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Purpose: To evaluate and compare intraocular lens (IOL) tilt between uneventful phacoemulsification with in-the-bag IOL implantation and sutured scleral fixation (SSF) of the lens bag with a capsular tension segment (type 6 D / Morcher) using a Sheimpflug camera., Setting: Clinical Practice, Hospital. Barcelona and A Coruña, Spain., Design: Retrospective, comparative multicenter study., Methods: IOL tilt was compared between patients who underwent sutured scleral fixation with a capsular tension segment in a single eye (SSF group, n = 15) with patients who underwent uneventful IOL implantation (control group, n = 12) that were matched by biometric measurements. Post-operative refractive accuracy of biometric formulas by means of mean absolute error (MAE) was also reported. All patients underwent a general ophthalmic evaluation, anterior segment photography, and postoperative optical biometry (Zeiss IOLMaster® 500). In addition, IOL tilt was measured with a Scheimpflug camera (Pentacam R, Oculus Optikgerate Gmbh)., Results: Mean vertical tilt was similar in both groups (2.20+/-2.47° SSF vs 1.97 +/- 1.79° control; p = 0.836) but mean horizontal tilt tended to higher values in the SSF series (2.09 +/- 2.74° vs 0.94 +/- 1.17°; p = 0.139). Considering post-operative refractive error in diopters by MAE calculations, there was an underestimation of IOL power in the SSF group which was only statistically significant for Barrett Universal II (1.07 vs 0.32; p = 0.028) and Hill-RBF (0.95 vs 0.26; p = 0.024) formulas, but not for SRK/T (0.99 vs 0.42; p = 0.285) and Kane (0.96 vs 0.33; p = 0.083)., Conclusion: Sutured scleral fixation of capsular tension segments in the presence of zonular instability does not seem to induce clinically significant IOL tilt compared to uneventful cataract extraction cases., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Purpose: To assess the influence of ocular biometric parameters on intraocular lens (IOL) tilt and decentration after cataract surgery., Methods: Patients scheduled for cataract surgery were screened for inclusion in this prospective cohort study. Tilt and decentration of the crystalline lens and IOL were measured using the CASIA2 (Tomey). Anterior chamber depth (ACD), lens thickness (LT), and axial length (AL) were preoperatively measured by the IOLMaster 700 (Carl Zeiss Meditec AG). Multivariate regression analysis was performed to assess the influence of ocular biometric parameters on IOL tilt and decentration after cataract surgery., Results: In total, 191 eyes of 120 patients were included. Age was positively correlated with IOL tilt, whereas ACD and AL were negatively correlated with IOL tilt. A strong positive correlation was found between preoperative crystalline lenses and postoperative IOLs in tilt magnitude ( r = 0.769, P < .001) and tilt direction ( r = 0.688, P < .001). A positive correlation was found between preoperative and postoperative lens decentration magnitude and decentration direction. Greater postoperative IOL tilt and decentration were significantly associated with greater preoperative crystalline lens tilt ( P < .001) and decentration ( P = .027)., Conclusions: IOL tilt was greater in older patients. Shorter AL and shallower ACD contributed to greater IOL tilt. The tilt and decentration of the IOL will be greater in patients with greater tilt and decentration of the crystalline lens. [ J Refract Surg . 2024;40(7):e438-e444.] .

Purpose: To study the effect of ocular biomechanics on the prediction error of intraocular lens (IOL) power calculation., Setting: Centro Hospitalar Universitário do Porto, Porto, Portugal., Design: Prospective longitudinal study., Methods: This study included 67 subjects. Before cataract surgery subjects underwent biometry with IOLMaster 700 and biomechanical analysis with Corvis Scheimpflug technology. The targeted spherical equivalent was calculated with SRK-T and Barrett Universal II. Associations between prediction error (PE), absolute prediction error (AE), and biometric and biomechanical parameters were performed with stepwise multivariate linear correlation analysis., Results: Using the SRKT formula, there was association between PE and Corvis Biomechanical Index (CBI, B = -0.531, P = .011) and between AE and the horizontal offset between the center of the pupil and the visual axis (angle κ, B = -0.274, P = .007). Considering the Barret Universal II formula, PE was independently associated with anterior chamber depth ( B = -0.279, P = .021) and CBI ( B = -0.520, P = .013) and AE was associated with angle κ ( B = -0.370, P = .007)., Conclusions: A large angle κ may reduce the predictability of IOL power calculation. Ocular biomechanics likely influence the refractive outcomes after IOL implantation. This study showed that eyes with softer corneal biomechanics had more myopic PE. This may relate to anteriorization of the effective lens position. Dynamic measurements may be the way to progress into future formulas., (Copyright © 2023 Published by Wolters Kluwer on behalf of ASCRS and ESCRS.)

Background: This study evaluates the impact of corneal power on the accuracy of 14 newer intraocular lens (IOL) calculation formulas in cataract surgery. The aim is to assess how these formulas perform across different corneal curvature ranges, thereby guiding more precise IOL selection., Methods: In this retrospective case series, 336 eyes from 336 patients who underwent cataract surgery were studied. The cohort was divided into three groups according to preoperative corneal power. Key metrics analyzed included mean prediction error (PE), standard deviation of PE (SD), mean absolute prediction error (MAE), median absolute error (MedAE), and the percentage of eyes with PE within ± 0.25 D, 0.50 D, ± 0.75 D, ± 1.00 D and ± 2.00 D., Results: In the flat K group (Km < 43 D), VRF-G, Emmetropia Verifying Optical Version 2.0 (EVO2.0), Kane, and Hoffer QST demonstrated lower SDs (± 0.373D, ± 0.379D, ± 0.380D, ± 0.418D, respectively) compared to the VRF formula (all P < 0.05). EVO2.0 and K6 showed significantly different SDs compared to Barrett Universal II (BUII) (all P < 0.02). In the medium K group (43 D ≤ Km < 46 D), VRF-G, BUII, Karmona, K6, EVO2.0, Kane, and Pearl-DGS recorded lower MAEs (0.307D to 0.320D) than Olsen (OLCR) and Castrop (all P < 0.03), with RBF3.0 having the second lowest MAE (0.309D), significantly lower than VRF and Olsen (OLCR) (all P < 0.05). In the steep K group (Km ≥ 46D), RBF3.0, K6, and Kane achieved significantly lower MAEs (0.279D, 0.290D, 0.291D, respectively) than Castrop (all P < 0.001)., Conclusions: The study highlights the varying accuracy of newer IOL formulas based on corneal power. VRF-G, EVO2.0, Kane, K6, and Hoffer QST are highly accurate for flat corneas, while VRF-G, RBF3.0, BUII, Karmona, K6, EVO2.0, Kane, and Pearl-DGS are recommended for medium K corneas. In steep corneas, RBF3.0, K6, and Kane show superior performance., (© 2024. The Author(s).)

Purpose: To assess the performance of the Camellin-Calossi formula in eyes with prior myopic laser vision correction., Methods: This was a retrospective case series. Patients included had a history of uncomplicated myopic laser vision correction and cataract surgery. The primary outcome measures were cumulative distribution of absolute refractive prediction error, absolute refractive prediction error, and refractive prediction error. These parameters were estimated post-hoc using the Camellin-Calossi, Shammas, Haigis-L, Barrett True-K with or without history, Masket, and Modified Masket formulas and their averages starting from biometric data, clinical records, postoperative refraction, and intraocular lens power implanted., Results: Seventy-seven eyes from 77 patients were included. The Camellin-Calossi, Shammas, Haigis-L, Barrett True-K No History, Masket, Modified Masket, and Barrett True-K formulas showed a median absolute refractive error (interquartile range) of 0.25 (0.53), 0.51 (0.56), 0.44 (0.65), 0.45 (0.59), 0.40 (0.61), 0.60 (0.70), and 0.55 (0.76), respectively. The proportion of eyes with an absolute refractive error of ±0.25, 0.50, 0.75, 1.00, 1.50, and 2.00 diopters (D) for the Camellin-Calossi formula was 54.5%, 72.7%, 85.7%, 92.2%, 98.7%, and 100%, respectively. The cumulative distribution of the Camellin-Calossi formula showed the best qualitative performances when compared to the others. A statistically significant difference was identified with all of the others except the Haigis-L using a threshold of 0.25, with the Shammas, Modified Masket, and Barrett True-K at a threshold of 0.50 D and the Barrett True-K and Modified Masket at a threshold of 1.00 D., Conclusions: The Camellin-Calossi formula is a valid option for intraocular lens power calculation in eyes with prior myopic laser vision correction. [ J Refract Surg . 2024;40(3):e156-e163.] .

