Anterior chamber depth, lens thickness and intraocular lens calculation formula accuracy: nine formulas comparison

2020 ◽  
pp. bjophthalmol-2020-317822
Author(s):  
Diogo Hipólito-Fernandes ◽  
Maria Elisa Luís ◽  
Rita Serras-Pereira ◽  
Pedro Gil ◽  
Vitor Maduro ◽  
...  
Keyword(s):  
Anterior Chamber ◽  
Intraocular Lens ◽  
Prediction Error ◽  
Anterior Chamber Depth ◽  
Case Series ◽  
Absolute Error ◽  
Power Calculation ◽  
Retrospective Case ◽  
Lens Thickness ◽  
Mean Prediction Error

Background/AimsTo investigate the influence of anterior chamber depth (ACD) and lens thickness (LT) on 9 intraocular lens (IOL) power calculation formulas accuracy, in patients with normal axial lengths.MethodsRetrospective case series, including patients having uncomplicated cataract surgery with insertion of a single IOL model, divided into three groups according to preoperative ACD. Each group was further subdivided into three subgroups, according to the LT. Using optimised constants, refraction prediction error was calculated for Barrett Universal II, Emmetropia Verifying Optical (EVO) V.2.0, Haigis, Hill-RBF V.2.0, Hoffer Q, Holladay 1, Kane, PEARL-DGS and SRK/T formulas. Mean prediction error, mean and median absolute error (MedAE) and the percentage of eyes within ±0.25D, ±0.50D and ±1.00D were also calculated.ResultsThe study included 695 eyes from 695 patients. For ACD ≤3.0 mm and ≥3.5 mm, mean prediction error of SRK/T, Hoffer Q and Holladay 1 was significantly different from 0 (p<0.05). PEARL-DGS, Kane, EVO V.2.0 and Barrett Universal II were more accurate than the Hoffer Q in ACD ≤3.0 mm (p<0.05). Kane, PEARL-DGS, EVO V.2.0 and Barrett Universal II revealed the lowest variance of mean and MedAE by ACD and LT subgroup. Haigis and Hill-RBF V.2.0 were significantly influenced by LT, independently of the ACD, with a myopic shift with thin lenses and a hyperopic shift with thick lenses (p<0.05).ConclusionNew generation formulas, particularly Kane, PEARL-DGS and EVO V.2.0, seem to be more reliable and stable even in eyes with extreme ACD-LT combinations.

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 Comparison of the Kane formula with existing formulas for intraocular lens power selection

2019 ◽  
Vol 4 (1) ◽  
pp. e000251 ◽  
Author(s):  
Benjamin J Connell ◽  
Jack X Kane
Keyword(s):  
Intraocular Lens ◽  
Axial Length ◽  
Prediction Error ◽  
Anterior Chamber Depth ◽  
Absolute Error ◽  
Case Review ◽  
Refractive Outcome ◽  
Retrospective Case ◽  
Length Range ◽  
Iol Power

ObjectiveTo compare the accuracy of a new intraocular lens (IOL) power formula (Kane formula) with existing formulas using IOLMaster, predominantly model 3, biometry (measures variables axial length, keratometry and anterior chamber depth) and optimised lens constants. To compare the accuracy of three new or updated IOL power formulas (Kane, Hill-RBF V.2.0 and Holladay 2 with new axial length adjustment) compared with existing formulas (Olsen, Barrett Universal 2, Haigis, Holladay 1, Hoffer Q, SRK/T).Methods and analysisA single surgeon retrospective case review was performed from patients having uneventful cataract surgery with Acrysof IQ SN60WF IOL implantation over 11 years in a Melbourne private practice. Using optimised lens constants, the predicted refractive outcome for each formula was calculated for each patient. This was compared with the actual refractive outcome to give the prediction error. Eyes were separated into subgroups based on axial length as follows: short (≤22.0 mm), medium (>22.0 to <26.0 mm) and long (≥26.0 mm).ResultsThe study included 846 patients. Over the entire axial length range, the Kane formula had the lowest mean absolute prediction error (p<0.001, all formulas). The mean postoperative difference from intended outcome for the Kane formula was −0.14+0.27×1 (95% LCL −1.52+0.93×43; 95% UCL +0.54+1.03×149). The formula demonstrated the lowest absolute error in the medium axial length range (p<0.001). In the short and long axial length groups, no formula demonstrated a significantly lower absolute mean prediction error.ConclusionUsing three variables (AL, K, ACD), the Kane formula was a more accurate predictor of actual postoperative refraction than the other formulae under investigation. There were not enough eyes of short or long axial length to adequately power statistical comparisons within axial length subgroups.

