1
|
Lischke R, Wiltfang R, Bechmann M, Kreutzer TC, Priglinger SG, Dirisamer M, Luft N. Intraocular lens power calculation using total keratometry and ray tracing in eyes with previous small incision lenticule extraction - A case series. Am J Ophthalmol Case Rep 2024; 34:102037. [PMID: 38487335 PMCID: PMC10937105 DOI: 10.1016/j.ajoc.2024.102037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 01/24/2024] [Accepted: 02/28/2024] [Indexed: 03/17/2024] Open
Abstract
Purpose To assess the IOL power calculation accuracy in post-SMILE eyes using ray tracing and a range of total keratometry based IOL calculation formulae. Observations Ray tracing showed excellent predictability in IOL power calculation after SMILE and its accuracy was clinically comparable with the Barrett TK Universal II and Haigis TK formula. Conclusions and importance Incorporating posterior corneal curvature measurements into IOL power calculation after SMILE seems prudent. The ray tracing method as well as selected TK-based formulae yielded excellent accuracy and should be favored in post-SMILE eyes.
Collapse
Affiliation(s)
- Roman Lischke
- University Eye Hospital, Ludwig-Maximilians-University, Munich, Germany
- Department of Ophthalmology and Optometry, Medical University of Innsbruck, Austria
| | - Rainer Wiltfang
- SMILE Eyes Clinic, Munich, Germany
- SMILE Eyes Clinic, Trier, Germany
| | - Martin Bechmann
- SMILE Eyes Clinic, Munich, Germany
- SMILE Eyes Clinic, Trier, Germany
| | | | - Siegfried G. Priglinger
- University Eye Hospital, Ludwig-Maximilians-University, Munich, Germany
- SMILE Eyes Clinic, Austria
| | - M. Dirisamer
- University Eye Hospital, Ludwig-Maximilians-University, Munich, Germany
- SMILE Eyes Clinic, Austria
| | - Nikolaus Luft
- University Eye Hospital, Ludwig-Maximilians-University, Munich, Germany
- SMILE Eyes Clinic, Austria
| |
Collapse
|
2
|
Wei Y, Liu Y, Li H, Song H. Theoretical Accuracy of the Raytracing Method for Intraocular Calculation of Lens Power in Myopic Eyes after Small Incision Extraction of the Lenticule. Klin Monbl Augenheilkd 2024; 241:221-229. [PMID: 37722612 PMCID: PMC10898958 DOI: 10.1055/a-2177-4998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/20/2023]
Abstract
AIM To evaluate the accuracy of the raytracing method for the calculation of intraocular lens (IOL) power in myopic eyes after small incision extraction of the lenticule (SMILE). METHODS Retrospective study. All patients undergoing surgery for myopic SMILE between May 1, 2020, and December 31, 2020, with Scheimpflug tomography optical biometry were eligible for inclusion. Manifest refraction was performed before and 6 months after refractive surgery. One eye from each patient was included in the final analysis. A theoretical model was invited to predict the accuracy of multiple methods of lens power calculation by comparing the IOL-induced refractive error at the corneal plane (IOL-Dif) and the SMILE-induced change of spherical equivalent (SMILE-Dif) before and after SMILE surgery. The prediction error (PE) was calculated as the difference between SMILE-Dif-IOL-Dif. IOL power calculations were performed using raytracing (Olsen Raytracing, Pentacam AXL, software version 1.22r05, Wetzlar, Germany) and other formulae with historical data (Barrett True-K, Double-K SRK/T, Masket, Modified Masket) and without historical data (Barrett True-K no history, Haigis-L, Hill Potvin Shammas PM, Shammas-PL) for the same IOL power and model. In addition, subgroup analysis was performed in different anterior chamber depths, axial lengths, back-to-front corneal radius ratio, keratometry, lens thickness, and preoperative spherical equivalents. RESULTS A total of 70 eyes of 70 patients were analyzed. The raytracing method had the smallest mean absolute PE (0.26 ± 0.24 D) and median absolute PE (0.16 D), and also had the largest percentage of eyes within a PE of ± 0.25 D (64.3%), ± 0.50 D (81.4%), ± 0.75 D (95.7%), and ± 1.00 D (100.0%). The raytracing method was significantly better than Double-K SRK/T, Haigis, Haigis-L, and Shammas-PL formulae in postoperative refraction prediction (all p < 0.001), but not better than the following formulae: Barrett True-K (p = 0.314), Barrett True-K no history (p = 0.163), Masket (p = 1.0), Modified Masket (p = 0.806), and Hill Potvin Shammas PM (p = 0.286). Subgroup analysis showed that refractive outcomes exhibited no statistically significant differences in the raytracing method (all p < 0.05). CONCLUSION Raytracing was the most accurate method in predicting target refraction and had a good consistency in calculating IOL power for myopic eyes after SMILE.