This study evaluated the accuracy of newer formulas (Barrett Universal II, EVO 2.0, Kane, Hoffer QST, and PEARL-DGS) and the Haigis formula in Korean patients with the Alcon TFNT multifocal intraocular lens. In total, 3100 randomly selected eyes of 3100 patients were retrospectively reviewed. After constant optimization, the standard deviation (SD) of the prediction error was assessed for the entire group, and the root mean square error was compared for short and long axial length (AL) subgroup analysis. The Cooke-modified AL (CMAL) was experimentally applied to the Haigis formula. All the newer formulas performed well, but they did not significantly outperform the Haigis formula. In addition, all the newer formulas exhibited significant myopic outcomes (- 0.23 to - 0.29 diopters) in long eyes. Application of the CMAL to the Haigis formula with single constant optimization produced similar behavior and higher correlation with the newer formulas. The CMAL-applied triple-optimized Haigis formula yielded a substantially smaller SD, even superior to the Barrett and Hoffer QST formulas. The AL modification algorithms such as the CMAL used in newer formulas to cope with optical biometry's overestimation of the AL in long eyes seemed to overcompensate, particularly in the long eyes of the East Asian population., (© 2024. The Author(s).)

This study evaluates the accuracy of a newly developed intraocular lens (IOL) power calculation method that applies four different IOL power calculation formulas according to 768 biometric subgroups based on keratometry, anterior chamber depth, and axial length. This retrospective cross-sectional study was conducted in at Korea University Ansan Hospital. A total of 1600 eyes from 1600 patients who underwent phacoemulsification and a ZCB00 IOL in-the-bag implantation were divided into two datasets: a reference dataset (1200 eyes) and a validation dataset (400 eyes). Using the reference dataset and the results of previous studies, the Eom IOL power calculator was developed using 768 biometric subgroups. The median absolute errors (MedAEs) and IOL Formula Performance Indexes (FPIs) of the Barrett Universal II, Haigis, Hoffer Q, Holladay 1, Ladas Super, SRK/T, and Eom formulas using the 400-eye validation dataset were compared. The MedAE of the Eom formula (0.22 D) was significantly smaller than that of the other four formulas, except for the Barrett Universal II and Ladas Super formulas (0.24 D and 0.23 D, respectively). The IOL FPI of the Eom formula was 0.553, which ranked first, followed by the Ladas Super (0.474), Barrett Universal II (0.470), Holladay 1 (0.444), Hoffer Q (0.396), Haigis (0.392), and SRK/T (0.361) formulas. In conclusion, the Eom IOL power calculator developed in this study demonstrated similar or slightly better accuracy than the Barrett Universal II and Ladas Super formulas and was superior to the four traditional IOL power calculation formulas., (© 2024. The Author(s).)

Purpose: To identify the equivalent K-readings and total keratometry zones that is optimally suitable for calculating the IOL spheroequivalent according to 7 formulas., Methods: The study included 40 patients (40 eyes) who underwent uneventful femtosecond laser-assisted cataract surgery and refractive lens exchange (RLE) with implantation of a trifocal diffractive IOL (PanOptix, Alcon inc.). Targeted emmetropia was achieved in all patients, no distance and near correction was needed. Retrospective IOL calculations were performed utilizing 7 formulas (SRK/T, Holladay 1 and 2, Haigis, Hoffer Q, Barrett Universal 2, Olsen) and Pentacam keratometry data: Holladay equivalent K-readings, total optical power by ray tracing (TCRP) centered on the apex and pupil in 10 zones (from 0.5 to 5 mm in 0.5 mm increments). For each formula/zone/map combination: postoperative predicted refraction (PPRs), mean absolute errors (MAEs), and median absolute errors (MedAEs) were analyzed., Results: According to EKR, the Haigis formula showed the lowest error in the central zones up to 3.5 mm, the TCRP zone for Holladay I and II formulas 4.0-4.5 mm, for HofferQ and SRK/T formulas 4.5-5.0 mm, and for Olsen and Barrett II Universal-5 mm., Conclusion: The use of keratometry data (EKR, TCRP) in the formulas adapted to SimK, with the correct choice of the evaluation zone of keratometric data, will increase the chance of hitting the refractive target., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

With the progress in refractive cataract surgery, more intraocular lens (IOL) power formulas have been introduced with the aim of reducing the postoperative refractive error. The postoperative IOL position is critical to IOL power calculations. Therefore, the improvements in postoperative IOL position prediction will enable better selection of IOL power and postoperative refraction. In the past, the postoperative IOL position was mainly predicted by preoperative anterior segment parameters such as preoperative axial length (AL), anterior chamber depth (ACD), and corneal curvature. In recent years, some novel methods including the intraoperative ACD, crystalline lens geometry, and artificial intelligence (AI) of prediction of postoperative IOL position have been reported. This article attempts to give a review about the research progress on prediction of the postoperative IOL position., (Copyright © 2024 Copyright: © 2024 Indian Journal of Ophthalmology.)

Purpose: To systematically review the literature and quantitatively synthesize the currently available evidence to compare the accuracy of different intraocular lens calculation formulas in eyes with long axial length (AL)., Design: Network meta-analysis., Methods: PubMed, Embase, Web of Science, and the Cochrane Library were systematically searched for studies published between January 2000 and June 2022. Included were prospective or retrospective clinical studies reporting the following outcomes in cataract patients with long AL (ie, ≥26 mm): percentage of eyes with a prediction error (PE) within ±0.25, ±0.50, and ±1.00 diopters (D). Network meta-analysis was conducted using R software (version 4.2.1)., Results: Ten prospective or retrospective clinical studies, including 1016 eyes and 11 calculation formulas, were identified. A traditional meta-analysis showed that for the percentage of eyes with PE within ±0.25 and ±0.50 D, the Olsen, Kane, and Emmetropia Verifying Optical (EVO) all had insignificantly higher percentages compared with others. Considering the percentage of eyes with PE within ±1.00 D, the original and modified Wang-Koch adjustment formulas for Holladay 1 (H1-WK and H1-MWK) and EVO formulas showed superiority, but the difference was insignificant. This network meta-analysis revealed that compared with the widely used Barrett Universal II (BUII) formula, the Olsen, Kane, and EVO formulas had higher percentages of eyes with PE within ±0.25, ±0.50, and ±1.00 D (all odds ratios >1 but P >.05). Based on the surface under the cumulative ranking area (SUCRA) values for the percentage of eyes with PE within ±0.25 D, the Olsen (96.4%), Kane (77.5%), and EVO (75.9%) formulas had the highest probability of being in the top 3 of the 11 formulas., Conclusions: The Olsen, Kane, and EVO formulas may perform better than others in calculating IOL power in eyes with long AL. Nevertheless, there is still considerable uncertainty in this regard and the accuracy of these formulas in highly myopic eyes should be confirmed in studies based on large multicenter registries., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Purpose: Predict intraocular lens position after cataract surgery using the IOL Master 700 and explore the associated ocular parameters compared with the results obtained from the anterior segment analysis system (Sirius, CSO Inc, Florence, Italy)., Methods: A total of 98 patients (106 eyes) were included in the retrospective study. The postoperative intraocular lens position was obtained using the IOL Master 700 and measured using Adobe Illustrator software. Correlation analysis and linear regression analysis were applied to study the correlation between the actual position of the postoperative intraocular lens (ALP) and the ocular parameters. In addition, Bland-Altman consistency analysis was used to compare the consistency between any two among the predicted intraocular lens position (ALPi) obtained using IOL Master 700 biometry, the predicted artificial lens position (ALPs) calculated using the anterior segment analysis system, or the ALP., Results: Ocular parameters, including preoperative anterior chamber depth, lens thickness, axial length, white-to-white, and postoperative refractive error were all correlated with ALP after cataract surgery (P < 0.05) using univariate analysis. However, in multivariate linear regression, only the first three variables were correlated with ALP. Compared with the equation obtained by the anterior segment analysis, the equation from IOL Master 700 biometry provided a better fit. The results of the consistency analysis showed that ALP, ALPi, and ALPs were in good agreement., Conclusion: IOL Master 700 biometry can help predict intraocular lens position after surgery, and its accuracy is better than that provided by the anterior segment analysis system., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: To aid preoperative risk assessment by identifying anatomic parameters corresponding with a higher risk of intraoperative floppy iris syndrome (IFIS) during cataract surgery., Methods: Prospective cohort study of 55 patients with α 1 -adrenergic receptor antagonist (α 1 -ARA) treatment and 55 controls undergoing cataract surgery. Anterior segment optical coherence tomography (AS-OCT), video pupilometer, and biometry measurements were performed preoperatively and analyzed regarding anatomic parameters that corresponded with a higher rate of IFIS. Those statistically significant parameters were evaluated with logistic regression analysis and receiver operating characteristic (ROC) curve., Results: Pupil diameter was significantly smaller in patients who developed IFIS compared to those who did not develop IFIS (AS-OCT 3.29 ± 0.85 vs. 3.63 ± 0.68, p = 0.03; Pupilometer 3.56 ± 0,87 vs. 3.95 ± 0.67, p = 0.02). Biometric evaluation revealed shallower anterior chambers in the IFIS group (ACD 3.12 ± 0.40 vs. 3.32 ± 0.42, p = 0.02). Cutoff values for 50% IFIS probability (p = 0.5) were PD = 3.18 mm for pupil diameter and ACD = 2.93 mm for anterior chamber depth. ROC curves of combined parameters were calculated for α 1 -ARA medication with pupil diameter and anterior chamber depth, which yielded an AUC of 0.75 for all IFIS grades., Conclusion: The combination of biometric parameters with history of α 1 -ARA medication can improve assessment of risk stratification for IFIS incidence during cataract surgery., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: To evaluate a recently introduced ESCRS online calculator for intraocular lens (IOL) calculation of a multifocal IOL in refractive lens exchange and cataract surgery in a prospective setting., Setting: Department of Ophthalmology, Goethe University Frankfurt, Germany., Design: Prospective, consecutive case series., Methods: Eyes that received lens extraction and multifocal IOL implantation were included. The mean prediction error, mean absolute error, and median absolute prediction error (MedAE) provided by the ESCRS online calculator were compared, as were the number of eyes within ±0.5 diopters (D), ±1.0 D, ±2.0 D of target refraction. The SRK/T formula was also included for comparison. Postoperative spherical equivalent was measured at 3 months. 1 eye per patient was included., Results: 88 eyes from 88 patients with a mean age of 62 ± 9.5 years were included. The MedAE was low for all formulas and ranged from 0.26 D (Kane), Hill-RBF (0.27 D), Hoffer Q Savini/Taroni (Hoffer QST) (0.27 D), Barrett Universal II (BUII) (0.28 D), Emmetropia Verifying Optical (EVO) (0.29 D), Cooke K6 (0.27 D), 0.30 D (Postoperative spherical Equivalent prediction using Artificial intelligence and Linear algorithms, by Debellemaniére, Gatinel, and Saad [Pearl DGS]) to 0.31 D (SRK/T). No statistically significant difference was found ( P = .627). Considering the number of eyes within ±0.5 D of the calculated refraction the best performing was again the Hill-RBF (84%, 74 eyes), again followed by Kane (71, 81%), EVO, Pearl DGS, Hoffer QST, BUII (each 80%, 70 eyes), Cooke K6 (78%, 69 eyes), and SRK/T (74%). Again, no statistically significant difference was found ( P = .39)., Conclusions: Using a recently introduced ESCRS online IOL calculator in multifocal IOLs leds to a high number of eyes reaching target refraction and low prediction errors. All formulas performed similarly well. Hill-RBF showed the highest number of eyes within ±0.5 D, but no significance was found., (Copyright © 2023 Published by Wolters Kluwer on behalf of ASCRS and ESCRS.)

