scholarly journals Evaluating newer generation intraocular lens calculation formulas in manual versus femtosecond laser-assisted cataract surgery

2021 ◽  
Vol 14 (8) ◽  
pp. 1174-1178
Author(s):  
Harrish Nithianandan ◽  
◽  
Eric S. Tam ◽  
Hannah Chiu ◽  
Rajiv Maini ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Cataract Surgery ◽  
Radial Basis Function ◽  
Intraocular Lens ◽  
Refractive Error ◽  
Basis Function ◽  
Case Series ◽  
Absolute Error ◽  
Iol Power ◽  
Intraocular Lens Calculation

AIM: To determine the refractive accuracy of the Haigis, Barrett Universal II (Barrett), and Hill-radial basis function 2.0 (Hill-RBF) intraocular lens (IOL) power calculations formulas in eyes undergoing manual cataract surgery (MCS) and refractive femtosecond laser-assisted cataract surgery (ReLACS). METHODS: This was a REB-approved, retrospective interventional comparative case series of 158 eyes of 158 patients who had preoperative biometry completed using the IOL Master 700 and underwent implantation of a Tecnis IOL following uncomplicated cataract surgery using either MCS or ReLACS. Target spherical equivalence (SE) was predicted using the Haigis, Barrett, and Hill-RBF formulas. An older generation formula (Hoffer Q) was included in the analysis. Mean refractive error (ME) was calculated one month postoperatively. The lens factors of all formulas were retrospectively optimized to set the ME to 0 for each formula across all eyes. The median absolute errors (MedAE) and the proportion of eyes achieving an absolute error (AE) within 0.5 diopters (D) were compared between the two formulas among MCS and ReLACS eyes, respectively. RESULTS: Of the 158 eyes studied, 64 eyes underwent MCS and 94 eyes underwent ReLACS. Among MCS eyes, the MedAE did not differ between the formulas (P=0.59), however among ReLACS eyes, Barrett and Hill-RBF were more accurate (P=0.001). Barrett and Hill-RBF were both more likely to yield AE<0.5 D among both groups (P<0.001). CONCLUSION: The Barrett and Hill-RBF formula lead to greater refractive accuracy and likelihood of refractive success when compare to Haigis in eyes undergoing ReLACS.

scholarly journals Assessment of the Influence of Keratometry on Intraocular Lens Calculation Formulas in Long Axial Length Eyes

2021 ◽  
Author(s):  
Shengjie Yin ◽  
Chengyao Guo ◽  
Kunliang Qiu ◽  
Tsz Kin Ng ◽  
Yuancun Li ◽  
...  
Keyword(s):  
Intraocular Lens ◽  
Axial Length ◽  
Case Series ◽  
Absolute Error ◽  
Power Calculation ◽  
Prediction Errors ◽  
Retrospective Case ◽  
Iol Power Calculation ◽  
Iol Power ◽  
Intraocular Lens Calculation

Abstract Purpose: Hyperopic surprises tend to occur in axial myopic eyes and other factors including corneal curvature have rarely been analyzed in cataract surgery, especially in eyes with long axial length (≥ 26.0 mm). Thus, the purpose of our study was to evaluate the influence of keratometry on four different formulas (SRK/T, Barrett Universal II, Haigis and Olsen) in intraocular lens (IOL) power calculation for long eyes.Methods: Retrospective case-series. 180 eyes with axial length (AL) ≥ 26.0 mm were divided into 3 keratometry (K) groups: K ≤ 42.0 D (Flat), K ≥ 46.0 D (Steep), 42.0 < K < 46.0 D (Average). Prediction errors (PE) were compared between different formulas. Multiple regression analysis was performed to investigate factors associated with the PE.Results: The mean absolute error was higher for all evaluated formulas in Steep group (ranging from 0.66 D to 1.02 D) than the Flat (0.34 D to 0.67 D) and Average groups (0.40 D to 0.74D). The median absolute errors predicted by Olsen formula were significantly lower than that predicted by Haigis formula (0.42 D versus 0.85 D in Steep and 0.29 D versus 0.69 D in Average) in Steep and Average groups (P = 0.012, P < 0.001, respectively). And the Olsen formula demonstrated equal accuracy to the Barrett II formula in Flat and Average groups. The predictability of the SRK/T formula was affected by the AL and K, while the predictability of Olsen and Haigis formulas was affected by the AL only. Conclusions: Steep cornea has more influence on the accuracy of IOL power calculation than the other corneal shape in long eyes. Overall, both the Olsen and Barrett Universal II formulas are recommended in long eyes with unusual keratometry.

