scholarly journals Comparison of aphakic refraction and biometry-based formulae for secondary in-the-bag and sulcus-implanted intraocular lens power estimation in children

2020 ◽  
Author(s):  
Ping-Jun Chang ◽  
Zhangliang Li ◽  
Fan Zhang ◽  
Lei Lin ◽  
Jiaojiao Kou ◽  
...  
Keyword(s):  
Power Calculation ◽  
Biometric Data ◽  
Iol Implantation ◽  
Iol Power Calculation ◽  
Refractive Outcomes ◽  
Intraocular Lens Power ◽  
Iol Power ◽  
Hyperopic Shift ◽  
Lens Power ◽  
Almost All

Purpose: To compare the accuracy of refractive outcomes in children undergoing secondary in-the-bag or cilliary sulcus IOL implantation, using aphakic refraction (AR)-based formulae and biometry-based formulae. Methods: In this retrospective study, 39 eyes of the in-the-bag IOL group and the other 26 eyes of the sulcus-implanted IOL group. Holladay 1, Hoffer Q, SRK/T and SRK II formulae were employed depending on the biometric data, while Hug and Khan formulae were used based on preoperative aphakic refraction. The prediction error (PE) and the absolute value of predicted error (APE) were compared between the two groups and formulae. Results: In the in-the-bag IOL group, non-significant differences of APE were found among the 6 formulae, while the Holladay 1, Hoffer Q, SRK/T and SRK II all demonstrated a significant hyperopic shift of median PE value compared to the Hug formula and Holladay 1 and SRK II also showed a significant hyperopic shift of PE compared to the Khan . Higher percentages of eyes with PE less than 1 D were found using Hoffer Q and SRK/T. In the sulcus-implanted group, the Holladay 1, Hoffer Q and SRK/T had a significantly smaller median value of APE than the Hug and Khan formulae, and the SRK II had a significantly smaller median value of APE than the Hug formula, while Holladay 1 had the lowest value of APE. Higher percentages of eyes within PE less than 1 D were found using Holladay 1, Hoffer Q and SRK/T, while the highest was SRK/T. Significantly larger hyperopic shifts of median PE value using all the 6 formulae were found in eyes with sulcus-implanted IOL than with in-the-bag implanted IOL . In in-the-bag implanted IOL group, the Hug and Khan formulae had significantly smaller APE values when compared with the sulcus-implanted IOL group. Conclusions: whether IOL was in the bag or sulcus implantation, almost all the formulae showed hyperopic shift, SRK/T showed the best accuracy. Biometry-based formulae were superior to AR-based formulae in accuracy of IOL power calculation, especially when IOL was implanted in the sulcus. In-the-bag IOL implantation should always be with higher priorities, especially when using AR-based formulae in IOL power calculation.

scholarly journals Accuracy of intraocular lens power calculation formulas in a steep cornea: A case report

2021 ◽  
pp. 29-33
Author(s):  
Ehab M Ghoneim ◽  
Ahmed A Hassaan
Keyword(s):  
Intraocular Lens ◽  
Power Calculation ◽  
Intraocular Lens Power Calculation ◽  
Iol Power Calculation ◽  
Intraocular Lens Power ◽  
Manifest Refraction ◽  
Iol Power ◽  
Lens Power ◽  
The Right ◽  
Lens Power Calculation

There is no enough knowledge about the accuracy of intraocular lens (IOL) power calculation formulas in steep corneas. This study may be the first one that compares the accuracy of the SRK II formula with Holladay1, Hoffer Q and Haigis formulas in steep corneas. We reported a case of a 60-year-old female, with a cataract in the left eye and with a steep cornea. We used the modern formulas; Holladay1, Hoffer Q and Haigis. The result (+7.0D) was unexpected compared to the manifest refraction and to the IOL power calculated in the right eye using the same formulas which was (+17.0D). We implanted (+12.0D) Sensar 1-piece IOL depending on our clinical experience. The post-operative refraction was (+0.00/-1.75axis106). Postoperative, we used the patient data to find the best formula in this case. We found that the SRK II (A118) result was (+11.5D) and thus this formula was the most accurate in this case. Keywords: SRK II; Holladay1; Hoffer Q; Haigis

scholarly journals Accuracy of Intraocular Lens Power Calculation Formulas for Highly Myopic Eyes

