Correcting astigmatism with toric intraocular lenses: Effect of posterior corneal astigmatism

Koch, Douglas D.; Jenkins, Richard B.; Weikert, Mitchell P.; Yeu, Elizabeth; Wang, Li

doi:10.1016/j.jcrs.2013.06.027

Cited by 250 publications

(201 citation statements)

References 13 publications

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“…One remarkable disadvantage of the VERION System is that posterior corneal surface measurement is not possible; this may have a significant role in a relatively high percentage of the patients, especially those waiting for toric IOL implantation. 11 Another disadvantage of the system is that another tool measuring the axial length is required for the completion of the calculations for cataract surgery (ie, IOL diopter planning).…”

Section: Discussionmentioning

confidence: 99%

Repeatability Data and Agreement of Keratometry With the VERION System Compared to the IOLMaster

Németh¹,

Szalai²,

Hassan³

et al. 2015

J Refract Surg

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he exact measurement of the radius of the curvature of the cornea is crucial for planning the diopter of the intraocular lenses (IOLs) for implantation during cataract surgery. The error in measurements of the keratometric data can lead to unwanted postoperative refractive error. Although keratometric mistakes are not the first or most frequent source of error in today's biometric methods, 1 keratometry has an undisputed and important role in cataract surgery. Moreover, cases of implantation of toric IOLs require more precise keratometric readings and cylinder axis determination than ever before.There are numerous papers showing that the repeatability of keratometric measurements is excellent in the case of the IOLMaster (Carl Zeiss Meditec, Jena, Germany), 2-4 although above 42.0 diopters (D), the cylinder axis has relatively low repeatability data.2 In the case of the Lenstar (Haag-Streit, Koeniz, Switzerland), the interclass coefficient of the variation of the astigmatism axis was 0.915 and the mean arithmetic difference between the two measurement sessions was 3.19°, with an absolute difference of a median of 9°. 5 The Lenstar keratometry has repeatable values, 6,7 but according to Zhao et al., 7 the Lenstar and the IOLMaster cannot be used interchangeably in relation to keratometric data. With regard to average keratometric data, it seems that the Lenstar is biometrically equivalent to the IOLMaster, 8 and the correlation between the cylinder axis measurements of the IOLMaster and the Lenstar is high.9 However, Rohrer et al. 9 observed that the differences between the axis value of the flattest meridian in the Lenstar and the IOLMaster in a large percentage of patients is unacceptably high. Besides these controversialTo analyze the repeatability of keratometric and white-to-white (WTW) distance measurements with the VERION Measurement Module (Alcon Laboratories, Inc., Fort Worth, TX) and to compare the measured data to the results of the IOLMaster (Carl Zeiss Meditec, Jena, Germany). METHODS:Three images were captured with the VERION and the flattest and steepest keratometric data, the astigmatism axis, and the WTW distance were recorded. Subsequently, the axial length, the keratometric data with axis, and the WTW distance were measured with an IOLMaster. The repeatability data of the keratometric value of the VERION System, converted to cross cylinder J 0 and J 45 vector components, were analyzed. The agreement data for keratometry obtained by the VERION System and the differences regarding keratometric data and WTW distance compared to IOLMaster were calculated. RESULTS:The measurements were conducted in 50 eyes of 50 healthy volunteers (median age: 50.32 years, range: 19.34 to 85.3 years). The flattest and the steepest keratometric data, the diopter of astigmatism, the J 0 and J 45 vector components, and WTW distance did not differ significantly between devices (P > .05). Intraclass correlation coefficients (range: 0.863 to 0.994) and Cronbach's alpha values (range: 0.950 to 0.998) were high for all p...

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Section: Discussionmentioning

confidence: 99%

Repeatability Data and Agreement of Keratometry With the VERION System Compared to the IOLMaster

Németh¹,

Szalai²,

Hassan³

et al. 2015

J Refract Surg

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“…A second study by Koch et al (35) reported in pseudophakic eyes the mean corneal astigmatism prediction error of four devices that calculate total corneal astigmatism based only on anterior surface measurements. The corneal astigmatism prediction error (the deviation from the actual total corneal astigmatism) was obtained by subtracting the actual corneal astigmatism (which is the difference between the postoperative manifest refraction corrected to the corneal plane and the effective toric IOL power calculated with the Holladay IOL Consultant Program (Holladay Consulting, Inc., Bell Air, USA) from the corneal astigmatism measured by each device.…”

Section: The Role Of the Posterior Corneamentioning

confidence: 99%

Surgical management of astigmatism with toric intraocular lenses

Ventura¹,

Wang²,

Weikert³

et al. 2014

Arquivos Brasileiros De Oftalmologia

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“…With new multifocal IOLs on board and refractive or presbyopic lens exchange becoming more popular, there is no room for inaccurate measurements. Addressing posterior corneal astigmatism has become an important issue when dealing with toric monofocal or toric multifocal IOLs [1][2][3][4]. The posterior corneal curvature can be assessed with optical coherence tomography (OCT) systems (Casia SS-1000, Tomey Corp.) and Scheimpflug camera-based devices such as Pentacam HR Ò (Oculus Optikgerate GmbH), Galilei Ò (Ziemer Ophthalmic Systems AG) and Sirius Ò (Schwind).…”

Section: Introductionmentioning

confidence: 99%

Comparison of anterior segment parameters and axial length measurements performed on a Scheimpflug device with biometry function and a reference optical biometer

Muzyka−Woźniak¹,

Oleszko

2018

Int Ophthalmol

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Purpose To compare measurements of axial length (AL), corneal curvature (K), anterior chamber depth (ACD) and white-to-white (WTW) distance on a new device combining Scheimpflug camera and partial coherence interferometry (Pentacam AXL) with a reference optical biometer (IOL Master 500). To evaluate differences between IOL power calculations based on the two biometers. Methods Ninety-seven eyes of 97 consecutive cataract or refractive lens exchange patients were examined preoperatively on IOL Master 500 and Pentacam AXL units. Comparisons between two devices were performed for AL, K, ACD and WTW. Intraocular lens (IOL) power targeting emmetropia was calculated with SRK/T and Haigis formulas on both devices and compared. Results There were statistically significant differences between two devices for all measured parameters (P \ 0.05), except ACD (P = 0.36). Corneal curvature measured with Pentacam AXL was significantly flatter then with IOL Master. The mean difference in AL was clinically insignificant (0.01 mm; 95% LoA 0.16 mm). Pentacam AXL yielded higher IOL power in 75% of eyes for Haigis formula and in 62% of eyes for SRK/T formula, with a mean difference within ± 0.5 D for 72 and 86% of eyes, respectively. Conclusions There were statistically significant differences between AL, K and WTW measurements obtained with the compared biometers. Flatter corneal curvature measurements on Pentacam AXL necessitate formulas optimisation for Pentacam AXL.

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Correcting astigmatism with toric intraocular lenses: Effect of posterior corneal astigmatism

Abstract: Corneal astigmatism was overestimated in WTR by all devices and underestimated in ATR by all except the Placido-dual Scheimpflug analyzer. A new toric IOL nomogram is proposed.

Cited by 250 publications

References 13 publications

Repeatability Data and Agreement of Keratometry With the VERION System Compared to the IOLMaster

Repeatability Data and Agreement of Keratometry With the VERION System Compared to the IOLMaster

Surgical management of astigmatism with toric intraocular lenses

Comparison of anterior segment parameters and axial length measurements performed on a Scheimpflug device with biometry function and a reference optical biometer

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