Corneal power estimation for intraocular lens power calculation after corneal laser refractive surgery in Chinese eyes

Jin, Haiying; Auffarth, Gerd U.; Guo, Huiling; Zhao, Peiquan

doi:10.1016/j.jcrs.2012.06.048

Cited by 17 publications

(11 citation statements)

References 27 publications

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“…There have been reports in which the first 2 techniques were applied to obtain the ratio of anterior corneal curvature to posterior corneal curvature, and the keratometric index was calculated regarding the total corneal power based on Gaussian optics formula as a benchmark. [ 1 , 5 , 6 , 17 ] However, to the best to our knowledge, until now there have been no reports on the keratometric index calculated by data derived from RTVue FD-OCT (RTVue, Optovue, Inc.).…”

Section: Introductionmentioning

confidence: 99%

Keratometric Index Obtained by Fourier-Domain Optical Coherence Tomography

et al. 2015

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PurposeTo determine the keratometric indices calculated based on parameters obtained by Fourier-domain optical coherence tomography (FD-OCT).MethodsThe ratio of anterior corneal curvature to posterior corneal curvature (Ratio) and keratometric index (N) were calculated within central 3 mm zone with the RTVue FD-OCT (RTVue, Optovue, Inc.) in 186 untreated eyes, 60 post-LASIK/PRK eyes, and 39 keratoconus eyes. The total corneal powers were calculated using different keratometric indices: Kcal based on the mean calculated keratometric index, K1.3315 calculated by the keratometric index of 1.3315, and K1.3375 calculated by the keratometric index of 1.3375. In addition, the total corneal powers based on Gaussian optics formula (Kactual) were calculated.ResultsThe means for Ratio in untreated controls, post-LASIK/PRK group and keratoconus group were 1.176 ± 0.022 (95% confidence interval (CI), 1.172–1.179), 1.314 ± 0.042 (95%CI, 1.303–1.325) and 1.229 ± 0.118 (95%CI, 1.191–1.267), respectively. And the mean calculated keratometric index in untreated controls, post-LASIK/PRK group and keratoconus group were 1.3299 ± 0.00085 (95%CI, 1.3272–1.3308), 1.3242 ± 0.00171 (95%CI, 1.3238–1.3246) and 1.3277 ± 0.0046 (95%CI, 1.3263–1.3292), respectively. All the parameters were normally distributed. The differences between Kcal and Kactual, K1.3315 and Kactual, and K1.3375 and Kactual were 0.00 ± 0.11 D, 0.21 ± 0.11 D and 0.99 ± 0.12 D, respectively, in untreated controls; -0.01 ± 0.20 D, 0.85 ± 0.18 D and 1.56 ± 0.16 D, respectively, in post-LASIK/PRK group; and 0.03 ± 0.67 D, 0.56 ± 0.70 D and 1.40 ± 0.76 D, respectively, in keratoconus group.ConclusionThe calculated keratometric index is negatively related to the ratio of anterior corneal curvature to posterior corneal curvature in untreated, post-LASIK/PRK, and keratoconus eyes, respectively. Using the calculated keratometric index may improve the prediction accuracies of total corneal powers in untreated controls, but not in post-LASIK/PRK and keratoconus eyes.

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Section: Introductionmentioning

confidence: 99%

Keratometric Index Obtained by Fourier-Domain Optical Coherence Tomography

et al. 2015

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“…18,19 IOL power calculation using adjusted corneal power calculated with the variable keratometric index also improved refractive outcomes in eyes with a history of previous refractive corneal surgery after cataract surgery. [20][21][22] There were no improvements in refractive outcomes when we applied the true net power and total corneal refractive power from Pentacam directly to IOL power calculation despite IOL constant optimization; instead, outcomes were worse in many cases. In line with this study, previous studies also found no superiority using the corneal power derived from both the anterior and posterior corneal measurements of a single Scheimpflug camera relative to using simulated K in IOL power calculation for normal eyes.…”

Section: Discussionmentioning

confidence: 97%

Use of the Posterior/Anterior Corneal Curvature Radii Ratio to Improve the Accuracy of Intraocular Lens Power Calculation: Eom's Adjustment Method

Kim

Eom

Lee

et al. 2018

Invest. Ophthalmol. Vis. Sci.

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“…However, the constants in their study were not optimized for each IOL model. Jin et al [22] found that when the Koch–Maloney method was used in Chinese eyes, an offset value of −6.2 was more appropriate than −6.1. However, in the present study, the results from IOL-Master did not show the same tendency.…”

Section: Discussionmentioning

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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Corneal power estimation for intraocular lens power calculation after corneal laser refractive surgery in Chinese eyes

Abstract: The algorithm was a relatively reliable method in IOL power calculation after corneal refractive surgery in Chinese eyes.

Cited by 17 publications

References 27 publications

Keratometric Index Obtained by Fourier-Domain Optical Coherence Tomography

Keratometric Index Obtained by Fourier-Domain Optical Coherence Tomography

Use of the Posterior/Anterior Corneal Curvature Radii Ratio to Improve the Accuracy of Intraocular Lens Power Calculation: Eom's Adjustment Method

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

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