Standard vs total keratometry for intraocular lens power calculation in cataract surgery combined with DMEK

Khan, Asher; Rangu, Neal; Murphy, David A.; Cooke, David L.; Siatkowski, Rhea L; Mittal, Aman; Wendelstein, Jascha; Riaz, Kamran M.

doi:10.1097/j.jcrs.0000000000001106

Cited by 8 publications

(5 citation statements)

References 27 publications

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“…It had been published that using adjusted conventional keratometry based on the postoperative posterior to preoperative anterior corneal curvature radii (PPPA) ratio and a ctious refractive index (FRI), reduces hyperopic DIRS, thus providing more accurate refractive outcomes than using standard keratometry; and it is non less effective than selecting a myopic target between − 0.50 and − 1.00 D. 28 On the other hand, more recently, a study in eyes undergoing triple-DMEK was published in which the authors concluded that the prediction accuracy of standard keratometry was superior to TK, being the SRK/T and multivariate formulae with the IOLup1D adjustment the most accurate. 27 These ndings are consistent with the results of our study. Even though the SRK/T formula with optimized constant was the one which showed a better performance (Table 4 and Fig.…”

Section: Discussionsupporting

confidence: 93%

“…8, 24,26 As described in the literature and supported by our ndings, obtaining accurate keratometric measurements in patients with FECD may be more challenging. 27 Nevertheless, persevering in obtaining measurements labelled as "Successful" by the biometer would be advantageous, as this approach would lead to a lower dispersion of data and enhance the predictability of refractive outcomes. We have shown a reduction in centroid ellipsoid radii of the DAVDs when analyzing the change in astigmatism in this subgroup (Fig.…”

Section: Discussionmentioning

confidence: 99%

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Optimizing IOL calculation in triple-DMEK: data from a real-life cohort

Velarde-Rodríguez,

Lorenzana-Blanco,

Corte-Alonso

et al. 2024

Preprint

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Aim To enhance the accuracy of intraocular lens (IOL) power calculation in patients undergoing simultaneous cataract surgery and Descemet membrane endothelial keratoplasty (triple-DMEK) by predicting corneal power changes.Methods Observational ambispective monocentric cohort study. Real life refractive outcomes and pre/post-operative corneal data from the IOL Master 700 (Zeiss) were merged in a linear corneal change model (LCCM), including traditional and new-generation formulae. The model was compared with the outcomes of optimizing IOL constants specifically for Triple-DMEK.Results 97 eyes of 69 patients with a follow-up of more than 3 months were analysed. Preoperative keratometry was unavailable in 9 eyes, in which IOL calculation was performed by manually with autorefractometer data and were analysed separately. Mean absolute error (MAE) for the former group was higher than for the measured one, 1.35 ± 1.16 D and 0.75 ± 0.70 D respectively. The median change in simulated keratometry (SimK) was − 0.21 ± 0.68 D and in total keratometry (TK) was − 0.62 ± 1.09 D, both statistically significant (p < 0.001). The lowest MAE was achieved by SRK/T with constant optimization (0.60 ± 0.58 D). The LCCM applied to any formula, showed similar MAE results to the constant optimization method (p > 0.05). However, the maximum absolute error for the optimization method was 2.08 ± 0.16 D, while for the LCCM method was 1.87 ± 0.13 D.Conclusions Keratometric readings in corneas with Fuchs´ dystrophy should be carefully measured. SimK and TK show a significant change during Triple-DMEK surgery. Optimizing IOL constants for this surgery improves the MAE, while using the LCCM could lead to a reduction of refractive surprises.

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Section: Discussionsupporting

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Optimizing IOL calculation in triple-DMEK: data from a real-life cohort

Velarde-Rodríguez,

Lorenzana-Blanco,

Corte-Alonso

et al. 2024

Preprint

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“…In a clinical retrospective comparative study, Danjo et when TK was used 46 . Similarly, studies have demonstrated that TK is superior to K in cases with complex corneal conditions such as combined corneal endothelial diseases and keratoconus 47,48 . Therefore, in designing this study, we used BUII with K preoperatively and compared TK and K postoperatively.…”

Section: Discussionmentioning

confidence: 97%

Comparison of the accuracy of 9 intraocular lens power calculation formulas after SMILE in Chinese myopic eyes