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Yichi Zhang ◽  
Xiao Ying Liang ◽  
Shu Liu ◽  
Jacky W. Y. Lee ◽  
Srinivasan Bhaskar ◽  
...  
Keyword(s):  
Intraocular Lens ◽  
Absolute Error ◽  
Power Calculation ◽  
Prediction Errors ◽  
Intraocular Lens Power Calculation ◽  
Iol Power Calculation ◽  
Predictive Error ◽  
Intraocular Lens Power ◽  
Iol Power ◽  
Lens Power

Purpose.To evaluate and compare the accuracy of different intraocular lens (IOL) power calculation formulas for eyes with an axial length (AL) greater than 26.00 mm.Methods.This study reviewed 407 eyes of 219 patients with AL longer than 26.0 mm. The refractive prediction errors of IOL power calculation formulas (SRK/T, Haigis, Holladay, Hoffer Q, and Barrett Universal II) using User Group for Laser Interference Biometry (ULIB) constants were evaluated and compared.Results.One hundred seventy-one eyes were enrolled. The Barrett Universal II formula had the lowest mean absolute error (MAE) and SRK/T and Haigis had similar MAE, and the statistical highest MAE were seen with the Holladay and Hoffer Q formulas. The interquartile range of the Barrett Universal II formula was also the lowest among all the formulas. The Barrett Universal II formulas yielded the highest percentage of eyes within ±1.0 D and ±0.5 D of the target refraction in this study (97.24% and 79.56%, resp.).Conclusions.Barrett Universal II formula produced the lowest predictive error and the least variable predictive error compared with the SRK/T, Haigis, Holladay, and Hoffer Q formulas. For high myopic eyes, the Barrett Universal II formula may be a more suitable choice.

Effective Ocular Biometry and Intraocular Lens Power Calculation

2016 ◽  
Vol 10 (02) ◽  
pp. 94 ◽  
Author(s):  
Magdalena Turczynowska ◽  
Katarzyna Koźlik-Nowakowska ◽  
Magdalena Gaca-Wysocka ◽  
Andrzej Grzybowski ◽  
◽  
...  
Keyword(s):  
Intraocular Lenses ◽  
Power Calculation ◽  
Intraocular Lens Power Calculation ◽  
Optical Instruments ◽  
Iol Power Calculation ◽  
Refractive Outcomes ◽  
Ocular Biometry ◽  
Iol Power ◽  
Clinical Measurements ◽  
Lens Power

Since the introduction of phacoemulsification, cataract surgery has evolved remarkably. The use of premium intraocular lenses (IOLs) (aspheric, toric, multifocal), refractive lens exchange and patients after refractive surgery procedures require extremely precise clinical measurements and IOL calculation formulas to achieve desired postoperative refraction. For many years, ultrasound biometry has been the standard for measurement of ocular parameters. The introduction of optical biometry (fast and non-invasive) has replaced ultrasound methods and is now considered as the clinical standard for ocular biometry. Recently, several modern optical instruments have been commercially launched and there are new methods available, including the empirical, analytical, numerical or combined methods to determine IOL power. The aim of this review is to present current techniques of ocular biometry and IOL power calculation formulas, which will contribute to achieve highly accurate refractive outcomes.

scholarly journals Accuracy of intraocular lens power calculation using Scheimpflug tomography and OKULIX ray tracing software in corneal scarring

2019 ◽  
Author(s):  
Karim Mahmoud Nabil
Keyword(s):  
Visual Acuity ◽  
Ray Tracing ◽  
Intraocular Lens ◽  
Absolute Error ◽  
Power Calculation ◽  
Corneal Scarring ◽  
Iol Power Calculation ◽  
Intraocular Lens Power ◽  
Iol Power ◽  
Lens Power