Purpose: To investigate the effect of corneal curvature (K) on the accuracy of 8 intraocular lens formulas in highly myopic eyes., Setting: Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China., Design: Retrospective consecutive case series., Methods: 302 eyes (302 patients) were analyzed in subgroups based on the K value. The mean refractive error, mean absolute error (MAE), median absolute error (MedAE), root-mean-square absolute prediction error (RMSAE) and proportions of eyes within ±0.25 diopter (D), ±0.50 D, ±0.75 D, ±1.00 D were statistical analyzed., Results: Emmetropia Verifying Optical (EVO) 2.0, Kane, and Radial Basis Function (RBF) 3.0 had the lower MAE (≤0.28) and RMSAE (≤0.348) and highest percentage of eyes within ±0.50 D (≥83.58%) in the flat (K ≤ 43 D) and steep K (K > 45 D) groups. Hoffer QST had the lowest MedAE (0.19), RMSAE (0.351) and the highest percentage of eyes within ±0.50 D (82.98%) in the normal K group (43 < K ≤ 45 D). When axial length (AL) ≤28 mm, all formulas showed close RMSAE values (0.322 to 0.373) in flat K group. When AL >28 mm, RBF 3.0 achieved the lowest MAE (≤0.24), MedAE (≤0.17) and RMSAE (≤0.337) across all subgroups., Conclusions: EVO 2.0, Kane, and RBF 3.0 were the most accurate in highly myopic eyes with a flat or steep K. Hoffer QST is recommended for long eyes with normal K values. RBF 3.0 showed the highest accuracy when AL >28 mm, independent of corneal curvature., (Copyright © 2023 Published by Wolters Kluwer on behalf of ASCRS and ESCRS.)

Background: To compare the accuracy of nine intraocular lens (IOL) power calculation formulas, including three traditional formulas (SRK/T, Haigis, and Hoffer Q) and six new-generation formulas (Barrett Universal II [BUII], Hill-Radial Basis Function [RBF] 3.0, Kane, Emmetropia verifying optical [EVO], Ladas Super, and Pearl-DGS) in patients who underwent cataract surgery after acute primary angle closure (APAC)., Methods: In this retrospective cross-sectional study, 44 eyes of 44 patients (APAC) and 60 eyes of 60 patients (control) were included. We compared the mean absolute error, median absolute error (MedAE), and prediction error after surgery. Subgroup analyses were performed on whether axial length (AL) or preoperative laser peripheral iridotomy affected the postoperative refractive outcomes., Results: In the APAC group, all formulas showed higher MedAE and more myopic shift than the control group (all P < 0.05). In APAC eyes with AL ≥ 22 mm, there were no differences in MedAEs according to the IOL formulas; however, in APAC eyes with AL < 22 mm, Haigis (0.49 D) showed lower MedAE than SRK/T (0.82 D) (P = 0.036) and Hill-RBF 3.0 (0.54 D) showed lower MedAE than SRK/T (0.82 D), Hoffer Q (0.75 D) or Kane (0.83 D) (P = 0.045, 0.036 and 0.027, respectively). Pearl-DGS (0.63 D) showed lower MedAE than Hoffer Q (0.75 D) and Kane (0.83 D) (P = 0.045 and 0.036, respectively). Haigis and Hill-RBF 3.0 showed the highest percentage (46.7%) of eyes with PE within ± 0.5 D in APAC eyes with AL < 22 mm. Iridectomized eyes did not show superior precision than the non-iridotomized eyes in the APAC group., Conclusions: Refractive errors in the APAC group were more myopic than those in the control group. Haigis and Hill-RBF 3.0 showed high precision in the eyes with AL < 22 mm in the APAC group., (© 2023. The Author(s).)

Purpose: To evaluate the accuracy of newer online intraocular lens (IOL) formulas in extremely elongated eyes (axial length > 30 mm)., Methods: This retrospective case series study included 236 patients (236 eyes). Postoperative refractive outcomes of the Barrett Universal II (BU II), Cooke K6 (K6), Emmetropia Verifying Optical (EVO) 2.0, Hoffer QST (HQST), Kane, Pearl-DGS, and Radial Basis Function (RBF) 3.0 formulas were compared. Subgroup analysis was performed in the extreme myopia group 1 (30 < axial length ≤ 32 mm), extreme myopia group 2 (32 < axial length ≤ 35 mm), and meniscus IOL group. The root mean square absolute prediction error (RMSAE) and proportions of eyes of prediction errors within ±0.50 diopters (D) were calculated for statistical analysis., Results: For the extreme myopia group 1, RBF 3.0 achieved the lowest RMSAE (0.361) and EVO 2.0 showed the highest proportion of eyes within ±0.50 diopters (85.06%). For the extreme myopia group 2, the RMSAE of the K6 (0.442) and EVO 2.0 (0.475) was significantly lower than the BU II (0.610), Kane (0.641), and HQST (0.759, P ≤ .016) formulas. In the meniscus IOL group, the K6 formula showed the lowest RMSAE (0.402) and the highest percentage within ±0.50 diopters (84.31%)., Conclusions: The EVO 2.0 and K6 formulas are recommended for IOL power calculation in eyes with extreme myopia. Modern artificial intelligence-based formulas should be used cautiously when the axial length is longer than 32 mm or meniscus IOLs are implanted. [ J Refract Surg . 2023;39(10):705-710.] .

Purpose: To investigate the performance of novel intraocular lens calculation formulae (Barrett Universal II, Emmetropia Verifying Optical, and Kane) and conventional formulae (Haigis, Hoffer Q, Holladay 1, and Sanders-Retzlaff-Kraff/T [SRK/T]) in patients who underwent pars plana vitrectomy or silicone oil removal combined with cataract surgery., Methods: In total, 301 eyes from 301 patients who underwent pars plana vitrectomy/silicone oil removal with concomitant cataract surgery were enrolled and divided into the following four groups according to preoperative diagnosis: silicone oil-filled eyes after pars plana vitrectomy, epiretinal membrane, primary retinal detachment, and macular hole., Results: Barrett Universal II exhibited the smallest mean absolute error (0.65 diopters [D]) and median absolute error (0.39 D) in total. In patients with primary retinal detachment, each formula exhibited the worst refractive outcomes in diverse vitreoretinal pathologies ( P < 0.01), and no difference in accuracy between the seven formulas was observed ( P = 0.075). For long eyes, the second linear (Wang-Koch 2) version of the Wang-Koch adjustment significantly reduced the median absolute error for Holladay 1 and SRK/T ( P < 0.001 and P = 0.019)., Conclusion: In combined surgery, both new and conventional formulas using the second linear version of the Wang-Koch 2 adjustment demonstrated satisfactory performance, with Barrett Universal II exhibiting the best overall performance. However, in patients with primary retinal detachment, all seven formulas showed less favorable performance., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the Opthalmic Communications Society, Inc.)

