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Langenbucher A, Cayless A, Kormanyos K, Wendelstein J, Hoffmann P, Szentmáry N. Monte-Carlo simulation for calculating phakic supplementary lenses based on a thick and thin lens model using anterior segment OCT data. Graefes Arch Clin Exp Ophthalmol 2024; 262:1553-1565. [PMID: 38150030 PMCID: PMC11031462 DOI: 10.1007/s00417-023-06331-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 07/26/2023] [Accepted: 11/30/2023] [Indexed: 12/28/2023] Open
Abstract
BACKGROUND Phakic lenses (PIOLs, the most common and only disclosed type being the implantable collamer lens, ICL) are used in patients with large or excessive ametropia in cases where laser refractive surgery is contraindicated. The purpose of this study was to present a strategy based on anterior segment OCT data for calculating the refraction correction (REF) and the change in lateral magnification (ΔM) with ICL implantation. METHODS Based on a dataset (N = 3659) containing Casia 2 measurements, we developed a vergence-based calculation scheme to derive the REF and gain or loss in ΔM on implantation of a PIOL having power PIOLP. The calculation concept is based on either a thick or thin lens model for the cornea and the PIOL. In a Monte-Carlo simulation considering, all PIOL steps listed in the US patent 5,913,898, nonlinear regression models for REF and ΔM were defined for each PIOL datapoint. RESULTS The calculation shows that simplifying the PIOL to a thin lens could cause some inaccuracies in REF (up to ½ dpt) and ΔM for PIOLs with high positive power. The full range of listed ICL powers (- 17 to 17 dpt) could correct REF in a range from - 17 to 12 dpt with a change in ΔM from 17 to - 25%. The linear regression considering anterior segment biometric data and the PIOLP was not capable of properly characterizing REF and ΔM, whereas the nonlinear model with a quadratic term for the PIOLP showed a good performance for both REF and ΔM prediction. CONCLUSION Where PIOL design data are available, the calculation concept should consider the PIOL as thick lens model. For daily use, a nonlinear regression model can properly predict REF and ΔM for the entire range of PIOL steps if a vergence calculation is unavailable.
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Affiliation(s)
- Achim Langenbucher
- Department of Experimental Ophthalmology, Saarland University, Kirrberger Str 100 Bldg. 2266424, Homburg/Saar, Germany.
| | - Alan Cayless
- School of Physical Sciences, The Open University, Milton Keynes, UK
| | - Kitti Kormanyos
- Department of Ophthalmology, Semmelweis-University, Budapest, Hungary
| | - Jascha Wendelstein
- Department of Experimental Ophthalmology, Saarland University, Kirrberger Str 100 Bldg. 2266424, Homburg/Saar, Germany
- Department of Ophthalmology and Optometry, Johannes-Kepler University, Linz, Austria
| | - Peter Hoffmann
- Augen- und Laserklinik Castrop-Rauxel, Castrop-Rauxel, Germany
| | - Nóra Szentmáry
- Department of Ophthalmology, Semmelweis-University, Budapest, Hungary
- Dr. Rolf M. Schwiete Center for Limbal Stem Cell and Aniridia Research, Saarland University, Homburg/Saar, Germany
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Langenbucher A, Szentmáry N, Cayless A, Gatinel D, Debellemanière G, Wendelstein J, Hoffmann P. Monte-Carlo simulation of a thick lens IOL power calculation. Acta Ophthalmol 2024; 102:e42-e52. [PMID: 37032495 DOI: 10.1111/aos.15666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 03/10/2023] [Accepted: 03/27/2023] [Indexed: 04/11/2023]
Abstract
BACKGROUND The purpose of this Monte-Carlo study is to investigate the effect of using a thick lens model instead of a thin lens model for the intraocular lens (IOL) on the resulting refraction at the spectacle plane and on the ocular magnification based on a large clinical data set. METHODS A pseudophakic model eye with a thin spectacle correction, a thick cornea (curvatures for both surfaces and central thickness) and a thick IOL (equivalent power PL derived from a thin lens IOL, Coddington factor CL (uniformly distributed from -1.0 to 1.0), either preset central thickness LT = 0.9 mm (A) or optic edge thickness ET = 0.2 mm, (B)) was set up. Calculations were performed on a clinical data set containing 21 108 biometric measurements of a cataractous population based on linear Gaussian optics to derive spectacle refraction and ocular magnification using the thin and thick lens IOL models. RESULTS A prediction model (restricted to linear terms without interactions) was derived based on the relevant parameters identified with a stepwise linear regression approach to provide a simple method for estimating the change in spectacle refraction and ocular magnification where a thick lens IOL is used instead of a thin lens IOL. The change in spectacle refraction using a thick lens IOL with (A) or (B) instead of a thin lens IOL with identical power was within limits of around ±1.5 dpt when the thick lens IOL was placed with its haptic plane at the plane of the thin lens IOL. In contrast, the change in ocular magnification from considering the IOL as a thick lens instead of a thin lens was small and not clinically significant. CONCLUSION This Monte-Carlo simulation shows the impact of using a thick lens model IOL with preset LT or ET on the resulting spherical equivalent refraction and ocular magnification. If IOL manufacturers would provide all relevant data on IOL design data and refractive index for all power steps, this would make it possible to perform direct calculations of refraction and ocular magnification.
