Prospective Multicenter Study of Toric IOL Outcomes When Dual Zone Automated Keratometry Is Used for Astigmatism Planning

Potvin, Richard; Gundersen, Kjell Gunnar; Masket, Samuel; Osher, Robert H.; Snyder, Michael E.; Vann, Robin; Solomon, Kerry D.; Hill, Warren

doi:10.3928/1081597x-20131115-03

Cited by 17 publications

(3 citation statements)

References 10 publications

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“…88.2% of the postoperative residual astigmatism were ≤ 0.75 D and 71.8% ≤ 0.5 D. These outcomes are very similar to previous studies. Potvin et al evaluated clinical outcomes of patients whose toric IOL calculations were based on the Lenstar LS900 dual zone automated keratometer and found that 76% of eyes had ≤0.50 D of astigmatism after 3 months [14]. Results using the Barrett toric calculator show 72-80% of the cases with a residual refractive astigmatism of 0.5 D or less [15,16].…”

Section: Discussionmentioning

confidence: 99%

Clinical evaluation of toric intraocular lens implantation based on iTrace wavefront keratometric astigmatism

Zhang

Zhou

et al. 2020

BMC Ophthalmol

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Background Currently, there is no standard technique for determining corneal astigmatism. The iTrace wavefront aberrometry of cornea calculated steep power and axis based on the best Zernike mathematical fit from all topo data within 4 mm circle. It was supposed to be more accurate than iTrace simulated keratometry which was calculated based on only 4 points on the circle of 3 mm. This aim of this study was to evaluate visual outcomes and rotational stability after toric intraocular lens (IOL) implantation using the wavefront aberrometry of the cornea with iTrace. Setting: Single site in China, Shanxi Eye Hospital, Shanxi, China. Design: Prospective case series. Methods The study included 85 eyes of 63 patients undergoing phacoemulsification and toric IOL implantation. The IOL power and cylinders were chosen with the help of the iTrace toric planning program using wavefront keratometric astigmatism. Astigmatic changes were assessed using Alpins vector method over a 3-month follow-up period. Results Preoperative mean corneal topographic astigmatism was 1.91 diopters (D) ± 0.69 (standard deviation). Postoperative mean refractive astigmatism decreased significantly to 0.48 D ± 0.34. Surgical induced astigmatism was 1.73 D ± 0.77 and the mean correction index was 0.89 ± 0.22, showing a slight undercorrection. The proportion of astigmatism ≤0.50 D increased from 0 to 71.8% postoperatively. Conclusions This is the first study on evaluation of clinical outcomes of toric IOL implantation in corneal astigmatism patients using iTrace wavefront keratometric readings. The findings show that use of iTrace built-in toric calculator is safe and effective for planning toric IOL surgery for wavefront keratometric astigmatism. Trial registration Current Controlled Trials ISRCTN94956424, Retrospectively registered (Date of registration: 05 February 2020).

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Section: Discussionmentioning

confidence: 99%

Clinical evaluation of toric intraocular lens implantation based on iTrace wavefront keratometric astigmatism

Zhang

Zhou

et al. 2020

BMC Ophthalmol

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“…IOLs [8], and reported lens tilt [9]. Several diagnostic devices based on different technologies are available to measure preoperative corneal power and astigmatism, including manual and automated keratometers; Placido-based corneal, point-source color light emitting diode, Scheimpflug imagebased, and scanning-slit corneal topographers; low-coherence reflectometers; and intraoperative aberrometers [10][11][12][13]. However, none of these methods are currently considered the gold standard.…”

Section: Discussionmentioning

confidence: 99%

Clinical Evaluation of Toric Intraocular Lens Implantation Based on iTrace Wavefront Keratometric Astigmatism