Purpose: To determine the optimal intraocular lens (IOL) calculation formula for vitrectomized eyes with diverse surgical and biometric characteristics., Setting: Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China., Design: Retrospective consecutive case series study., Methods: This study included 974 vitrectomized eyes (974 patients) scheduled for phacoemulsification with IOL implantation. 11 formulas were evaluated: Barrett Universal II (BUII), Emmetropia Verifying Optical, Hoffer-QST, Kane, Ladas Super Formula, Pearl-DGS, Radial Basis Function (RBF), Haigis, HofferQ, Holladay1, and SRK/T. Risk factors for prediction error (PE) exceeding 1 diopter (D) were determined using multiple logistic regression. Subgroup analyses were performed based on surgical history and biometric parameters., Results: The risk of hyperopic PE (>1 D) was higher in patients with silicone oil tamponade (odds ratio [OR], 1.82) and longer axial length (AL) (OR, 1.55), while patients with previous scleral buckling (OR, 2.43) or ciliary sulcus IOL implantation (OR, 6.65) were more susceptible to myopic PE (<-1 D). The Kane formula had the highest overall prediction accuracy, and also the best in silicone oil-filled eyes and the flat cornea subgroup. The BUII and RBF displayed the optimal performance in eyes with previous scleral buckle and steep cornea, respectively. In eyes with an AL ≥ 26 mm, the Holladay1 with the nonlinear version of the Wang-Koch AL adjustment (Holladay1-WKn) showed the lowest absolute PE and highest percentage within ± 1.0 D of PE., Conclusions: The Kane achieved the highest overall prediction accuracy in vitrectomized eyes. The optimal formula for eyes with previous scleral buckle, steep cornea, or long AL was BUII, RBF, and Holladay1-WKn, respectively., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of ASCRS and ESCRS.)

Purpose: To provide a simplified method to optimize lens constants to zero the mean prediction error (ME) of an intraocular lens (IOL) calculation formula, without the need to program the formula itself, by exploring the influence of IOL and corneal power on the refractive impact of variations in effective lens position., Design: Theoretical development of an optimized formula and retrospective clinical evaluation on documented datasets., Methods: Retrospective data from 8878 patients with cataracts with pre- and postoperative measurements available using 4 IOL models and 6 IOL power calculation formulas were examined. A schematic eye model was used to study the impact of small variations in effective lens position (ELP) on the postoperative spherical equivalent (SE) refraction. The impact of keratometry (K) and IOL power (P) on SE was investigated. A theoretical thick lens model was used to devise a formula to zero the average prediction error of an IOL power calculation formula. This was achieved by incrementing the predicted ELP, which could then be translated into an increment in the IOL constant. This method was tested on documented real-life postoperative datasets, using different IOL models and single-constant optimized IOL calculation formulas., Results: For small variations in ELP, there was an exponential relationship between IOL power and the resultant postoperative refractive variation. The ELP adjustment necessary to zero the ME equated to a ratio between the ME and the mean of the following expression: 0.0006 * (P 2 +2K * P) on the considered datasets. The accuracy of the values obtained using this formula was confirmed on documented postoperative datasets, and on published and nonpublished formulas., Conclusion: The proposed method allows surgeons without special expertise to optimize an IOL constant to nullify the ME on a documented dataset without coding the different formulas. The influence of individual eyes is proportional to the squared power of the implanted IOL., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Purpose: To investigate the refractive accuracy of intraocular lens (IOL) power calculation for biometric formulas in phacovitrectomy., Methods: This retrospective study included 357 eyes of 357 patients who underwent phacovitrectomy using four commonly available IOL power formulas: Hoffer Q (87 eyes), Holladay 1 (78 eyes), Holladay 2 (91 eyes), and SRK/T (101 eyes). The mean refractive error (ME) and the mean absolute refractive error (MAE) were calculated based on the predicted postoperative refraction error, and they were compared using analysis of variance test. Subjects were divided into high myopic eyes (axial length, ≥26 mm) and nonhigh myopic eyes (axial length, &lt;26 mm)., Results: The ME and the MAE after phacovitrectomy did not show a significant difference among the four IOL power formulas (p = 0.546 and p = 0.495, respectively). There was no significant statistical difference in formulas when the eyes were grouped into high myopia and nonhigh myopia (ME: p = 0.526 and p = 0.482, respectively; MAE: p = 0.715 and p = 0.627, respectively). The ME showed myopic shift in all formulas regardless of IOL formula used. The ME showed greater myopic shift in high myopia group than nonhigh myopia group in all formulas., Conclusions: Our study did not find evidence for superiority of any formula in phacovitrectomy. However, in phacovitrectomy, possible myopic shift should be considered for IOL power calculation. Especially, in phacovitrecotmy in patients with high myopia, more myopic shift should be considered when selecting IOL.

Background: We evaluated whether the best-fit intraocular lens (IOL) power formula for the first operated eye (BF1) was also the most accurate formula for the second eye., Methods: This was a retrospective study of 152 patients who underwent uncomplicated delayed bilateral cataract surgery with a minimum delay of 3 weeks using only one 1-piece IOL (HOYA, Vivinex) at the Medical University of Vienna, Austria. Seven different formulae (Barrett Universal II, Castrop, Haigis, Hoffer Q, Holladay 1, Kane, and SRK/T) were investigated to test the formula selection approach with regard to the calculated mean and median absolute prediction errors (MAE/MedAE)., Results: The mean intraindividual difference in axial length was 0.2 mm (±0.3 mm). BF1 coincided with the best-fit formula for the second eye (BF2) in 56% of patients (p < 0.05). Using BF1 for the second eye led to a lower MedAE (0.22 dioptre, D) than using a formula at random (0.33 D) and was less accurate than using the best-fit formula for each eye separately (0.1 D). The MedAEs of all formulae were generally low, ranging from 0.28 to 0.35 D., Conclusion: Using BF1 for the second eye led to a lower MedAE than the random selection of a formula. Therefore, BF1 can be used for the second eye if the surgeon is unsure of the choice of formula., (© 2023 The Authors. Clinical & Experimental Ophthalmology published by John Wiley & Sons Australia, Ltd on behalf of Royal Australian and New Zealand College of Ophthalmologists.)

Background: To assess and compare the accuracy of 10 intraocular lens (IOL) power calculation formulas after cataract surgery in eyes with an axial length (AL) shorter than or equal to 22.00 mm., Methods: A retrospective case series included 100 eyes with an AL ≤ 22.00 mm that underwent uneventful cataract surgery. The refractive prediction error (PE) was calculated using 10 different IOL power calculation formulas: Barrett Universal II, EVO 2.0, Haigis, Hill RBF 2.0, Hoffer Q, Holladay 1 and 2, Kane, SRK/T and SuperLadas. The median absolute prediction error (MedAE ± SD) and mean absolute prediction error (MAE ± SD) were calculated after adjusting the mean prediction error (ME) to 0., Results: Hoffer Q obtained the lowest MedAE (0.292 D) after adjusting the ME to 0, followed very closely by EVO 2.0 (0.298 D) and Kane (0.300 D). EVO 2.0 and Kane obtained both the lowest MAE after adjusting the ME to 0 (0.386). Differences in MAE among the different formulas were not statistically significant (p > 0.05)., Conclusions: Our study reflects a tendency of the EVO 2.0 formula and the Kane formula along with the older Hoffer Q formula, to predict more accurately the refractive outcomes in short eyes that undergo cataract phacoemulsification surgery compared to the other formulas, despite this difference could not be statistically proved., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)

This retrospective study examined the effect of the size of training data on the accuracy of machine learning-assisted SRK/T power calculation. Clinical records of 4800 eyes of 4800 Japanese patients with intraocular lenses (IOLs) were reviewed. A support vector regressor (SVR) was used for refining the SRK/T formula, and dataset sizes for training and evaluation were reduced from full to 1/64. The prediction errors from the postoperative refractions were calculated, and the proportion within ± 0.25 D, ± 0.50 D, and ± 1.00 D of errors were compared with those using full data. The influence of the difference in A-constant was also evaluated. Prediction errors within ± 0.50 D in the use of full data were obtained with the dataset of ≥ 150 eyes (P = 0.016), whereas the datasets of ≥ 300 eyes were required for the error within ± 0.25 D (P < 0.030). The prediction errors did not alter with the A-constant values among IOLs with open-loop haptics, except for IOLs with plated haptics. In conclusion, the accuracy of SVR-assisted SRK/T could be achieved with the training dataset of ≥ 150 eyes for the Japanese population, and the calculation was versatile for any open-looped IOLs., (© 2023. The Author(s).)

