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Geggel HS. Intraocular Lens Power Selection after Radial Keratotomy: Topography, Manual, and IOLMaster Keratometry Results Using Haigis Formulas. Ophthalmology 2015; 122:897-902. [PMID: 25601534 DOI: 10.1016/j.ophtha.2014.12.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 12/02/2014] [Accepted: 12/03/2014] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To compare final spherical equivalent (SE) refractions in patients who previously underwent radial keratotomy (RK) undergoing routine cataract surgery using keratometry (K) values from the Tomey (Topographic Modeling System [TMS]; Tomey Corp., Phoenix, AZ) Placido topographer, manual keratometer, and IOLMaster (Carl Zeiss Meditec AG, Jena, Germany) keratometer using the Haigis formulas. DESIGN Retrospective case series. SUBJECTS A total of 26 RK eyes (20 patients) with a minimum of 3 months postoperative follow-up. METHODS The following K values were evaluated: TMS topography (flattest K within first 9 rings, average K, minimum K), manual K, IOLMaster K. The final refractive goal was -0.50 diopters (D) for all eyes. The Haigis formula with target refraction -0.50 D was used. In addition, because of observed hyperopic overcorrections, IOLMaster K with the Haigis formula set to -1.00 D but with a final refractive goal of -0.50 D was also tested. The Haigis-L formula using IOLMaster K values was separately evaluated. MAIN OUTCOME MEASURES Mean final SE refraction, percent final SE within ideal (-0.12 to -1.00 D), acceptable (0.25 to -1.50 D), or unacceptable (<-1.50 or >0.25 D) range and within ±0.50 D and ±1.00 D of the intended result. RESULTS Best results with minimal overcorrections were achieved with TMS flattest K (mean -0.68±0.60 D, 73% within ±0.50 D, and 88% within ±1.00 D of the surgical goal) and IOLMaster K set for target -1.00 D (mean -0.66±0.61 D, 69% within ±0.50 D, and 88% within ±1.00 D of the surgical goal). Other values produced more hyperopic (manual, IOLMaster K set for target -0.50 D, average topography) or higher myopic (minimum topography, Haigis-L) results. CONCLUSIONS For simplicity, using the IOLMaster K values combined with the Haigis formula set for target refraction -1.00 D produces acceptable results aiming for -0.50 D final SE refractions in former RK patients undergoing routine cataract surgery.
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Lanza M, Iaccarino S, Cennamo M, Lanza A, Coen G. New Scheimpflug camera device in measuring corneal power changes after myopic laser refractive surgery. Cont Lens Anterior Eye 2014; 38:115-9. [PMID: 25554500 DOI: 10.1016/j.clae.2014.12.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Revised: 12/06/2014] [Accepted: 12/06/2014] [Indexed: 10/24/2022]
Abstract
PURPOSE To assess the accuracy of a combined Scheimpflug camera-Placido disk device (Sirius, CSO, Italy) in evaluating corneal power changes after myopic photorefractive keratectomy (PRK). METHODS Two hundred and thirty-seven eyes of 237 patients that underwent myopic PRK with a refractive error, measured as spherical equivalent, ranging from -10.75 D to -0.5D (mean -4.63 ± 2.21D), were enrolled in this study. Corneal power evaluation using Sirius were performed before, 1, 3 and 6 months after myopic PRK. Mean simulated keratometry (SimK) and mean pupil power (MPP) were measured. Correlations between changes in corneal power, measured with SimK and MPP, and variations in subjective refraction, calculated at corneal plane, were evaluated using Pearson test at every follow up; differences between preoperative and postoperative data were evaluated with the Student paired t-test. RESULTS A good correlation has been detected between the variations in subjective refraction measured at corneal plane 1, 3 and 6 months after myopic PRK and both SimK (R(2) = 0.8463; R(2) = 0.8643; R(2) = 0.7102, respectively) and MPP (R(2) = 0.6622; R(2) = 0.5561; R(2) = 0.5522, respectively) but corneal power changes are statistically undervalued for both parameters (p < 0.001). CONCLUSIONS Even if our data should be confirmed in further studies, SimK and MPP provided by this new device do not seem to accurately reflect the changes in corneal power after myopic PRK.
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Affiliation(s)
- Michele Lanza
- Multidisciplinary Department of Medical, Surgical and Dental Sciences, Seconda Università di Napoli, Napoli, Italy; Centro Grandi Apparecchiature, Seconda Università di Napoli, Napoli, Italy.
| | - Stefania Iaccarino
- Centro Grandi Apparecchiature, Seconda Università di Napoli, Napoli, Italy
| | - Michela Cennamo
- Centro Grandi Apparecchiature, Seconda Università di Napoli, Napoli, Italy
| | - Alessandro Lanza
- Multidisciplinary Department of Medical, Surgical and Dental Sciences, Seconda Università di Napoli, Napoli, Italy
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McNabb RP, Farsiu S, Stinnett SS, Izatt JA, Kuo AN. Optical coherence tomography accurately measures corneal power change from laser refractive surgery. Ophthalmology 2014; 122:677-86. [PMID: 25487424 DOI: 10.1016/j.ophtha.2014.10.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 08/22/2014] [Accepted: 10/06/2014] [Indexed: 11/28/2022] Open
Abstract
PURPOSE To determine the ability of motion-corrected optical coherence tomography (OCT) to measure the corneal refractive power change due to LASIK. DESIGN Evaluation of a diagnostic test or technology in a cohort. SUBJECTS A total of 70 eyes from 37 subjects undergoing LASIK were measured preoperatively. A total of 39 eyes from 22 subjects were measured postoperatively and completed the study. METHODS Consecutive patients undergoing LASIK at the Duke Eye Center who consented to participate were imaged with Placido-ring topography, Scheimpflug photography, and OCT on the day of their surgery. Patients were then reimaged with the same imaging systems at the postoperative month 3 visit. Change in preoperative to postoperative corneal refractive power as measured by each of the imaging modalities was compared with the preoperative to postoperative change in manifest refraction (MRx) using the t test with generalized estimating equations. MAIN OUTCOME MEASURES Corneal refractive power change due to LASIK as measured by Placido-ring topography, Scheimpflug photography, and OCT compared with the MRx change vertexed to the corneal plane. The change in MRx should correspond to the change in the corneal refractive power from LASIK and was considered the reference measurement. RESULTS In 22 individuals (39 eyes) returning after LASIK, we found no significant difference between the clinically measured pre- to post-LASIK change in MRx and both Scheimpflug photography (P = 0.714) and OCT (P = 0.216). In contrast, keratometry values from Placido-ring topography were found to be significantly different from the measured refractive change (P < 0.001). In addition, of the 3 imaging modalities, OCT recorded the smallest mean absolute difference from the reference measurement with the least amount of variability. CONCLUSIONS Motion-corrected OCT more accurately measures the change in corneal refractive power due to laser refractive surgery than other currently available clinical devices. By offering accurate corneal refractive power measurements in normal and surgically modified subjects, OCT offers a compelling alternative to current clinical devices for determining corneal refractive power.
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Affiliation(s)
- Ryan P McNabb
- Department of Biomedical Engineering, Duke University, Durham, North Carolina; Department of Ophthalmology, Duke University, Durham, North Carolina.
| | - Sina Farsiu
- Department of Biomedical Engineering, Duke University, Durham, North Carolina; Department of Ophthalmology, Duke University, Durham, North Carolina
| | - Sandra S Stinnett
- Department of Ophthalmology, Duke University, Durham, North Carolina; Department of Biostatistics and Bioinformatics, Duke University, Durham, North Carolina
| | - Joseph A Izatt
- Department of Biomedical Engineering, Duke University, Durham, North Carolina; Department of Ophthalmology, Duke University, Durham, North Carolina
| | - Anthony N Kuo
- Department of Ophthalmology, Duke University, Durham, North Carolina
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Abstract
PURPOSE After corneal refractive surgery, there is an overestimation of the corneal power with the devices routinely used to measure it. Therefore, the objective of this study was to determine whether, in patients who underwent photorefractive keratectomy (PRK), it is possible to predict the earlier preoperative anterior corneal power from the postoperative (PO) posterior corneal power. A comparison is made using a formula published by Saiki for laser in situ keratomileusis patients and a new one calculated specifically from PRK patients. METHODS The Saiki formula was tested in 98 eyes of 98 patients (47 women) who underwent PRK for myopia or myopic astigmatism. Moreover, anterior and posterior mean keratometry (Km) values from a Scheimpflug camera were measured to obtain a specific regression formula. RESULTS The mean (±SD) preoperative Km was 43.50 (±1.39) diopters (D) (range, 39.25 to 47.05 D). The mean (±SD) Km value calculated with the Saiki formula using the 6 months PO posterior Km was 42.94 (±1.19) D (range, 40.34 to 45.98 D) with a statistically significant difference (p < 0.001). Six months after PRK in our patients, the posterior Km was correlated with the anterior preoperative one by the following regression formula: y = -4.9707x + 12.457 (R² = 0.7656), where x is PO posterior Km and y is preoperative anterior Km, similar to the one calculated by Saiki. CONCLUSIONS Care should be taken in using the Saiki formula to calculate the preoperative Km in patients who underwent PRK.