Zhang

Zhou

et al. 2020

Preprint

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Background: There was no standard technique for measuring corneal astigmatism. The iTrace wavefront aberrometry of cornea calculated steep power and axis based on the best Zernike mathematical fit from all topo data within 4 mm circle. It was supposed to be more accurate than iTrace simulated keratometry which was calculated based on only 4 points on the circle of 3 mm. This study evaluated visual outcomes, rotational stability after performing toric intraocular lens (IOL) implantation planning based on the wavefront aberrometry of the cornea with iTrace. Setting: Single site in China, Shanxi Eye Hospital, Shanxi, China. Design: Prospective case series. Methods ： The study included 85 eyes of 63 patients undergoing phacoemulsification and toric IOL implantation. The IOL power and cylinders were chosen with the help of the iTrace toric planning program using wavefront keratometric astigmatism. Over a 3-month follow-up period, astigmatic changes were assessed using the Alpins vector method. Results ： Preoperative mean corneal topographic astigmatism was 1.91 diopters (D) ± 0.69 (standard deviation). Postoperative mean refractive astigmatism decreased significantly to 0.48 D ± 0.34. Surgical induced astigmatism was 1.73 D ± 0.77 and the mean correction index was 0.89 ± 0.22, showing a slight undercorrection. The proportion of astigmatism ≤ 0.50 D increased from 0 to 71.8% postoperatively. Conclusions ： This is the first study evaluating the clinical outcomes of using iTrace wavefront keratometric readings to plan a toric IOL implantation. The findings show that the iTrace built-in toric calculator with wavefront keratometric astigmatism for toric IOL planning is safe and effective.

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“…Manual keratometry, optical low-coherence reflectometry (OLCR), partial coherence interferometry (PCI), and topographers have traditionally been used for measuring the curvature of the eye’s anterior surface to determine the power and axis of toric IOLs. 10 Total corneal power (TCP) and astigmatism were calculated based on the assumptions that there exists a fixed ratio between the anterior and posterior curvatures and that the minimal refractive power of the posterior surface is inconsequential. However, a discrepancy was observed between results obtained through different modalities.…”

Section: Introductionmentioning

confidence: 99%

Comparison of using Galilei Dual Scheimpflug Analyzer G4 and Barrett formula in predicting low cylinder preoperatively for cataract surgeries

Sun

et al. 2019

European Journal of Ophthalmology

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Purpose: To compare corneal astigmatism estimation from Barrett toric calculator, with measurement from Galilei Dual Scheimpflug Analyzer G4 in low corneal cylinder patients. Methods: Preoperative corneal astigmatism was measured using Auto Kerato-Refractometer (AutoKM), IOL Master, and Galilei G4 (combined Placido-dual Scheimpflug analyzer) and was processed by Barrett toric calculator with measurements obtained from Auto Kerato-Refractometer and from IOL Master. A total of 42 eyes undergoing cataract surgery with nontoric intraocular lens implantation were included. Corneal astigmatism was calculated based on manifest refractive astigmatism with implications of surgically induced astigmatism. Errors in predicted residual astigmatism were calculated by the difference between postoperative manifest cylindrical refractive error and preoperative corneal cylinder using vector analysis. Results: Centroid error in predicted residual astigmatism was with-the-rule 0.36 D for AutoKM and 0.48 D for IOL Master, was lower at 0.24 D for the Barrett–IOL Master, and was lowest at 0.21 D for the Barrett–AutoKM ( p < .001). The Galilei G4 demonstrated the highest centroid error for SimK (0.53 D) and lower for total corneal power (0.49 D). The Barrett toric calculator obtained the lowest median absolute error in predicted residual astigmatism for AutoKM (0.43 D) and IOL Master (0.54 D). The Barrett–IOL Master demonstrated that 61% and 76% of eyes were within 0.50 and 0.75 D of the predicted residual astigmatism, respectively. Conclusion: The Barrett–IOL Master had more accurate prediction of residual astigmatism for low astigmatism eyes before cataract surgery compared to Galilei Dual Scheimpflug Analyzer G4 in this study.

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Prospective Multicenter Study of Toric IOL Outcomes When Dual Zone Automated Keratometry Is Used for Astigmatism Planning

Abstract: In this series of eyes from multiple centers, the calculation of toric IOL power using dual-zone automated keratometry measurements produced clinical results that were better than results in the literature where manual keratometry was used.

Cited by 17 publications

References 10 publications

Clinical evaluation of toric intraocular lens implantation based on iTrace wavefront keratometric astigmatism

Clinical evaluation of toric intraocular lens implantation based on iTrace wavefront keratometric astigmatism

Clinical Evaluation of Toric Intraocular Lens Implantation Based on iTrace Wavefront Keratometric Astigmatism

Comparison of using Galilei Dual Scheimpflug Analyzer G4 and Barrett formula in predicting low cylinder preoperatively for cataract surgeries

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