Abstract Background: To evaluate the accuracy of intraocular lens power (IOL) calculation using Scheimpflug tomography and OKULIX ray tracing software in corneal scarring. Methods: This study was conducted on 40 consecutive eyes, 20 cases with corneal scarring and coexisting cataract, and 20 controls with clear cornea, which underwent uneventful phacoemulsification and IOL implantation following Scheimpflug tomography and OKULIX ray tracing software and third generation IOL power calculation formulas for IOL power calculation. Accuracy of IOL power calculation was evaluated by subtracting expected and achieved spherical refraction 3 months postoperatively and was recorded as mean absolute error (MAE). Distance uncorrected visual acuity (UCVA) for each eye was measured using Snellen chart preoperatively and 3 months postoperatively; visual acuity was scored and converted to the logarithm of the minimum angle of resolution (LogMar). Results: In cases of corneal scarring, 20 eyes (100 %) yielded a postoperative spherical refraction which differed less than 1 diopter (D) from predicted, in 16 eyes (80 %) the postoperative spherical refraction was within 0.50 D from expected. The MAE was 0.2 D in cases, which did not differ significantly compared to controls (MAE 0.1 D). In corneal scarring cases, distance UCVA showed significant improvement from 1.3 Log Mar (Snellen equivalent 20/400) preoperatively to 0.5 Log Mar (Snellen equivalent 20/60) 3 months postoperatively. Conclusion: Scheimpflug tomography combined with OKULIX ray tracing software for calculation of IOL power provides accurate results in cases of corneal scarring.

scholarly journals Comparison of accuracy of Partial Coherence Interferometry based Zeiss IOL Master 500 and Immersion Ultrasound [Ocuscan RXP] for intraocular lens power calculation

2016 ◽  
Vol 14 (4) ◽  
Author(s):  
Vijaya Pai ◽  
Divya Shastri ◽  
Asha Kamath
Keyword(s):  
Intraocular Lens ◽  
Refractive Error ◽  
Partial Coherence ◽  
Power Calculation ◽  
Partial Coherence Interferometry ◽  
Iol Power Calculation ◽  
Intraocular Lens Power ◽  
Iol Power ◽  
Group B ◽  
Lens Power

Aim: To compare accuracy of intraocular lens power (IOL) calculation using Partial coherence Interferometry based Carl Zeiss IOL master 500 and Immersion ultrasound (Alcon Ocuscan RXP). Methods: A prospective randomized study of patients who underwent clear corneal phacoemulsification with foldable (IOL) by a single surgeon, during the period September 2010 to 2012. Group A included those patients in whom IOL power calculation using Immersion ultrasound (Ocuscan RXP) was used. Group B included those patients in whom IOL power calculation using Partial coherence Interferometry based Zeiss IOL master was used. SRK T formula was used to calculate the IOL power in both the groups. Postoperative final refraction was done at 6 weeks. Unaided visual acuity and best corrected visual acuity was assessed. Postoperative refractive error was compared with predicted refractive error with each biometry method. Statistical analysis was done using SPSS 16.5. Continuous variables expressed as mean (standard deviation). P < 0.05 was considered significant.Results: There were 50 patients in Group A, 44 patients in Group B. Axial length of the patients varied from 22-26mm in both the groups. The postoperative refraction using Ocuscan, 88% had refractive error ≤± 0.5 D, 94% had ≤±1.00D, and 100% had ≤±2.0D of emmetropia. Using Zeiss IOL Master 72.7% had ≤± 0.5 D, 100% had ≤±1.00D of refractive error. Difference in absolute postoperative refractive error using Ocuscan vs. IOL Master was not statistically significant. Conclusion: In our study both ultrasound Ocuscan and IOL master were accurate in calculating intraocular lens power and achieving postoperative refraction closer to emmetropia. 

scholarly journals Accuracy of intraocular lens power calculation in pediatric cataracts with less than a 20 mm axial length of the eye

2014 ◽  
Vol 6 (1) ◽  
pp. 56-64 ◽  
Author(s):  
Purushottam Joshi ◽  
Raman Mehta ◽  
Suma Ganesh
Keyword(s):  
Axial Length ◽  
Prediction Error ◽  
Power Calculation ◽  
Pediatric Cataract ◽  
Intraocular Lens Power Calculation ◽  
Iol Power Calculation ◽  
Intraocular Lens Power ◽  
Iol Power ◽  
The Absolute ◽  
Lens Power

