Accuracy of the Barrett True-K formula for intraocular lens power prediction after laser in situ keratomileusis or photorefractive keratectomy for myopia

Abulafia, Adi; Hill, Warren; Koch, Douglas D.; Wang, Li; Barrett, Graham D.

doi:10.1016/j.jcrs.2015.11.039

Cited by 148 publications

(133 citation statements)

References 20 publications

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“…With a similar population, Alfonso et al noted that 27% of eyes were >0.50D away from the target refraction; these eyes also had previous hyperopic LASIK and were implanted with the ReSTOR SN60D3 lens (Alcon Laboratories, Inc.). 12 Of note also is that Abulafia et al 5 who used the Barrett True-K formula in patients with previous myopic LASIK or photorefractive keratectomy noted that 67% were within AE0.50D from target refraction while 91% of eyes in the current study were within AE0.50D from target. Results in the current study are also better than reported in other studies using other calculation methods where the highest reported percent of eyes within AE0.5D was 84%.…”

Section: Discussionsupporting

confidence: 42%

“…noted that 27% of eyes were >0.50D away from the target refraction; these eyes also had previous hyperopic LASIK and were implanted with the ReSTOR SN60D3 lens (Alcon Laboratories, Inc.) . Of note also is that Abulafia et al . who used the Barrett True‐K formula in patients with previous myopic LASIK or photorefractive keratectomy noted that 67% were within ±0.50D from target refraction while 91% of eyes in the current study were within ±0.50D from target.…”

Section: Discussionmentioning

confidence: 46%

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Clinical outcomes with distance‐dominant multifocal and monofocal intraocular lenses in post‐LASIK cataract surgery planned using an intraoperative aberrometer

Fisher

Potvin²

2018

Clinical Exper Ophthalmology

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ImportanceStudies evaluating the clinical benefits of intraoperative aberrometry (IA) in cataract surgery are limited.BackgroundThe study was designed to determine whether IA improved clinical outcomes of post‐laser in situ keratomileusis (LASIK) cataract surgery with different intraocular lenses (IOLs) implanted.DesignA retrospective chart review of clinical outcomes from one surgeon at one surgical centre was conducted. It included post‐LASIK cataract surgeries where IA was used for the confirmation of IOL power, with either a distant‐dominant multifocal IOL or a monofocal IOL implanted.ParticipantsRecords for 44 eyes of 31 patients were analysed.MethodsDifferences in visual acuity (VA) and refractions by lens type were compared, and the effects of IA were evaluated.Main Outcome MeasuresUncorrected distance VA and the percentage of eyes with a spherical equivalent refraction within 0.5D of the intended correction were the primary outcome measures.ResultsThere was no statistically significant difference in the percentage of eyes with uncorrected distance VA of 20/25 or better between IOL groups (P = 0.41). More eyes in the multifocal group had a refraction within 0.50D of intended (P = 0.03). In 39% of cases, the preoperative and IA power calculations suggested the same IOL power. When not equal, the IA results were not significantly more likely to be ‘best’ (P = 0.08).Conclusions and RelevanceResults suggest that a history of previous LASIK is not a contraindication to use of distant‐dominant multifocal IOLs. IA did not appear to improve clinical outcomes in post‐LASIK eyes, although a positive trend was evident.

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Section: Discussionsupporting

confidence: 42%

Section: Discussionmentioning

confidence: 46%

Clinical outcomes with distance‐dominant multifocal and monofocal intraocular lenses in post‐LASIK cataract surgery planned using an intraoperative aberrometer

Fisher

Potvin²

2018

Clinical Exper Ophthalmology

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“…This relatively simple regression formula, originally developed for eyes with prior laser refractive photoablation, modifies the predicted IOL power by taking into account the surgically induced refractive change at the corneal plane 3 . The unpublished Barrett True K formula can be used with or without considering the surgically induced refractive change because it employs an internal regression formula to estimate the surgically induced change in manifest refraction when those data are unavailable 13 . Interestingly, in this sample of post-SMILE eyes, the accuracy of the Barrett True K formula was not clinically significantly deteriorated when preoperative refractive data were not entered but estimated (Barrett True K No History formula).…”