Purpose: To evaluate the role of a new parameter, iris root depth (IRD), in intraocular lens power calculation using ultrasound biomicroscopy (UBM) in primary angle-closure diseases (PACDs), and to compare the accuracy of 6 formulas in PACDs: Barrett Universal II (BUII), Haigis, Hill-Radial Basis Function (RBF) v. 3.0, Hoffer Q, Kane and Sanders Retzlaff Kraff/Theoretical (SRK)/T., Setting: Zhongshan Ophthalmic Center, Guangzhou, China., Design: Retrospective consecutive case series., Methods: Patients diagnosed with PACDs who had undergone cataract surgery were reviewed to first evaluate the performance of 6 formulas. Then preoperative UBM examinations of 58 eyes were used to measure IRD and predict effective lens position (ELP) to generate the Haigis IRD formula. The accuracy of Haigis IRD was compared with BUII, Haigis and Kane formulas. The SD of predicted error was the main indicator evaluating formula performance, according to heteroscedastic analysis., Results: 103 eyes (103 patients) were included. The SDs of Kane (0.59, P = .01), RBF 3.0 (0.61, P = .02) and SRK/T formula (0.62, P = .04) were significantly lower than Hoffer Q. Modified with IRD, Haigis IRD generated the lowest SD (0.41), which was significantly lower than Haigis formula (0.54, P = .03) and was equal to Kane formula (0.45, P = .37)., Conclusions: Kane, RBF 3.0 and SRK/T were more accurate in PACD eyes. Optimized with IRD, Haigis IRD formula achieved the lowest SD and had comparable accuracy with Kane formula. IRD could be a promising parameter to improve accuracy of IOL power calculation for PACDs., (Copyright © 2023 Published by Wolters Kluwer on behalf of ASCRS and ESCRS.)

Purpose: This study aims to investigate whether a combination of the total corneal power (TCP) and virtual axial length (AL) based on Gaussian optics makes the refractive prediction accuracy of the Barrett Universal II (BUII) formula better than the conventional anterior keratometry (K) and axial length., Methods: The TCP and the virtual AL were calculated in two ways: the corneal index strategy and the TK index strategy. The former uses the corneal refractive index n 1 as a variable, and the latter uses the TK index n x as a variable. In a dataset of 225 eyes, the calculated TCP and the virtual AL were input into the BUII formula along with the anterior chamber depth, lens thickness, and white-to-white measured with the IOLMaster 700, and the refractive prediction accuracy was evaluated by the mean numerical prediction error (MNE), standard deviation (SD), mean absolute prediction error (MAE), median absolute prediction error (MedAE), percentages of eyes with prediction error (PE) within ± 0.50 diopter, and IOL formula performance index (FPI). The refractive prediction outcomes also underwent subgroup analyses and were compared with those of the anterior keratometry-based BUII-K of the IOLMaster 700., Results: In the corneal index strategy, the FPI had the highest value at approximately n 1  = 1.346. In the TK index strategy, the FPI had the highest value at approximately n x  = 1.3858. There was no tendency for the refractive prediction outcomes of the BUII-n 1  = 1.346 and the BUII-n x  = 1.3858 to be inferior to those of the BUII-K, particularly in the medium range of subgroups., Conclusion: The combination of the actual TCP and the virtual AL based on Gaussian optics may lead to a better refractive prediction accuracy of the BUII formula than that of BUII-K., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: To derive a formula for accurate axial length (AL) assessment using routine ultrasound in silicone oil-filled eyes, where optical biometry is unavailable or not possible., Methods: This was a prospective, consecutive, nonrandomized study of 50 eyes of 50 patients conducted in a tertiary care hospital in North India. AL measurements were taken using both manual A-scan and IOL master, both in silicone oil-filled status and 3 weeks after silicone oil removal. A correction factor of 0.7 was used for AL adjustment in oil-filled eyes. The corrected AL (cAL) was compared with IOL master values in oil-filled eyes. Agreement analysis was carried out using Bland Altman plot. Linear regression analysis was done using uncorrected manual AL to find a new equation. Data was analyzed using Stata 14. A P value <0.05 was taken as significant., Results: The study included 40 males and 10 females, with an age range of 6-83 years (mean 41.9 years). The mean AL of the oil-filled eye as measured by manual A-scan was 31.76 mm ± 3.09 and by IOL master was 24.7 mm ± 1.74. Linear regression analysis was performed in randomly selected 35 eyes of the observed data to obtain a new equation: predicted AL (PAL) = 14 + 0.3 × manual AL. The mean difference between PAL and optically measured AL with silicone oil in situ was 0.98 ± 1.67., Conclusion: We propose a new formula for better prediction of the correct AL in silicone oil-filled eyes using ultrasound-based AL measurement., Competing Interests: None

Improvement in biometry and formulas has raised the bar for accurate intraocular lens (IOL) power calculation. However, when we look closely at the performance of a specific IOL model, we often find that the prediction error varies with the implant power. This phenomenon has no explanation other than that the optic design of the IOL has shifted over the power range, thereby disrupting the assumptions of the calculations. By this report, we call the industry to be more transparent and disclose the basic information about the IOL design that is important for accurate IOL power calculation. The relevant information concerns the refractive index, the central optic thickness, the anterior and posterior curvature radii, the toricity location, the spherical aberration, and haptic angulation. The goal is to predict possible shifts in principal planes or IOL position over the power range causing a refractive surprise if not corrected for., (Copyright © 2023 Published by Wolters Kluwer on behalf of ASCRS and ESCRS.)

Purpose: The ideal formula for intraocular lens (IOL) power calculation following cataract surgery in pediatric eyes till date has no answer. We compared the predictability of the Sanders-Retzlaff-Kraff (SRK) II and the Barrett Universal (BU) II formula and the effect of axial length, keratometry, and age., Methods: This was a retrospective analysis of children who were under eight years of age and who underwent cataract surgery with IOL implantation under general anesthesia between September 2018 and July 2019. The prediction error of SRK II formula was calculated by subtracting the target refraction and the actual postoperative spherical equivalent. Preoperative biometry values were used to calculate the IOL power using the BU II formula with the same target refraction that was used in SRK II. The predicted spherical equivalent of the BU II formula was then back-calculated using the SRK II formula with the IOL power obtained with the BU II formula. The prediction errors of the two formulae were compared for statistical significance., Results: Seventy-two eyes of 39 patients were included in the study. The mean age at surgery was 3.8 ± 2 years. The mean axial length was 22.1 ± 1.5 mm, and the mean keratometry was 44.7 ± 1.7 D. The group with an axial length >24 mm showed a significant and strong positive correlation (r = 0.93, P = 0) on comparison mean absolute prediction errors using the SRK II formula. There was a strong negative correlation between the mean prediction error in the overall keratometry group using the BU II formula (r = -0.72, P < 0.000). There was no significant correlation between age and refractive accuracy using the two formulae in any of the subgroups of age., Conclusion: There is no perfect answer to an ideal formula for IOL calculation in children. IOL formulae need to be chosen keeping in mind the varying ocular parameters., Competing Interests: None