Collapse
Affiliation(s)
- Yinjuan Wei
- Department of Cataract, Tianjin Eye Hospital, Tianjin, China
- Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin, China
| | - Yianzhu Liu
- Department of Cataract, Tianjin Eye Hospital, Tianjin, China
- Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin, China
| | - Hongyu Li
- Department of Ophthalmology, Chinese PLA General Hospital, Beijing, China
| | - Hui Song
- Department of Cataract, Tianjin Medical University Eye Hospital, Tianjin, China
| |
Collapse
|
3
|
Meziane Elotmani A, Messerschmidt-Roth A, Nehme A, Müller HH, Sekundo W. Comparison of intraocular lens power calculation formulas with and without total keratometry and ray tracing in patients with previous myopic SMILE. J Cataract Refract Surg 2023; 49:467-473. [PMID: 36700932 DOI: 10.1097/j.jcrs.0000000000001139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 01/03/2023] [Indexed: 01/27/2023]
Abstract
PURPOSE To evaluate the prediction error (PE) variance and absolute median PE of different intraocular lens (IOL) calculation formulas including last-generation formulas such as Barrett True-K with K, Okulix and total keratometry (TK)-based calculations with Haigis, and Barrett True-K in a simulation model in post-small-incision lenticule extraction (SMILE) eyes. SETTINGS Department of Ophthalmology, University Hospital Marburg, Marburg, Germany. DESIGN Prospective study. METHODS Preoperative measurements included IOL power calculation before and after SMILE surgery. The target refraction was set to be the lowest myopic refractive error in pre-SMILE eyes. The IOL power targeting at the lowest myopic refractive error in pre-SMILE eyes was selected for the post-SMILE IOL calculation of the same eye. The difference between the predicted refraction of pre- and post-SMILE eyes with the same IOL power was defined as IOL difference. The refractive change induced by SMILE was defined as the difference between preoperative and postoperative manifest refraction. RESULTS 98 eyes from 49 patients underwent bilateral myopic SMILE. The PE variance of Okulix was not significantly different compared with Barrett True-K with TK ( P = .471). The SDs of the mean PEs were ±0.413 D (Haigis-TK), ±0.453 D (Okulix), ±0.471 D (Barrett True-K with TK), ±0.556 D (Haigis-L), and ±0.576 D (Barrett True-K with K). The mean absolute PE was 0.340 D, 0.353 D, 0.404 D, 0.511 D, and 0.715 D for Haigis-TK, Okulix, Barrett True-K with TK, Barrett True-K with K, and Haigis-L, respectively. The highest percentage of eyes within ±0.50 D was achieved by Okulix, followed by Haigis-TK, Barrett True-K with TK, Barrett True-K with K, and Haigis-L. CONCLUSIONS Results suggest that Haigis in combination with TK, Okulix, and Barrett True-K with and without TK offer good options for accurate IOL power calculation after SMILE. Haigis-L showed a tendency for myopic shift in eyes after previous SMILE.
Collapse
Affiliation(s)
- Anouar Meziane Elotmani
- From the Department of Ophthalmology, University Hospital Marburg (UKGM), Philipps University of Marburg, Marburg, Germany (Elotmani, Messerschmidt-Roth, Nehme, Sekundo); Institute of Medical Bioinformatics and Biostatistics, Philipps University of Marburg, Marburg, Germany (Müller)
| | | | | | | | | |
Collapse
|
4
|
Wendelstein J, Heath M, Riaz KM, Seiler T, Cooke DL, Langenbucher A, Hoffmann P, Kohnen T. Biometry and Intraocular Lens Power Calculation in Eyes with Prior Laser Vision Correction (LVC) - A Review. Klin Monbl Augenheilkd 2022; 239:971-981. [PMID: 35973684 DOI: 10.1055/a-1896-0881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
Abstract
BACKGROUND An intraocular lens (IOL) calculation in eyes that have undergone laser vision correction (LVC) poses a significant clinical issue in regards to both patient expectation and accuracy. This review aims to describe the pitfalls of IOL power calculation after LVC and give an overview of the current methods of IOL power calculation after LVC. REVIEW Problems after LVC derive from the measurement of anterior corneal radii, central corneal thickness, asphericity, and the predicted effective lens position. A central issue is that most conventional 3rd generation formulas estimate lens position amongst other parameters on keratometry, which is altered in post-LVC eyes. CONCLUSION An IOL power calculation results in eyes with prior LVC that are notably impaired in eyes without prior surgery. Effective corneal power including anterior corneal curvature, posterior corneal curvature, CCT (central corneal thickness), and asphericity is essential. Total keratometry in combination with the Barrett True-K, EVO (emmetropia verifiying optical formula), or Haigis formula is relatively uncomplicated and seems to provide good results, as does the Barrett True-K formula with anterior K values. The ASCRS ( American Society of Cataract and Refractive Surgery) calculator combines results of various formulae and averages results, which allows a direct comparison between the different methods. Tomography-based raytracing and the Kane and the Castrop formulae need to be evaluated by future studies.