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Bialer OY, Kaiserman I, Bahar I. Accuracy of Scheimpflug Holladay equivalent keratometry readings after corneal refractive surgery in the absence of clinical history. Ophthalmic Res 2014; 52:217-23. [PMID: 25402842 DOI: 10.1159/000363140] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 04/18/2014] [Indexed: 11/19/2022]
Abstract
BACKGROUND AND OBJECTIVE To identify the most accurate combination of Pentacam's equivalent keratometry readings (EKR) and intraocular lens power formula when the clinical history is unavailable. PATIENTS AND METHODS A total of 18 patients underwent cataract surgery after refractive surgery. The Pentacam 4.5- and 3.0-mm EKR were combined with the SRK II, SRK/T, Hoffer-Q, and Holladay I and II formulas. RESULTS The smallest deviation from the predicted value was achieved by combining the 4.5 EKR with the Holladay II formula (mean arithmetic deviation, -0.2 ± 0.4 dpt). CONCLUSION The 4.5-mm EKR + Holladay II formula can accurately calculate intraocular lens power in patients with previous refractive surgery.
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Affiliation(s)
- Omer Y Bialer
- Department of Ophthalmology, Rabin Medical Center, Petach Tikva, Israel
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De Bernardo M, Capasso L, Caliendo L, Paolercio F, Rosa N. IOL power calculation after corneal refractive surgery. BIOMED RESEARCH INTERNATIONAL 2014; 2014:658350. [PMID: 25136609 PMCID: PMC4129218 DOI: 10.1155/2014/658350] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 07/03/2014] [Indexed: 11/17/2022]
Abstract
PURPOSE To describe the different formulas that try to overcome the problem of calculating the intraocular lens (IOL) power in patients that underwent corneal refractive surgery (CRS). METHODS A Pubmed literature search review of all published articles, on keyword associated with IOL power calculation and corneal refractive surgery, as well as the reference lists of retrieved articles, was performed. RESULTS A total of 33 peer reviewed articles dealing with methods that try to overcome the problem of calculating the IOL power in patients that underwent CRS were found. According to the information needed to try to overcome this problem, the methods were divided in two main categories: 18 methods were based on the knowledge of the patient clinical history and 15 methods that do not require such knowledge. The first group was further divided into five subgroups based on the parameters needed to make such calculation. CONCLUSION In the light of our findings, to avoid postoperative nasty surprises, we suggest using only those methods that have shown good results in a large number of patients, possibly by averaging the results obtained with these methods.
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Affiliation(s)
- Maddalena De Bernardo
- Department of Medicine and Surgery, University of Salerno, Via Salvatore Allende1, Baronissi, 84081 Salerno, Italy
| | - Luigi Capasso
- U.O.C. Corneal Transplant Unit, Pellegrini Hospital, 80100 Naples, Italy
| | - Luisa Caliendo
- Department of Medicine and Surgery, University of Salerno, Via Salvatore Allende1, Baronissi, 84081 Salerno, Italy
| | - Francesco Paolercio
- U.O.C. Eye Day Surgery, De Luca e Rossano Hospital, 80069 Vico Equense, Italy
| | - Nicola Rosa
- Department of Medicine and Surgery, University of Salerno, Via Salvatore Allende1, Baronissi, 84081 Salerno, Italy
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Savini G, Calossi A, Camellin M, Carones F, Fantozzi M, Hoffer KJ. Corneal ray tracing versus simulated keratometry for estimating corneal power changes after excimer laser surgery. J Cataract Refract Surg 2014; 40:1109-15. [PMID: 24874768 DOI: 10.1016/j.jcrs.2013.11.032] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2013] [Revised: 10/25/2013] [Accepted: 11/01/2013] [Indexed: 11/19/2022]
Abstract
PURPOSE To evaluate whether the refractive changes induced by excimer laser surgery can be accurately measured by corneal ray tracing performed by a combined rotating Scheimpflug camera-Placido-disk corneal topographer (Sirius). SETTING Private practices. DESIGN Evaluation of diagnostic test. METHODS This multicenter retrospective study comprised patients who had myopic or hyperopic excimer laser refractive surgery. Preoperatively and postoperatively, 2 corneal power measurements--simulated keratometry (K) and mean pupil power--were obtained. The mean pupil power was the corneal power calculated over the entrance pupil by ray tracing through the anterior and posterior corneal surfaces using Snell's law. Agreement between the refractive and corneal power change was analyzed according to Bland and Altman. Regression analysis and Bland-Altman plots were used to evaluate agreement between measurements. RESULTS The study evaluated 72 eyes (54 patients). The difference between the postoperative and preoperative simulated K values underestimated the refractive change after myopic correction and overestimated it after hyperopic correction. Agreement between simulated K changes and refractive changes was poor, especially for higher amounts of correction. A proportional bias was detected (r = -0.77; P<.0001), and the 95% limits of agreement (LoA) were -0.15 -0.14 × ±0.62 diopters (D). The difference between the postoperative and preoperative mean pupil power showed an excellent correlation with the refractive change (r(2) = 0.98). The mean pupil power did not overestimate or underestimate the refractive change. The 95% LoA ranged between -0.97 D and +0.56 D. CONCLUSION Corneal ray tracing accurately measured corneal power changes after excimer laser refractive surgery. FINANCIAL DISCLOSURES Dr. Calossi is consultant to Costruzione Strumenti Oftalmici. Dr. Carones is consultant to Wavelight Laser Technologie AG. No other author has a financial or proprietary interest in any material or method mentioned.
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Affiliation(s)
- Giacomo Savini
- From the Studio Oculistico d'Azeglio (Savini), Bologna, the Department of Physics (Optics and Optometry) (Calossi), University of Florence, Florence, Sekal Microchirurgia Rovigo (Camelin), Rovigo, Carones Ophthalmology Center (Carones), Milan, and Studio Oculistico Fantozzi (Fantozzi), Pescia, Italy; the School of Optometry and Ophthalmology and Eye Hospital (Savini), Wenzhou Medical University, Wenzhou, Zhejiang, China; the Department of Ophthalmology (Hoffer), University of California, Los Angeles, and St. Mary's Eye Center, Santa Monica, California, USA.
