Protocols for Studies of Intraocular Lens Formula Accuracy

Hoffer, Kenneth J.; Aramberri, Jaime; Haigis, W.; Olsen, Thomas; Savini, Giacomo; Shammas, H. John; Bentow, Stanley S.

doi:10.1016/j.ajo.2015.05.029

Cited by 226 publications

(192 citation statements)

References 13 publications

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“…We followed the protocols recently published in an Editorial in the American Journal of Ophthalmology, comparing IOL power calculation formulas typically evaluated the accuracy of the formula of interest by comparing the MAE or MedAE of each formula [13–15]. We did not perform an analysis stratifying according to axial length due to the limited number of study participants.…”

Section: Discussionmentioning

confidence: 99%

The effect of ocular biometric factors on the accuracy of various IOL power calculation formulas

et al. 2017

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BackgroundTo evaluate how differences in ocular biometry affects the Hoffer Q, Holladay 1, SRK/T, and Haigis intraocular lens power calculation formulae predictions.MethodsThis study was performed on 91 eyes of 91 patients who underwent uneventful cataract surgery. Ocular biometry values were measured using the IOL Master 500, and intraocular lens (IOL) power was calculated using the Haigis, Hoffer Q, Holladay 1, and SRK/T formulas. We calculated the expected difference (ED) of each 3rd generation formula from the Haigis formula by subtracting the predicted refraction of the Haigis formula from the predicted refraction of each 3rd generation formula. Post-operative anterior chamber depth (ACD) was measured at 1 month after surgery using the IOL master. We calculated errors of each formula by subtracting predicted from manifest refraction at post-operative 1 month. Correlation analysis was performed between ocular biometry values, formula expectation values, formula errors and absolute formula errors.ResultsMultiple regression analysis revealed that preoperative ACD was the only significant factor for ED prediction in all of the 3rd generation formulas. For mean errors, axial length and post-operative 1-month change of ACD (delta ACD) correlated significantly with the errors in all 3rd generation formulas, but not with errors of the Haigis formula. Median absolute error (MedAE) of the formulas were 0.40 D for the Hoffer Q formula, 0.37 D for the Holladay formula, 0.34 D for the SRK/T formula, and 0.41 D for the Haigis formula. The MAE of the formulas were 0.50 ± 0.47 D for the Hoffer Q formula, 0.50 ± 0.50 D for the Holladay formula, 0.47 ± 0.51 D for the SRK/T formula, and 0.50 ± 0.47 D for the Haigis formula.ConclusionRegarding ED between the third generation and Haigis formulas, preoperative ACD demonstrated the greatest influence. Calculating mean absolute errors of the formulas, all IOL formulas showed excellent and comparable accuracy. Post-operative change (delta) of ACD correlated significantly with errors of third generation formulas according to simulated ACD.

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Section: Discussionmentioning

confidence: 99%

The effect of ocular biometric factors on the accuracy of various IOL power calculation formulas

et al. 2017

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“…In the existing formula, biometric data obtained by the ILM700 were used (AL, K, ACD, and LT in the Barrett Universal II formula; AL, K, and ACD in the Haigis formula; and AL and K in the SRK/T formula). Based on the training dataset, the optimized lens constants (a0 of the Haigis formula and A constants of the SRK/T formula) were determined such that the arithmetic prediction error was zero on average 39 . The Haigis formula was used in a standard mode with standard values for a1 (0.4) and a2 (0.1).…”

Section: Development Of Iol Power Calculation Based On Paraxial Ray Tmentioning

confidence: 99%

Development of a new intraocular lens power calculation method based on lens position estimated with optical coherence tomography

