Topography-based intraocular lens power selection

Preußner, Paul-Rolf; Wahl, Joachim; Weitzel, Daniela

doi:10.1016/j.jcrs.2004.09.016

Cited by 51 publications

(50 citation statements)

References 23 publications

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“…11 The eccentricity e parameter describes the asphericity of the anterior corneal shape. 11,20 When the cornea is spherical, e is 0. The normal cornea is prolate when e is between 0 and 1.…”

Section: Discussionmentioning

confidence: 99%

“…10,11 The optics in the pseudophakic eye consist of both surfaces of the cornea and the IOL and the retina. In this study, the anterior corneal curvature was calculated from the anterior topography data measured by the Placido topographer or the AS-OCT system.…”

Section: Preoperative Examinationmentioning

confidence: 99%

“…9,10 Ray-tracing IOL power calculation using Placido topography data is commercially available. 11 In the calculation using Okulix software (Tomey Corp.), the IOL power and its predicted postoperative refraction are calculated with AL and anterior corneal curvature data by ray tracing from the retina throughout a pseudophakic eye. A previous study 12 reports that ray-tracing calculations provide better visual outcomes than SRK/ T-based calculations after laser in situ keratomileusis (LASIK).…”

mentioning

confidence: 99%

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Ray-tracing intraocular lens power calculation using anterior segment optical coherence tomography measurements

Minami¹,

Kataoka²,

Matsunaga³

et al. 2012

Journal of Cataract and Refractive Surgery

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Section: Discussionmentioning

confidence: 99%

Section: Preoperative Examinationmentioning

confidence: 99%

mentioning

confidence: 99%

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Ray-tracing intraocular lens power calculation using anterior segment optical coherence tomography measurements

Minami¹,

Kataoka²,

Matsunaga³

et al. 2012

Journal of Cataract and Refractive Surgery

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“…31 There is also some literature regarding the actual calculation-beyond a simple analysis-of optical components, such as IOLs, employing RRT. [32][33][34][35][36][37][38][39][40] There are other published studies that are not directly IOL-or refractive-surgery-related; for instance, some studies used RRT for the analysis of schematic eyes. [41][42][43] Fink et al simulated human optics with real ray-tracing.…”

Section: Introductionmentioning

confidence: 99%

The Individual Virtual Eye: a Computer Model for Advanced Intraocular Lens Calculation

Einighammer

Oltrup

Bende

et al. 2009

Journal of Optometry

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PURPOSE:To describe the individual virtual eye, a computer model of a human eye with respect to its optical properties. It is based on measurements of an individual person and one of its major application is calculating intraocular lenses (IOLs) for cataract surgery. METHODS: The model is constructed from an eye's geometry, including axial length and topographic measurements of the anterior corneal surface. All optical components of a pseudophakic eye are modeled with computer scientific methods. A spline-based interpolation method efficiently includes data from corneal topographic measurements. The geometrical optical properties, such as the wavefront aberration, are simulated with real ray-tracing using Snell's law. Optical components can be calculated using computer scientific optimization procedures. The geometry of customized aspheric IOLs was calculated for 32 eyes and the resulting wavefront aberration was investigated. RESULTS: The more complex the calculated IOL is, the lower the residual wavefront error is. Spherical IOLs are only able to correct for the defocus, while toric IOLs also eliminate astigmatism. Spherical aberration is additionally reduced by aspheric and toric aspheric IOLs. The efficient implementation of time-critical numerical ray-tracing and optimization procedures allows for short calculation times, which may lead to a practicable method integrated in some device. CONCLUSIONS: The individual virtual eye allows for simulations and calculations regarding geometrical optics for individual persons. This leads to clinical applications like IOL calculation, with the potential to overcome the limitations of those current calculation methods that are based on paraxial optics, exemplary shown by calculating customized aspheric IOLs. (J Optom 2009;2:70-82 ©2009 Spanish Council of Optometry) KEY WORDS: real ray-tracing; Snell's law; corneal topography; wavefront aberration; intraocular lens calculation. RESUMEN OBJETIVO:Describir el ojo virtual individualizado, que es un modelo computacional de ojo humano con respecto a sus propiedades ópticas. Está basado en las medidas realizadas en cada persona, de manera individual. Una de sus principales aplicaciones es el cálculo de lentes intraoculares (LIO) para cirugía de cataratas. MÉTODOS:El modelo está construido a partir de datos de geometría ocular; en particular, la longitud axial y las medidas topográficas de la cara anterior de la córnea. Todos los componentes ópticos de un ojo pseudofáquico se modelan por medio de métodos computacionales científicos. El método de interpolación por splines permite incluir de manera eficiente los datos obtenidos en las medidas de topografía corneal. Las propiedades relacionadas con la óptica geométrica, como el patrón de aberración del frente de onda, se obtienen a partir de la simulación de un trazado de rayos reales, el cual emplea la ley de Snell. Los componentes ópticos se pueden calcular empleando procedimientos computacionales de optimización. Para 32 ojos distintos, se calculó la geometría de la c...

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“…This was confirmed in a large-population study 25 in which the mean anterior corneal eccentricity values were used. In a further step in this direction, personalized corneal eccentricities, calculated from the anterior corneal topography, were introduced into the nonparaxial ray-tracing procedure, 26 showing their influence in the calculation, especially in post-LASIK eyes. The effect of the rest of the anterior corneal aberrations was not considered in the calculation, although a visual impression was generated to subjectively judge their impact.…”

mentioning

confidence: 99%

Effect of corneal aberrations on intraocular lens power calculations

Cánovas¹,

Abenza²,

Alcón³

et al. 2012

Journal of Cataract and Refractive Surgery

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Topography-based intraocular lens power selection

Abstract: Intraocular power selection after corneal refractive surgery should be based on all the information corneal topography provides.

Cited by 51 publications

References 23 publications

Ray-tracing intraocular lens power calculation using anterior segment optical coherence tomography measurements

Ray-tracing intraocular lens power calculation using anterior segment optical coherence tomography measurements

The Individual Virtual Eye: a Computer Model for Advanced Intraocular Lens Calculation

Effect of corneal aberrations on intraocular lens power calculations

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