Collapse
Affiliation(s)
- Jascha Wendelstein
- IROC, Institut für Refraktive und Ophthalmo-Chirurgie, Zürich, Switzerland.,Abteilung für Augenheilkunde und Optometrie, Johannes Kepler Universität Linz, Linz, Austria.,Institut für Experimentelle Ophthalmologie, Universität des Saarlandes, Homburg/Saar, Germany
| | - Michael Heath
- College of Medicine, University of Oklahoma, Norman, Oklahoma, United States
| | - Kamran M Riaz
- University of Oklahoma, Dean McGee Eye Institute, Oklahoma City, Oklahoma, United States
| | - Theo Seiler
- IROC, Institut für Refraktive und Ophthalmo-Chirurgie, Zürich, Switzerland.,Universitätsklinik für Augenheilkunde, Inselspital, Bern, Switzerland.,Klinik für Augenheilkunde, Universitätsklinikum Düsseldorf, Düsseldorf, Germany
| | - David L Cooke
- Great Lakes Eye Care, Saint Joseoph, United States.,Department of Neurology and Ophthalmology, Michigan State University, East Lansing, Michigan, United States
| | - Achim Langenbucher
- Institut für Experimentelle Ophthalmologie, Universität des Saarlandes, Homburg/Saar, Germany
| | - Peter Hoffmann
- Augen- und Laserklinik Castrop-Rauxel, Castrop-Rauxel, Germany
| | - Thomas Kohnen
- Klinik für Augenheilkunde, Goethe-Universität, Frankfurt, Germany
| |
Collapse
|
5
|
IOL Power Calculations and Cataract Surgery in Eyes with Previous Small Incision Lenticule Extraction. J Clin Med 2022; 11:jcm11154418. [PMID: 35956035 PMCID: PMC9369542 DOI: 10.3390/jcm11154418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 06/30/2022] [Accepted: 07/27/2022] [Indexed: 02/01/2023] Open
Abstract
Small incision lenticule extraction (SMILE), with over 5 million procedures globally performed, will challenge ophthalmologists in the foreseeable future with accurate intraocular lens power calculations in an ageing population. After more than one decade since the introduction of SMILE, only one case report of cataract surgery with IOL implantation after SMILE is present in the peer-reviewed literature. Hence, the scope of the present multicenter study was to compare the IOL power calculation accuracy in post-SMILE eyes between ray tracing and a range of empirically optimized formulae available in the ASCRS post-keratorefractive surgery IOL power online calculator. In our study of 11 post-SMILE eyes undergoing cataract surgery, ray tracing showed the smallest mean absolute error (0.40 D) and yielded the largest percentage of eyes within ±0.50/±1.00 D (82/91%). The next best conventional formula was the Potvin–Hill formula with a mean absolute error of 0.66 D and an ±0.50/±1.00 D accuracy of 45 and 73%, respectively. Analyzing this first cohort of post-SMILE eyes undergoing cataract surgery and IOL implantation, ray tracing showed superior predictability in IOL power calculation over empirically optimized IOL power calculation formulae that were originally intended for use after Excimer-based keratorefractive procedures.
Collapse
|
6
|
IOL power calculation with ray tracing based on anterior segment OCT and adjusted axial length after myopic excimer laser surgery. J Cataract Refract Surg 2022; 48:947-953. [PMID: 35121684 DOI: 10.1097/j.jcrs.0000000000000902] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 01/27/2022] [Indexed: 11/27/2022]
Abstract
PURPOSE To report the results of intraocular lens (IOL) power calculation by ray-tracing in eyes with previous myopic excimer laser surgery. SETTING G.B. Bietti Foundation I.R.C.C.S., Rome, Italy. DESIGN Retrospective interventional case series. METHODS A series of consecutive patients undergoing phacoemulsification and IOL implantation after myopic excimer laser was investigated. IOL power was calculated using ray-tracing software available on the anterior segment optical coherence tomographer MS-39 (CSO, Italy). Axial length (AL) was measured by optical biometry and 4 values were investigated: 1) that from the printout, 2) the modified Wang/Koch formula, 3) the polynomial equation for the Holladay 1 and 4) for the Holladay 2 formula. The mean prediction error (PE), median absolute error (MedAE), percentage of eyes with a PE within ±0.50 diopters (D) were reported. RESULTS We enrolled 39 eyes. Entering the original AL into ray-tracing led to a mean hyperopic PE (+0.56 ±0.54 D), whereas with the Wang/Koch formula a mean myopic PE (-0.41 ±0.53D) was obtained. The Holladay 1 and 2 polynomial equations lead to the lowest PEs (-0.10 ±0.49 and +0.08 ±0.49 D respectively), lowest MedAE (0.37 and 0.25 D) and highest percentages of eyes with a PE within ±0.50 D (71.79 and 76.92%). Calculations based on the Holladay 2 polynomial equation showed a statistically significant difference compared to other methods used (including Barrett-True K formula), with the only exception of the Holladay 1 polynomial equation. CONCLUSIONS IOL power can be accurately calculated by ray-tracing with adjusted AL according to the Holladay 2 polynomial equation.
Collapse
|
7
|
Development of a New Method for Calculating Intraocular Lens Power after Myopic Laser In Situ Keratomileusis by Combining the Anterior-Posterior Ratio of the Corneal Radius of the Curvature with the Double-K Method. J Clin Med 2022; 11:jcm11030522. [PMID: 35159971 PMCID: PMC8837081 DOI: 10.3390/jcm11030522] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 12/12/2021] [Accepted: 01/17/2022] [Indexed: 02/05/2023] Open
Abstract
Background: A new method, the Iida–Shimizu–Shoji (ISS) method, is proposed for calculating intraocular lens (IOL) power that combines the anterior–posterior ratio of the corneal radius of the curvature after laser in situ keratomileusis (LASIK) and to compare the predictability of the method with that of other IOL formulas after LASIK. Methods: The estimated corneal power before LASIK (Kpre) in the double-K method was 43.86 D according to the American Society of Cataract and Refractive Surgery calculator, and the K readings of the IOL master were used as the K values after LASIK (Kpost). The factor for correcting the target refractive value (correcting factor [C-factor]) was calculated from the correlation between the anterior–posterior ratio of the corneal radius of the curvature and the refractive error obtained using this method for 30 eyes of 30 patients. Results: Fifty-nine eyes of 59 patients were included. The mean values of the numerical and absolute prediction errors obtained using the ISS method were −0.02 ± 0.45 diopter (D) and 0.35 ± 0.27 D, respectively. The prediction errors using the ISS method were within ±0.25, ±0.50, and ±1.00 D in 49.2%, 76.3%, and 96.6% of the eyes, respectively. The predictability of the ISS method was comparable to or better than some of the other formulas. Conclusions: The ISS method is useful for calculating the IOL power in eyes treated with cataract surgery after LASIK.