| | - Antonio Calossi
- From the Studio Oculistico d'Azeglio (Savini), Bologna, the Department of Physics (Optics and Optometry) (Calossi), University of Florence, Florence, Sekal Microchirurgia Rovigo (Camelin), Rovigo, Carones Ophthalmology Center (Carones), Milan, and Studio Oculistico Fantozzi (Fantozzi), Pescia, Italy; the School of Optometry and Ophthalmology and Eye Hospital (Savini), Wenzhou Medical University, Wenzhou, Zhejiang, China; the Department of Ophthalmology (Hoffer), University of California, Los Angeles, and St. Mary's Eye Center, Santa Monica, California, USA
| | - Massimo Camellin
- From the Studio Oculistico d'Azeglio (Savini), Bologna, the Department of Physics (Optics and Optometry) (Calossi), University of Florence, Florence, Sekal Microchirurgia Rovigo (Camelin), Rovigo, Carones Ophthalmology Center (Carones), Milan, and Studio Oculistico Fantozzi (Fantozzi), Pescia, Italy; the School of Optometry and Ophthalmology and Eye Hospital (Savini), Wenzhou Medical University, Wenzhou, Zhejiang, China; the Department of Ophthalmology (Hoffer), University of California, Los Angeles, and St. Mary's Eye Center, Santa Monica, California, USA
| | - Francesco Carones
- From the Studio Oculistico d'Azeglio (Savini), Bologna, the Department of Physics (Optics and Optometry) (Calossi), University of Florence, Florence, Sekal Microchirurgia Rovigo (Camelin), Rovigo, Carones Ophthalmology Center (Carones), Milan, and Studio Oculistico Fantozzi (Fantozzi), Pescia, Italy; the School of Optometry and Ophthalmology and Eye Hospital (Savini), Wenzhou Medical University, Wenzhou, Zhejiang, China; the Department of Ophthalmology (Hoffer), University of California, Los Angeles, and St. Mary's Eye Center, Santa Monica, California, USA
| | - Marco Fantozzi
- From the Studio Oculistico d'Azeglio (Savini), Bologna, the Department of Physics (Optics and Optometry) (Calossi), University of Florence, Florence, Sekal Microchirurgia Rovigo (Camelin), Rovigo, Carones Ophthalmology Center (Carones), Milan, and Studio Oculistico Fantozzi (Fantozzi), Pescia, Italy; the School of Optometry and Ophthalmology and Eye Hospital (Savini), Wenzhou Medical University, Wenzhou, Zhejiang, China; the Department of Ophthalmology (Hoffer), University of California, Los Angeles, and St. Mary's Eye Center, Santa Monica, California, USA
| | - Kenneth J Hoffer
- From the Studio Oculistico d'Azeglio (Savini), Bologna, the Department of Physics (Optics and Optometry) (Calossi), University of Florence, Florence, Sekal Microchirurgia Rovigo (Camelin), Rovigo, Carones Ophthalmology Center (Carones), Milan, and Studio Oculistico Fantozzi (Fantozzi), Pescia, Italy; the School of Optometry and Ophthalmology and Eye Hospital (Savini), Wenzhou Medical University, Wenzhou, Zhejiang, China; the Department of Ophthalmology (Hoffer), University of California, Los Angeles, and St. Mary's Eye Center, Santa Monica, California, USA
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108
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Ray tracing software for intraocular lens power calculation after corneal excimer laser surgery. Jpn J Ophthalmol 2014; 58:276-81. [DOI: 10.1007/s10384-014-0304-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 11/29/2013] [Indexed: 10/25/2022]
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109
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Xu K, Hao Y, Qi H. Intraocular lens power calculations using a Scheimpflug camera to measure corneal power. Biotech Histochem 2013; 89:348-54. [DOI: 10.3109/10520295.2013.867532] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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110
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Algorithm for Correcting the Keratometric Error in the Estimation of the Corneal Power in Eyes With Previous Myopic Laser Refractive Surgery. Cornea 2013; 32:1454-9. [DOI: 10.1097/ico.0b013e31829e1eb5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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111
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Kim EC, Cho K, Hwang HS, Hwang KY, Kim MS. Intraocular lens prediction accuracy after corneal refractive surgery using K values from 3 devices. J Cataract Refract Surg 2013; 39:1640-6. [DOI: 10.1016/j.jcrs.2013.04.045] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 04/08/2013] [Accepted: 04/18/2013] [Indexed: 11/26/2022]
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Shammas HJ, Shammas MC, Hill WE. Intraocular lens power calculation in eyes with previous hyperopic laser in situ keratomileusis. J Cataract Refract Surg 2013; 39:739-44. [PMID: 23608568 DOI: 10.1016/j.jcrs.2012.11.031] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 11/05/2012] [Accepted: 11/28/2012] [Indexed: 11/26/2022]
Abstract
PURPOSE To establish a corneal correction equation for the Shammas post-hyperopic laser in situ keratomileusis (LASIK) (Shammas-PHL) formula and to evaluate its accuracy in cases with and without available pre-LASIK data. SETTING Private practices, Lynwood, California, and Mesa, Arizona, USA. DESIGN Retrospective comparative observational study. METHODS The corrected corneal power (Kc) was calculated in each eye by adding the refractive change at the corneal level to the pre-LASIK keratometric (K) readings. By comparing Kc with the measured post-LASIK K readings (Kpost), the following equation was derived: Kc = 1.0457 Kpost-1.9538. This equation was combined with the Shammas original formula to obtain the Shammas-PHL formula. RESULTS The new formula was evaluated in 18 eyes with previous LASIK data and in 24 eyes with no previous LASIK data. Using the Shammas-PHL formula, the mean arithmetic prediction error was -0.03 diopter (D) ± 0.72 (SD) (range -1.57 to +1.54 D) and the median absolute error was 0.38 D in 18 eyes with available pre-LASIK data and 0.05 ± 0.58 D (range -0.56 to +1.40 D) and 0.43 D, respectively, in the 24 eyes with no pre-LASIK data. CONCLUSION The Shammas-PHL formula can be used in post-hyperopic LASIK cases whether or not the pre-LASIK data are available.
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Affiliation(s)
- H John Shammas
- Department of Ophthalmology, the Keck School of Medicine of the University of Southern California, Los Angeles, California, USA.
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113
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Awwad ST, Kilby A, Bowman RW, Verity SM, Cavanagh HD, Pessach Y, McCulley JP. The accuracy of the double-K adjustment for third-generation intraocular lens calculation formulas in previous keratorefractive surgery eyes. Eye Contact Lens 2013; 39:220-7. [PMID: 23584043 DOI: 10.1097/icl.0b013e31828af126] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To evaluate the effect of the double-K (DK) modification on third-generation formulas. METHODS Thirty-eight previously myopic and 24 previously hyperopic eyes that underwent phacoemulsification with intraocular lens (IOL) insertion after Laser in situ keratomileusis (LASIK) were evaluated. Pre-LASIK refraction and keratometry, post-LASIK topography, axial length (AL), IOL type and power, and 1-month postphacoemulsification refraction were recorded spherical equivalent after phacoemulsification (SE(postphaco)). Measured corneal power was adjusted using published and validated methods for postmyopic and posthyperopic LASIK. For each eye, and using SE(postphaco), different DK-IOL formulas were used to calculate the corresponding IOL power, the outcome measure, which was compared with the implanted IOL. RESULTS DK-Holladay 1 yielded the highest Pearson correlation coefficient (PCC), 0.955 for myopes and 0.943 for high myopes (AL>26 mm). Mean error (ME) and mean absolute error (MAE) for myopes for DK Sanders-Retzlaff-Kraff theoretical formula [DK-SRK/T] were 0.44±0.84 D and 0.75±0.61 D for DK-SRK/T compared with -0.04±0.67 D and 0.52±0.40 D for DK-Holladay 1 (P<0.001 and P=0.016, respectively), and 0.03±0.88 and 0.64±0.58 for DK-Hoffer Q. For high myopes, ME and MAE were 0.75±0.81 D and 0.84±0.69 D for DK-SRK/T, and -0.05±0.74 D (P<0.0001) and 0.57±0.45 D (P=0.019) for DK-Holladay 1. About 29% of DK-SRK/T eyes with large AL had MAE>1.5 D, compared with 0% for DK-Holladay 1 and 14% for DK-Hoffer-Q. Eyes with previous hyperopic LASIK faired similarly for all formulas, with similar PCCs, and only 8% in each category with MAE>1.5 D. CONCLUSIONS DK-SRK/T overestimates IOL power in eyes with large AL, especially with concomitant steep pre-lasik keratometry. Among third-generation formulas, DK-Holladay 1 seems more accurate to use in postmyopic LASIK eyes.