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 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 Intraocular lens power calculation formulas accuracy in combined phacovitrectomy: an 8-formulas comparison study

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Diogo Hipólito-Fernandes ◽  
Maria Elisa Luís ◽  
Diogo Maleita ◽  
Pedro Gil ◽  
Vitor Maduro ◽  
...  
Keyword(s):  
Intraocular Lens ◽  
Prediction Error ◽  
Retrospective Chart Review ◽  
Absolute Error ◽  
Power Calculation ◽  
Myopic Shift ◽  
Iol Power ◽  
Group 3 ◽  
Group 2 ◽  
Group 1

Abstract Background Our study aimed to assess and compare the accuracy of 8 intraocular lens (IOL) power calculation formulas (Barrett Universal II, EVO 2.0, Haigis, Hoffer Q, Holladay 1, Kane and PEARL-DGS) in patients submitted to combined phacovitrectomy for vitreomacular (VM) interface disorders. Methods Retrospective chart review study including axial-length matched patients submitted to phacoemulsification alone (Group 1) and combined phacovitrectomy (Group 2). Using optimized constants in both groups, refraction prediction error of each formula was calculated for each eye. The optimised constants from Group 1 were also applied to patients of Group 2 – Group 3. Outcome measures included the mean prediction error (ME) and its standard deviation (SD), mean (MAE) and median (MedAE) absolute errors, in diopters (D), and the percentage of eyes within ± 0.25D, ± 0.50D and ± 1.00D. Results A total of 220 eyes were included (Group 1: 100; Group 2: 120). In Group 1, the difference in formulas absolute error was significative (p = 0.005). The Kane Formula had the lowest MAE (0.306) and MedAE (0.264). In Group 2, Kane had the overall best performance, followed by PEARL-DGS, EVO 2.0 and Barrett Universal II. The ME of all formulas in both Groups 1 and 2 were 0.000 (p = 0.934; p = 0.971, respectively). In Group 3, a statistically significant myopic shift was observed for each formula (p < 0.001). Conclusion Surgeons must be careful regarding IOL power selection in phacovitrectomy considering the systematic myopic shift evidenced—constant optimization may help eliminating such error. Moreover, newly introduced formulas and calculation methods may help us achieving increasingly better refractive outcomes both in cataract surgery alone and phacovitrectomy.

Project hyperopic power prediction: accuracy of 13 different concepts for intraocular lens calculation in short eyes

2021 ◽  
pp. bjophthalmol-2020-318272
Author(s):  
Jascha Wendelstein ◽  
Peter Hoffmann ◽  
Nino Hirnschall ◽  
Isaak Raphael Fischinger ◽  
Siegfried Mariacher ◽  
...  
Keyword(s):  
Intraocular Lens ◽  
Prediction Error ◽  
Case Series ◽  
Power Calculation ◽  
Power Prediction ◽  
Patient Cohort ◽  
Iol Power Calculation ◽  
Iol Power ◽  
Length Data ◽  
Axial Eye Length

PurposeTo evaluate the accuracy of intraocular lens (IOL) power calculation in a patient cohort with short axial eye length to assess the performance of IOL power calculation schemes in strong hyperopes.MethodologyThe study was a single centre, single surgeon retrospective consecutive case series at the Augen- und Laserklinik, Castrop-Rauxel, Germany. Inclusion of patients after uneventful cataract surgery implanting either spherical (SA60AT) or aspheric (ZCB00) IOLs. Inclusion criteria were axial eye length <21.5 mm and/or emmetropising IOL power >28.5 D. Lens constants were optimised on a separate patient cohort considering the full bandwidth of axial eye length. Data of one single eye per patient were randomly included. The outcome measures were: mean absolute prediction error (MAE), median absolute prediction error, mean prediction error with SD and median prediction error and the percentage of eyes with an MAE within 0.25 D, 0.5 D, 0.75 D and 1.0 D.ResultsA total of 150 eyes from 150 patients were assessed. Okulix, PEARL-DGS, Kane and Castrop provided a statistically significantly smaller MAE compared with the Hoffer Q and SRK/T formulae.ConclusionIn our patient cohort with short axial eye length, the use of PEARL-DGS, Okulix, Kane or Castrop formulae showed the lowest MAE. The Castrop formula has not been published before, but will be disclosed with a ready-to-use Excel sheet as an addendum to this paper.

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