scholarly journals Prediction accuracy of conventional and total keratometry for intraocular lens power calculation in femtosecond laser-assisted cataract surgery

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Soyoung Ryu ◽  
Ikhyun Jun ◽  
Tae-im Kim ◽  
Kyoung Yul Seo ◽  
Eung Kweon Kim
Keyword(s):  
Femtosecond Laser ◽  
Cataract Surgery ◽  
Intraocular Lens ◽  
Intraclass Correlation ◽  
Absolute Error ◽  
Power Calculation ◽  
Prediction Errors ◽  
Intraocular Lens Power Calculation ◽  
Iol Power Calculation ◽  
Severance Hospital

AbstractThis study evaluated the accuracy of total keratometry (TK) and standard keratometry (K) for intraocular lens (IOL) power calculation in eyes treated with femtosecond laser-assisted cataract surgery. The retrospective study included a retrospective analysis of data from 62 patients (91 eyes) who underwent uneventful femtosecond laser-assisted cataract surgery with Artis PL E (Cristalens Industrie, Lannion, France) IOL implantation by a single surgeon between May 2020 and December 2020 in Severance Hospital, Seoul, South Korea. The new IOLMaster 700 biometry device (Carl Zeiss Meditec, Jena, Germany) was used to calculate TK and K. The mean absolute error (MAE), median absolute error (MedAE), and the percentages of eyes within prediction errors of ± 0.25 D, ± 0.50 D, and ± 1.00 D were calculated for all IOL formulas (SRK/T, Hoffer-Q, Haigis, Holladay 1, Holladay 2, and Barrett Universal II). There was strong agreement between K and TK (intraclass correlation coefficient = 0.99), with a mean difference of 0.04 D. For all formulas, MAE tended to be lower for TK than for K, and relatively lower MAE and MedAE values were observed for SRK/T and Holladay 1. Furthermore, for all formulas, a greater proportion of eyes fell within ± 0.25 D of the predicted postoperative spherical equivalent range in the TK group than in the K group. However, differences in MAEs, MedAEs, and percentages of eyes within the above prediction errors were not statistically significant. In conclusion, TK and K exhibit comparable performance for refractive prediction in eyes undergoing femtosecond laser-assisted cataract surgery.

scholarly journals Hyperopic Shift caused by Capsule Contraction Syndrome after Microincision Foldable Intraocular Lens Implantation: case series

2018 ◽  
Author(s):  
Tae Gi Kim ◽  
Sang Woong Moon
Keyword(s):  
Cataract Surgery ◽  
Intraocular Lens ◽  
Refractive Error ◽  
Nd:Yag Laser ◽  
Case Series ◽  
Intraocular Lens Implantation ◽  
Lens Implantation ◽  
Hyperopic Shift ◽  
The Mean ◽  
Anterior Capsulotomy

Abstract Background: Increasing interest in microincision cataract surgery has led to the use of more flexible intraocular lens (IOL). Flexible IOL may cause more IOL deformation and refractive error when capsule contraction syndrome (CCS) occurred. In this retrospective observational case series study, the aim was to report four cases of hyperopic shift caused by CCS after phacoemulsification with microincision foldable intraocular lens implantation. Case presentation: All of four patients underwent phacoemulsification and in-the-bag implantation of an Akreos MI60 (Bausch and Lomb) IOL from 2010 to 2016 in our clinic. These patients had been diagnosed with CCS and had undergone Nd:YAG laser anterior capsulotomy. The mean age of the patients with CCS was 66.8 ± 6.7 years and the mean time for development of CCS after the cataract surgery was 9.3 ± 6.9 months. The mean spherical equivalent (SE) value at the time of the CCS diagnosis was 0.88 ± 0.91 D, which had shown a hyperopic shift compared to the SE value of − 0.91 ± 1.29 D after cataract surgery. The mean SE decreased by − 0.47 ± 1.14 D after Nd:YAG laser anterior capsulotomy. The mean age, axial length, anterior chamber depth, and preoperative SE were not significantly different between the patient with CCS and the patients without CCS. Conclusions: In the case of IOL implantation with flexible materials in microincision cataract surgery, CCS can cause a hyperopic shift. Refractive error caused by CCS can be effectively corrected by Nd:YAG laser anterior capsulotomy. Key Words: Capsule contraction syndrome, Microincision cataract surgery, Refractive change, Nd:YAG laser anterior capsulotomy, Intraocular lens

