in the imaging capability of a pseudophakic eye implanted with an intraocular lens (IOL). From the very beginning, optical design has played an essential role in this progress. New IOL designs need, on the one hand, theoretical eye models able to predict optical imaging performance and on the other hand, testing methods, verification through in vitro and in vivo measurements, and clinical validation. The implant of an IOL requires a precise biometry of the eye, a prior calculation from physiological data, and an accurate position inside the eye. Otherwise, the effects of IOL calculation errors or misplacements degrade the image very quickly. The incorporation of wavefront aberrometry into clinical ophthalmology practice has motivated new designs of IOLs to compensate for high order aberrations in some extent. Thus, for instance, IOLs with an aspheric design have the potential to improve optical performance and contrast sensitivity by reducing the positive spherical aberration of human cornea. Monofocal IOLs cause a complete loss of accommodation that requires further correction for either distance or near vision. Multifocal IOLs address this limitation using the principle of simultaneous vision. Some multifocal IOLs include a diffractive zone that covers the aperture in part or totally. Reduced image contrast and undesired visual phenomena, such as halos and glare, have been associated to the performance of multifocal IOLs. Based on a different principle, accommodating IOLs rely on the effort of the ciliary body to increase the effective power of the optical system of the eye in near vision. Finally, we present a theoretical approach that considers the modification of less conventional ocular parameters to compensate for possible refractive errors after the IOL implant.

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Effect of decentration and tilt on the image quality of aspheric intraocular lens designs in a model eye

Cited by 153 publications

References 49 publications

Determinants of visual quality after endothelial keratoplasty

Determinants of visual quality after endothelial keratoplasty

Simulation of the Through-Focus Modulation Transfer Functions According to the Change of Spherical Aberration in Pseudophakic Eyes

New trends in intraocular lens imaging

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