Purpose: To compare the effects of secondary in-the-bag vs ciliary sulcus intraocular lens (IOL) implantation on the accuracy of IOL power calculation in pediatric eyes., Design: Prospective nonrandomized interventional study., Methods: Pediatric aphakic eyes that underwent either in-the-bag or ciliary sulcus secondary IOL implantation were included. The mean prediction error (PE), mean absolute error (MAE), median absolute error, and percentages of eyes with PE within ±0.25 diopter (D), ±0.50 D, ±0.75 D, and ±1.00 D were calculated and compared using SRK/T formula., Results: One hundred fourteen eyes (38.26%) received in-the-bag IOL implantation and 184 (61.74%) underwent ciliary sulcus IOL implantation. Compared with the sulcus group, the capsular group displayed significantly lower MAE and higher percentage of eyes within ±0.50 D of PE (MAE: 0.90 vs 1.56 D; ±0.50 D: 40.40% vs 14.29%, both P < .001). The eyes receiving in-the-bag IOL implantation (sulcus IOL implantation β: -1.060, 95% CI: -1.415 to -0.705; P < .001), unilateral (β: 0.647, 95% CI: 0.144-1.150; P = .012), or with deeper anterior chamber depth (β: 0.362, 95% CI: 0.068-0.656; P = .016) were prone to maintain hyperopia (PE > 0). To reduce PE, when the predicted capsular IOL power was between 11.50 and 30.00 D, the power of a sulcus-implanted IOL should be reduced by 0.50 to 2.50 D accordingly (the exact amount of reduction is positively related to the predicted power)., Conclusions: In-the-bag implantation yielded smaller PE in pediatric eyes undergoing secondary IOL implantation. Adjustment of IOL power for ciliary sulcus implantation is required to reduce PE, and the amount of adjustment is positively correlated with the IOL power predicted by SRK/T formula., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Purpose: To evaluate the influence of posterior corneal asphericity on the refractive error using SRK-T and Barrett formulas for the intraocular lens (IOL) power calculation for Lucidis Extended Depth of Focus (EDOF) IOL., Setting: This study was carried out at a tertiary ophthalmology center in Geneva, Switzerland., Design: A retrospective study. Medical records from all enrolled patients were analyzed and the following information was extracted retrospectively, over 1 month following surgery., Methods: We retrospectively reviewed 75 eyes that underwent cataract surgery and were implanted with a Lucidis EDOF IOL. We measured the posterior corneal asphericity (Q value), axial length (AL), and anterior chamber depth (ACD) and then calculated the IOL power using SRK-T and Barrett formulas., Results: Seventy-five eyes were included, all of which had 1-month postoperative data. In the cohort, 32 eyes were from females (43%) and 43 from males (57%). The mean age of the study population was 73 ± 8.8 years. The mean AL was 23.5 ± 0.98 and the mean ACD was 3.13 ± 0.3. The mean posterior Q value was - 0.35 ± 0.2. In a regression analysis, we found a statistically significant relationship between the error in refraction prediction and the posterior Q value, irrespective of the formula used. The relationship between posterior corneal asphericity and the refraction prediction error was stronger for the Barrett II Universal formula than for the SRK-T formula., Conclusions: Posterior corneal asphericity was correlated with the refractive error of calculation of both SRK-T and Barrett formulas, with a stronger correlation to the latter formula., Competing Interests: The authors declare that they have no conflict of interest., (Thieme. All rights reserved.)

Background: We assessed the correlation of posterior corneal asphericity and the refractive prediction error of the SRK-T and Barrett II Universal formulas for eyes following phacovitrectomy with peeling of the internal limiting membrane (ILM)., Patients and Methods: We retrospectively analyzed 41 eyes of 41 patients following a combined phacovitrectomy with ILM peeling. Surgeries were performed by one fellowship-trained vitreoretinal surgeon between 2016 and 2021., Results: Of the 41 patients, 41 eyes were included, with all having at least 1 month of postoperative data. Of the 41 eyes, 19 eyes were female (46%) and 22 were male (54%). The average age of the study population was 77.5 ± 10.7 years. The mean axial length (AL) was 22.7 ± 4.6 mm and the mean anterior chamber depth (ACD) was 3 ± 0.8 mm. The mean posterior Q value was - 0.29 ± 0.27. The mean absolute error (MAE) values 1-month postoperatively for the SRK-T and Barrett II Universal formulas were 0.73 and 0.65, respectively. Regression analysis yielded a significant correlation between posterior corneal asphericity and SRK-T MAE (r = 0.35, R 2  = 0.12, p < 0.05) only., Conclusions: Posterior corneal surface asphericity is correlated to the refractive error of the SRK-T formula for eyes following phacovitrectomy., Competing Interests: The authors declare that they have no conflict of interest., (Thieme. All rights reserved.)

Purpose: To evaluate the accuracy of newer generation intraocular lens (IOL) power calculation formulas (EVO 2.0 and Kane) with established formulas (Barrett Universal II, Haigis and SRK/T) in pediatric cataract patients., Methods: Retrospective study. We enrolled 110 eyes (110 patients) in Eye Hospital of Wenzhou Medical University. All patients underwent uneventful cataract surgery and implanted with posterior chamber IOL in the bag. We calculate the mean prediction errors (PE) and percentage within 1 diopter (D) at 1 month to assess the accuracy, and percentage > 2D was defined as prediction accident. Then, we performed subgroup analysis according to age and axial length (AL)., Results: The mean age and AL were 37.45 ± 23.28 months and 21.16 ± 1.29 mm. The mean PE for all patients was as follows: Barrett (- 0.30), EVO (0.18), Haigis (- 0.74), Kane (- 0.36), and SRK/T (0.58), p < 0.001. In addition, EVO and SRK/T formulas were relatively accurate in patients younger than 24 months and with AL ≤ 21 mm, while EVO got lower prediction accident rate than SRK/T (3/41 vs 8/41, 4/52 vs 5/52). Moreover, Barrett, EVO, and Kane formulas achieved better accuracy and lower prediction accident rate in patients older than 24 months and with AL > 21 mm (both > 51/69 and 43/58, and < 3/69 and 3/58)., Conclusions: In patients older than 24 months and with AL > 21 mm, Barrett, EVO, and Kane formulas were relatively accurate, while in patients younger than 24 months and with AL ≤ 21 mm, EVO was more accurate, followed by SRK/T formula., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Prcis: The pseudoexfoliation glaucoma group produced higher mean absolute error (MAE) and higher percentages of large-magnitude prediction error, in all investigated intraocular lens formulas. Postoperative anterior chamber angle and change in intraocular pressure (IOP) were associated with absolute error., Purpose: The purpose of this study is to evaluate refractive outcomes of cataract surgery in patients with pseudoexfoliation glaucoma (PXG) and to determine the predictive factors for refractive errors., Materials and Methods: Fifty-four eyes with PXG, 33 eyes with primary open angle glaucoma (POAG) and 58 normal eyes undergoing phacoemulsification, in Haydarpasa Numune Training and Research Hospital, Istanbul, Turkey, were included in this prospective study. The follow-up was 3 months. Preoperative and postoperative anterior segment parameters measured by Scheimpflug camera were compared after adjusting for age, sex, and axial length. The mean prediction error, MAE, and percentages of large-magnitude prediction error (>±1.0 D) in SRK/T, Barrett Universal II, and Hill-RBF formulas were compared., Results: There was a significantly greater anterior chamber angle (ACA) enlargement in PXG eyes compared with POAG ( P =0.006) and normals ( P =0.04). The PXG group showed significantly higher MAE in SRK/T, Barrett Universal II, and Hill-RBF (0.72, 0.79, and 0.79 D, respectively) than POAG (0.43, 0.25, and 0.31 D, respectively) and normals (0.34, 0.36, 0.31 D, respectively) ( P <0.0001). The large-magnitude error was significantly more frequent in the PXG group among the 3 groups with SRK/T (37%, 18%, and 12%, respectively) ( P =0.005), Barrett Universal II (32%, 9%, and 10%, respectively) ( P =0.005), and Hill-RBF (32%, 9%, and 9%, respectively) ( P =0.002). The MAE was correlated with postoperative ACA and IOP decrease in Barrett Universal II ( P =0.02 and 0.007, respectively) and Hill-RBF ( P =0.03 and 0.02, respectively)., Conclusions: PXG may be a predictor for refractive surprise after cataract surgery. Prediction errors may be due to IOP-lowering effect of surgery and larger postoperative ACA than expected, in the presence of zonular weakness., Competing Interests: Disclosure: The authors declare no conflict of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

To compare the accuracy of the modern biometric formulas in cataract surgery according to axial length and lens type. It is a Cross-sectional design from 365 patients who underwent cataract surgery. The SRK/T, Hoffer Q, Haigis, and Holladay I formulas were extracted from the IOLMaster 500 biometer. Barret formulas and the Kane were obtained from the online calculator. Patients are classified according to axial length (AL) into three groups: AL ≤ 22 mm, 22 < AL < 25 mm, and AL ≥ 25 mm. In addition, implanted intraocular lenses are classified as Monofocal, extended focus, and Multifocal. There are no significant differences between the formulas. In short, the Kane formula was more accurate than the other biometric formulas. Kane and SRK/T were the most accurate in monofocal lenses, with the lowest residual refractive error. The Holladay I formula obtained the lowest mean absolute error with the highest number of eyes with minimum residual ± 0.5Dp in the multifocal lenses in the 22 < AL < 25 mm eyes. In the long AL eyes, SRK/T and Kane's obtained the lowest mean absolute error and the best percentage of eyes with ± 0.5Dp of residual refractive error. There are no significant differences between the formulas. However Kane's formula has shown high accuracy, especially in short and long eyes with monofocal lenses., (© 2023. The Author(s).)