scholarly journals Improving Intraocular Lens Calculation in Fuchs Endothelial Dystrophy According To Preoperative Degree of Corneal Edema

2021 ◽  
Author(s):  
Beatriz Gargallo-Martinez ◽  
Amanda Ortiz-Gomariz ◽  
Ana Maria Gomez-Ramirez ◽  
Angel Ramon Gutiérrez-Ortega ◽  
Jose Javier Garcia-Medina
Keyword(s):  
Cataract Surgery ◽  
Intraocular Lens ◽  
Refractive Error ◽  
Target Selection ◽  
Corneal Transplantation ◽  
Corneal Edema ◽  
Power Calculation ◽  
Iol Power Calculation ◽  
Iol Power ◽  
Fuchs Endothelial Dystrophy

Abstract Fuchs endothelial dystrophy (FED) is a bilateral, asymmetric, progressive corneal endothelium disorder that causes corneal edema. Resolution of corneal edema is only possible by corneal transplantation. Cataract surgery is a common surgery that replaces the natural lens of the eye by an artificial intraocular lens (IOL). The IOL-power calculation depends mainly on the anterior corneal keratometry and the axial length. In patients with FED, anterior keratometry may be affected by corneal edema and calculations may be less accurate. Therefore, the aim of this study is to establish the theorical postoperative refractive error due to corneal edema resolution after Descemet stripping endothelial keratoplasty combined with cataract surgery and IOL implantation. For this, anterior keratometry was measure preoperatively with edematous cornea and postoperatively after corneal edema resolution. Both keratometries were compared and used to calculate the respective theorical IOL-powers. The difference between target IOLs was used to establish the theorical refractive error due to corneal edema resolution. The results showed that corneal edema resolution induces a change in anterior keratometry, which affects IOL-power calculations and causes a hyperopic shift. The patients with moderate-to-severe preoperative corneal edema had higher theorical refractive error so their target selection should be adjusted for additional − 0.50D.

scholarly journals T2 formula in a highly myopic population, comparison with other methods and description of an improved approach for estimating corneal height

2019 ◽  
Author(s):  
Carlos Alberto Idrobo ◽  
Gisella Santaella ◽  
Ángela María Gutiérrez
Keyword(s):  
Intraocular Lens ◽  
Estimation Method ◽  
Case Series ◽  
Crystalline Lens ◽  
Absolute Error ◽  
Prediction Errors ◽  
Retrospective Case ◽  
Height Estimation ◽  
Population Comparison ◽  
Intraocular Lens Calculation

Abstract ABSTRACT Background: To determine the accuracy of the T2 formula as applied to highly myopic eyes, to compare the T2 formula to the SRK/T and Holladay 1 formulas, and to describe possible ways to improve the estimation of corneal height and prediction error in two settings, the Hadassah Hospital, Ophthalmology Department, Jerusalem, Israel and Clínica Barraquer, Bogotá, Colombia. Methods: In this retrospective case series , optical biometer measurements were taken for 63 highly myopic patients (> 25 mm ) undergoing uneventful crystalline lens phacoemulsification and insertion of an acrylic intraocular lens. Prediction errors were obtained, with estimations of ± 0.50 D, ± 1.00 D, and greater than ± 2.00 D. A method to improve the corneal height calculation is described. Results: The SRK/T formula (mean absolute error [MAE] = 0.418; median absolute error [MedAE] = 0.352) was the most accurate, followed by the T2 (MAE = 0.435; MedAE = 0.381) and Holladay 1 (MAE = 0.455; MedAE = 0.389) formulas. Both the SRK/T and T2 formulas overestimated corneal height, but values were higher with the T2 formula. Corneal height was more precisely estimated using an alternative method that, when combined with axial length optimization, resulted in lower MAE (0.425) and MedAE (0.365) values than when applying the T2 formula alone. Conclusions: The T2 formula seems to be less accurate than the SRK/T formula in highly myopic eyes. An improved corneal height estimation method is described for the the T2 formula. Key words: T2 formula, high myopia, corneal height estimation, cataract surgery, intraocular lens calculation .

