scholarly journals Comparison of intraocular lens power calculation results before and after glaucoma surgery

2020 ◽  
Vol 13 (4) ◽  
pp. 15-20
Author(s):  
Dmitrii Fedorovich Belov ◽  
Vadim Petrovich Nikolaenko
Keyword(s):  
Intraocular Lens ◽  
Anterior Chamber Depth ◽  
Glaucoma Surgery ◽  
Power Calculation ◽  
Ahmed Glaucoma Valve ◽  
Iol Power Calculation ◽  
Iol Calculation ◽  
Before And After ◽  
Iol Power ◽  
Target Refraction

Aim to compare intraocular lens (IOL) power calculation before and after different types glaucoma procedures. Material and methods.Into the study, 115 patients were included, divided into 3 groups: group 1 patients, in whom sinustrabeculectomy was performed (n= 86); group 2 patients with implanted Ex-PRESS shunt (n= 19), group 3 patients after Ahmed glaucoma valve implantation (n= 10). For each patient before surgery optical biometry (IOL-Master 500) was performed and IOL power calculation using Barrett Universal II Formula (target refraction emmetropia). Baseline data were compared with corresponding examinations results obtained in 6 months after glaucoma procedure, to evaluate its effect on main biometric parameters of the eye and the IOL calculation accuracy. Results.Despite significant changes of optical and anatomic indices, mean values of target refraction before and after glaucoma surgery did not differ significantly: 0.00 0.03 versus 0.03 0.52 D (p= 0.628), 0.00 0.1 versus 0.19 0.61 D (p= 0.173), 0.04 0.08 versus 0.11 0.42 D (p= 0.269) for groups, respectively. However, there was a pronounced trend to the increase of target refraction data scattering. Conclusion.Glaucoma procedures cause changes of biometrical parameters of the eye, which leads to decrease in accuracy of IOL calculation. Consequently, when choosing intraocular lens, it is recommended to use measurement results obtained after glaucoma surgery. Keywords:intraocular lens; IOL power calculation; glaucoma; sinustrabeculectomy; Ex-PRESS shunt; Ahmed glaucoma valve; biometry; phacoemulsification; axial length; anterior chamber depth; keratometry.

scholarly journals Comparison of the influence of pupil dilation on predicted postoperative refraction and recommended intraocular lens power among Barrett Universal II, Haigis, and SRK/T calculation formulas: a retrospective study

2019 ◽  
Author(s):  
Takeshi Teshigawara ◽  
Akira Meguro ◽  
Nobuhisa Mizuki
Keyword(s):  
Retrospective Study ◽  
Intraocular Lens ◽  
Significant Positive Correlation ◽  
Anterior Chamber Depth ◽  
Pupil Dilation ◽  
Power Calculation ◽  
Positive Correlation ◽  
Iol Calculation ◽  
Before And After ◽  
Iol Power

Abstract Background We investigated the effect of pupil dilation on predicted postoperative refraction (PPR) and recommended intraocular lens (IOL) power calculated using three different generations of IOL power calculation formulas: Barrett Universal II (Barrett) (new generation), Haigis (4th generation), and SRK/T (3rd generation).Methods This retrospective study included 150 eyes. The following variables were measured and calculated using an optical biometer before and after dilation: anterior chamber depth (ACD), lens thickness (LT), white-to-white (WTW), mean absolute change (MAC) in PPR, and recommended IOL power. PPR and recommended IOL power were calculated by Barrett, Haigis, and SRK/T IOL calculation formulas. Correlations between all changes were analyzed. The influence of pupil dilation on recommended IOL power calculated by each formula was also analyzed.Results MAC in PPR before and after dilation was highest in Barrett, followed by Haigis and SRK/T. Significant differences were found among each MAC. Significant changes were observed before and after dilation in ACD and LT but not in WTW. In Barrett and Haigis, there was a significant positive correlation between change in PPR and change in ACD and a negative correlation between change in PPR and change in LT. Correlations were strongest in Barret followed by Haigis, especially in LT. Change in PPR in Barrett also demonstrated a significant positive correlation with change in WTW. The recommended IOL power using Barrett and Haigis changed before and after dilation in 23.3% and 19.3% cases; SRK/T showed no change.Conclusions In PPR and recommended IOL power, pupil dilation influenced Barrett most strongly, followed by Haigis and SRK/T. Given the stronger correlation between the change in PPR in Barrett and the change in ACD, LT, and WTW, the change of ACD, LT, and WTW is more important to the influence of dilation on Barrett. The influence of dilation on each formula and variables, including ACD, LT, and WTW is key to improving IOL calculation.

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 Comparing the Lenstar Optical Biometer and the Verion Image-Guided System for intraocular lens power calculation

2020 ◽  
Vol 1 (4) ◽  
pp. 236-243
Author(s):  
Mun Wai Lee
Keyword(s):  
Intraocular Lens ◽  
Pearson Correlation ◽  
Case Series ◽  
Power Calculation ◽  
Image Guided ◽  
Iol Power Calculation ◽  
Significant Difference ◽  
Iol Calculation ◽  
Iol Power ◽  
Optical Biometer