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Affiliation(s)
- Achim Langenbucher
- Department of Experimental Ophthalmology, Saarland University, Homburg/Saar, Germany
| | - Nóra Szentmáry
- Dr. Rolf M. Schwiete Center for Limbal Stem Cell and Aniridia Research, Saarland University, Homburg/Saar, Germany
- Department of Ophthalmology, Semmelweis-University, Budapest, Hungary
| | - Alan Cayless
- School of Physical Sciences, The Open University, Milton Keynes, UK
| | | | | | - Jascha Wendelstein
- Department of Experimental Ophthalmology, Saarland University, Homburg/Saar, Germany
- Institut für Refraktive- und Ophthalmo-Chirurgie (IROC), Zurich, Switzerland
- Department of Ophthalmology, Johannes Kepler University Linz, Linz, Austria
| | - Peter Hoffmann
- Augen- und Laserklinik Castrop-Rauxel, Castrop-Rauxel, Germany
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Wendelstein JA, Casazza M, Reifeltshammer S, Riaz K, Pantanelli S, Mariacher S, Seiler TG, Kohnen T, Bolz M. Unilateral intraindividual comparison and bilateral performance of a monofocal spherical and diffractive extended depth of field intraocular lens mix-and-match approach. Clin Exp Ophthalmol 2024; 52:31-41. [PMID: 38050340 DOI: 10.1111/ceo.14315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 10/04/2023] [Accepted: 10/08/2023] [Indexed: 12/06/2023]
Abstract
BACKGROUND To evaluate the intraindividual visual performance of a spherical and extended depth of field (EDOF) IOL used in a mix-and-match approach. METHODS Single centre (tertiary care centre), retrospective consecutive case series. Included patients had uneventful cataract surgery with implantation of a spherical monofocal IOL (CT Spheris 204) in the dominant eye and a diffractive EDOF IOL (AT LARA 829) in the non-dominant eye. Monocular and binocular defocus curves and visual acuity at various distances were assessed. In addition, binocular reading speed, contrast sensitivity, and patient satisfaction using QOV, Catquest 9SF, and glare/halo questionnaires are reported. RESULTS A total of 29 patients (58 eyes) were included. We observed significant intra-individual differences for monocular DCIVA, DCNVA, UIVA, and UNVA. There were no differences in monocular BCDVA or UDVA. The monocular defocus curves for the two IOLs significantly differed at defocus steps between -1.0 and -3.5 D. 93.10% of patients reported they would opt for the same combination of IOLs. CONCLUSION Excellent uncorrected and corrected distance visual acuity was demonstrated in both groups. The mix-and-match approach described in this study yielded good intermediate vision and improved near vision with high-patient satisfaction.
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Affiliation(s)
- Jascha A Wendelstein
- Medical Faculty, Johannes Kepler University Linz, Linz, Austria
- Department of Ophthalmology and Optometry, Kepler University Hospital GmbH, Johannes Kepler University Linz, Linz, Austria
- Institute of Experimental Ophthalmology, Saarland University, Homburg, Germany
- IROC-Institut für Refraktive und Ophthalmo-Chirurgie, Zürich, Switzerland
| | - Marina Casazza
- Medical Faculty, Johannes Kepler University Linz, Linz, Austria
- Department of Ophthalmology and Optometry, Kepler University Hospital GmbH, Johannes Kepler University Linz, Linz, Austria
| | - Sophia Reifeltshammer
- Medical Faculty, Johannes Kepler University Linz, Linz, Austria
- Department of Ophthalmology and Optometry, Kepler University Hospital GmbH, Johannes Kepler University Linz, Linz, Austria
| | - Kamran Riaz
- Dean A. McGee Eye Institute, University of Oklahoma, Oklahoma City, Oklahoma, USA
| | - Seth Pantanelli
- Department of Ophthalmology, Penn State College of Medicine, Hershey, Pennsylvania, USA
| | - Siegfried Mariacher
- Medical Faculty, Johannes Kepler University Linz, Linz, Austria
- Department of Ophthalmology and Optometry, Kepler University Hospital GmbH, Johannes Kepler University Linz, Linz, Austria
| | - Theo G Seiler
- IROC-Institut für Refraktive und Ophthalmo-Chirurgie, Zürich, Switzerland
- Klinik für Augenheilkunde, Universitätsklinikum Düsseldorf, Duesseldorf, Germany
- Universitätsklinik für Augenheilkunde, Bern, Switzerland
| | - Thomas Kohnen
- Department of Ophthalmology, Goethe University, Frankfurt, Germany
| | - Matthias Bolz
- Medical Faculty, Johannes Kepler University Linz, Linz, Austria
- Department of Ophthalmology and Optometry, Kepler University Hospital GmbH, Johannes Kepler University Linz, Linz, Austria
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Rangu N, Seiler TG, Riaz KM, Cooke DL, Langenbucher A, Fischinger IR, Kohnen T, Wendelstein J. Considerations on the Calculation of Multifocal Duet Implantation in a Monovision Scenario for the Correction of Presbyopia - A Case Example. Klin Monbl Augenheilkd 2023; 240:1284-1291. [PMID: 37647937 DOI: 10.1055/a-2162-7758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Affiliation(s)
