Cataract in the Adult Eye Preferred Practice Pattern

Purpose To assess the accuracy of 7 intraocular lens (IOL) power formulas (Barrett Universal II, Haigis, Hoffer Q, Holladay 1, Holladay 2, SRK/T, and T2) using IOLMaster biometry and optimized lens constants. Setting Public hospital ophthalmology department. Design Retrospective case series. Methods Data from patients having uneventful cataract surgery with Acrysof IQ SN60WF IOL implantation over 5 years were obtained from the biometry and patient charts. Optimized lens constants were calculated for each formula and used to determine the predicted refractive outcome 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 (AL) as follows: short (≤22.0 mm), medium (>22.0 to Results The study included 3241 patients. The Barrett Universal II formula had the lowest mean absolute prediction error over the entire AL range ( P P P P Conclusion In eyes with an AL longer than 22.0 mm, the Barrett Universal II formula was a more accurate predictor of actual postoperative refraction than the other formulas. Financial Disclosure None of the authors has a financial or proprietary interest in any material or method mentioned.

Intraocular lens power formula accuracy: Comparison of 7 formulas.

Protocols for studies of intraocular lens formula accuracy.

Purpose To evaluate and compare the accuracy of 2 toric intraocular lens (IOL) calculators with or without a new regression formula. Setting Ein-Tal Eye Center, Tel-Aviv, Israel, and the Lions Eye Institute, Nedlands, Western Australia, Australia. Design Retrospective case series. Methods A new regression formula (Abulafia-Koch) was developed to calculate the estimated total corneal astigmatism based on standard keratometry measurements. The error in the predicted residual astigmatism was calculated by the Alcon and Holladay toric IOL calculators with and without adjustments by the Abulafia-Koch formula. These results were compared with those of the Barrett toric calculator. Results Data from 78 eyes were evaluated to validate the Abulafia-Koch formula. The centroid errors in predicted residual astigmatism were against-the-rule with the Alcon (0.55 diopter [D]) and Holladay (0.54 D) toric calculators and decreased to 0.05 D ( P x -axis], P  = .776 [ y -axis]) and 0.04 D ( P x -axis], P  = .726 [ y -axis]) with adjustments by the Abulafia-Koch formula. The Alcon and the Holladay toric calculators had a higher proportion of eyes within ±0.50 D of the predicted residual astigmatism with the Abulafia-Koch formula (76.9% and 78.2%, respectively) than without it (both 30.8%). There were no significant differences between the results of the Abulafia-Koch-modified Alcon and the Holladay toric calculators and those of the Barrett toric calculator. Conclusion Adjustment of commercial toric IOL calculators by the Abulafia-Koch formula significantly improved the prediction of postoperative astigmatic outcome. Financial Disclosure Dr. Abulafia received a speaker's fee from Haag-Streit AG. Dr. Barrett has licensed the Barrett Toric Calculator to Haag-Streit AG. Dr. Koch is a consultant to Alcon Laboratories, Inc., Abbott Medical Optics, Inc., and Revision Optics, Inc. Dr. Hill is a paid consultant to Haag-Streit AG and Alcon Laboratories, Inc. None of the other authors has a financial or proprietary interest in any material or method mentioned.

New regression formula for toric intraocular lens calculations

Multifocal and Extended Depth-of-Focus Intraocular Lenses in 2020.

Purpose To evaluate and compare the accuracy of formulas and methods for calculating the intraocular lens (IOL) power for eyes with an axial length (AL) greater than 26.0 mm. Setting Ein-Tal Eye Center, Tel-Aviv, Israel. Design Retrospective case series. Methods The postoperative refraction results in myopic eyes with an AL over 26.0 mm were compared with the predicted refractions calculated using standard formulas (Holladay 1, SRK/T, Hoffer Q, and Haigis) with optical IOL constants, User Group for Laser Interference Biometry constants, and an AL-adjustment method and using new-generation formulas (Barrett Universal II, Holladay 2, and Olsen). Results In 76 (71.7%) of 106 eyes, the IOL was 6.0 diopters (D) or more (Group A) and in 30 eyes (28.3%) was less than 6.0 D (Group B). In Group A, the SRK/T, Hoffer Q, Haigis, Barrett Universal II, Holladay 2, and Olsen methods met the benchmark criteria of having a prediction error of ±0.5 D in at least 71.0% of eyes and ±1.0 D in 93.0% of eyes. In Group B, only the Barrett Universal II formula and the Holladay 1 and Haigis formulas using the AL-adjusted method met those criteria. Conclusion When selecting IOLs for high and extreme myopia, choosing appropriate formulas and methods can yield accurate refractive results that meet benchmark criteria. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Intraocular lens power calculation for eyes with an axial length greater than 26.0 mm: Comparison of formulas and methods