Introduction: Selection of an appropriately-powered IOL is a complex issue, especially in eyes with an axial length of less than 20 mm in pediatric cataract. Objective: To assess the accuracy of IOL power calculation formulae in pediatric cataracts in eyes with an axial length of less than 20 mm. Materials and methods: The records of children less than 15 years old with congenital cataract who had undergone primary IOL implantation were analyzed. Main outcome measures: The variables studied were axial length, keratometric values and the prediction error. The data were analyzed for prediction error determination using the SRK II, SRK T, Holladay 1 and Hoffer Q IOL power calculation formulae. The formula that gave the best prediction error was identified. Results: Twenty-eight eyes of 19 children were included in the study. The absolute prediction error was found to be 1.84 ± 2.09 diopters (D) with SRK II, 2.93±3.55D with SRK T, 3.63±4.06D with Holladay 1, and 4.83±5.02D with Hoffer Q. The number of eyes with the absolute prediction error within 0.5 D was 6 (21.42%) with SRK II, 4 (14.28%) with SRK T, 1 (3.57%) with Holladay 1, and 3 (10.71%) with Hoffer Q. The absolute prediction error with SRK II formula was significantly better than that with other formulae (P < .001). The axial length influenced the absolute prediction error with Hoffer Q formula (P = 0.04). The mean keratometry influenced the prediction error with SRK T formula (P = 0.02), Holladay 1 formula (P = 0.02) and Hoffer Q formula (P = 0.02). Conclusion: Although the absolute prediction error tends to remain high with all the present IOL power calculation formulae, SRK II was the most predictable formula in this study. DOI: http://dx.doi.org/10.3126/nepjoph.v6i1.10773 Nepal J Ophthalmol 2014; 6 (2): 56-64

Intraocular Lens Power Calculation – Still Searching for the Holy Grail

2015 ◽  
Vol 09 (01) ◽  
pp. 13
Author(s):  
Nino Hirnschall ◽  
Oliver Findl ◽  
◽  
Keyword(s):  
Intraocular Lens ◽  
Power Calculation ◽  
Refractive Outcome ◽  
Intraocular Lens Power Calculation ◽  
Iol Power Calculation ◽  
Lens Position ◽  
Intraocular Lens Power ◽  
Iol Power ◽  
Lens Power ◽  
Lens Power Calculation

Since the introduction of optical biometry and modern intraocular lens (IOL) power calculation formulae, the refractive outcome after cataract surgery improved significantly. This is necessary, as patient demand for spectacle independence is increasing. However, especially when it comes to short and long eyes, all formulae have their difficulties in predicting the effective lens position – and, therefore, the post-operative refractive outcome. This review summarises the development of IOL power calculation formulae, explains their basics and presents some alternative calculation methods.

scholarly journals Accuracy of intraocular lens power calculation using Scheimpflug tomography and OKULIX ray tracing software in corneal scarring

2020 ◽  
Author(s):  
karim Mahmoud nabil
Keyword(s):  
Visual Acuity ◽  
Ray Tracing ◽  
Intraocular Lens ◽  
Pearson Correlation ◽  
Power Calculation ◽  
Corneal Scarring ◽  
Iol Power Calculation ◽  
Intraocular Lens Power ◽  
Iol Power ◽  
Lens Power

Abstract Background: To evaluate the accuracy of intraocular lens power (IOL) calculation using Scheimpflug tomography and OKULIX ray tracing software in corneal scarring. Methods: This study was conducted on 40 consecutive eyes, 20 cases with corneal scarring and coexisting cataract, and 20 controls with clear cornea, which underwent uneventful phacoemulsification and IOL implantation following Scheimpflug tomography and OKULIX ray tracing software and third generation IOL power calculation formulas for IOL power calculation. Accuracy of IOL power calculation was evaluated by subtracting expected and achieved spherical refraction 3 months postoperatively and was recorded as mean absolute error (MAE). Distance uncorrected visual acuity (UCVA) for each eye was measured using Snellen chart preoperatively and 3 months postoperatively; visual acuity was scored and converted to the logarithm of the minimum angle of resolution (LogMar).Values were recorded as mean ±SD (standard deviation). Student t-test (t) and Mann Whitney test (U) were used for parametric comparison of the means. Intra class Correlation (ICC) coefficient and Pearson correlation Coefficient (r) were used to assess agreement. A P value less than 0.05 was considered statistically significant. Results: In cases of corneal scarring, 20 eyes (100 %) yielded a postoperative spherical refraction which differed less than 1 diopter (D) from predicted, in 16 eyes (80 %) the postoperative spherical refraction was within 0.50 D from expected. The MAE was 0.2 D in cases, which did not differ significantly compared to controls (MAE 0.1 D). In corneal scarring cases, distance UCVA showed significant improvement from 1.3 Log Mar (Snellen equivalent 20/400) preoperatively to 0.5 Log Mar (Snellen equivalent 20/60) 3 months postoperatively. Conclusion: Scheimpflug tomography combined with OKULIX ray tracing software for calculation of IOL power provides accurate results in cases of corneal scarring.

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.

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