Satou

Shimizu

Tsunehiro

et al. 2020

Sci Rep

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A new method is developed and validated for intraocular lens (IOL) power calculation based on paraxial ray tracing of the postoperative IOL positions, which are obtained with the use of anterior segment optical coherence tomography. Of the 474 eyes studied, 137 and 337 were grouped into training and validation sets, respectively. The positions of the implanted IOLs of the training datasets were characterized with multiple linear regression analyses one month after the operations. A new regression formula was developed to predict the postoperative anterior chamber depth with the use of the stepwise analysis results. In the validation dataset, postoperative refractive values were calculated according to the paraxial ray tracing of the cornea and lens based on the assumption of finite structural thicknesses with separate surface curvatures. the predicted refraction error was calculated as the difference of the expected postoperative refraction from the spherical-equivalent objective refraction values. The percentage error (within ±0.50 diopters) of the new formula was 84.3%. This was not significantly correlated to the axial length or keratometry. The developed formula yielded excellent postoperative refraction predictions and could be applicable to eyes with abnormal proportions, such as steep or flat corneal curvatures and short and long axial lengths.open Scientific RepoRtS | (2020) 10:6501 | https://doi.org/10.1038/s41598-020-63546-ywww.nature.com/scientificreports www.nature.com/scientificreports/ previously reported the relationship between the crystalline lens parameter and the IOL position 18 . Goto et al. 19 developed a formula to predict postoperative ACD, including the angle-to-angle (ATA) depth obtained by presented a method to accurately estimate and quantify the entire shape of the crystalline lens from OCT data, and reported that the preoperative anterior segment parameters were exceptionally valuable for estimating the IOL position. Yoo et al. 17 reported improvements in refractive outcomes by the ray-tracing method using the equatorial plane position of the lens.Paraxial ray tracing repeats simple calculations without special software or complexity. The predictive accuracy of IOL power calculations with paraxial ray tracing including the IOL positions predicted by the AS-OCT has not been clarified.Correspondingly, the aims of the present study are a) the development of a new formula based on paraxial ray tracing for IOL power calculations that utilize the postoperative IOL positions obtained using AS-OCT, and b) the validation of the accuracy of the developed formula. Scientific RepoRtS |(2020) 10:6501 | https://doi.

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“…Hoffer Q [13], Holladay I [14], and SRK/T [15] were optimized by the function of What If Analysis in the Excel software, and a double linear regression analysis was used for Haigis [16]. However, Constants of SRK II [17] were not optimized because it was considered to be an outdated regression formula [18]. Then, the optimized constants were used in post-LASIK eyes.…”

Section: Methodsmentioning

confidence: 99%

Prediction accuracy of intraocular lens power calculation methods after laser refractive surgery

Liu

Liao

2017

BMC Ophthalmol

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BackgroundThis study aimed to evaluate the prediction accuracy of postoperative refractions using partial coherence interferometry (IOL-Master) and applanation ultrasound (AL-3000) assisted with corneal topography (TMS-4) in eyes that had undergone myopic laser-assisted in situ keratomileusis (LASIK).MethodsHaigis-L formula, Koch–Maloney method using Haigis formula, Shammas clinically derived K-value (simulated keratometric value) correction (Shammas c.d.) using Haigis formula, and Shammas post-LASIK (Shammas-PL) formula were used in eyes with myopic LASIK. Constants were derived from the optimized constants in 133 virgin eyes. Refractive outcomes were determined by streak retinoscopy and subjective manifest refraction. Methods and formulas were evaluated by mean error (ME), standard deviation (SD), range of error, mean absolute error (MAE), median absolute error, 95% confidence interval of MAE, and percentage of eyes within ±0.5 diopter (D), ±1.0 D, and ±1.5 D of prediction.ResultsSDs of the Haigis-L, Koch-Maloney method using the Haigis formula, Shammas c.d. using the Haigis formula, and the Shammas-PL formula using IOL-Master were 0.721, 0.695, 0.695, and 0.698; and those using AL-3000 assisted with TMS-4 were 0.782, 0.741, 0.743, and 0.778, respectively.ConclusionsNo-history methods that corrected corneal power with measurements using IOL-Master were promising in myopic post-LASIK eyes, but still a gap in prediction accuracy exists between virgin eyes and post-LASIK eyes.Electronic supplementary materialThe online version of this article (doi:10.1186/s12886-017-0439-x) contains supplementary material, which is available to authorized users.

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Protocols for Studies of Intraocular Lens Formula Accuracy

Cited by 226 publications

References 13 publications

The effect of ocular biometric factors on the accuracy of various IOL power calculation formulas

The effect of ocular biometric factors on the accuracy of various IOL power calculation formulas

Development of a new intraocular lens power calculation method based on lens position estimated with optical coherence tomography

Prediction accuracy of intraocular lens power calculation methods after laser refractive surgery

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