Purpose To evaluate and compare the accuracy of different methods to measure and predict postoperative astigmatism with toric intraocular lens (IOL) implantation. Setting Ein-Tal Ophthalmology Center, Tel-Aviv, Israel. Design Retrospective case series. Methods Postoperative corneal astigmatism was measured with 3 devices (IOLMaster 500; optical low-coherence reflectometry [OLCR]–based Lenstar LS 900; Atlas topographer) and compared with the manifest astigmatic refractive outcome in patients with toric IOLs. The error in the predicted residual astigmatism was calculated by vector analysis according to the measurement and calculation method used to predict the required toric IOL cylinder power. Results The centroid errors in predicted residual astigmatism were against the rule with the Alcon and Holladay toric calculators (0.53 to 0.56 diopter [D]), were lower with the Baylor nomogram (0.21 to 0.26 D), and were lowest for the Barrett toric calculator (0.01 to 0.16 D) ( P P Conclusion Prediction of astigmatic outcomes with toric IOLs can be improved with appropriate measuring devices and methods to establish the required toric IOL power. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Prediction of refractive outcomes with toric intraocular lens implantation.

Purpose To assess visual outcomes and patient satisfaction for trifocal and extended depth of focus (EDOF) intraocular lenses (IOLs) compared to monofocal IOLs with and without monovision. Methods Consecutive patients underwent bilateral cataract extraction surgery and implantation of either monofocal IOLs, monofocal IOLs using monovision, EDOF IOLs, or trifocal IOLs. Patients with preoperative biometric data, postoperative refraction, and visual acuity who completed a questionnaire regarding satisfaction and side effects were included. Visual outcome, spectacle independence, patient satisfaction, and subjective photic phenomena were assessed. Results Each group comprised 50 patients (100 eyes). The mean postoperative uncorrected distance, intermediate, and near visual acuities (logMAR) were: 0.17 ± 0.14 (Snellen 20/30), not applicable, and not applicable for monofocal; 0.08 ± 0.12 (Snellen 20/24), not applicable, and 0.07 ± 0.12 (Snellen 20/23) for monovision; 0.03 ± 0.08 (Snellen 20/21), 0.08 ± 0.12 (Snellen 20/24), and 0.23 ± 0.17 (Snellen 20/34) for EDOF; 0.07 ± 0.09 (Snellen 20/23), 0.08 ± 0.11 (Snellen 20/24), and 0.02 ± 0.06 (Snellen 20/21) for trifocal. Spectacle independence was reported by 36%, 70%, 74%, and 92% of patients, respectively. Postoperative halos and/or glare were experienced by 2%, 6%, 14%, and 38%, respectively, of which 2%, 0%, 6%, and 10%, respectively, were functionally disturbing. A total of 64%, 72%, 78%, and 76%, respectively, would choose the same IOL again. Conclusions Patient satisfaction rates were high in all groups. Trifocal IOLs were more effective in improving unaided whole range of vision, but were associated with a higher rate of photic phenomena. The EDOF IOL and monovision provided partial spectacle independence with less photic phenomena. [J Refract Surg. 2019;35(7):434-440.].

Visual Outcomes and Patient Satisfaction for Trifocal, Extended Depth of Focus and Monofocal Intraocular Lenses.

Background

To evaluate the accuracy of predicted refraction using multifocal intraocular lenses (IOLs) with power calculation based on two biometric devices and multiple IOL power calculation formulas.