Introduction: This study aims to evaluate the accuracy of the measurement parameters of the new Verion Image Guided System compared with an established standard of care. Purpose: To compare the keratometry (K) and white-to-white (WTW) measurements obtained from the Lenstar Optical Biometer (LS) with those from the Verion Image-Guided System (VR) and their effect on intraocular lens (IOL) power calculation. Design: Prospective comparative case series. Materials and methods: Sixty patients going for cataract surgery had biometry measurements and IOL calculation with the LS. Axial length from LS was used together with K and WTW measurements from VR for IOL calculation as well. IOL selection was done using the Barrett Universal II formula targeting emmetropia. The prediction error (PE) within 0.25 D, 0.5 D, and 1 D of refractive target and the mean absolute error (MAE) were calculated for both the LS and VR. Results: Keratometry measurements and steep axis from the VR were closely correlated with the LS (Pearson correlation coefficient K1, r = 0.958; K2, r = 0.952; axis, r = 0.950). The WTW measurements were less so (WTW, r = 0.471). The MAE was 0.317 and 0.347 for LS and VR, respectively. PE within 0.25 D was 48.3% and 40%; within 0.5 D was 83.3% and 76.7%; and within 1 D was 98.3% and 96.7% for LS and VR, respectively. There was no statistically significant difference in MAE between the LS and VR (p = 0.74) Conclusion: Using the K and WTW measurements from the Verion Image-Guided System for IOL power calculation did provide comparable results with the Lenstar. The Lenstar had a higher proportion of eyes within 0.5 D of refractive target but the difference was not statistically significant.  

scholarly journals Influence of pupil dilation on the Barrett Universal II (new generation), Haigis (4th generation), and SRK/T (3rd generation) intraocular lens calculation formulas: a retrospective study

2020 ◽  
Author(s):  
Takeshi Teshigawara ◽  
Akira Meguro ◽  
Nobuhisa Mizuki
Keyword(s):  
Retrospective Study ◽  
Intraocular Lens ◽  
Significant Positive Correlation ◽  
Pupil Dilation ◽  
Power Calculation ◽  
Positive Correlation ◽  
Iol Calculation ◽  
Before And After ◽  
Iol Power ◽  
New Generation

Abstract Background: We investigated the effect of pupil dilation on predicted postoperative refraction (PPR) and recommended intraocular lens (IOL) power calculated using three different generations of IOL power calculation formulas: Barrett Universal II (Barrett) (new generation), Haigis (4th generation), and SRK/T (3rd generation). Methods: This retrospective study included 150 eyes. All variables were measured and calculated using a ZEISS IOL Master 700. The following variables were measured before and after dilation: anterior chamber depth (ACD), lens thickness (LT), white-to-white (WTW). PPR and recommended IOL power were calculated by Barrett, Haigis, and SRK/T IOL calculation formulas. The change in each variable before and after dilation, and correlations between all changes were analyzed using the Wilcoxon signed-rank test and the Spearman’s rank-order correlation test, respectively. The influence of pupil dilation on recommended IOL power calculated by each formula was also analyzed. Results: The mean absolute change (MAC) in PPR before and after dilation was highest in Barrett, followed by Haigis and SRK/T. Significant differences were found among each MACs (P < 0.0001). Significant changes were observed before and after dilation in ACD and LT (P < 0.0001) but not in WTW. In Barrett and Haigis, there was a significant positive correlation between change in PPR and change in ACD (P < 0.0001) and a negative correlation between change in PPR and change in LT (P < 0.0001). Correlations were strongest in Barret followed by Haigis, especially in LT. Change in PPR in Barrett also demonstrated a significant positive correlation with change in WTW (P = 0.022). The recommended IOL power using Barrett and Haigis changed before and after dilation in 23.3% and 19.3% cases; SRK/T showed no change. Conclusions: In PPR and recommended IOL power, pupil dilation influenced Barrett most strongly, followed by Haigis and SRK/T. Given the stronger correlation between the change in PPR in Barrett and the change in ACD, LT, and WTW, the change of ACD, LT, and WTW is more important to the influence of dilation on Barrett. The influence of dilation on each formula and variable, including ACD, LT, and WTW, is key to improving IOL calculation.

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 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 Resulting choice of toric intraocular lens using three devices and online Barrett calculator

2020 ◽  
Author(s):  
jing dong ◽  
yaqin zhang ◽  
xiaogang wang
Keyword(s):  
Intraocular Lens ◽  
Nonparametric Test ◽  
Partial Coherence ◽  
Power Calculation ◽  
Toric Iol ◽  
Partial Coherence Interferometry ◽  
Iol Power Calculation ◽  
Scheimpflug Imaging ◽  
Iol Power ◽  
Clinic Practice

Abstract PURPOSE: To investigate interdevice agreement among toric power calculation difference based on corneal topography/ray-tracing aberrometry (iTrace), partial coherence interferometry (IOLMaster 500), and Scheimpflug imaging (Pentacam) for the measurement of anterior corneal astigmatism. METHODS: The analysis included 101 eyes with regular astigmatism of 101 subjects. The main outcome measures were corneal cylinder power, axis of astigmatism, keratometry values. The toric power and intraocular lens (IOL) power was calculated using online Barrett toric calculator. Interdevice measurement and calculation agreement was assessed using paired sample t-test, and nonparametric test. RESULTS: Significant interdevice difference existed for astigmatism magnitude, flat keratometry, steep keratometry and mean keratometry between iTrace and IOLMaster (all P < 0.01). Significant interdevice difference existed for flat keratometry, steep keratometry and mean keratometry (all P < 0.001) but not astigmatism magnitude (P = 0.325) between iTrace and Pentacam. Significant interdevice difference existed for astigmatism magnitude, steep keratometry and mean keratometry (all P < 0.01) but not flat keratometry (P = 0.310) between IOLMaster and Pentacam. For toric IOL power calculation, iTrace calculation was statistically higher than IOLMaster (0.49±0.36, P <0.001) and Pentacam (0.39±0.42, P <0.001). Moreover, Pentacam IOL power calculation was statistically lower than IOLMaster (-0.10±0.39, P =0.009). Toricity calculation difference was also existed among the three groups (P = 0.004).CONCLUSIONS: The toric IOL power and toricity calculation difference based on iTrace, IOLMaster 500, and Pentacam anterior keratometry data should be noticed in clinic practice.

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