Purpose: To compare the prediction accuracy of the Barrett True-K for keratoconus with standard formulas (SRK/T, Barrett Universal II, and Kane) and the Kane keratoconus formula., Setting: Shaare Zedek Medical Center, Jerusalem, Israel, and University Eye Clinic, Maastricht, the Netherlands., Design: Multicenter retrospective case series., Methods: Eyes with stable keratoconus undergoing cataract surgery were included. The predicted refractions were calculated for SRK/T, Barrett Universal II, Barrett True-K for keratoconus (predicted and measured), Kane, and Kane adjusted for keratoconus formulas. Primary outcomes were prediction error (PE), absolute error (AE), and percentage of eyes with PE ±0.25 diopters (D), ±0.50 D, and ±1.00 D. Subgroup analyses were performed based on the severity of the keratoconus., Results: 57 eyes were included in the study. The PE was not significantly different from zero for SRK/T, Barrett True-K (predicted and measured), and Kane keratoconus formulas (range 0.09 to 0.22 D, P > .05). The AE of Barrett True-K predicted (median 0.14 D) and Barrett True-K measured (median 0.10 D) were significantly lower from Barrett Universal II (median 0.47 D) and Kane (median 0.50 D), P < .001., Conclusions: The Barrett True-K formulas for keratoconus had higher prediction accuracy as compared with new generation formulas and a similar prediction accuracy as compared with the Kane keratoconus formula., (Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of ASCRS and ESCRS.)

Purpose: To assess the accuracy of intraocular lens (IOL) calculation formulas in pediatric patients with multifocal IOL implantation with optic capture in Berger space., Methods: This prospective observational study enrolled 68 children (101 eyes), aged 3 to 14 years, who received multifocal IOL (Tecnis ZMB00; Abbott Medical Optics) implantation with optic capture in Berger space from June 2019 to June 2020 in Qingdao Eye Hospital. Ocular biometry was performed using the IOLMaster 700 (Carl Zeiss Meditec). The IOL power and intended postoperative refraction were calculated using the Hoffer Q, Barrett Universal II, Holladay, Holladay2, SRK/T, Haigis, and SRKII formulas. The refractive state of patients, prediction error, and absolute prediction error were evaluated., Results: The mean absolute error of the formulas was significantly different (0.49 diopters [D], Hoffer Q; 0.52 D, Barrett Universal II; 0.47 D, Holladay; 0.54 D, Holladay2; 0.52 D, SRK/T; 0.67 D, Haigis; 0.99 D, SRKII; P < .001). However, the Hoffer Q, Barrett Universal II, Holladay, Holladay2, and SRK/T formulas had a similar accuracy in predicting refractive error within ±0.50 D (62.4%, 59.4%, 62.4%, 62.4%, and 58.4%). There was a trend toward a greater prediction error in eyes with a shorter axial length (≤ 22 mm) or a steeper cornea (> 43.50 D), for which the Hoffer Q and Holladay2 formulas were more accurate. When the axial length was greater than 22 mm or the corneal curvature was 43.50 D or less, the Holladay, Hoffer Q, and Barrett Universal II formulas were more accurate., Conclusions: For patients with pediatric cataract treated with multifocal IOL implantation with optic capture in Berger space, the Hoffer Q, Barrett Universal II, Holladay, Holladay2, and SRK/T formulas performed better than the other formulas. [ J Pediatr Ophthalmol Strabismus . 2023;60(2):139-146.] .

Purpose: To compare the prediction accuracy of standard keratometry (K) and total keratometry (TK) for intraocular lens (IOL) power calculation in eyes undergoing combined cataract surgery and Descemet membrane endothelial keratoplasty (triple DMEK)., Setting: Tertiary care academic referral center., Design: Retrospective case series., Methods: Review of 83 eyes (63 patients) that underwent triple DMEK between 2019 and 2021. Biometry measurements were obtained using a swept-source optical biometer (IOLMaster 700). 63 eyes were used for statistical analysis. Mean error, mean absolute error (MAE), SD, median absolute error, maximum absolute error, root mean squared prediction error, and the percentage of eyes within prediction errors of ±0.50 diopters (D) and ±1.00 D were calculated for 9 multivariate and third-generation formulas using K and TK values (Barrett Universal II, Yeo EVO 2.0, Cooke K6, Kane, Pearl-DGS, Haigis, Holladay 1, Hoffer Q, and SRK/T). Formulas were additionally tested by using the prediction for an IOL power 1 D below the IOL used (IOLup1D)., Results: For all formulas, MAE was lower for K than for TK by an average of 0.21 D. The lowest MAE value observed was 0.67 D for "adjusted" SRK/T using K, and the highest MAE values observed were 1.24 D and 1.24 D for nonadjusted Hoffer Q and Haigis using TK, respectively. Overall, lower MAE values were observed for multivariate formulas and SRK/T., Conclusions: In triple DMEK eyes, the prediction accuracy of K was higher than that of TK. The most accurate formulas were SRK/T and multivariate formulas using K with the IOLup1D adjustment., (Copyright © 2023 Published by Wolters Kluwer on behalf of ASCRS and ESCRS.)

Purpose: To evaluate the refractive outcomes of scleral-sutured IOL 2 mm posterior to the limbus in post-traumatic eyes using SRK/T formula., Methods: This single-center retrospective case series included 35 eyes from 35 post-traumatic patients undergoing scleral-suture of ErgomaX IOLs by a single experienced surgeon. Preoperative predicted refraction, procedure-related complications, and postoperative spherical equivalent (SE) at least 1 month after surgery were recorded. The prediction error (PE) was calculated as the difference between the postoperative SE and preoperative predicted refraction., Results: Of the 35 post-traumatic patients, 28 patients were aphakia without capsular support, and 7 patients were traumatic lens dislocation or subluxation. The mean age at surgery was 56.03 ± 14.56 years and 28 patients were men (80%). The mean postoperative spherical equivalent (SE) and postoperative astigmatism were - 1.23 ± 0.82 D and 1.57 ± 1.14 D, respectively. The mean prediction error (ME) of SRK/T formula was - 0.17 D. The mean absolute error (MAE) was 0.48D. The prediction accuracy was 60.0% for refractive errors of ± 0.50 D and 85.7% for refractive errors of ± 1.00D. Multiple linear regression analyses revealed that IOL power has positive correlation with PE., Conclusion: Assumption of in-the-bag IOL position when calculating IOL (52501TY, ErgomaX) power for standardizing scleral-sutured IOL 2 mm posterior to the limbus demonstrates acceptable refractive outcomes. The accuracy of IOL power calculation using the SRK/T formula for eyes needing low IOL power or high IOL power may be affected by the uncertain position of postoperative IOL and further studies are needed., (© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)

Background: The precision of refractive outcomes after uneventful cataract surgery largely depends on the biometry and intraocular lens (IOL) formula used for selecting the IOL. To improve the accuracy of post-op refractive outcomes, several new IOL power calculation formulae have come up. This review would aim to summarise the differences among the new formulae in their performance among normal and variable ocular biometry conditions like short and long axial lengths., Methods: A literature review was performed by searching the PubMed and Cochrane databases from 2016 to 2021, identified 483 articles, of which 51 were included in the review., Results: We identified 15 new IOL formulas (including updates on older formulas) of which, only 8 newer formulas (BUII, Hill-RBF 2.0, Kane, Pearl DGS, LSF AI, Naesar 2, EVO 2.0 and VRF) met the eligibility criteria. They were compared according to the reported median absolute error, mean absolute error and percentage of eyes within 0.5D., Conclusion: The Kane formula and Barrett Universal-II formula performed better than other formulas over the entire axial length (AL) spectrum. In the long eye (AL > 26.0 mm) sub-group, the Kane formula was the most accurate, while in the short eye (AL < 22.0 mm) sub-group, both Kane and EVO 2.0 formulas fared better than other formulas.

Purpose: To evaluate the per operative intra-ocular lens (IOL) power calculation using intra-operative aberrometry (ORA) and its comparison with conventional methods., Methods: Patients with cataract planned for phacoemulsification by a single surgeon under topical anesthesia were enrolled in this prospective observational study in this prospective observational study. All patients underwent pre-operative biometry (Manual SRK-II and IOLMaster ® 500) to determine the intra-ocular lens (IOL) power. Intra-operative aberrometry using ORA was also performed; however, IOL was inserted according to IOLMaster ® (SRK/T). Spherical equivalent (SE) was recorded on post-operative days 1, 7, and 30. Patients were divided into three groups based on axial lengths for analysis. Comparative analysis was performed for the calculated IOL powers and prediction errors of ORA with conventional methods. Adjusted IOL power to calculate the emmetropic IOL using the LiHue formula was also determined and was compared with existing methods. A P-value less than 0.05 was considered statistically significant., Results: A total of 115 eyes from 113 patients were included, with a median age of 54.90 ± 14.3 years. The mean axial length was found to be 23.94 ± 2.3 mm. There was good agreement (87%) between ORA and IOLMaster ® for calculated IOL powers with a mean difference of 0.047 ± 0.5D between the two (P = 0.33). A positive correlation was found between IOL power calculated using ORA, IOLMaster ® , SRK-II, and adjusted IOL., Conclusion: The use of intra-operative aberrometry (ORA) to calculate IOL power in patients undergoing uncomplicated phacoemulsification is non-inferior relative to standard pre-operative measurement and planning., Competing Interests: None

