Intraocular Lens Power Calculation Using IOLMaster and Various Formulas in Short Eyes
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Purpose: To evaluate the predictability of intraocular lens (IOL) power calculations using the IOLMaster and four different IOL power calculation formulas (Haigis, Hoffer Q, SRK II, and SRK/T) for cataract surgery in eyes with a short axial length (AL).Methods: The present study was a retrospective comparative analysis which included 25 eyes with an AL shorter than 22.0 mm that underwent uneventful phacoemulsification with IOL implantation from July 2007 to December 2008 at Seoul National University Boramae Hospital.Preoperative AL and keratometric power were measured by the IOLMaster, and power of the implanted IOL was determined using Haigis, Hoffer Q, SRK II, and SRK/T formulas.Postoperative refractive errors two months after surgery were measured using automatic refracto-keratometry (Nidek) and were compared with the predicted postoperative power.The mean absolute error (MAE) was defined as the average of the absolute value of the difference between actual and predicted spherical equivalences of postoperative refractive error.Results: The MAE was smallest with the Haigis formula (0.37 ± 0.26 diopter [D]), followed by those of SRK/T (0.53 ± 0.25 D), SRK II (0.56 ± 0.20 D), and Hoffer Q (0.62 ± 0.16 D) in 25 eyes with an AL shorter than 22.0 mm.The proportion with an absolute error (AE) of less than 1 D was greatest in the Haigis formula (96%), followed by those in the SRK II (88%), SRK-T (84%), and Hoffer Q (80%).Conclusions: The MAE was less than 0.7 D and the proportion of AE less than 1 D was more than 80% in all formulas.The IOL power calculation using the Haigis formula showed the best results for postoperative power prediction in short eyes.Keywords:
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Purpose: To evaluate the predictability of intraocular lens (IOL) power calculations using the IOLMaster and four different IOL power calculation formulas (Haigis, Hoffer Q, SRK II, and SRK/T) for cataract surgery in eyes with a short axial length (AL).Methods: The present study was a retrospective comparative analysis which included 25 eyes with an AL shorter than 22.0 mm that underwent uneventful phacoemulsification with IOL implantation from July 2007 to December 2008 at Seoul National University Boramae Hospital.Preoperative AL and keratometric power were measured by the IOLMaster, and power of the implanted IOL was determined using Haigis, Hoffer Q, SRK II, and SRK/T formulas.Postoperative refractive errors two months after surgery were measured using automatic refracto-keratometry (Nidek) and were compared with the predicted postoperative power.The mean absolute error (MAE) was defined as the average of the absolute value of the difference between actual and predicted spherical equivalences of postoperative refractive error.Results: The MAE was smallest with the Haigis formula (0.37 ± 0.26 diopter [D]), followed by those of SRK/T (0.53 ± 0.25 D), SRK II (0.56 ± 0.20 D), and Hoffer Q (0.62 ± 0.16 D) in 25 eyes with an AL shorter than 22.0 mm.The proportion with an absolute error (AE) of less than 1 D was greatest in the Haigis formula (96%), followed by those in the SRK II (88%), SRK-T (84%), and Hoffer Q (80%).Conclusions: The MAE was less than 0.7 D and the proportion of AE less than 1 D was more than 80% in all formulas.The IOL power calculation using the Haigis formula showed the best results for postoperative power prediction in short eyes.
