scholarly journals Cataract Surgery following Sequential Myopic and Hyperopic LASIK

2018 ◽  
Vol 9 (2) ◽  
pp. 264-268
Author(s):  
Tao Ming Thomas Chia ◽  
Hoon C. Jung
Keyword(s):  
Cataract Surgery ◽  
Intraocular Lens ◽  
Calculation Method ◽  
Cataract Extraction ◽  
Power Calculation ◽  
Iol Implantation ◽  
Patient Dissatisfaction ◽  
Iol Power Calculation ◽  
Iol Power

We report a case of patient dissatisfaction after sequential myopic and hyperopic LASIK in the same eye. We discuss the course of management for this patient involving eventual cataract extraction and intraocular lens (IOL) implantation with attention to the IOL power calculation method used.

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 Improving the prediction of effective lens position for intraocular lens power calculations

2020 ◽  
Vol 17 (2) ◽  
pp. 233-242
Author(s):  
Juanita Noeline Chui ◽  
Keith Ong
Keyword(s):  
Cataract Surgery ◽  
Intraocular Lens ◽  
Sagittal Plane ◽  
Anterior Chamber Depth ◽  
Posterior Chamber ◽  
Power Calculation ◽  
Iol Power Calculation ◽  
Lens Position ◽  
Iol Power ◽  
Corneal Apex

Purpose: Achieving the desired post-operative refraction in cataract surgery requires accurate calculations for intraocular lens (IOL) power. Latest-generation formulae use anterior-chamber depth (ACD)—the distance from the corneal apex to the anterior surface of the lens—as one of the parameters to predict the post-operative IOL position within the eye, termed the effective lens position (ELP). Significant discrepancies between predicted and actual ELP result in refractive surprise. This study aims to improve the predictability of ELP. We hypothesise that predictions based on the distance from the corneal apex to the mid-sagittal plane of the cataractous lens would more accurately reflect the position of the principal plane of the non-angulated IOL within the capsular bag. Accordingly, we propose that predictions derived from ACD + ½LT (length thickness) would be superior to those from ACD alone. Design: Retrospective cohort study, comparing ELP predictions derived from ACD to aproposed prediction parameter. Method: This retrospective study includes data from 162 consecutive cataract surgery cases, with posterior-chamber IOL (AlconSN60WF) implantation. Pre- and postoperative biometric measurements were made using the IOLMaster700 (ZEISS, Jena, Germany). The accuracy and reliability of ELP predictions derived from ACD and ACD + ½LT were compared using software-aided analyses. Results: An overall reduction in average ELP prediction error (PEELP) was achieved using the proposed parameter (root-mean-square-error [RMSE] = 0.50 mm), compared to ACD (RMSE = 1.57 mm). The mean percentage PEELP, comparing between eyes of different axial lengths, was 9.88% ± 3.48% and −34.9% ± 4.79% for predictions derived from ACD + ½LT and ACD, respectively. A 44.10% ± 5.22% mean of differences was observed (p < 0.001). Conclusion: ACD + ½LT predicts ELP with greater accuracy and reliability than ACD alone; its use in IOL power calculation formulae may improve refractive outcomes.

scholarly journals Nuances of preoperative care before cataract extraction. What do we overlook when performing biometry, calculating IOL power, and examining the eye?

2021 ◽  
Vol 21 (3) ◽  
pp. 159-163
Author(s):  
A.B. Movsisyan ◽  
◽  
A.E. Egorov ◽  
◽  
◽  
...  
Keyword(s):  
Cataract Surgery ◽  
Macular Degeneration ◽  
Cataract Extraction ◽  
Preoperative Care ◽  
Age Related Macular Degeneration ◽  
Power Calculation ◽  
Iol Power Calculation ◽  
Postoperative Changes ◽  
Age Related ◽  
Iol Power

Modern cataract surgery is increasingly regarded as a refractive procedure. The focus has shifted from practicing and refining surgical steps towards personalized intraocular lens (IOL) choice based on the eye parameters of each individual. The best possible refractive outcome is now the priority. All components of biometry contribute to IOL power calculation accuracy. Therefore, any errors, a method of evaluating each parameter, and a technician’s experience are important. In addition, refraction, macular disorders, and prior surgical procedures affect IOL choice, preoperative care, and the extent of surgery. Moreover, subsequent changes in the IOL position that results in refractive errors after cataract surgery (this depends on the formula for IOL power calculation) should also be considered. The accuracy of IOL power calculation is affected by the inaccuracy of current biometry techniques and postoperative changes of the globe. Personalization of theoretical formulas provides better accuracy of IOL power calculations to meet modern trends in intraocular correction. Supplements containing macular pigments prevent macular degeneration and protect the macular zone. Keywords: cataract, refraction, cataract surgery, biometry, IOL power calculation, IOL power calculation formulas, retina, age-related macular degeneration. For citation: Movsisyan A.B., Egorov A.E. Nuances of preoperative care before cataract extraction. What do we overlook when performing biometry, calculating IOL power, and examining the eye? Russian Journal of Clinical Ophthalmology. 2021;21(3):159–163 (in Russ.). DOI: 10.32364/2311-7729-2021-21-3-159-163.