Li,

Yuan,

Yang

et al. 2023

Preprint

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As of 2021, over 2.8 million cases of small incision lenticule extraction (SMILE) procedures had been performed in China. However, there remains limited knowledge regarding the selection of intraocular lens (IOL) power calculation formulas for post-SMILE cataract patients. This study included 52 eyes of 26 myopic patients from northern China who underwent SMILE at Tianjin Eye Hospital from September 2022 to February 2023 and was designed to investigate the performance of multiple IOL calculation formulas in post-SMILE patients using a theoretical surgical model. We compared the postoperative results obtained from three artificial intelligence (AI)-based formulas and six conventional formulas provided by the American Society of Cataract and Refractive Surgery (ASCRS). These formulas were applied to calculate IOL power using both total keratometry (TK) and keratometry (K) values, and the results were compared to the preoperative results obtained from the Barrett Universal II (BUII) formula in SMILE cases. Among the evaluated formulas, the results obtained from Emmetropia Verifying Optical 2.0 Formula with TK (EVO-TK) (0.40 ± 0.29 D, range 0 to 1.23 D), Barrett True K with K (BTK-K, 0.41 ± 0.26 D, range 0.01 to 1.19 D), and Masket with K (Masket-K, 0.44 ± 0.33 D, range 0.02 to 1.39 D) demonstrated the closest proximity to BUII. Notably, the highest proportion of prediction errors within 0.5 D was observed with BTK-K (71.15%), EVO-TK (69.23%), and Masket-K (67.31%), with BTK-K showing a significantly higher proportion compared to Masket-K (p < 0.001). Our research indicates that in post-SMILE patients, EVO-TK, BTK-K, and Masket-K may yield more accurate calculation results. At the current stage, AI-based formulas do not demonstrate significant advantages over conventional formulas. However, the application of historical data can enhance the performance of these formulas.

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“…LT and WTW can be added optionally. (5) The PEARL-DGS formula (www.iolsolver.com) uses obligatory parameters AL, K, and ACD. Optional parameters are LT, CCT, and WTW.…”

Section: Iol Power Calculationmentioning

confidence: 99%

“…Improvements in commonly used intraocular lens (IOL) power calculation schemes led to new-generation formulas that aim to reduce trend errors and achieve better refractive outcomes and higher patient satisfaction, especially in cases that are more demanding. 2–11 Among these new formulas, the Barrett Universal II (BU2), Emmetropia Verifying Optical (EVO) 2.0, Hill–Radial Basis Function (RBF) 3.0, Kane, Castrop, and PEARL-DGS formulas are among the more commonly used IOL formulas in studies and clinical practice that offer free online calculation websites (accessible via https://iolcalculator.escrs.org/ and/or https://iolcon.org/lpcm.php).…”

mentioning

confidence: 99%

Influence and predictive value of optional parameters in new-generation intraocular lens formulas

Wendelstein

Rothbächer

Heath

et al. 2023

J Cataract Refract Surg

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Purpose: To evaluate the accuracy of various variations of new-generation multivariate intraocular lens (IOL) power calculation using the Barrett Universal II, Castrop, Emmetropia Verifying Optical 2.0, Hill–Radial Basis Function 3.0, Kane, and PEARL-DGS formulas with and without optional biometric parameters. Setting: Tertiary care academic medical center. Design: Retrospective case series. Single-center study. Methods: Inclusion of patients after uneventful cataract surgery implanting AU00T0 IOLs. Data from one eye per patient were randomly included. Eyes with a corrected distance visual acuity worse than 0.1 logMAR were excluded. IOLCON-optimized constants were used for all formulas other than the Castrop formula. The outcome measures were prediction error (PE) and absolute prediction error (absPE) for the 6 study formulas. Results: 251 eyes from 251 patients were assessed. Excluding lens thickness led to statistically significant differences in absPE in several formulas. Leaving out horizontal corneal diameter did not impact absPE in several formulas. Differences in PE offset were observed between the various formula variations. Conclusions: When using multivariate formulas with an A-constant, including certain optional parameters is vital for optimal refractive results. Formula variations excluding certain biometric parameters need specifically optimized constants and do not perform similarly when using the constant of the respective formula using all parameters.

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Standard vs total keratometry for intraocular lens power calculation in cataract surgery combined with DMEK

Cited by 8 publications

References 27 publications

Optimizing IOL calculation in triple-DMEK: data from a real-life cohort

Optimizing IOL calculation in triple-DMEK: data from a real-life cohort

Comparison of the accuracy of 9 intraocular lens power calculation formulas after SMILE in Chinese myopic eyes

Influence and predictive value of optional parameters in new-generation intraocular lens formulas

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