Collapse
|
8
|
Nabil K. Accuracy of intraocular lens power calculation using Scheimpflug tomography and OKULIX ray-tracing software in paracentral corneal scarring not interfering with postoperative refraction. DELTA JOURNAL OF OPHTHALMOLOGY 2022. [DOI: 10.4103/djo_79_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
|
9
|
Predictability of intraocular lens power calculation after small-incision lenticule extraction for myopia. J Cataract Refract Surg 2021; 47:304-310. [PMID: 32932366 DOI: 10.1097/j.jcrs.0000000000000405] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 08/03/2020] [Indexed: 11/25/2022]
Abstract
PURPOSE To evaluate and compare the predictability of intraocular lens (IOL) power calculation after small-incision lenticule extraction (SMILE) for myopia and myopic astigmatism. SETTING Department of Ophthalmology, Philipps University of Marburg, Marburg, Germany. DESIGN Retrospective comparative case series. METHODS Preoperative evaluation included optical biometry using IOLMaster 500 and corneal tomography using Pentacam HR. The corneal tomography measurements were repeated at 3 months postoperatively. The change of spherical equivalent due to SMILE was calculated by the manifest refraction at corneal plane (SMILE-Dif). A theoretical model, involving the virtual implantation of the same IOL before and after SMILE, was used, and the IOL power calculations were performed using ray tracing (OKULIX, version 9.06) and third- (Hoffer Q, Holladay 1, and SRK/T) and fourth-generation (Haigis-L and Haigis) formulas. The difference between the IOL-induced refractive error at corneal plane before and after SMILE (IOL-Dif) was compared with SMILE-Dif. The prediction error (PE) was calculated as the difference between SMILE-Dif-IOL-Dif. RESULTS The study included 204 eyes that underwent SMILE. The PE with ray tracing was -0.06 ± 0.40 diopter (D); Haigis-L, -0.39 ± 0.62 D; Haigis, 0.70 ± 0.48 D; Hoffer Q, 0.84 ± 0.47 D; Holladay 1, 1.21 ± 0.51 D; and SRK/T, 1.46 ± 0.54 D. The PE with ray tracing was significantly smaller compared with that of all formulas (P ≤ .001). The PE variance with ray tracing was σ2 = 0.159, being significantly more homogenous compared with that of all formulas (P ≤ .011, F ≥ 6.549). Ray tracing resulted in an absolute PE of 0.5 D or lesser in 81.9% of the cases, followed by Haigis-L (53.4%), Haigis (35.3%), Hoffer Q (25.5%), Holladay 1 (6.4%), and SRK/T (2.9%) formulas. CONCLUSIONS Ray tracing was the most accurate approach for IOL power calculation after myopic SMILE.
Collapse
|
10
|
Wen D, Yu J, Zeng Z, McAlinden C, Hu L, Feng K, Wang Y, Song B, Chen S, Ning R, Jin Y, Wang Q, Yu AY, Huang J. Network Meta-analysis of No-History Methods to Calculate Intraocular Lens Power in Eyes With Previous Myopic Laser Refractive Surgery. J Refract Surg 2020; 36:481-490. [PMID: 32644171 DOI: 10.3928/1081597x-20200519-04] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Accepted: 05/19/2020] [Indexed: 01/10/2024]
Abstract
PURPOSE To systematically compare and rank the predictability of no-history intraocular lens (IOL) power calculation methods after myopic laser refractive surgery. METHODS PubMed, Embase, the Cochrane Library, and the U.S. trial registry (www.ClinicalTrial.gov) were used to systematically search trials published up to August 2019. Included were case series studies reporting the following outcomes in patients with cataract undergoing phacoemulsification after laser refractive surgery: percentage of eyes with a refractive prediction error (PE) within ±0.50 and ±1.00 diopters (D), mean absolute error (MAE), and median absolute error (MedAE). A network meta-analysis was conducted using the STATA software version 13.1 (STATACorp LLC). RESULTS Nineteen studies involving 1,098 eyes and 19 formulas were identified. A network meta-analysis for the percentage of eyes with a PE within ±0.50 D found that ray-tracing (Okulix), intraoperative aberrometry (Optiwave Refractive Analysis [ORA]), BESSt, and Seitz/Speicher/Savini (Triple-S) (D-K SRK/T), and Fourier-Domain OCT-Based formulas were more predictive than the Wang/Koch/Maloney, Shammas-PL, modified Rosa, Ferrara, and Equivalent K reading at 4.5 mm using the Double-K Holladay 1 formulas. With regard to ranking, the top four formulas as per the surface under the cumulative ranking curve (SUCRA) values for the percentage of eyes with a PE within ±0.50 D were the Okulix, ORA, BESSt, and Triple-S (D-K SRK/T). With regard to MAE, the ORA showed lower errors when compared to the Shammas-PL formula. In this regard, the top four formulas based on the SUCRA values were the Triple-S, BESSt, ORA, and Fourier-Domain OCT-Based formulas. The SToP (SRK/T), ORA, Fourier-Domain OCT-Based, and BESSt formulas had the lowest MedAE. CONCLUSIONS Considering all three outcome measures of highest percentages of eyes with a PE within ±0.50 and ±1.00 D, lowest MAE, and lowest MedAE, the top three no-history formulas for IOL power calculation in eyes with previous myopic corneal laser refractive surgery were: ORA, BESSt, and Triple-S (D-K SRK/T). [J Refract Surg. 2020;36(7):481-490.].
Collapse
|
11
|
Luft N, Siedlecki J, Schworm B, Kreutzer TC, Mayer WJ, Priglinger SG, Dirisamer M. Intraocular Lens Power Calculation after Small Incision Lenticule Extraction. Sci Rep 2020; 10:5982. [PMID: 32249851 PMCID: PMC7136233 DOI: 10.1038/s41598-020-63118-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 03/14/2020] [Indexed: 11/09/2022] Open
Abstract
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.