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 Post Cataract Surgery Refractive Error in Myopic Patients Using SRK/T Versus Holladay 1 Formula for IOL Power Calculation

2019 ◽  
Vol 34 (2) ◽  
Author(s):  
Sidra Anwar, Atif Mansoor Ahmad, Irum Abbas, Zyeima Arif
Keyword(s):  
Intraocular Lens ◽  
Refractive Error ◽  
Axial Length ◽  
Power Calculation ◽  
Mean Error ◽  
Iol Power Calculation ◽  
Group A ◽  
Iol Power ◽  
The Mean ◽  
Group B

Purpose: To compare post-operative mean refractive error with SandersRetzlaff-Kraff/theoretical (SRK-T) and Holladay 1 formulae for intraocular lens (IOL) power calculation in cataract patients with longer axial lengths. Study Design: Randomized controlled trial. Place and Duration of Study: Department of Ophthalmology, Shaikh Zayed Hospital Lahore from 01 January 2017 01 January, 2018. Material and Methods: A total of 80 patients were selected from Ophthalmology Outdoor of Shaikh Zayed Hospital Lahore. The patients were randomly divided into two groups of 40 each by lottery method. IOL power calculation was done in group A using SRK-T formula and in group B using Holladay1 formula after keratomery and A-scan. All patients underwent phacoemulsification with foldable lens implantation. Post-operative refractive error was measured after one month and mean error was calculated and compared between the two groups. Results: Eighty cases were included in the study with a mean age of 55.8 ± 6.2 years. The mean axial length was 25.63 ± 0.78mm, and the mean keratometric power was 43.68 ± 1.1 D. The mean post-operative refractive error in group A (SRK/T) was +0.36D ± 0.33D and in group B (Holladay 1) it was +0.68 ± 0.43. The Mean Error in group A was +0.37D ± 0.31D as compared to +0.69D ± 0.44D in group B. Conclusion: SRK/T formula is superior to Holladay 1 formula for cases having longer axial lengths. Key words: Phacoemulsification, intraocular lens power, longer axial length, biometry.

Comparison of the accuracy of 11 intraocular lens power calculation formulas

2020 ◽  
pp. 112067212096203
Author(s):  
David Carmona-González ◽  
Alfredo Castillo-Gómez ◽  
Carlos Palomino-Bautista ◽  
Marta Romero-Domínguez ◽  
María Ángeles Gutiérrez-Moreno
Keyword(s):  
Intraocular Lens ◽  
Case Series ◽  
University Hospital ◽  
Power Calculation ◽  
Refractive Outcome ◽  
Retrospective Case ◽  
Intraocular Lens Power Calculation ◽  
Iol Power Calculation ◽  
Refractive Outcomes ◽  
Iol Power

Purpose To compare the accuracy of 11 intraocular lens (IOL) power calculation formulas (SRK-T, Hoffer Q, Holladay I, Haigis, Holladay II, Olsen, Barrett Universal II, Hill-RBF, Ladas Super formula, EVO and Kane). Setting Private university hospital (QuironSalud, Madrid, Spain). Design Retrospective case series Methods Data were compiled from 481 eyes of 481 patients who had undergone uneventful cataract surgery with IOL insertion. Preoperative biometric measurements were made using an IOL Master® 700. Respective ULIB IOL constants ( http://ocusoft.de/ulib/c1.htm ) for each of 4 IOL models implanted were used to calculate the predictive refractive outcome for each formula. This was compared with the actual refractive outcome determined 3 months postoperatively. The primary outcome was mean absolute prediction error (MAE). The study sample was divided according to axial length (AL) into three groups of eyes: short (⩽22.00 mm), normal (22.00–25.00 mm) and long (⩾25.00 mm). Results The Barrett Universal II and Haigis formulas yielded the lowest MAEs over the entire AL range ( p < .01, except EVO) as well as in the long ( p < .01, all formulas) and normal ( p < .01, except Haigis, Holladay II, Olsen and LSF) eyes. In the short eyes, the lower MAEs were provided by Haigis and EVO ( p < .01 except Hoffer Q, SRK/T and Holladay I). Conclusions Barrett Universal II was the most accurate for IOL power calculation in the normal and long eyes. For short eyes, the formulas Haigis and EVO seem best at predicting refractive outcomes.

scholarly journals An innovative approach for determining the customized refractive index of ectatic corneas in cataractous patients

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Shiva Pirhadi ◽  
Keivan Maghooli ◽  
Khosrow Jadidi
Keyword(s):  
Refractive Index ◽  
Cataract Surgery ◽  
Ray Tracing ◽  
Prediction Error ◽  
Power Calculation ◽  
Corneal Power ◽  
Iol Power Calculation ◽  
Iol Power ◽  
Hyperopic Shift ◽  
The Difference

Abstract The aim of this study is to determine the customized refractive index of ectatic corneas and also propose a method for determining the corneal and IOL power in these eyes. Seven eyes with moderate and severe corneal ectatic disorders, which had been under cataract surgery, were included. At least three months after cataract surgery, axial length, cornea, IOL thickness and the distance between IOL from cornea, and aberrometry were measured. All the measured points of the posterior and anterior parts of the cornea converted to points cloud and surface by using the MATLAB and Solidworks software. The implanted IOLs were designed by Zemax software. The ray tracing analysis was performed on the customized eye models, and the corneal refractive index was determined by minimizing the difference between the measured aberrations from the device and resulted aberrations from the simulation. Then, by the use of preoperative corneal images, corneal power was calculated by considering the anterior and posterior parts of the cornea and refractive index of 1.376 and the customized corneal refractive index in different regions and finally it was entered into the IOL power calculation formulas. The corneal power in the 4 mm region and the Barrett formula resulted the prediction error of six eyes within ± 1 diopter. It seems that using the total corneal power along with the Barrett formula can prevent postoperative hyperopic shift, especially in eyes with advanced ectatic disorders.

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