- Neal Rangu
- The University of Oklahoma College of Medicine, Oklahoma City, United States
| | - Theo G Seiler
- Institute for refractive and ophthalmic surgery (IROC), Zürich, Switzerland
- Department of Ophthalmology, Inselspital, Bern, Switzerland
- Department of Ophthalmology, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Kamran M Riaz
- Department of Ophthalmology, University of Oklahoma, Dean McGee Eye Institute, Oklahoma City, Oklahoma, United States
| | - David L Cooke
- Great Lakes Eye Care, St. Joseph, Michigan, United States
- Department of Neurology and Ophthalmology, Michigan State University, East Lansing, Michigan, United States
| | - Achim Langenbucher
- Institute of Experimental Ophthalmology, Saarland University, Homburg/Saar, Germany
| | - Isaak Raphael Fischinger
- Eye Day Clinic at the Spreebogen, Berlin, Germany
- Department of Ophthalmology and Optometry, Kepler University Hospital, Linz, Austria
| | - Thomas Kohnen
- Department of Ophthalmology, Goethe-University, Frankfurt, Germany
| | - Jascha Wendelstein
- Institute for refractive and ophthalmic surgery (IROC), Zürich, Switzerland
- Institute of Experimental Ophthalmology, Saarland University, Homburg/Saar, Germany
- Department of Ophthalmology and Optometry, Kepler University Hospital, Linz, Austria
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Langenbucher A, Hoffmann P, Cayless A, Gatinel D, Debellemanière G, Wendelstein J, Szentmáry N. Considerations of a thick lens formula for intraocular lens power calculation. Z Med Phys 2022:S0939-3889(22)00124-6. [PMID: 36543612 DOI: 10.1016/j.zemedi.2022.11.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 11/15/2022] [Accepted: 11/16/2022] [Indexed: 12/23/2022]
Abstract
BACKGROUND In recent years, some lens manufacturers have committed to providing lens shape data for some of their lens models. The purpose of this study is to present a strategy for prediction of intraocular lens power and residual refraction based on a pseudophakic model eye containing 5 refractive surfaces and to show its applicability using worked examples. METHODS A pseudophakic model eye with a thin spectacle correction, a thick cornea (radius of curvatures for both surfaces and central thickness) and a thick IOL (either radius of curvatures RLa and RLp for front and back surface or equivalent power PL and Coddington factor CL; and either central thickness LT or edge thickness and optic diameter) was set up. Calculations were performed based on linear Gaussian optics (vergence formulae). Formulae were provided to derive the lens power/shape and the residual equivalent spectacle refraction SEQ. From the lens shape the location of the haptic plane HP, the image sided principal plane of the lens HL, and the ocular magnification OM were extracted. RESULTS The calculation of a thick intraocular lens and the prediction of residual refraction is presented with reference to 3 working examples: A) lens varied in PL and shifted with its haptic plane keeping the CL constant, B) lens varied in CL and shifted with its haptic plane keeping PL constant, and C) CL and PL of the lens varied keeping its haptic plane position in the eye constant. For each combination of parameters (PL, CL, or haptic plane shift) the parameters influencing SEQ, OM and HL-HP were analysed. CONCLUSION Some modern optical biometers currently on the market provide the radii of curvature of both corneal surface and all relevant distances in the eye. With additional data on the lens shape, it would be possible to improve lens power calculations by switching from thin to thick lens models for the cornea and for the lens. This would overcome one of the major drawbacks of current lens power calculation methods.
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Affiliation(s)
- Achim Langenbucher
- Department of Experimental Ophthalmology, Saarland University, Homburg/Saar, Germany.
| | - Peter Hoffmann
- Augen- und Laserklinik Castrop-Rauxel, Castrop-Rauxel, Germany
| | - Alan Cayless
- School of Physical Sciences, The Open University, Milton Keynes, United Kingdom
| | | | | | - Jascha Wendelstein
- Department of Experimental Ophthalmology, Saarland University, Homburg/Saar, Germany; Institut für Refraktive- und Ophthalmo-Chirurgie (IROC), Zurich, Switzerland; Department of Ophthalmology, Johannes Kepler University Linz, Austria
| | - Nóra Szentmáry
- Dr. Rolf M. Schwiete Center for Limbal Stem Cell and Aniridia Research, Saarland University, Homburg/Saar, Germany; Department of Ophthalmology, Semmelweis-University, Budapest, Hungary
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