scholarly journals Correlation of Binocular Refractive Errors and Calculation of Intraocular Lens Power for the Second Eye

2020 ◽  
Author(s):  
Pengcheng Zhang ◽  
Yuhuan Yang ◽  
Hong Yan ◽  
Jie Zhang ◽  
Weijia Yan
Keyword(s):  
Cataract Surgery ◽  
Intraocular Lens ◽  
Refractive Error ◽  
Control Group ◽  
Refractive Errors ◽  
Age Related ◽  
Department Of Ophthalmology ◽  
Group A ◽  
Iol Power ◽  
Lens Power

Abstract Background: How to reduce the refractive error has always been a tricky problem. The aim of this study was to verify the correlation between binocular refractive errors (RE) after sequential cataract surgery and explore the individualized calculation method of intraocular lens (IOL) for the second eye.Methods: This is a prospective study. One hundred eighty-eight affected eyes of 94 age-related cataract patients with sequential cataract surgery from the Department of Ophthalmology, Tangdu Hospital, china, were recruited. Complete case data of 94 patients were included for correlation analysis of binocular RE. Thereafter, data of patients with RE values greater than 0.50 diopter (D) in the first eyes were extracted and divided randomly into two groups- Group A and B. As the adjustment group, in group A we modified the IOL power for the second eyes according to 50% of the RE of the first eye, and group B was the control group without modify. The mean absolute refractive error (MARE) values of the second eyes were evaluated one month after surgery.Results: The correlation coefficient of binocular RE after sequential cataract surgery was 0.760 (P < 0.001). After the IOL power of the second eyes were adjusted, the MARE of the second eyes was 0.57±0.41 D while MARE of the first eyes was 1.18±0.85 D, and the difference was statistically significant (P<0.001).Conclusions: Binocular REs were correlated positively after sequential cataract surgery. The RE of the second eye can be reduced by adjusting the IOL power based on 50% of the postoperative RE of the first eye.

scholarly journals Correlation of Binocular Refractive Errors and Calculation of Intraocular Lens Power for the Second Eye

2020 ◽  
Author(s):  
Pengcheng Zhang ◽  
Yuhuan Yang ◽  
Hong Yan ◽  
Jie Zhang ◽  
Weijia Yan
Keyword(s):  
Cataract Surgery ◽  
Intraocular Lens ◽  
Refractive Error ◽  
Control Group ◽  
Refractive Errors ◽  
Age Related ◽  
Department Of Ophthalmology ◽  
Group A ◽  
Iol Power ◽  
Lens Power

Abstract Background How to reduce the refractive error has always been a tricky problem. The aim of this study was to verify the correlation between binocular refractive errors (RE) after sequential cataract surgery and explore the individualized calculation method of intraocular lens (IOL) for the second eye. Methods This is a prospective study. One hundred eighty-eight affected eyes of 94 age-related cataract patients with sequential cataract surgery from the Department of Ophthalmology, Tangdu Hospital, china, were recruited. Complete case data of 94 patients were included for correlation analysis of binocular RE. Thereafter, data of patients with RE values greater than 0.50 diopter (D) in the first eyes were extracted and divided randomly into two groups- Group A and B. As the adjustment group, in group A we modified the IOL power for the second eyes according to 50% of the RE of the first eye, and group B was the control group without modify. The mean absolute refractive error (MARE) values of the second eyes were evaluated one month after surgery. Results The correlation coefficient of binocular RE after sequential cataract surgery was 0.760 ( P < 0.001). After the IOL power of the second eyes were adjusted, the MARE of the second eyes was 0.57±0.41 D while MARE of the first eyes was 1.18±0.85 D, and the difference was statistically significant ( P <0.001). Conclusions Binocular REs were correlated positively after sequential cataract surgery. The RE of the second eye can be reduced by adjusting the IOL power based on 50% of the postoperative RE of the first eye.