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Affiliation(s)
- Shady T Awwad
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9057, USA
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114
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Comparison of intraocular lens power calculation methods after myopic laser refractive surgery without previous refractive surgery data. J Cataract Refract Surg 2013; 39:1327-35. [DOI: 10.1016/j.jcrs.2013.03.032] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Revised: 02/20/2013] [Accepted: 03/08/2013] [Indexed: 11/17/2022]
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Galvis V, Tello A, Niño C, Camacho PA. Intraocular lens power calculation after photorefractive surgery: modified double-K method. J Cataract Refract Surg 2013; 39:1450-1. [PMID: 23988254 DOI: 10.1016/j.jcrs.2013.07.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Indexed: 11/19/2022]
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116
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Savini G, Ducoli P, Hoffer KJ. Intraocular lens power calculation with the Scheimpflug camera after refractive surgery. J Cataract Refract Surg 2013; 39:1280. [PMID: 23889878 DOI: 10.1016/j.jcrs.2013.05.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Indexed: 11/19/2022]
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118
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Canto AP, Chhadva P, Cabot F, Galor A, Yoo SH, Vaddavalli PK, Culbertson WW. Comparison of IOL Power Calculation Methods and Intraoperative Wavefront Aberrometer in Eyes After Refractive Surgery. J Refract Surg 2013; 29:484-9. [DOI: 10.3928/1081597x-20130617-07] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Accepted: 03/19/2013] [Indexed: 11/20/2022]
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Abstract
PURPOSE OF REVIEW Since its introduction in the 1980s, more than 40 million people worldwide have undergone some form of kerato-refractive surgery. Many of these individuals are now candidates for cataract surgery and pose the challenge of attaining first-rate refractive outcomes in nonvirgin eyes. Numerous approaches have been developed to estimate intraocular lens (IOL) power in eyes postrefractive surgery. This review highlights the most practical, relevant options for accurate IOL power determination in these cases. RECENT FINDINGS With refined techniques and advances in instrumentation, more accurate assessments of true corneal power and thus, IOL power, are possible in postrefractive eyes. Optical coherence tomography and other corneal tomography instruments have markedly improved accuracy in this process. However, when expensive, modern equipments are not readily available, and online IOL calculators such as the American Society of Cataract and Refractive Surgery (ASCRS) calculator have become efficient, reliable options. Recent evidence confirms the accuracy of these online calculators. SUMMARY Emerging literature supports the use of methods that do not rely on prior refractive data in IOL power determination. Online IOL calculators provide user-friendly, efficient options that greatly facilitate accurate IOL power determination for cataract surgery in eyes that have undergone prior kerato-refractive surgery.
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Saiki M, Negishi K, Kato N, Ogino R, Arai H, Toda I, Dogru M, Tsubota K. Modified double-K method for intraocular lens power calculation after excimer laser corneal refractive surgery. J Cataract Refract Surg 2013; 39:556-62. [DOI: 10.1016/j.jcrs.2012.10.044] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Revised: 10/12/2012] [Accepted: 10/16/2012] [Indexed: 10/27/2022]
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Date RC, Yu F, Miller KM. Confirmation and refinement of the Diehl-Miller nomogram for intraocular lens power calculation after laser in situ keratomileusis. J Cataract Refract Surg 2013; 39:745-51. [PMID: 23489917 DOI: 10.1016/j.jcrs.2012.12.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 11/27/2012] [Accepted: 12/03/2012] [Indexed: 11/19/2022]
Abstract
PURPOSE To validate the Diehl-Miller equation for achieving emmetropia after cataract surgery in post-laser in situ keratomileusis (LASIK) eyes and to present a refined equation. SETTING Jules Stein Eye Institute, Los Angeles, California, USA. DESIGN Cohort study. METHODS Preoperative and postoperative refractive and cataract surgery data were collected from the medical records of post-LASIK patients. The IOL power data and postoperative refractive information were used to calculate the true target refractive error that should have been chosen to achieve emmetropia. Regression analysis of the combined data from Diehl-Miller and the current study was used to develop a refined equation. Diehl-Miller relates the manifest refraction spherical equivalent (MRSE) change induced by LASIK to an adjusted target postoperative refractive error to be used in intraocular lens (IOL) power calculations. RESULTS Twenty-three eyes of 18 patients were evaluated. The target refractive error calculated by Diehl-Miller differed from the true target refractive error by an absolute mean of 0.481 diopter (D) ±0.376 (SD). Regression analysis of the combined data from Diehl-Miller and the current study yielded the following 2nd-order polynomial equation: Target refractive error = -0.0198 (MRSE change)(2) +0.170 (MRSE change)-0.0079. The calculated target refractive error fell within ±0.50 D of the true target in 49% of patients and within ±1.00 D in 93% of patients. CONCLUSIONS This study validated that the Diehl-Miller equation accurately predicts the target refractive error to achieve emmetropia in post-LASIK eyes. The slightly refined Diehl-Date-Miller equation and associated lookup tables can be used to avoid postoperative refractive surprises.
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Affiliation(s)
- Rishabh C Date
- Jules Stein Eye Institute and the Department of Ophthalmology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California 90095-7002, USA
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Savini G, Hoffer KJ, Carbonelli M, Barboni P. Scheimpflug analysis of corneal power changes after myopic excimer laser surgery. J Cataract Refract Surg 2013; 39:605-10. [PMID: 23465330 DOI: 10.1016/j.jcrs.2012.12.031] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 11/30/2012] [Accepted: 12/14/2012] [Indexed: 11/19/2022]
Abstract
PURPOSE To assess the ability of corneal power measurements by a rotating Scheimpflug camera to measure the refractive change induced by myopic excimer laser surgery. SETTING G.B. Bietti Foundation-IRCCS, Rome, Italy. DESIGN Evaluation of diagnostic test. METHODS The following corneal power measurements by the Pentacam Scheimpflug camera were analyzed: average keratometry (K), true net power (calculated by Gaussian optics formula), and total corneal refractive power (TCRP) at 2.0 mm, 3.0 mm, and 4.0 mm, calculated by ray tracing on a ring and as the average of the zone inside the ring. The difference between the preoperative and postoperative values was compared with the subjective surgically induced refractive change (SIRC) and with the difference between the preoperative and the postoperative anterior corneal power measured by Placido corneal topography (Keratron). RESULTS In 36 consecutive eyes, the average K significantly underestimated the SIRC as determined by subjective refraction (-4.47 diopters [D] ± 1.81 [SD]) and corneal topography (-4.38 ± 1.81 D). The 3.0 mm and 4.0 mm ring total corneal refractive power significantly overestimated the SIRC. The remaining values did not show statistically significant differences with respect to the SIRC. The 3.0 mm zone TCRP and the 2.0 mm ring TCRP provided the lowest median difference compared with the SIRC (-0.07 D and -0.17 D, respectively) and the closest agreement. CONCLUSIONS The corneal power values provided by the Scheimpflug camera accurately reflected the SIRC after myopic excimer laser surgery. The best options seem to be the 3.0 mm zone TCRP and the 2.0 mm ring TCRP.
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Saiki M, Negishi K, Kato N, Arai H, Toda I, Torii H, Dogru M, Tsubota K. A new central-peripheral corneal curvature method for intraocular lens power calculation after excimer laser refractive surgery. Acta Ophthalmol 2013; 91:e133-9. [PMID: 23289447 DOI: 10.1111/aos.12007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE To propose the central-peripheral (C-P) method, which requires no data history to calculate intraocular lens (IOL) powers for eyes that underwent laser in situ keratomileusis (LASIK), and compare the accuracy of the C-P method with other IOL formulas for eyes after LASIK. METHODS Sixteen patients with cataract (25 eyes) who underwent myopic LASIK were analysed retrospectively. The C-P method is a modified double-K method using the SRK/T formula, in which the estimated pre-LASIK keratometric power calculated from the post-LASIK peripheral anterior sagittal power (also called the axial power) is used for the Kpre in the double-K method using the SRK/T formula, and the post-LASIK anterior sagittal power is used for the Kpost. We compared the accuracy of the C-P method with other popular IOL calculation formulas for use in eyes after LASIK. RESULTS The median values of the arithmetic and absolute prediction errors with the C-P method were 0.11 diopter (D) (range, -1.67 to 1.97 D) and 0.55 D (range, 0.02-1.97 D), respectively. The prediction error using the C-P method was within ±0.5 D in 48% of eyes, within -1.0 to +0.5 D in 60% of eyes, and within ±1.0 D in 68% of eyes. The C-P method resulted in a significantly higher percentage of eyes within ±0.5 D than the BESSt formula, Shammas-PL formula, true net power method, double-K method using 43.5 D for Kpre, and Feiz-Mannis method. CONCLUSION The C-P method may be a good option for calculating IOL powers in eyes undergoing cataract surgery after LASIK when the preoperative LASIK data are unavailable.
