Anterior chamber depth, lens thickness and intraocular lens calculation formula accuracy: nine formulas comparison

Hipólito-Fernandes, Diogo; Luís, Maria Elisa; Pereira, Rita Gonçalves; Gil, Pedro; Maduro, Vitor; Feijão, João; Alves, Nuno L.

doi:10.1136/bjophthalmol-2020-317822

Cited by 50 publications

(47 citation statements)

References 16 publications

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“…The Kane formula is another newer method which composes regression and elements of arti cial intelligence based on theoretical optics [17]. As has been reported in recent studies, the Kane formula outperformed other existing formulas regardless of the AL and ACD values [14,16,18]. However, this formula was inferior to the Olsen formula and ranked as the second accurate one in our study, although without statistical signi cance.…”

Section: Discussionsupporting

confidence: 70%

Comparison of Accuracy of Intraocular Lens Power calculation for Eyes with an Axial Length Greater Than 29.0 mm

Guo

Yin

Qiu

et al. 2021

Preprint

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PurposeTo evaluate and compare the accuracy of six different formulas (EVO 2.0, Kane, SRK/T, Barrett Universal II, Haigis and Olsen) in intraocular lens (IOL) power calculation for extremely long eyes.MethodsRetrospective case-series. 73 eyes with axial length (AL) ≥ 29.0 mm and 920H IOL implantation were included. Prediction errors (PE) were calculated and compared between different formulas. Multiple regression analysis was performed to investigate factors associated with the PE.ResultsThe Kane formula had mean prediction error close to zero (-0.01 D, P = 0.841), whereas the EVO 2.0, SRK/T, Barrett Universal II, Haigis and Olsen formulas produced hyperopic outcomes (all P < 0.001). The median absolute error produced by the EVO 2.0, Kane, Barrett Universal II and Olsen formulas showed no significant difference (0.33 D, 0.30 D, 0.29 D, 0.34 D, respectively, pairwise comparison P > 0.05), but was significantly lower than that of the SRK/T and Haigis formulas (0.85 D, 0.80 D, respectively, pairwise comparison P＜ 0.001). The accuracy of the SRK/T formula in extremely myopic eyes was affected by the AL, suggesting that a longer AL was always associated with a hyperopic surprise and a shorter AL was always associated with a myopic surprise, whereas the accuracy of other formulas was less affected by the AL.ConclusionsFor cataract patients with axial length greater than 29.0 mm, the accuracy of the EVO 2.0, Kane, Barrett Universal II and Olsen formulas is comparable and significantly better than that of the SRK/T and Haigis formulas.

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Section: Discussionsupporting

confidence: 70%

Comparison of Accuracy of Intraocular Lens Power calculation for Eyes with an Axial Length Greater Than 29.0 mm

Guo

Yin

Qiu

et al. 2021

Preprint

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“…The impact of LT on IOL calculation has been confirmed in recent studies. Hyperopic shift is associated with a thicker lens, while a myopic shift is associated with a thin lens, especially for the Haigis formula which did not include LT [19,25,44]. Even for formulas that included LT, the effect of LT on refractive error is varied with different ALs, with the greatest effect seen in eyes with AL less than 22 mm [18].…”

Section: Discussionmentioning

confidence: 98%

“…In this study, multiple risk factors for LT were identified, including older age, male gender, thicker central cornea, shallower ACD, larger WTW, and flatter anterior corneal curvature. For patients with these characteristics, surgeons need to know whether they have extreme LT before surgery, which may result in a greater hyperopic shift after surgery [19], and then proceed to use IOL formulas to gain a stable performance in a wide range of LT.…”

Section: Discussionmentioning

confidence: 99%

“…Vega et al found that the effect of LT on the accuracy of the Barrett Universal II formula was the greatest in eyes with AL ≤ 22 mm but less in eyes with AL ≥ 26 mm [18]. Even among patients with normal ALs (22-26 mm), a higher prediction error may be seen with an extreme LT, especially for the Haigis and Hill-RBF V2.0 formulas [19]. Thus, investigating the distribution of LT against AL is required.…”

Section: Introductionmentioning

confidence: 99%

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Lens thickness and associated ocular biometric factors among cataract patients in Shanghai