Section: Discussionmentioning

confidence: 99%

Intraocular Lens Power Calculation after Small Incision Lenticule Extraction

Luft

Schworm

Kreutzer

et al. 2020

Sci Rep

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With more than 1.5 million Small Incision Lenticule Extraction (SMILE) procedures having already been performed worldwide in an ageing population, intraocular lens (IOL) power calculation in post-SMILE eyes will inevitably become a common challenge for ophthalmologists. Since no refractive outcomes of cataract surgery following SMILE have been published, there is a lack of empirical data for optimizing IOL power calculation. Using the ray tracing as the standard of reference-a purely physical method that obviates the need for any empirical optimization-we analyzed the agreement of various IOL power calculation formulas derived from the American Society of Cataract and Refractive Surgeons (ASCRS) post-keratorefractive surgery online calculator. In our study of 88 post-SMILE eyes, the Masket formula showed the smallest mean prediction error [−0.36 ± 0.32 diopters (D)] and median absolute error (0.33D) and yielded the largest percentage of eyes within ±0.50D (70%) in reference to ray tracing. Non-inferior refractive prediction errors and ±0.50D accuracies were achieved by the Barrett True K, Barrett True K No History and the Potvin-Hill formula. Use of these formulas in conjunction with ray tracing is recommended until sufficient data for empirical optimization of IOL power calculation after SMILE is available.

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“…Wang et al [13] evaluated various IOL formulas from the American Society of Cataract and Refractive Society post-LASIK IOL calculator [24] and showed that formulas using no prior data and refractive change after LASIK were more accurate than the clinical history method. Abulafia et al [34] found that the Barrett True K No History formula had significantly smaller variance in prediction error than the Shammas formula and performed similar to the Haigis-L and Modified-Masket formulas. A meta-analysis by Chen et al [35] concluded that the clinical history method was significantly inaccurate in predicting postoperative refraction than the Haigis-L formula.…”

Section: Discussionmentioning

confidence: 99%

Visual Outcomes, Quality of Vision, and Quality of Life of Diffractive Multifocal Intraocular Lens Implantation after Myopic Laser In Situ Keratomileusis: A Prospective, Observational Case Series

Chang

Chan

et al. 2017

Journal of Ophthalmology

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Purpose. To report visual performance and quality of life after implantation of a bifocal diffractive multifocal intraocular lens (MIOL) in postmyopic laser in situ keratomileusis (LASIK) patients. Methods. Prospective, observational case series. Patients with prior myopic LASIK who had implantation of Tecnis ZMA00/ZMB00 MIOL (Abbott Medical Optics) at Hong Kong Sanatorium and Hospital were included. Postoperative examinations included monocular and binocular distance, intermediate and near visual acuity (VA), and contrast sensitivity; visual symptoms (0–5); satisfaction (1–5); spectacle independence rate; and quality of life. Results. Twenty-three patients (27 eyes) were included. No intraoperative complications developed. Mean monocular uncorrected VA at distance, intermediate, and near were 0.13 ± 0.15 (standard deviation), 0.22 ± 0.15, and 0.16 ± 0.15, respectively. Corresponding mean values for binocular uncorrected VA were 0.00 ± 0.10, 0.08 ± 0.13, and 0.13 ± 0.10, respectively. No eyes lost >1 line of corrected distance VA. Contrast sensitivity at different spatial frequencies between operated and unoperated eyes did not differ significantly (all P > 0.05). Mean score for halos, night glare, starbursts, and satisfaction were 1.46 ± 1.62, 1.85 ± 1.69, 0.78 ± 1.31, and 3.50 ± 1.02, respectively. Eighteen patients (78%) reported complete spectacle independence. Mean composite score of the quality-of-life questionnaire was 90.31 ± 8.50 out of 100. Conclusions. Implantation of the MIOL after myopic LASIK was safe and achieved good visual performance.

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Accuracy of the Barrett True-K formula for intraocular lens power prediction after laser in situ keratomileusis or photorefractive keratectomy for myopia

Abstract: The Barrett True-K formula was either equal to or better than alternative methods available on the ASCRS online calculator for predicting IOL power in eyes with previous myopic LASIK or PRK.

Cited by 148 publications

References 20 publications

Clinical outcomes with distance‐dominant multifocal and monofocal intraocular lenses in post‐LASIK cataract surgery planned using an intraoperative aberrometer

Clinical outcomes with distance‐dominant multifocal and monofocal intraocular lenses in post‐LASIK cataract surgery planned using an intraoperative aberrometer

Intraocular Lens Power Calculation after Small Incision Lenticule Extraction

Visual Outcomes, Quality of Vision, and Quality of Life of Diffractive Multifocal Intraocular Lens Implantation after Myopic Laser In Situ Keratomileusis: A Prospective, Observational Case Series

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