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Affiliation(s)
- Megumi Saiki
- Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
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Comparison of methods to measure corneal power for intraocular lens power calculation using a rotating Scheimpflug camera. J Cataract Refract Surg 2013; 39:598-604. [PMID: 23403064 DOI: 10.1016/j.jcrs.2012.11.022] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 10/20/2012] [Accepted: 11/09/2012] [Indexed: 01/14/2023]
Abstract
PURPOSE To assess the accuracy of corneal power measurements provided by a Scheimpflug camera (Pentacam HR) for intraocular lens (IOL) power calculation in unoperated eyes and compare the results with those of simulated keratometry (SimK) performed with a Placido-disk corneal topographer (Keratron). SETTING Private practice. DESIGN Evaluation of diagnostic test. METHODS Eight Scheimpflug camera corneal power measurements were analyzed: (1) average K, (2) true net power calculated using the Gaussian optics formula, (3) total corneal refractive power at 2.0 mm calculated by ray tracing on a ring and (4) as the average of the zone inside the ring, (5) total corneal refractive power at 3.0 mm on a ring and (6) as the average of the zone inside the ring, (7) the equivalent K reading at 3.0 mm and (8) at 4.5 mm. The IOL power was calculated using the Hoffer Q, Holladay 1, and SRK/T formulas. RESULTS No statistically significant differences were observed between any corneal power measurements, including simulated K, in 41 consecutive patients. The latter showed slightly lower mean absolute errors with all 3 formulas (range 0.26 to 0.27 diopter [D]). The Scheimpflug camera gave the lowest median absolute errors with all formulas; that is, the 3.0 mm equivalent K reading with the Hoffer Q formula (0.18 D) and Holladay 1 formula (0.17 D) and the 2.0 mm total corneal refractive power ring with the SRK/T formula (0.18 D). CONCLUSION Corneal power measurements provided by the Scheimpflug camera and Placido disk corneal topographer displayed comparable accuracy in IOL power calculation.
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Potvin R, Hill W. New algorithm for post-radial keratotomy intraocular lens power calculations based on rotating Scheimpflug camera data. J Cataract Refract Surg 2013; 39:358-65. [PMID: 23337527 DOI: 10.1016/j.jcrs.2012.09.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 09/07/2012] [Accepted: 09/12/2012] [Indexed: 12/01/2022]
Abstract
PURPOSE To provide an algorithm to calculate intraocular lens (IOL) power for post-radial keratometry (RK) eyes based on data extracted from the Pentacam Scheimpflug camera and to compare calculations with those from an existing standard. SETTING Private practice, Mesa, Arizona. DESIGN Case series. METHODS Relevant IOL calculation and postoperative refractive data were obtained for eyes that had previous RK but no additional keratorefractive procedures or subsequent cataract surgery. Various Scheimpflug measurements from examinations before cataract surgery over a range of zone diameters were used to calculate IOL power using an Aramberri double-K-modified Holladay 1 formula. Results were compared with actual postsurgical data and IOL calculations based on the mean of the 1.0 mm to 4.0 mm rings from the Atlas topography system. RESULTS Data were obtained for 83 eyes of 57 patients, including more than 120 different measures per eye from the Scheimpflug system. The mean pupil-centered sagittal front power over the central 4.0 mm zone provided the best results after adjustment for central corneal thickness (CCT). Results were similar to those obtained when the IOL power was calculated using the topography system; 42% of eyes were within ± 0.50 diopter (D) of the target, and 76% of eyes were within ± 1.00 D. CONCLUSION In this large series of eyes, the calculation of IOL power after RK using sagittal front-surface power and CCT from the Scheimpflug system produced results equivalent to the multizone approach with the topography system.
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The role of presbyopia-correcting intraocular lenses after laser in situ keratomileusis. Curr Opin Ophthalmol 2013. [DOI: 10.1097/icu.0b013e32835ab457] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Canovas C, Abenza S, Alcon E, Villegas EA, Marin JM, Artal P. Effect of corneal aberrations on intraocular lens power calculations. J Cataract Refract Surg 2012; 38:1325-32. [PMID: 22814039 DOI: 10.1016/j.jcrs.2012.03.033] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Revised: 02/07/2012] [Accepted: 03/03/2012] [Indexed: 11/25/2022]
Abstract
PURPOSE To use ray tracing to determine the influence of corneal aberrations on the prediction of the optimum intraocular lens (IOL) power for implantation in normal eyes and eyes with previous laser in situ keratomileusis (LASIK). SETTING Hospital Universitario Virgen de la Arrixaca, Murcia, Spain. DESIGN Case series. METHODS The optimum IOL power was calculated by ray tracing using a patient-customized eye model in cataract surgery cases. The calculation can be performed with or without inclusion of the patient's corneal aberrations. Standard predictions were also generated using current state-of-the-art IOL power calculation techniques. The results for all predictions were compared with the optimum IOL power after cataract surgery. RESULTS For patients without previous LASIK (n = 18), the standard approaches and the ray-tracing procedure gave a similar mean absolute residual error and variance. The incorporation of corneal aberrations did not improve the accuracy of the ray-tracing prediction in these cases. For post-LASIK patients (n = 10), the ray-tracing prediction incorporating corneal aberrations generated the most accurate results. The difference between the prediction with and without considering corneal aberrations correlated with the amount of corneal spherical aberration (r(2) = 0.82), resulting in a difference of up to 3.00 diopters in IOL power in some cases. CONCLUSIONS Ray tracing using patient-customized eye models was a robust procedure for IOL power calculation. The incorporation of corneal aberrations is crucial in post-LASIK eyes, primarily because of the elevated corneal spherical aberration. FINANCIAL DISCLOSURE Mrs. Canovas and Dr. Artal hold a provisional patent application on the ray-tracing procedure. Mrs. Canovas is an employee of Abbott Medical Optics Groningen B.V. No other author has a financial or proprietary interest in any material or method mentioned.
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Affiliation(s)
- Carmen Canovas
- Laboratorio de Óptica, Centro de Investigacion en Optica y Nanofisica, Universidad de Murcia, Campus de Espinardo, Murcia, Spain.
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Jung SH, Han KE, Sgrignoli B, Kim TI, Lee HK, Kim EK. Intraocular lens power calculations for cataract surgery after phototherapeutic keratectomy in granular corneal dystrophy type 2. J Refract Surg 2012; 28:714-24. [PMID: 23062002 DOI: 10.3928/1081597x-20120921-07] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 08/30/2012] [Indexed: 11/20/2022]
Abstract
PURPOSE To investigate the predictability of various intraocular lens (IOL) power calculation methods in granular corneal dystrophy type 2 (GCD2) with prior phototherapeutic keratectomy (PTK) and to suggest the more predictable IOL power calculation method. METHODS Medical records of 20 eyes from 16 patients with GCD2, all having undergone cataract surgery after PTK, were retrospectively evaluated. Postoperative cataract refractive errors were compared with target diopters (D) using IOL power calculation methods as follows: 1) myopic and 2) hyperopic Haigis-L formula in IOLMaster (Carl Zeiss Meditec); 3) SRK/T formula using 4.5-mm zone Holladay equivalent keratometry readings (EKRs) (single-K Holladay EKRs method); 4) central keratometry power of true net power map in the Pentacam system (Oculus Optikgeräte GmbH); and 5) clinical history, Aramberri double-K, and double-K Holladay EKRs methods. Topographic status of corneal curvature after PTK was evaluated. RESULTS Fourteen (70%) of 20 eyes showed central island formation after PTK. When central island was present, the mean absolute error (MAE) using the hyperopic Haigis-L formula was 0.25±0.15 D. When central island was not present, the myopic Haigis-L formula showed MAE of 0.33±0.16 D. When central island formation and IOLMaster keratometry underestimation were present, the hyperopic Haigis-L formula showed the least MAE of 0.26±0.08 D when switching the IOL-Master keratometry values equal to 4.5-mm zone Holladay EKRs. CONCLUSIONS In planning for cataract surgery after PTK in GCD2, topographic analysis for central island formation is necessary. With or without central island formation, the hyperopic or myopic Haigis-L formula can be applied. When IOLMaster keratometry shows underestimation, the Haigis-L formula using 4.5-mm zone Holladay EKRs can be considered.