Design

A retrospective study conducted in a private practice ophthalmology clinic.



Participants

Seventy-three eyes of 48 patients were evaluated.



Methods

Consecutive cases of eyes that had undergone successful cataract surgery with an implantation of a multifocal IOL (SN6AD1, Alcon Laboratories, Inc., Fort Worth, TX, USA) by a single surgeon were enrolled. Patients were meticulously screened for suitability for a multifocal IOL implantation according to our clinic guidelines. Two biometric measurement devices (IOLMaster-500 [Carl Zeiss Meditec AG, Jena, Germany] and Lenstar-LS900 [Haag-Streit AG, Koeniz, Switzerland]) were used under strict validation criteria to evaluate the predicted refraction errors for the Holladay 1, SRK/T, Hoffer Q, Haigis, Holladay 2, Barrett Universal II and Olsen formulas.



Main Outcome Measures

Predicted refractive sphere equivalent (RSE) errors.



Results

The measurements obtained from the two biometric devices were highly correlated. The standard deviation of the error in predicted RSE and the median absolute error were similar for the IOLMaster and the Lenstar devices using all formulas, ranging from 0.27 dioptres (D) to 0.31D and from 0.15D to 0.21D, respectively. A high percentage of eyes had an error in predicted RSE within ±0.5D from target refraction, ranging from 86.3% to 93.2%.



Conclusions

High accuracy can be achieved in multifocal IOL power calculations by appropriate patient selection, precise biometry and appropriate IOL calculation formulas.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/ceo.12478

Accuracy of predicted refraction with multifocal intraocular lenses using two biometry measurement devices and multiple intraocular lens power calculation formulas

To compare ocular measurements of three optical biometry devices and their application in intraocular lens (IOL) power calculations. One hundred and forty eyes which had undergone cataract extraction surgery with preoperative biometry with OA­-2000, IOLMaster-500, and Lenstar-LS900 were enrolled. Biometry measurements of the three devices were compared. The deviation of the postoperative refraction from the preoperative refractive target was calculated with different formulas (Barrett Universal II, Hoffer Q, Holladay I, and SRK/T). Errors in the predicted astigmatism using the Barrett toric calculator were calculated for the toric IOLs. Additional 6465 eyes in which the IOLMaster-500 failed to measure axial length (AL) were reviewed. The percentage of successful measurements using the OA-2000 in those eyes was calculated. High agreement was found between the three devices for AL, anterior chamber depth, and average keratometry measurements (interclass correlation confidents: 1.000, 0.970, and 0.998, respectively, P < 0.001). The mean absolute prediction errors were similar using all formulas, ranging from 0.25 to 0.29 D, with no statistical significant difference between the three devices per each formula. The OA-2000 yielded a lower against-the-rule (ATR) centroid error in the predicted astigmatism than the IOLMaster-500 and Lenstar-LS900 (0.06 D ± 0.59 at 13.4° vs. 0.20 D ± 0.61 at 14.8° and 0.16 D ± 0.55 at 21.4°, respectively, P < 0.001, X-axis). Among 301 cases with unsuccessful AL readings using the IOLMaster-500, the OA-2000 had 284 (94.35%) successful measurements. The OA-2000 measurements showed good agreement with those of the IOLMaster-500 and Lenstar-LS900. Our results may suggest a potential advantage of the OA-2000 device in toric IOLs calculations and AL measurement success rate.

/pdf/accuracy-of-intraocular-lens-power-calculation-using-three-1e2w0rdw8u.pdf

Adi Levy

Papers

Intraocular lens power calculation for eyes with an axial length greater than 26.0 mm: Comparison of formulas and methods

Prediction of refractive outcomes with toric intraocular lens implantation.

Visual Outcomes and Patient Satisfaction for Trifocal, Extended Depth of Focus and Monofocal Intraocular Lenses.

Accuracy of predicted refraction with multifocal intraocular lenses using two biometry measurement devices and multiple intraocular lens power calculation formulas

Accuracy of intraocular lens power calculation using three optical biometry measurement devices: the OA-2000, Lenstar-LS900 and IOLMaster-500.