Improving toric intraocular lens calculations using total surgically induced astigmatism for a 2.5 mm temporal incision

Holladay, Jack T.; Pettit, G. H.

doi:10.1016/j.jcrs.2018.09.028

Cited by 29 publications

(24 citation statements)

References 28 publications

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“…Recent efforts to refine SIA calculation based on preoperative corneal astigmatism and postoperative refractive astigmatism have shown promise in this regard. 24 There are limitations to the current study. While the sample size was calculated to be sufficient to demonstrate the differences between toric IOL calculations, larger sample sizes are always helpful.…”

Section: Discussionmentioning

confidence: 88%

<p>Clinical Outcomes of Toric Intraocular Lenses: Differences in Expected Outcomes When Using a Calculator That Considers Effective Lens Position and the Posterior Cornea vs One That Does Not</p>

Yeu

Cheung

Potvin³

2020

OPTH

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Purpose: To compare toric intraocular lens (IOL) outcome accuracy after using an online toric calculator that accounted for posterior corneal astigmatism versus a traditional calculator that only accounted for anterior corneal astigmatism. Patients and Methods: This was a single-arm, non-masked, non-randomized prospective study in a single private practice in Norfolk, Virginia, USA, evaluating clinical outcomes of toric IOL implantation based on a calculator that considered posterior corneal astigmatism (PCA) and effective lens position (ELP). Of interest was the distribution of the residual refraction (sphere and cylinder) at 40-70 days postoperative. Residual refractive cylinder (RRC) was compared to the back-calculated theoretical results using a legacy calculator that did not consider PCA. Distance visual acuity (best-corrected and uncorrected) and the manifest refraction were also measured, along with preoperative and postoperative keratometry. Results: Forty-six eyes of 34 subjects were available for analysis. All eyes had a spherical equivalent refraction within 0.5D of intended. Uncorrected visual acuity was 20/25 or better in 86% of eyes targeted for emmetropia. Residual cylinder was 0.50D or less in 96% of eyes, with a maximum of 0.75D measured. The difference between residual cylinder and the expected cylinder from calculations was significantly lower for the calculator that included consideration of PCA and ELP relative to the one that did not. Conclusion: Use of a toric IOL calculator that includes consideration of posterior corneal astigmatism is recommended to optimize clinical outcomes.

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Section: Discussionmentioning

confidence: 88%

<p>Clinical Outcomes of Toric Intraocular Lenses: Differences in Expected Outcomes When Using a Calculator That Considers Effective Lens Position and the Posterior Cornea vs One That Does Not</p>

Yeu

Cheung

Potvin³

2020

OPTH

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“…Accordingly, we did not evaluate posterior corneal astigmatism in this study. Although the amount of posterior corneal astigmatism is far smaller than that of anterior corneal astigmatism, total corneal astigmatism using a corneal tomographer would be beneficial for understanding the precise SIA of cataract surgery (13,14). Secondly, we only examined the patients undergoing cataract surgery through a 2.8 mm clear corneal incision.…”

Section: Discussionmentioning

confidence: 99%

Comparison of Mean and Centroid of Surgically Induced Astigmatism After Standard Cataract Surgery

et al. 2021

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Purpose: To compare the arithmetic mean of surgically induced astigmatism (M-SIA) and the centroid of surgically induced astigmatism (C-SIA) after standard cataract surgery.Methods: We retrospectively examined 200 eyes of 100 consecutive patients undergoing bilateral cataract surgery through a 2.8 mm temporal clear corneal incision. We quantitatively measured the magnitude and axis of corneal astigmatism preoperatively and 3 months postoperatively using an automated keratometer (TONOREFF-II, Nidek). We assessed the M-SIA, the C-SIA, and the double angle plots for the display of the individual SIA distributions.Results: For bilateral data analysis, the magnitude of corneal astigmatism significantly increased from 0.66 ± 0.39 D preoperatively to 0.74 ± 0.46 D postoperatively (paired t-test, p = 0.012). The M-SIA was 0.50 ± 0.36 D. On the other hand, the C-SIA was 0.18 ± 0.60 D at an axis of 97°. For unilateral analysis, we obtained similar outcomes between the right and left eye groups.Conclusions: According to our experience, standard cataract surgery induces the M-SIA by approximately 0.5 D. The magnitude of the C-SIA largely decreased to approximately 40% of the M-SIA, and the direction of the C-SIA showed a tendency toward with-the-rule astigmatism. It should be noted that the M-SIA was considerably different from the C-SIA, especially when selecting the appropriate toric IOL model and power.

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“…aspx, accessed on February 26 th , 2020). Other methods were then developed by Abulafia et al (64), Savini and Naeser (58), Goggin et al (65), and Holladay et al (66), as well as by some IOL manufacturers (67). Other recently introduced toric calculators are those developed by Kane (https://www.…”

Section: Calculation Of Toric Iolsmentioning

confidence: 99%

Recent developments in intraocular lens power calculation methods—update 2020

2020

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For many decades only a few formulas have been available to calculate the intraocular lens (IOL) power for patients undergoing cataract surgery: the Haigis, Hoffer Q, Holladay 1 and 2 and SRK/ T. In recent years, several new formulas for IOL power calculation have been introduced with the aim of improving the accuracy of refraction prediction in eyes undergoing cataract surgery. These include the Barrett Universal II, the Emmetropia Verifying Optical (EVO), the Kane, the Naeser 2, the Olsen, the Panacea, the Pearl DGS, the Radial Basis Function (RBF), the T2 and the VRF formulas. Although most of them are unpublished so that their structure is unknown, we give an overview of each formula and report the results of the studies that have compared them. Their performance in short and long eyes is provided and a special focus is given on the issue of segmented axial length, which is a promising method to obtain more accurate outcomes in short and long eyes. Here, the group refractive index originally developed for the IOLMaster may not represent the best method to convert the optical path length into a physical distance.The issue of posterior and total corneal astigmatism (TCA) is discussed in relation to toric IOLs; the latest formulas for toric IOLs and their results are also reported.

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Improving toric intraocular lens calculations using total surgically induced astigmatism for a 2.5 mm temporal incision

Cited by 29 publications

References 28 publications

<p>Clinical Outcomes of Toric Intraocular Lenses: Differences in Expected Outcomes When Using a Calculator That Considers Effective Lens Position and the Posterior Cornea vs One That Does Not</p>

<p>Clinical Outcomes of Toric Intraocular Lenses: Differences in Expected Outcomes When Using a Calculator That Considers Effective Lens Position and the Posterior Cornea vs One That Does Not</p>

Comparison of Mean and Centroid of Surgically Induced Astigmatism After Standard Cataract Surgery

Recent developments in intraocular lens power calculation methods—update 2020

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