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Affiliation(s)
- Se Hwan Jung
- Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea
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Jin H, Auffarth GU, Guo H, Zhao P. Corneal power estimation for intraocular lens power calculation after corneal laser refractive surgery in Chinese eyes. J Cataract Refract Surg 2012; 38:1749-57. [PMID: 22925179 DOI: 10.1016/j.jcrs.2012.06.048] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Revised: 06/04/2012] [Accepted: 06/05/2012] [Indexed: 11/29/2022]
Affiliation(s)
- Haiying Jin
- Department of Ophthalmology, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
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Feng L, Lei F, Burns SA, Shao L, Yang Y. Retinal measurements using time domain OCT imaging before and after myopic Lasik. Ophthalmic Physiol Opt 2012; 32:222-7. [PMID: 22512373 DOI: 10.1111/j.1475-1313.2012.00905.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE To compare retinal measurements obtained by time domain optical coherence tomography (OCT) devices before and after myopic laser in situ keratomileusis (Lasik) and to assess the interaction of Lasik and retinal structures as measured by time domain OCT. METHODS Fifty-three patients randomly selected participated in the study. Only the right eye of each subject was included in the study. Comprehensive ophthalmic examinations including refraction examination, slit lamp examination, dilated fundus examination, corneal topography, corneal thickness, intraocular pressure, and retinal Stratus OCT scans were acquired for each patient before myopic Lasik and 3months after surgery. RESULTS Total macular volume (TMV) changed significantly between preoperative and postoperative measurements (p=0.003). No statistical differences were found between preoperative and postoperative disc area, rim area, cup/disk vert. ratio, or average foveal thickness (p>0.05). The variation in TMV correlated significantly with the change in spherical refraction equivalent, maximal corneal curvature, minimal corneal curvature, and corneal ablation depth. CONCLUSIONS Most retinal OCT measurements undergo no obvious changes after myopic Lasik. The increased TMV measurements we measured after Lasik seem to be correlated with the alteration in corneal shape. The exact mechanism for this change is not clear, while we examined several possibilities including subclinical macular oedema, magnification changes, errors in OCT analysis and IOP, none of these seem to be a likely cause.
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Affiliation(s)
- Lei Feng
- Eye Center, Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
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Tang M, Wang L, Koch DD, Li Y, Huang D. Intraocular lens power calculation after previous myopic laser vision correction based on corneal power measured by Fourier-domain optical coherence tomography. J Cataract Refract Surg 2012; 38:589-94. [PMID: 22440433 DOI: 10.1016/j.jcrs.2011.11.025] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Revised: 10/26/2011] [Accepted: 11/02/2011] [Indexed: 10/28/2022]
Abstract
PURPOSE To use Fourier-domain optical coherence tomography (OCT) to measure corneal power and calculate intraocular lens (IOL) power in cataract surgeries after laser vision correction. SETTING Doheny Eye Institute, Los Angeles, California, and Cullen Eye Institute, Houston, Texas, USA. DESIGN Prospective comparative case series. METHODS Patients with previous myopic laser vision correction who had monofocal IOL implantation were enrolled. A Fourier-domain OCT system was used to measure corneal power and pachymetry. Axial length and anterior chamber depth were measured with partial coherence biometry. An OCT-based IOL formula was developed, and the mean absolution error (MAE) of postoperative refraction was compared with that for the Haigis-L formula. At Doheny, corneal power was also measured using the clinical history method, the contact lens overrefraction method, and slit-scanning tomography total optical power. RESULTS Sixteen eyes of 16 patients were enrolled at the 2 sites. Previous laser vision correction ranged from -9.81 to -0.88 diopter (D). The MAE was 0.50 D for OCT-based IOL calculation and 0.76 D for the Haigis-L formula (P=.14). In the 6 eyes enrolled at Doheny, the MAE of OCT-based IOL calculation was 0.60 D. In comparison, the contact lens overrefraction (MAE = 1.46 D, P<.05) and clinical history (MAE = 1.78 D, P<.05) methods were worse. Slit-scanning tomography gave an MAE of 1.28 D (P>.05). CONCLUSION The predictive accuracy of OCT-based IOL power calculation was equal to or better than current standards in post-laser vision correction eyes.
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Affiliation(s)
- Maolong Tang
- Center for Ophthalmic Optics and Lasers, Doheny Eye Institute, University of Southern California, Los Angeles, California, USA
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Savini G, Barboni P, Carbonelli M, Hoffer KJ. Accuracy of corneal power measurements by a new Scheimpflug camera combined with Placido-disk corneal topography for intraocular lens power calculation in unoperated eyes. J Cataract Refract Surg 2012; 38:787-92. [DOI: 10.1016/j.jcrs.2011.11.037] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Revised: 11/11/2011] [Accepted: 11/16/2011] [Indexed: 11/29/2022]
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Hill WE. May consultation #4. J Cataract Refract Surg 2012. [DOI: 10.1016/j.jcrs.2012.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Guo H, Goncharov AV, Dainty C. Comparison of retinal image quality with spherical and customized aspheric intraocular lenses. BIOMEDICAL OPTICS EXPRESS 2012; 3:681-691. [PMID: 22574257 PMCID: PMC3345798 DOI: 10.1364/boe.3.000681] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 02/20/2012] [Accepted: 02/24/2012] [Indexed: 05/29/2023]
Abstract
We hypothesize that an intraocular lens (IOL) with higher-order aspheric surfaces customized for an individual eye provides improved retinal image quality, despite the misalignments that accompany cataract surgery. To test this hypothesis, ray-tracing eye models were used to investigate 10 designs of mono-focal single lens IOLs with rotationally symmetric spherical, aspheric, and customized surfaces. Retinal image quality of pseudo-phakic eyes using these IOLs together with individual variations in ocular and IOL parameters, are evaluated using a Monte Carlo analysis. We conclude that customized lenses should give improved retinal image quality despite the random errors resulting from IOL insertion.
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Kwitko S, Marinho DR, Rymer S, Severo N, Arce CG. Orbscan II and double-K method for IOL calculation after refractive surgery. Graefes Arch Clin Exp Ophthalmol 2012; 250:1029-34. [PMID: 22456944 DOI: 10.1007/s00417-012-1974-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2011] [Revised: 02/13/2012] [Accepted: 02/16/2012] [Indexed: 10/28/2022] Open
Abstract
BACKGROUND Precise IOL calculation in post-refractive surgery patients is still a challenge for the cataract surgeon. The purpose of this study is to test whether adding Orbscan II values into the double-K method improves IOL calculation in this group of patients. METHODS A prospective study with 43 eyes previously submitted to refractive surgery that underwent cataract extraction. IOL calculation was performed with double-K method. Post-K value was derived from Orbscan total-mean power map. The average corneal curvature of the general population (43.8D) was used as the pre-K value. Refraction results 30 days after surgery were compared with refraction that would be obtained if we used: (1) post-K values from keratometry, (2) post-K values from topography, and (3) pre-K values from Orbscan total-mean power. Anterior chamber depth measures obtained with the IOL Master and Orbscan II were compared. RESULTS Mean postoperative spherical equivalent (SE) was -0.25 ± 1.10 D in eyes submitted to radial keratotomy , -1.04 ± 1.42 D in eyes previously submitted to myopic Lasik, and +0.05 ± 1.76 D in those submitted to hyperopic surgeries. Had we inputted post-K values derived from keratometer and from topography, we would have obtained significantly higher postoperative refractive errors in eyes previously submitted to myopic refractive surgery (p < 0.05). Refractions using pre-K derived from the central 8 mm Orbscan instead of 43.8 D were similar in all studied groups (p > 0.05). Anterior chamber depth measured with IOL Master or Orbscan were similar. CONCLUSIONS Orbscan measurements used as the post-K values into the double-K method provide a precise IOL calculation, especially in post myopic refractive surgery patients.
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Affiliation(s)
- Sérgio Kwitko
- Department of Ophthalmology, Hospital de Clínicas de Porto Alegre, Federal University of Rio Grande do Sul, Av. Dr. Nilo Peçanha 724/401, São Paulo, Brazil.