scholarly journals Secondary Piggyback Intraocular Lens for Management of Residual Ametropia after Cataract Surgery

2021 ◽  
Author(s):  
Zahra Karjou ◽  
Mohammad-Reza Jafarinasab ◽  
Mohammad-Hassan Seifi ◽  
Kiana Hassanpour ◽  
Bahareh Kheiri
Keyword(s):  
Cataract Surgery ◽  
Intraocular Lens ◽  
Refractive Error ◽  
Case Series ◽  
Iol Implantation ◽  
Secondary Iol Implantation ◽  
Absolute Residual ◽  
Safe Technique ◽  
One Year ◽  
Piggyback Iol

Purpose: To investigate the indications, clinical outcomes, and complications of secondary piggyback intraocular lens (IOL) implantation for correcting residual refractive error after cataract surgery. Methods: In this prospective interventional case series, patients who had residual refractive error after cataract surgery and were candidates for secondary piggyback IOL implantation between June 2015 and September 2018 were included. All eyes underwent secondary IOL implantation with the piggyback technique in the ciliary sulcus. The types of IOLs included Sulcoflex and three-piece foldable acrylic lenses. Patients were followed-up for at least one year. Results: Eleven patients were included. Seven patients had hyperopic ametropia, and four patients had residual myopia after cataract surgery. The preoperative mean of absolute residual refractive error was 7.20 ± 7.92, which reached 0.42 ± 1.26 postoperatively (P < 0.001). The postoperative spherical equivalent was within ±1 diopter of target refraction in all patients. The average preoperative uncorrected distance visual acuity was 1.13 ± 0.35 LogMAR, which significantly improved to 0.41 ± 0.24 LogMAR postoperatively (P = 0.008). There were no intraor postoperative complications during the 22.4 ± 9.5 months of follow-up. Conclusion: Secondary piggyback IOL implantation is an effective and safe technique for the correction of residual ametropia following cataract surgery. Three-piece IOLs can be safely placed as secondary piggyback IOLs in situations where specifically designed IOLs are not available.

scholarly journals Gradient Boosting Decision Tree Algorithm for the Prediction of Postoperative Intraocular Lens Position in Cataract Surgery

2020 ◽  
Author(s):  
Tingyang Li ◽  
Kevin Yang ◽  
Joshua Stein ◽  
Nambi Nallasamy
Keyword(s):  
Decision Tree ◽  
Cataract Surgery ◽  
Intraocular Lens ◽  
Anterior Chamber Depth ◽  
Absolute Error ◽  
Gradient Boosting ◽  
Tree Model ◽  
Lens Position ◽  
Iol Power ◽  
Testing Set

Purpose: To develop a method for predicting postoperative anterior chamber depth (ACD) in cataract surgery patients based on preoperative biometry, demographics, and intraocular lens (IOL) power. Methods: Patients who underwent cataract surgery and had both preoperative and postoperative biometry measurements were included. Patient demographics and IOL power were collected from the Sight Outcomes Research Collaborative (SOURCE) database. A gradient boosting decision tree model was developed to predict the postoperative ACD. The mean absolute error (MAE) and median absolute error (MedAE) were used as evaluation metrics. The performance of the proposed method was compared to five existing formulas. Results: 847 patients were assigned randomly in a 4:1 ratio to a training/validation set (678 patients) and a testing set (169 patients). Using preoperative biometry and patient sex as predictors, the presented method achieved an MAE of 0.106 (SD: 0.098) on the testing set, and a MedAE of 0.082. MAE was significantly lower than that of the five existing methods (p < 0.01). When keratometry was excluded, our method attained an MAE of 0.123 (SD: 0.109), and a MedAE of 0.093. When IOL power was used as an additional predictor, our method achieved an MAE of 0.105 (SD: 0.091) and a MedAE of 0.080. Conclusions: The presented machine learning method achieved accuracy surpassing that of previously reported methods in the prediction of postoperative ACD. Translational Relevance: Increasing accuracy of postoperative ACD prediction with the presented algorithm has the potential to improve refractive outcomes in cataract surgery.

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