Collapse
Affiliation(s)
- Nikolaus Luft
- University Eye Hospital, Ludwig-Maximilians-University, Munich, Germany. .,SMILE Eyes Clinic, Linz, Austria.
| | - Jakob Siedlecki
- University Eye Hospital, Ludwig-Maximilians-University, Munich, Germany.,SMILE Eyes Clinic, Linz, Austria
| | - Benedikt Schworm
- University Eye Hospital, Ludwig-Maximilians-University, Munich, Germany.,SMILE Eyes Clinic, Linz, Austria
| | - Thomas C Kreutzer
- University Eye Hospital, Ludwig-Maximilians-University, Munich, Germany
| | - Wolfgang J Mayer
- University Eye Hospital, Ludwig-Maximilians-University, Munich, Germany
| | - Siegfried G Priglinger
- University Eye Hospital, Ludwig-Maximilians-University, Munich, Germany.,SMILE Eyes Clinic, Linz, Austria
| | - Martin Dirisamer
- University Eye Hospital, Ludwig-Maximilians-University, Munich, Germany.,SMILE Eyes Clinic, Linz, Austria
| |
Collapse
|
12
|
Yagi-Yaguchi Y, Negishi K, Saiki M, Torii H, Tsubota K. Comparison of the Accuracy of Newer Intraocular Lens Power Calculation Methods in Eyes That Underwent Previous Phototherapeutic Keratectomy. J Refract Surg 2019; 35:310-316. [PMID: 31059580 DOI: 10.3928/1081597x-20190410-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 04/09/2019] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate the accuracy of intraocular lens (IOL) power calculations using ray tracing software in patients who had undergone phototherapeutic keratectomy (PTK). METHODS In this retrospective case series, 37 eyes of 22 patients (mean age: 69.4 years; range: 56 to 85 years) who underwent cataract surgery after PTK were reviewed. The prediction error, defined as the difference between the estimated postoperative spherical equivalent and the postoperative manifest refraction at the spectacle plane, was calculated using the following formulas: OKULIX (Tedics, Dortmund, Germany), PhacoOptics (IOL Innovations ApS, Aarhus, Denmark), Barrett True K No History (NH), and Camellin-Calossi. The PhacoOptics formula was used in three different ways: historical method (H), no history method (NH), and C-constant method (C). The median values of the arithmetic and absolute prediction errors among these six IOL calculation methods were compared. RESULTS The median arithmetic errors (in diopters [D]) and percentages of eyes within ±0.50 D of the absolute errors were as follows: OKULIX (0.33, range: -2.20 to 2.50, 30.6%), PhacoOptics (H) (-0.12, range: -3.28 to 4.85, 22.2%), PhacoOptics (NH) (-0.25, range: -2.08 to 1.70, 48.4%), PhacoOptics (C) (0.04, range: -1.40 to 2.18, 48.5%), Barrett True K (NH) (-0.35, range: -1.90 to 1.89, 48.6%), and Camellin-Calossi (-0.19, range: -1.78 to 1.47, 59.5%). CONCLUSIONS The PhacoOptics, especially the C-constant method (C), and Camellin-Calossi formulas were good options for calculating IOL powers in eyes that underwent PTK. [J Refract Surg. 2019;35(5):310-316.].
Collapse
|
13
|
Nabil KM. Accuracy of minus power intraocular lens calculation using OKULIX ray tracing software. Int Ophthalmol 2018; 39:1803-1808. [PMID: 30141002 DOI: 10.1007/s10792-018-1007-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 08/17/2018] [Indexed: 11/25/2022]
Abstract
PURPOSE The purpose of this retrospective study was to assess the accuracy of minus power intraocular lens calculation using partial coherence interferometry and OKULIX ray tracing software. METHODS We included 25 consecutive, myopic eyes with axial length ≥ 30 mm (25 patients, 13 males and 12 females, and 57.6 ± 10.3 years old), which underwent phacoemulsification and implantation of a minus power intraocular lens in the capsular bag. Axial length measurement and corneal topography were performed using the OA-1000 optical biometer and Topographic Modeling System TMS-5, respectively. The IOL power was calculated using SRK/T formula and OKULIX ray tracing software. The implanted IOL power was chosen based on OKULIX ray tracing software calculation aiming for - 2 diopters (D) of myopia. RESULTS SRK/T calculated IOL power (- 6.3 ± 2.8 D) showed statistically significant difference compared to OKULIX calculated IOL power (- 4.7 ± 2.6 D), rs 0.994 p < 0.001. The expected refraction with implanted IOL was - 1.7 ± 0.9 D based on OKULIX ray tracing software calculation. A statistically significant difference was reported between implanted IOL and OKULIX calculated IOL power (2.7 ± 1.4 D), rs 0.981 p < 0.001. A statistically significant difference was reported between the expected refraction with implanted IOL and the achieved spherical refraction at 1 month postoperatively (1.4 ± 0.7 D), rs 0.77 p < 0.001. The achieved spherical refraction at 1 month postoperatively was 0.2 ± 0.2 D. CONCLUSIONS Although OKULIX ray tracing software yielded more accurate minus power intraocular lens calculation in extreme myopia, compared to SRK/T formula, yet it still shows tendency toward hyperopia.