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Purpose: To evaluate the stabilization time of astigmatism and refractive errors after cataract surgery using phacoemulsification and foldable lens implantation.Patients and Methods: The present cross-sectional study was carried out with convenience sampling method and included patients who underwent cataract surgery using phacoemulsification and implantation of foldable intraocular lens. The patients were evaluated and their data including age, sex, uncorrected visual acuity, best corrected visual acuity, corneal cylinder, cylinder axis, Sim K, and intra ocular pressure were recorded prior to the surgery as well as in days 2, 3, 4, weeks 1, 2, 5 and day 75 post surgery. Results: Eighty one eyes of 77 patients with mean age of 61.39 ± 10.9 years were evaluated. The mean follow up time was 60.5 ± 48.86 days. The mean keratometry before surgery was 44.90 ± 1.85 diopters, while the mean axial length, the mean intraocular pressure and the mean astigmatism were 23.15 ± 1.98 mm, 14.01 ± 2.95 mmHg and 0.99 ± 1.10 diopters, respectively. The mean postoperative keratometry at last visit was 45.34 ± 1.80 diopters, and the mean intraocular pressure and astigmatism were, 12.46 ± 2.87 mmHg and 1.14 ± 0.96 diopters, respectively. The mean time for refraction stabilization was 11.46 ± 11.40 days and the mean stabilization time for astigmatism was 10.18 ± 11.34 days.
Conclusion: In the present study the mean stabilization time for refraction and astigmatism after cataract surgery in an Iranian population using phacoemulsification and foldable lens implantation was comparable with previous studies.
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Abstract We aimed to compare refractive outcomes between total keratometry using a swept-source optical biometer and conventional keratometry in cataract surgery with refractive multifocal intraocular lens (IOL) implantation. We included patients who underwent cataract surgery with refractive multifocal IOL implantation. The IOL power was calculated using conventional formulas (Haigis, SRK/T, Holladay 2, and Barrett Universal II) as well as a new formula (Barrett TK Universal II). The refractive mean error, mean absolute error, and median absolute error were compared, as were the proportions of eyes within ± 0.25 diopters (D), ± 0.50 D, and ± 1.00 D of prediction error. In total 543 eyes of 543 patients, the absolute prediction error of total keratometry was significantly higher than that of conventional keratometry using the SRK/T ( P = 0.034) and Barrett Universal II ( P = 0.003). The proportion of eyes within ± 0.50 D of the prediction error using the SRK/T and Barrett Universal II was also significantly higher when using conventional keratometry than total keratometry ( P = 0.010 for SRK/T and P = 0.005 for Barrett Universal II). Prediction accuracy of conventional keratometry was higher than that of total keratometry in cataract surgery with refractive multifocal IOL implantation.
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To 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).A 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).The 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.Using 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.
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To analyze the results of phacoemulsification cataract surgery in eyes that had had refractive surgery and to compare the predictability of various methods of intraocular lens (IOL) power calculation.Instituto de la Visión, Buenos Aires, Argentina.The study involved 7 cases that had phacoemulsification after radial keratotomy or laser in situ keratomileusis. The spherical equivalent (SE) and visual acuity were evaluated preoperatively and postoperatively to assess the changes before cataract development. The IOL power calculated with conventional keratometry (CK), adjusted keratometry, the clinical history method (CHM), corneal topography (CT), and the contact lens method (CLM) was compared with the final refractive and keratometric results measured with the BackCalcs (Holladay(R) IOL Consultant Program, Holladay Consulting, Inc.) to assess the accuracy and predictability of each method.The mean SE was -4.82 diopters (D) +/- 5.13 (SD) before phacoemulsification and +0.19 +/- 1.01 D after phacoemulsification, and the mean best corrected visual acuity was 0.39 +/- 0.07 (20/50) and 0.80 +/- 0.06 (20/25), respectively.Post-phacoemulsification refraction in cases with previous refractive surgery appeared to be predictable when the appropriate calculation method was applied. When all the data were available, the CHM provided the best results. Adjusted keratometry and CT seemed to be more accurate than CK and the CLM.