Meng

Wei

et al. 2021

Eye and Vis

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Background To evaluate the distribution of lens thickness (LT) and its associations with other ocular biometric factors among cataract patients in Shanghai. Methods Twenty-four thousand thirteen eyes from 24,013 cataract patients were retrospectively included. Ocular biometric factors including LT, central corneal thickness (CCT), anterior chamber depth (ACD), white-to-white (WTW) distance, anterior corneal curvature, and axial length (AL) were obtained using the IOLMaster700. The associations between LT and general or ocular factors were assessed. Results The mean age was 62.5 ± 13.6 years and 56.1% were female. The mean LT was 4.51 ± 0.46 mm. The LT was greater in older patients (P < 0.001). LT was positively correlated with CCT, while negatively correlated with ACD, WTW, and anterior corneal curvature (P < 0.001). Multivariate analysis revealed that increased LT was associated with older age, male gender, thicker CCT, shallower ACD, larger WTW, and flatter anterior corneal curvature (P < 0.001). LT changed with a variable behavior according to AL. In short eyes LT increased as AL increased, then decreased with longer AL in normal eyes and moderate myopic eyes, but increased again as AL increased in highly myopic eyes. Thickest LT was found in the 20.01–22 mm AL group. The correlation between LT and other biometric factors remained significant when stratified by ALs. Conclusions In a large Chinese cataractous population, we found that the thicker lens may be associated with older age, male gender, thicker CCT, shallower ACD, larger WTW, and flatter anterior corneal curvature. As AL increased, the change of LT was nonlinear, with the thickest lens seen in the 20–22 mm AL group.

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“…Normal cornea, irregular cornea, and AL will be examined in future studies. Evaluating the effects of ACD and lens thickness (LT) on nine IOL power calculation formulas accuracy in individuals with normal axial lengths, it was found that new generation formulas, particularly Kane, PEARL-DGS (Prediction Enhanced by Artificial Intelligence and Output Linearization) and Emmetropia Verifying Optical (EVO) formula 26 (version 2.0), have higher reliability and stability even in eyes with extreme ACD-LT combinations [33]. Furthermore, the improvement of post-IOL refractive accuracy can provide doctors with more confidence for operating on post-corneal refractive surgery patients, reduce the proportion of refractive enhancement surgery, and might help more people enjoy the advantages of multifocal IOL in daily life.…”

Section: Discussionmentioning

confidence: 99%

Comparative clinical accuracy analysis of the newly developed ZZ IOL and four existing IOL formulas for post-corneal refractive surgery eyes

Zhang¹,

Shao²,

Li³

et al. 2021

BMC Ophthalmol

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Background Intraocular lens (IOL) calculation using traditional formulas for post-corneal refractive surgery eyes can yield inaccurate results. This study aimed to compare the clinical accuracy of the newly developed Zhang & Zheng (ZZ) formula with previously reported IOL formulas. Study design Retrospective study. Methods Post-corneal refractive surgery eyes were assessed for IOL power using the ZZ, Haigis-L, Shammas, Barrett True-K (no history), and ray tracing (C.S.O Sirius) IOL formulas, and their accuracy was compared. No pre-refractive surgery information was used in the calculations. Results This study included 38 eyes in 26 patients. ZZ IOL yielded a lower arithmetic IOL prediction error (PE) compared with ray tracing (P = 0.04), whereas the other formulas had values like that of ZZ IOL (P > 0.05). The arithmetic IOL PE for the ZZ IOL formula was not significantly different from zero (P = 0.96). ZZ IOL yielded a lower absolute IOL PE compared with Shammas (P < 0.01), Haigis-L (P = 0.02), Barrett true K (P = 0.03), and ray tracing (P < 0.01). The variance of the mean arithmetic IOL PE for ZZ IOL was significantly smaller than those of Shammas (P < 0.01), Haigis-L (P = 0.03), Barrett True K (P = 0.02), and ray tracing (P < 0.01). The percentages of eyes within ± 0.5 D of the target refraction with the ZZ IOL, Shammas, Haigis-L, Barrett True-K, and ray-tracing formulas were 86.8 %, 45.5 %, 66.7 %, 73.7 %, and 50.0 %, respectively (P < 0.05 for Shammas and ray tracing vs. ZZ IOL). Conclusions The ZZ IOL formula might offer superior outcomes for IOL power calculation for post-corneal refractive surgery eyes without prior refractive data.

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Anterior chamber depth, lens thickness and intraocular lens calculation formula accuracy: nine formulas comparison

Cited by 50 publications

References 16 publications

Comparison of Accuracy of Intraocular Lens Power calculation for Eyes with an Axial Length Greater Than 29.0 mm

Comparison of Accuracy of Intraocular Lens Power calculation for Eyes with an Axial Length Greater Than 29.0 mm

Lens thickness and associated ocular biometric factors among cataract patients in Shanghai

Comparative clinical accuracy analysis of the newly developed ZZ IOL and four existing IOL formulas for post-corneal refractive surgery eyes

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