Collapse
Affiliation(s)
- Karim Mahmoud Nabil
- Department of Ophthalmology, Faculty of Medicine, University of Alexandria, 19 Amin Fekry Street, Raml station, Alexandria, 21523, Egypt.
| |
Collapse
|
14
|
Lanza M, Koprowski R, Bifani Sconocchia M. Improving accuracy of corneal power measurement with partial coherence interferometry after corneal refractive surgery using a multivariate polynomial approach. Biomed Eng Online 2018; 17:108. [PMID: 30103748 PMCID: PMC6090680 DOI: 10.1186/s12938-018-0542-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 08/09/2018] [Indexed: 11/16/2022] Open
Abstract
Background To improve accuracy of IOLMaster (Carl Zeiss, Jena, Germany) in corneal power measurement after myopic excimer corneal refractive surgery (MECRS) using multivariate polynomial analysis (MPA). Methods One eye of each of 403 patients (mean age 31.53 ± 8.47 years) was subjected to MECRS for a myopic defect, measured as spherical equivalent, ranging from − 9.50 to − 1 D (mean − 4.55 ± 2.20 D). Each patient underwent a complete eye examination and IOLMaster scan before surgery and at 1, 3 and 6 months follow up. Axial length (AL), flatter keratometry value (K1), steeper keratometry value (K2), mean keratometry value (KM) and anterior chamber depth measured from the corneal endothelium to the anterior surface of the lens (ACD) were used in a MPA to devise a method to improve accuracy of KM measurements. Results Using AL, K1, K2 and ACD measured after surgery in polynomial degree 2 analysis, mean error of corneal power evaluation after MECRS was + 0.16 ± 0.19 D. Conclusions MPA was found to be an effective tool in devising a method to improve precision in corneal power evaluation in eyes previously subjected to MECRS, according to our results.
Collapse
Affiliation(s)
- Michele Lanza
- Multidisciplinary Department of Medical, Surgical and Dental Sciences, Campania University "Luigi Vanvitelli", Via de Crecchio 16, 80100, Naples, Italy.
| | - Robert Koprowski
- Department of Biomedical Computer Systems, Faculty of Computer Science and Materials Science, Institute of Computer Science, University of Silesia, Sosnowiec, Poland
| | - Mario Bifani Sconocchia
- Multidisciplinary Department of Medical, Surgical and Dental Sciences, Campania University "Luigi Vanvitelli", Via de Crecchio 16, 80100, Naples, Italy
| |
Collapse
|
15
|
Savini G, Hoffer KJ. Intraocular lens power calculation in eyes with previous corneal refractive surgery. EYE AND VISION 2018; 5:18. [PMID: 30038922 PMCID: PMC6053834 DOI: 10.1186/s40662-018-0110-5] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Accepted: 06/22/2018] [Indexed: 01/14/2023]
Abstract
Background This review aims to explain the reasons why intraocular lens (IOL) power calculation is challenging in eyes with previous corneal refractive surgery and what solutions are currently available to obtain more accurate results. Review After IOL implantation in eyes with previous LASIK, PRK or RK, a refractive surprise can occur because i) the altered ratio between the anterior and posterior corneal surface makes the keratometric index invalid; ii) the corneal curvature radius is measured out of the optical zone; and iii) the effective lens position is erroneously predicted if such a prediction is based on the post-refractive surgery corneal curvature. Different methods are currently available to obtain the best refractive outcomes in these eyes, even when the perioperative data (i.e. preoperative corneal power and surgically induced refractive change) are not known. In this review, we describe the most accurate methods based on our clinical studies. Conclusions IOL power calculation after myopic corneal refractive surgery can be calculated with a variety of methods that lead to relatively accurate outcomes, with 60 to 70% of eyes showing a prediction error within 0.50 diopters.
Collapse
Affiliation(s)
| | - Kenneth J Hoffer
- 2Stein Eye Institute, University of California, Los Angeles, CA USA.,St. Mary's Eye Center, Santa Monica, CA USA
| |
Collapse
|
16
|
Steinwender G, Shajari M, Kohnen T. Refractive Outcomes After Femtosecond Laser-Assisted Cataract Surgery in Eyes With Anterior Chamber Phakic Intraocular Lenses. J Refract Surg 2018; 34:338-342. [PMID: 29738590 DOI: 10.3928/1081597x-20180228-01] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 02/02/2018] [Indexed: 11/20/2022]
Abstract
PURPOSE To report the efficacy, predictability, and safety of femtosecond laser-assisted cataract surgery (FLACS) in eyes with anterior chamber phakic intraocular lenses (IOLs). METHODS This retrospective case series included eyes with previous implantation of an angle-supported and an iris-fixated phakic IOL for the correction of myopia that underwent a combined procedure of phakic IOL ex-plantation and FLACS with in-the-bag implantation of a posterior chamber IOL. Postoperative corrected distance visual acuity (CDVA), predictability of refractive outcome, and occurrence of intraoperative and postoperative complications were analyzed. RESULTS Ten eyes of 7 patients with significant cataract were included: 5 eyes with an angle-supported foldable hydrophobic phakic IOL, 4 eyes with an angle-supported polymethylmethacrylate (PMMA) phakic IOL, and 1 eye with an iris-fixated PMMA phakic IOL. Mean follow-up after FLACS was 8.4 ± 5.8 months. Mean interval between phakic IOL implantation and FLACS was 11.9 ± 4.0 years. After the combined procedure of phakic IOL explantation and FLACS, mean manifest refractive spherical equivalent (MRSE) was -0.11 ± 0.49 diopters (D) and MRSE was within ± 0.75 D of target refraction in all eyes. Four eyes received a toric posterior chamber IOL after phacoemulsification. Mean preoperative CDVA of 0.40 ± 0.23 logMAR improved significantly to 0.22 ± 0.11 logMAR postoperatively (P = .027). No intraoperative or postoperative complications occurred. CONCLUSIONS The results in this series showed that FLACS in eyes with previous implantation of both rigid and foldable anterior chamber phakic IOLs offers good refractive outcomes with a high level of predictability and safety. [J Refract Surg. 2018;34(5):338-342.].