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Abstract Purpose To evaluate if total keratometry (TK) is better than standard keratometry (K) for predicting an accurate intraocular lens (IOL) refractive outcome for cataract surgery in four IOL power calculation formulas. Methods 449 eyes that underwent monofocal intraocular lens implantation were enrolled in this study. IOLMaster 700 was used for optical biometry. Median absolute prediction error (MedAE), mean absolute error (MAE), median absolute prediction error (MedAE), proportions of eyes within ± 0.25 diopters (D), ± 0.50 D, ± 0.75 D, ± 1.00 D, ± 2.00 D adjusted prediction error, and formula performance index (FPI) were calculated for each K- and TK-based formula. Results Overall, the accuracy of each TK and K formula was comparable. The MAEs and MedAEs showed no difference between the K-based and the TK-based formula. The percent of eyes within ± 0.25 D for TK was not significantly different from that for K. The analysis of PE across various optical dimensions revealed that TK had no effect on the refractive results in eyes with different preoperative axial length, anterior chamber depth, keratometry, and lens thickness. K-based Barrett Universal II formula performed showed the leading FPI score and had the best refractive prediction outcomes among the four formulas. Conclusion In all investigated formulas, the predictive accuracy of TK-based formulas is not superior than that of standard K-based formulas. TK cannot substitute K for IOL power calculation in monofocal IOL implantation cataract surgery.
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To compare the accuracy of intraocular lens power prediction for eyes with average keratometry (K) readings greater than 46.00 diopters (D) and lower than 42.00 D.Ein-Tal Eye Center, Tel-Aviv, Israel.Retrospective case series.Eyes having cataract extraction surgery with steep and flat preoperative corneal curvatures determined with the Lenstar-LS900 device were enrolled. Refractive prediction errors for the Barrett Universal II, Haigis, Hill-RBF, Hoffer-Q, Holladay 1, Holladay 2, Olsen, and SRK/T formulas were compared. Optimized K values for the SRK/T formula were back-calculated for each group. Validation was performed using an additional dataset.The study comprised 171 eyes (79, K reading >46.00 D; 92, K reading <42.00 D). For K readings greater than 46.00 D, myopic errors were noted using the SRK/T and Hill-RBF formulas and hyperopic errors using the Olsen C-constant and Haigis (-0.31 D, -0.17 D, 0.18 D, and 0.17 D, respectively). The percentage of eyes with an absolute error within ±0.50 D from target refraction ranged from 60.8% (SRK/T) to 83.0% (Hill-RBF). For K readings lower than 42.00 D, myopic errors were seen using the Haigis, Hill-RBF, Hoffer-Q, and Olsen-C formulas (-0.31 D, -0.14 D, -0.22 D, and -0.17 D, respectively) and a hyperopic error using the SRK/T formula (0.16 D). The refractive prediction within ±0.50 D ranged between 75.0% (Haigis) and 96.7% (Barrett Universal II).Power calculation for eyes with flat corneas and steep corneas requires the use of specific formulas for accurate postoperative results. An adjustment method of the SRK/T formula is proposed.
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Abstract Purpose To evaluate if total keratometry (TK) is better than standard keratometry (K) for predicting an accurate intraocular lens (IOL) refractive outcome in virgin eyes using four IOL power calculation formulas. Methods 447 eyes that underwent monofocal intraocular lens implantation were enrolled in this study. IOLMaster 700 (Carl Zeiss Meditech, Jena, Germany) was used for optical biometry. Prediction error (PE), mean absolute prediction error (MAE), median absolute prediction error (MedAE), proportions of eyes within ± 0.25 diopters (D), ± 0.50 D, ± 0.75 D, ± 1.00 D, ± 2.00 D prediction error, and formula performance index (FPI) were calculated for each K- and TK-based formula. Results Overall, the accuracy of each TK and K formula was comparable. The MAEs and MedAEs showed no difference between most of the K-based and the TK-based formula; only the MAE of TK was significantly higher than that of K using the Haigis. The percent of eyes within ± 0.25 D PE for TK was not significantly different from that for K. The analysis of PE across various optical dimensions revealed that TK had no effect on the refractive results in eyes with different preoperative axial length, anterior chamber depth, keratometry, and lens thickness. The K-based Barrett Universal II formula performed excellently, showed the leading FPI score, and had the best refractive prediction outcomes among the four formulas. Conclusion TK and K can be used for IOL power calculation in monofocal IOL implantation cataract surgery in virgin eyes, as both are comparable. In all investigated formulas, the predictive accuracy of TK-based formulas is not superior to that of standard K-based formulas.
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