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Su CC, Wang IJ, Hu FR. Predictability of intraocular lens power calculations based on formulas on the ASCRS website after myopic laser refractive surgery. Taiwan J Ophthalmol 2012. [DOI: 10.1016/j.tjo.2012.01.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Camellin M, Savini G, Hoffer KJ, Carbonelli M, Barboni P. Scheimpflug camera measurement of anterior and posterior corneal curvature in eyes with previous radial keratotomy. J Refract Surg 2012; 28:275-9. [PMID: 22386371 DOI: 10.3928/1081597x-20120221-03] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2011] [Accepted: 02/03/2012] [Indexed: 11/20/2022]
Abstract
PURPOSE To compare the anterior and posterior corneal curvature in eyes with previous radial keratotomy (RK) to normal unoperated eyes. METHODS In this retrospective observational case series, 29 eyes from 29 consecutive patients were analyzed and compared to a control group of 71 unoperated eyes. Corneal imaging was obtained by a rotating Scheimpflug camera (Pentacam, Oculus Optikgeräte GmbH). Anterior and posterior corneal curvature radii were measured at the 3-mm zone. RESULTS The mean anterior and posterior corneal radii were 9.54 ± 0.89 and 8.54 ± 1.01 mm, respectively, both values being significantly higher than in the control group (7.81 ± 0.28 and 6.40 ± 0.24 mm, respectively, P<.0001). The mean anterior-to-posterior corneal curvature ratio was 1.12 ± 0.07, a value significantly lower than in the control group (1.22 ± 0.03, P<.0001). Mean corneal flattening was more evident in the posterior (33.44%) than in the anterior (22.15%) corneal curvature. The mean keratometric index, as calculated with the Gullstrand equation for thick lenses, was 1.3319 ± 0.0026, a value significantly higher than in the control group (1.3281 ± 0.0011, P<.0001). Linear regression detected a significant and directly proportional relationship between the number of radial incisions and flattening of both corneal surfaces (P<.0001). CONCLUSIONS After RK, both corneal surfaces flatten but do not deform in parallel as commonly accepted, as shown by the fact that the anterior-to-posterior corneal curvature ratio decreases. This finding invalidates the standard keratometric index and thus has relevant implications for intraocular lens power calculation in RK eyes.
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Demill DL, Hsu M, Moshirfar M. Evaluation of the American Society of Cataract and Refractive Surgery intraocular lens calculator for eyes with prior radial keratotomy. Clin Ophthalmol 2011; 5:1243-7. [PMID: 21966194 PMCID: PMC3180491 DOI: 10.2147/opth.s24514] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND The purpose of this study was to evaluate the American Society of Cataract and Refractive Surgery (ASCRS) intraocular lens (IOL) calculator for eyes with prior radial keratotomy and assess the accuracy of its methods in predicting IOL power in patients with previous radial keratotomy. METHODS This retrospective study included data from 15 eyes with previous radial keratotomy and subsequent cataract surgery. The average central power and Humphrey Atlas methods from the ASCRS IOL calculator, along with an average IOL power produced from an average of these two methods (ASCRS average), were compared. Primary outcome measures for each method were mean arithmetic and absolute IOL prediction error, variance in mean arithmetic IOL prediction error, and the percentage of refractive outcomes within ±0.50, ±1.00, ±1.50, and ±2.00 diopters (D). RESULTS The average central power method and the ASCRS average were significantly more accurate than the Humphrey Atlas method in terms of mean absolute IOL prediction error (1.03 D and 1.02 D versus 1.53; P = 0.04 and P = 0.01, respectively). In addition, the average central power method and ASCRS average produced a higher percentage of refractive outcomes within ±0.50 D when compared with the Humphrey Atlas method (60% and 46.67% versus 0%, respectively). A comparison of the average central power method and the ASCRS average demonstrated a smaller variance and higher percentage of patients within ±1.00 D when using the ASCRS average. CONCLUSION The ASCRS calculator for eyes with prior radial keratotomy is an easily accessible and valuable online tool for calculating IOL power in patients with previous radial keratotomy. We found that the ASCRS average produced by the calculator provided the best IOL prediction. We recommend using it with the addition of 1.00 to 1.50 D to its IOL power prediction.
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Affiliation(s)
- David L Demill
- John A Moran Eye Center, University of Utah, Salt Lake City, UT, USA
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140
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Canovas C, Artal P. Customized eye models for determining optimized intraocular lenses power. BIOMEDICAL OPTICS EXPRESS 2011; 2:1649-1662. [PMID: 21698026 PMCID: PMC3114231 DOI: 10.1364/boe.2.001649] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Revised: 04/10/2011] [Accepted: 05/19/2011] [Indexed: 05/28/2023]
Abstract
We have developed a new optical procedure to determine the optimum power of intraocular lenses (IOLs) for cataract surgery. The procedure is based on personalized eye models, where biometric data of anterior corneal shape and eye axial length are used. A polychromatic exact ray-tracing through the surfaces defining the eye model is performed for each possible IOL power and the area under the radial MTF is used as a metric. The IOL power chosen by the procedure maximizes this parameter. The IOL power for 19 normal eyes has been determined and compared with standard regression-based predictions. The impact of the anterior corneal monochromatic aberrations and the eye's chromatic aberration on the power predictions has been studied, being significant for those eyes with severe monochromatic aberrations, such as post-LASIK cataract patients, and for specific IOLs with low Abbe numbers.
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Affiliation(s)
- Carmen Canovas
- Laboratorio de Óptica, Instituto Universitario de Investigación en Óptica y Nanofísica, Universidad de Murcia, Campus de Espinardo (Edificio 34), 30100 Murcia, Spain
- AMO Groningen B.V., Van Swietenlaan 5, 9728NX, Groningen, The Netherlands
| | - Pablo Artal
- Laboratorio de Óptica, Instituto Universitario de Investigación en Óptica y Nanofísica, Universidad de Murcia, Campus de Espinardo (Edificio 34), 30100 Murcia, Spain
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141
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Visual quality after diffractive intraocular lens implantation in eyes with previous hyperopic laser in situ keratomileusis. J Cataract Refract Surg 2011; 37:1090-6. [DOI: 10.1016/j.jcrs.2010.11.043] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Revised: 10/29/2010] [Accepted: 11/04/2010] [Indexed: 11/17/2022]
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Zhu Z, Janunts E, Eppig T, Sauer T, Langenbucher A. Tomography-Based Customized IOL Calculation Model. Curr Eye Res 2011; 36:579-89. [DOI: 10.3109/02713683.2011.566978] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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143
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Dooley I, Charalampidou S, Nolan J, Loughman J, Molloy L, Beatty S. Estimation of effective lens position using a method independent of preoperative keratometry readings. J Cataract Refract Surg 2011; 37:506-12. [PMID: 21333875 DOI: 10.1016/j.jcrs.2010.09.027] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 09/19/2010] [Accepted: 09/28/2010] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate the validity of a keratometry (K)-independent method of estimating effective lens position (ELP) before phacoemulsification cataract surgery. SETTING Institute of Eye Surgery, Whitfield Clinic, Waterford, Ireland. DESIGN Evaluation of diagnostic test or technology. METHODS The anterior chamber diameter and corneal height in eyes scheduled for cataract surgery were measured with a rotating Scheimpflug camera. Corneal height and anterior chamber diameter were used to estimate the ELP in a K-independent method (using the SRK/T [ELP(rs)] and Holladay 1 [ELP(rh)] formulas). RESULTS The mean ELP was calculated using the traditional (mean ELP(s) 5.59 mm ± 0.52 mm [SD]; mean ELP(h) 5.63 ± 0.42 mm) and K-independent (mean ELP(rs) 5.55 ± 0.42 mm; mean ELP(rh) ± SD 5.60 ± 0.36 mm) methods. Agreement between ELP(s) and ELP(rs) and between ELP(h) and ELP(rh) were represented by Bland-Altman plots, with mean differences (± 1.96 SD) of 0.06 ± 0.65 mm (range -0.59 to +0.71 mm; P=.08) in association with ELP(rs) and -0.04 ± 0.39 mm (range -0.43 to +0.35 mm; P=.08) in association with ELP(rh). The mean absolute error for ELP(s) versus ELP(rs) estimation and for ELP(h) versus ELP(rh) estimation was 0.242 ± 0.222 mm (range 0.001 to 1.272 mm) and 0.152 ± 0.137 mm (range 0.001 to 0.814 mm), respectively. CONCLUSION This study confirms that the K-independent ELP estimation method is comparable to traditional K-dependent methods and may be useful in post-refractive surgery patients.
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Affiliation(s)
- Ian Dooley
- Department of Ophthalmology, Waterford Regional Hospital, Institute of Eye Surgery, Dublin, Ireland.