Collapse
|
17
|
Camps VJ, Miret JJ, García C, Tolosa A, Piñero DP. Simulation of the Effect of Different Presbyopia-Correcting Intraocular Lenses With Eyes With Previous Laser Refractive Surgery. J Refract Surg 2018; 34:222-227. [DOI: 10.3928/1081597x-20180130-02] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 12/20/2017] [Indexed: 01/31/2023]
|
18
|
Ghoreyshi M, Khalilian A, Peyman M, Mohammadinia M, Peyman A. Comparison of OKULIX ray-tracing software with SRK-T and Hoffer-Q formula in intraocular lens power calculation. J Curr Ophthalmol 2017; 30:63-67. [PMID: 29564411 PMCID: PMC5859630 DOI: 10.1016/j.joco.2017.06.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 06/11/2017] [Accepted: 06/24/2017] [Indexed: 11/16/2022] Open
Abstract
Purpose To compare the performance of OKULIX ray-tracing software with SRK-T and Hoffer Q formula in intraocular lens (IOL) power calculation in patients presenting with cataract. Methods In this prospective study, 104 eyes of 104 patients with cataract who underwent phacoemulsification and IOL implantation were recruited. Three IOL brands were used and for all eyes, IOL power calculation was performed using SRK-T, Hoffer Q formula and also OKULIX ray-tracing software. For all patients, axial length and keratometry data was obtained with IOLMaster 500 device and IOL power was determined using Hoffer Q and SRK-T formula. The IOL powers were also calculated using the OKULIX ray-tracing software combined with CASIA AS-OCT and IOLMaster 500 device. Optically measured axial length of eyes were inserted to OKULIX software from IOLMaster 500 device, and anterior and posterior tomographic and corneal pachymetry data was imported from CASIA AS-OCT into the OKULIX. The performance of each calculation methods was measured by subtracting the predicted postoperative refraction from the postoperative manifest refraction spherical equivalent (MRSE). For each of the 3 methods, the mean absolute prediction error was determined, too. Results The mean value absolute prediction error by OKULIX, SRK-T and Hoffer Q formulas, respectively, were 0.42 (±0.03), 0.36 (±0.02) and 0.37 (±0.02). The mean absolute prediction error by OKULIX had no significant difference between three IOL groups (P = 0.96), and it was confirmed that there was no meaningful statistically difference in mean absolute prediction error between the OKULIX, SRK-T and Hoffer Q formula. (P = 0.25). Also in each group of implanted IOLs, all three formulas worked with the same accuracy. The prediction error using OKULIX were within ±0.50 diopter in 63.5% of eyes and within ±1.00 diopter in 94.2% of eyes. Conclusion OKULIX ray-tracing IOL power measurements provides reliable and satisfactory postoperative results, which are comparable to other 3rd generation formulas of SRK-T and Hoffer Q.
Collapse
|
19
|
Intraocular lens power calculation following laser refractive surgery. EYE AND VISION 2015; 2:7. [PMID: 26605363 PMCID: PMC4655459 DOI: 10.1186/s40662-015-0017-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 03/11/2015] [Indexed: 11/10/2022]
Abstract
Refractive outcomes following cataract surgery in patients that have previously undergone laser refractive surgery have traditionally been underwhelming. This is related to several key issues including the preoperative assessment (keratometry) and intraocular lens power calculations. Peer-reviewed literature is overwhelmed by the influx of methodology to manipulate the corneal or intraocular lens (IOL) powers following refractive surgery. This would suggest that the optimal derivative formula has yet been introduced. This review discusses the problems facing surgeons approaching IOL calculations in these post-refractive laser patients, the existing formulae and programs to address these concerns. Prior published outcomes will be reviewed.
Collapse
|
20
|
Gyldenkerne A, Ivarsen A, Hjortdal JØ. Assessing the corneal power change after refractive surgery using Scheimpflug imaging. Ophthalmic Physiol Opt 2015; 35:299-307. [PMID: 25703372 DOI: 10.1111/opo.12202] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 01/05/2015] [Indexed: 11/29/2022]
Abstract
PURPOSE To investigate whether the Pentacam HR could accurately predict the surgically induced refractive change in patients operated with small-incision lenticule extraction (SMILE) for myopia or femto-second laser in situ keratomileusis (FS-LASIK) for myopia or hyperopic astigmatism. METHODS Data from three groups consisting of (1) 410 myopic eyes of 410 patients operated with SMILE, (2) 111 myopic eyes of 111 patients operated with FS-LASIK, and (3) 40 eyes of 40 patients with hyperopic astigmatism operated with FS-LASIK were retrospectively analysed. The change in manifest refraction due to surgery was compared with the objectively measured change in corneal power by the Pentacam HR in three different ways: Sagittal Power (calculated as for placido topographers), True Net Power (calculated by a Gaussian optics formula), and Total Corneal Refractive Power (calculated by ray tracing). Multiple linear regression analysis was performed to investigate which parameters influenced the Pentacam HR's prediction of the change in subjective refraction due to surgery. RESULTS The Total Corneal Refractive Power Apex, Zone calculation in a diameter of 4.0 mm effectively predicted the surgically induced refractive change for all three patient groups. The spherical equivalent was predicted with an error of 0.08 ± 0.41 D for the SMILE eyes, 0.05 ± 0.61 D for the myopic eyes operated with FS-LASIK, and -0.15 ± 0.49 D for the hyperopic astigmatic eyes treated with FS-LASIK. Regression showed that preoperative refractive error had a significant impact on the prediction error of the Pentacam HR. CONCLUSIONS Ray tracing calculations based on Scheimpflug imaging accurately assessed the change in manifest refraction due to corneal laser surgery.