Objective: To compare the accuracy of intraoperative wavefront aberrometry to preoperative biometry formulae for predicting intraocular lens power., Design: Retrospective, consecutive case series., Participants: Eyes undergoing cataract extraction with at least 1 month of follow-up after surgery at an ambulatory surgical centre in Toronto., Methods: Consecutive sample of 228 cataract extractions with monofocal, trifocal, or toric intraocular lens implantation from November 1, 2017, to December 31, 2019. The spherical equivalent was predicted preoperatively with Barrett Universal II, Hill-Radial Basis Function (RBF), SRK/T, Holladay I, Holladay II, Haigis, and HofferQ using biometry measurements and intraoperatively with wavefront aberrometry. The primary outcomes were mean prediction error and proportion of eyes with a spherical equivalent within 0.5 D of the refractive target at postoperative month 1., Results: The analysis included 159 eyes with 52% females and a mean age of 69.4 years. Formulae with the lowest mean prediction error were Hill-RBF (0.32 D ± 0.02 D), Barrett Universal II (0.32 D ± 0.02 D), intraoperative aberrometry (0.32 D ± 0.02 D), SRK/T (0.33 D ± 0.02 D), Holladay II (0.34 D ± 0.03 D), Holladay I (0.35 D ± 0.02 D), Haigis (0.37 D ± 0.02 D), and HofferQ (0.42 D ± 0.02 D). There were no statistically significant differences between intraoperative aberrometry and the preoperative formulae. Formulae with the highest proportion of eyes within 0.5 D of the refractive target were intraoperative aberrometry (82%), Barrett Universal II (81%), Hill-RBF (80%), SRK/T (77%), Holladay II (76%), Holladay I (75%), Haigis (71%), and HofferQ (70%)., Conclusions: Intraoperative aberrometry and modern preoperative biometry formulae are equally effective at reaching the refractive target. In normal eyes, intraoperative aberrometry does not appear to provide any additional benefit to modern prediction formulae., (Copyright © 2021 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.)

Purpose: To evaluate quantitatively ocular biometric parameters and intraocular lens (IOL) power measurements after ptosis surgery., Setting: Adiyaman University Hospital, Adiyaman, Turkey., Design: Comparative prospective clinical study., Methods: This study comprised involutional ptosis patients divided into droopy eyelid severity groups: Group 1: >4 mm, Group 2: 3 to 4 mm, and Group 3: 1 to 2 mm. The patients underwent anterior levator resection, and preoperative and postoperative biometry measurements at 3 months postoperatively were obtained., Results: The Group 1 sample size was 19, Group 2 was 22, and Group 3 was 16. The mean flattest keratometry (K 1 ), steepest keratometry (K 2 ), and mean keratometry (K m ) values significantly decreased at 3 months postoperatively in Group 1 ( P < .001 for all). The mean K 1 , K 2 , and K m values nonsignificantly decreased at 3 months postoperatively in Groups 2 and 3 ( P > .05 for all). The mean corneal astigmatism magnitude decreased at 3 months postoperatively in Group 1 ( P < .01), Group 2 ( P = .186), and Group 3 ( P = .952). The mean recommended IOL powers targeting emmetropia increased postoperatively in Group 1 and were similar preoperatively and postoperatively in Groups 2 and 3. In Group 1, the mean changes after ptosis surgery by the formula were 0.47 diopters (D) for SRK/T, 0.52 D for Hoffer Q, 0.55 D for Haigis, 0.50 D for Barrett Universal II, and 0.55 D for Holladay 2., Conclusions: Ptosis >4 mm significantly affects corneal curvature values and IOL power calculations when cataract surgery is planned. Surgeons might consider altering their lens power choice accordingly if cataract surgery is to be sequentially followed by ptosis repair., (Copyright © 2022 Published by Wolters Kluwer on behalf of ASCRS and ESCRS.)

Purpose: To compare the accuracy of the new-generation intraocular lens power calculation formulae in axial myopic eyes., Methods: Four databases, PubMed, Web of Science, EMBASE and Cochrane library, were searched to select relevant studies published between Apr 11, 2011, and Apr 11, 2021. Axial myopic eyes were defined as an axial length more than 24.5 mm. There are 13 formulae to participate in the final comparison (SRK/T, Hoffer Q, Holladay I, Holladay II, Haigis for traditional formulae, Barrett Universal II, Olsen, T2, VRF, EVO, Kane, Hill-RBF, LSF for the new-generation formulae). The primary outcomes were the percentage of eyes with a refractive prediction error in ± 0.5D and ± 1.0D., Results: A total of 2273 eyes in 15 studies were enrolled in the final meta-analysis. Overall, the new-generation formulae showed a relatively more accurate outcome in comparison with traditional formulae. The percentage of eyes with a predictive refraction error in ± 0.5D (± 1.0D) of Kane, EVO and LSF was higher than 80% (95%), which was only significantly different from Hoffer Q (all P < 0.05). Moreover, another two new-generation formulae, Barrett Universal II and Olsen, had higher percentages than SRK/T, Hoffer Q, Holladay I and Haigis for eyes with predictive refraction error in ± 0.5D and ± 1.0D (all P < 0.05). In ± 0.5D group, Hill-RBF was better than SRK/T (P = 0.02), and Holladay I was better than EVO (P = 0.03) and LSF (P = 0.009), and Hoffer Q had a lower percentage than EVO, Kane, Hill-RBF and LSF (P = 0.007, 0.004, 0.002, 0.03, respectively). Barrett Universal II was better than T2 (P = 0.02), and Hill-RBF was better than SRK/T (P = 0.009). No significant difference was found in other pairwise comparison., Conclusion: The new-generation formula is more accurate in intraocular lens power calculation for axial myopic eyes in comparison with the third- or fourth-generation formula., (© 2022. The Author(s).)

Purpose: To investigate factors associated with refractive outcomes after phacovitrectomy for epiretinal membrane (ERM)., Methods: Retrospective review of patients undergoing phacovitrectomy for ERM was done. The main outcome measure was predictive refraction error (PE), defined as observed refraction error - target refraction error, calculated by the SRK/T, Haigis, and SRK II formulae. PE was measured at postoperative 1, 3, and 6 months. Simple and multiple linear regression analysis were used to evaluate factors associated with PE., Results: A total of 53 eyes of 53 patients were included. The mean PEs at postoperative 1, 3, and 6 months were all negative, implying myopic shift in all patients regardless of the intraocular lens formula used. Haigis formula showed the least myopic shift among the three formulae (p = 0.001, Friedman test). There was no significant difference in PE depending on preoperative central macular thickness (CMT) in subgroup analysis. On stepwise multiple linear regression analysis, ERM etiology (β = 0.759, p = 0.004, SRK/T formula; β = 0.733, p = 0.008, Haigis formula; β = 0.933, p < 0.001, SRK II formula), preoperative anterior chamber depth (β = -0.662, p = 0.013, Haigis formula; β = -0.747, p = 0.003, SRK II formula), and decrease of CMT (β = -0.003, p = 0.025, SRK/T formula) were significantly associated with PE at postoperative 6 months., Conclusions: Myopic shift in PE was observed after combined phacovitrectomy for epiretinal membrane. ERM etiology, preoperative anterior chamber depth, and decrease of CMT were significantly associated with PE at postoperative 6 months. There was no difference in PE after surgery between the two groups defined by CMT (≥500 and <500 μm).

Purpose: To compare the accuracy of intraocular lens (IOL) power calculations among IOL formulas after phacovitrectomy., Methods: We prospectively enrolled 206 eyes of 206 patients who underwent 25-gauge phacovitrectomy, without gas tamponade, for macular pathology. Pre-operative optical biometry used the IOLMaster 700 to calculate the IOL power with the new formulas, i.e. the Barrett Universal II (BU II), Emmetropia Verifying Optical version 2.0, Hill-Radial Basis Function (RBF) version 3.0, Kane, and Ladas Super Formula, and conventional formulas, i.e. Haigis, Hoffer Q, Holladay 1, Holladay 2, and Sanders-Retzlaff-Kraff/T (SRK/T). A single-piece foldable IOL was implanted in all cases. Manifest refractions were measured before and 3 months after surgery., Results: The BU II formula showed the lowest standard deviation and mean and median absolute errors and had the highest percentage of eyes with a refractive prediction error within ± 0.25 D. The absolute error was significantly lower with the four new formulas, except the Hill-RBF, than with the Hoffer Q (all p =  ≤ 0.010) and Holladay 1 formulas (all p =  < 0.010). The absolute error with the BU II formula was also lower than that with the Holladay 2 (p = 0.012) and SRK/T (p = 0.024) formulas., Conclusion: Overall, the new IOL formulas, except the Hill-RBF, were superior to some of the conventional formulas for calculating IOL power in phacovitrectomy., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)