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Rabsilber TM, Haigis W, Auffarth GU, Mannsfeld A, Ehmer A, Holzer MP. Intraocular lens power calculation after intrastromal femtosecond laser treatment for presbyopia: Theoretic approach. J Cataract Refract Surg 2011; 37:532-7. [PMID: 21251797 DOI: 10.1016/j.jcrs.2010.10.042] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Revised: 10/06/2010] [Accepted: 10/06/2010] [Indexed: 11/26/2022]
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Rosa N, De Bernardo M, Borrelli M, Lanza M. New factor to improve reliability of the clinical history method for intraocular lens power calculation after refractive surgery. J Cataract Refract Surg 2011; 36:2123-8. [PMID: 21111316 DOI: 10.1016/j.jcrs.2010.07.017] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Revised: 06/24/2010] [Accepted: 07/02/2010] [Indexed: 11/19/2022]
Abstract
PURPOSE To determine whether the refractive error in an eye developing cataract after refractive surgery represents actual regression or is cataract related and whether the method to gather this information would allow the use of history-related formulas in intraocular lens (IOL) power calculation after refractive surgery. SETTING Second University of Naples, Naples, Italy. DESIGN Case series. METHODS The refractive effects, axial length (AL), and mean keratotomy (K) values were evaluated in eyes before and 6 months after photorefractive keratectomy for myopia or for myopic or mixed astigmatism. RESULTS The study evaluated 257 eyes of 166 patients (93 women). Before surgery, there was a high correlation between refractive error and the product of AL and K (AL × K) (r(2) = 0.8213). In patients with refractive results close to emmetropia, the mean AL × K was 1005.91 ± 25.88 (SD), meaning that in the range of 954 and 1058, there was a 95% possibility that the patients were almost fully corrected. The following regression formula was obtained to calculate the amount of refractive error independent of cataract onset: Refractive error = -0.0157 × (AL × K) + 16.437. CONCLUSIONS The regression formula determined whether the refraction depended on the onset of cataract and estimated the amount of undercorrection or overcorrection that occurred after refractive surgery, leading to improved estimation of the power of the IOL to be implanted. It may allow the use of history-related formulas in IOL power calculation for eyes that have had corneal refractive surgery.
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Affiliation(s)
- Nicola Rosa
- Centro Grandi Apparecchiature, Second University of Naples, Naples, Italy.
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Forseto AS, Nosé RM, Nosé W. Toric intraocular lens misalignment inducing astigmatism after refractive surgery. J Refract Surg 2011; 27:691-3. [PMID: 21323300 DOI: 10.3928/1081597x-20110208-01] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Accepted: 01/18/2011] [Indexed: 11/20/2022]
Abstract
PURPOSE To report the unexpected induction of astigmatism after phacoemulsification and toric intraocular lens (IOL) implantation in an eye with previous corneal refractive surgery. METHODS Case report of a 46-year-old man with bilateral nuclear cataract and previous photorefractive keratectomy. Because corneal topography identified regular corneal astigmatism at the central optical zone, phacoemulsification and implantation of a one-piece hydrophobic acrylic toric IOL were performed. RESULTS Unexpected induction of astigmatism occurred in the first operated eye despite proper alignment of the IOL according to the preoperative calculations using simulated K values to determine toric IOL power and alignment. A retrospective qualitative analysis of corneal topography showed mismatching of the steepest meridian, leading to an off-axis IOL. Secondary IOL rotation improved both uncorrected and corrected distance visual acuity. CONCLUSIONS Qualitative analysis of the corneal topography is mandatory during the assessment of toric IOL alignment in eyes with previous corneal refractive surgery to identify the actual location of the steepest meridian.
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Affiliation(s)
- Adriana S Forseto
- Eye Clinic Day Hospital, Metropolitan University of Santos, Sao Paulo, Brazil.
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McCarthy M, Gavanski GM, Paton KE, Holland SP. Intraocular lens power calculations after myopic laser refractive surgery: a comparison of methods in 173 eyes. Ophthalmology 2010; 118:940-4. [PMID: 21131054 DOI: 10.1016/j.ophtha.2010.08.048] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Revised: 08/27/2010] [Accepted: 08/27/2010] [Indexed: 11/18/2022] Open
Abstract
PURPOSE To evaluate and compare published methods of intraocular lens (IOL) power calculation after myopic laser refractive surgery in a large, multi-surgeon study. DESIGN Retrospective case series. PARTICIPANTS A total of 173 eyes of 117 patients who had uneventful LASIK (89) or photorefractive keratectomy (84) for myopia and subsequent cataract surgery. METHODS Data were collected from primary sources in patient charts. The Clinical History Method (vertex corrected to the corneal plane), the Aramberri Double-K, the Latkany Flat-K, the Feiz and Mannis, the R-Factor, the Corneal Bypass, the Masket (2006), the Haigis-L, and the Shammas.cd postrefractive adjustment methods were evaluated in conjunction with third- and fourth-generation optical vergence formulas, as appropriate. Intraocular lens power required for emmetropia was back-calculated using stable post-cataract surgery manifest refraction and implanted IOL power, and then formula accuracy was compared. MAIN OUTCOME MEASURES Prediction error arithmetic mean ± standard deviation (SD), range (minimum and maximum), and percent within 0 to -1.0 diopters (D), ±0.5 D, ±1.0 D, and ±2.0 D relative to target refraction. RESULTS The top 5 corneal power adjustment techniques and formula combinations in terms of mean prediction errors, standard deviations, and minimizing hyperopic "refractive surprises" were the Masket with the Hoffer Q formula, the Shammas.cd with the Shammas-PL formula, the Haigis-L, the Clinical History Method with the Hoffer Q, and the Latkany Flat-K with the SRK/T with mean arithmetic prediction errors and standard deviations of -0.18±0.87 D, -0.10±1.02 D, -0.26±1.13 D, -0.27±1.04 D, and -0.37±0.91 D, respectively. CONCLUSIONS By using these methods, 70% to 85% of eyes could achieve visual outcomes within 1.0 D of target refraction. The Shammas and the Haigis-L methods have the advantage of not requiring potentially inaccurate historical information.
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Affiliation(s)
- Martin McCarthy
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, Canada.
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Savini G, Hoffer KJ, Carbonelli M, Barboni P. Intraocular lens power calculation after myopic excimer laser surgery: clinical comparison of published methods. J Cataract Refract Surg 2010; 36:1455-65. [PMID: 20692555 DOI: 10.1016/j.jcrs.2010.02.029] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Revised: 02/19/2010] [Accepted: 02/23/2010] [Indexed: 11/28/2022]
Abstract
PURPOSE To compare results of intraocular lens (IOL) power calculation methods after myopic excimer laser surgery. SETTING Private practice. METHODS In this prospective study, eyes having phacoemulsification after myopic excimer laser surgery were classified into Group 1 (preoperative corneal power available, refractive change known), Group 2 (preoperative corneal power available, refractive change uncertain), and Group 3 (preoperative corneal power unavailable, refractive change known even if uncertain). The IOL power was calculated using the following methods: clinical history, Awwad, Camellin/Calossi, Diehl, Feiz, Ferrara, Latkany, Masket, Rosa, Savini, Shammas, Seitz/Speicher, and Seitz/Speicher/Savini. RESULTS The lowest mean absolute errors (MAEs) in IOL power prediction in Group 1 (n = 12) and Group 2 (n = 11), respectively, were with the methods of Seitz/Speicher/Savini (0.51 diopter [D] +/- 0.44 [SD] and 0.55 +/- 0.50 D), Seitz/Speicher (0.58 +/- 0.47 D and 0.54 +/- 0.45 D), Savini (0.60 +/- 0.44 D and 0.65 +/- 0.63 D), Masket (0.82 +/- 0.49 D and 0.69 +/- 0.51 D), and Shammas (0.77 +/- 0.43 D and 1.11 +/- 0.50 D). In Group 3 (n = 5), the lowest MAEs were with the methods of Masket (0.23 +/- 0.27 D), Savini (0.49 +/- 0.86 D), Seitz/Speicher/Savini (0.68 +/- 0.36 D), Shammas (0.84 +/- 0.98 D), and Camellin/Calossi (0.91 +/- 0.84 D). CONCLUSIONS When corneal power is known, the Seitz/Speicher method (with or without Savini adjustment) seems the best solution to obtain an accurate IOL power prediction. Otherwise, the Masket method may be the most reliable option.
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Wang L, Hill WE, Koch DD. Evaluation of intraocular lens power prediction methods using the American Society of Cataract and Refractive Surgeons Post-Keratorefractive Intraocular Lens Power Calculator. J Cataract Refract Surg 2010; 36:1466-73. [DOI: 10.1016/j.jcrs.2010.03.044] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Revised: 02/11/2010] [Accepted: 03/22/2010] [Indexed: 10/19/2022]
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