Collapse
Affiliation(s)
- Anders Gyldenkerne
- Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark
| | | | | |
Collapse
|
21
|
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.
Collapse
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
| | | |
Collapse
|
22
|
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]
|
23
|
Savini G, Bedei A, Barboni P, Ducoli P, Hoffer KJ. Intraocular lens power calculation by ray-tracing after myopic excimer laser surgery. Am J Ophthalmol 2014; 157:150-153.e1. [PMID: 24099275 DOI: 10.1016/j.ajo.2013.08.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2013] [Revised: 08/02/2013] [Accepted: 08/05/2013] [Indexed: 11/30/2022]
Abstract
PURPOSE To investigate the refractive outcomes of intraocular lens (IOL) power calculation by ray-tracing after myopic excimer laser surgery. DESIGN Prospective, interventional case series. METHODS setting: Multicenter study. participants: Twenty-one eyes of 21 patients undergoing phacoemulsification and IOL implantation after myopic laser in situ keratomileusis or photorefractive keratectomy were enrolled. intervention: IOL power calculation was performed using internal software of a Scheimpflug camera combined with a Placido disc corneal topographer (Sirius; CSO). Exact ray-tracing was carried out after the axial length (measured either by immersion ultrasound biometry or partial coherence interferometry), target refraction, and pupil size had been entered. main outcome measures: Median absolute error, mean absolute error, and mean arithmetic error in refraction prediction, that is, the difference between the expected refraction (as calculated by the software) and the actual refraction 1 month after surgery. RESULTS The mean postoperative refraction was -0.43 ± 1.08 diopters (D), with a range between -1.28 and 0.85 D. The mean arithmetic error was -0.13 ± 0.49 D. The median and mean absolute errors were +0.25 D and 0.36 D, respectively. Also, 71.4% of the eyes were within ± 0.50 D of the predicted refraction, 85.7% were within ± 1.00 D, and 100% within ± 1.50 D. CONCLUSIONS Ray-tracing can calculate IOL power accurately in eyes with prior myopic laser in situ keratomileusis and photorefractive keratectomy, with no need for preoperative data.
Collapse
Affiliation(s)
- Giacomo Savini
- Giovanni Battista Bietti Foundation, Istituto di Ricerca e Cura a Carattere Scientifico, Rome, Italy.
| | - Andrea Bedei
- Casa di Cura San Camillo, Forte dei Marmi, Italy
| | | | - Pietro Ducoli
- Giovanni Battista Bietti Foundation, Istituto di Ricerca e Cura a Carattere Scientifico, Rome, Italy
| | - Kenneth J Hoffer
- Jules Stein Eye Institute, University of California, Los Angeles, Los Angeles, California, and St. Mary's Eye Center, Santa Monica, California
| |
Collapse
|
24
|
Miyata K, Otani S, Honbou N, Minami K. Use of Scheimpflug corneal anterior-posterior imaging in ray-tracing intraocular lens power calculation. Acta Ophthalmol 2013; 91:e546-9. [PMID: 23890181 DOI: 10.1111/aos.12139] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To examine improvement with the use of Scheimpflug imaging of the anterior and posterior corneal surfaces in the accuracy of ray-tracing intraocular lens (IOL) power calculation for normal cataractous eyes. METHODS Prospective case series comprised 136 eyes of 136 consecutive patients who had undergone cataract surgeries. Scheimpflug imaging of the cornea was included with routine preoperative examinations. Postoperative refractions were predicted using three methodologies; ray-tracing calculation using Scheimpflug imaging and Placido topography, ray-tracing calculations using Placido topography, and the SRK/T formula using autokeratometry. Prediction errors from the manifest refraction at 1 month postoperatively were compared between the methods. Influence of the posterior corneal curvature was also evaluated. RESULTS Mean prediction errors were 0.008, -0.103 and -0.042 D, respectively without significant difference between the three methods (p = 0.23). The prediction errors were significantly correlated with the posterior corneal curvature when the Scheimpflug imaging was not used (p < 0.03). CONCLUSION Use of Scheimpflug imaging in ray-tracing IOL power calculation was as accurate as the other calculations in normal cases, showing no bias in the posterior corneal curvature, as is the case with the other calculations.
Collapse
|
25
|
Hoffmann P, Wahl J, Preußner PR. Accuracy of Intraocular Lens Calculation With Ray Tracing. J Refract Surg 2012; 28:650-5. [DOI: 10.3928/1081597x-20120815-08] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Accepted: 08/03/2012] [Indexed: 11/20/2022]
|
26
|
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]
|
27
|
von Mohrenfels CW, Salgado J, Khoramnia R, Maier M, Lohmann CP. Clinical Results with the Light Adjustable Intraocular Lens After Cataract Surgery. J Refract Surg 2010; 26:314-20. [DOI: 10.3928/1081597x-20090617-12] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Accepted: 05/07/2009] [Indexed: 01/25/2023]
|
28
|
Comparison of ray-tracing method and thin-lens formula in intraocular lens power calculations. J Cataract Refract Surg 2009; 35:650-62. [DOI: 10.1016/j.jcrs.2008.12.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2008] [Revised: 12/05/2008] [Accepted: 12/17/2008] [Indexed: 11/21/2022]
|
29
|
Haigis W. Intraocular lens calculation after refractive surgery for myopia: Haigis-L formula. J Cataract Refract Surg 2008; 34:1658-63. [DOI: 10.1016/j.jcrs.2008.06.029] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2008] [Accepted: 06/20/2008] [Indexed: 10/21/2022]
|
30
|
Bibliography. Current world literature. Corneal and external disorders. Curr Opin Ophthalmol 2008; 19:363-6. [PMID: 18545022 DOI: 10.1097/icu.0b013e328308161d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|