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Na KS, An D, Kim HS, Kim EC. Relation between change of effective lens position and toric IOL rotation after toric IOL implantation. CANADIAN JOURNAL OF OPHTHALMOLOGY 2024:S0008-4182(24)00154-6. [PMID: 38889881 DOI: 10.1016/j.jcjo.2024.05.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 04/16/2024] [Accepted: 05/12/2024] [Indexed: 06/20/2024]
Abstract
OBJECTIVE To evaluate the relationship between change of effective lens position (ELP) and toric intraocular lens (IOL) rotation in patients with increasing postoperative refractive astigmatism after successful toric IOL implantation. METHODS The subjects include 61 people (61 eyes) with increasing residual astigmatism >0.5 D 3 months after successful toric IOL implantation. Clinical measurements included preoperative, 1-week, and 1-, 2-, and 3-month postoperative visual acuity; refraction; keratometer; anterior and posterior corneal astigmatism; ELP by Scheimpflug camera imaging; and IOL axis by slit-lamp biomicroscopic photograph with pupil dilation. RESULTS Residual astigmatism in postoperative month 3 (0.81 ± 0.50 D) is higher than that at postoperative week 1 (0.41 ± 0.38 D; p < 0.05). ELP decreased by 264.44 ± 163.25 μm, and the IOL rotated by 2.91 ± 1.44 degrees from week 1 to month 3 (p < 0.05). The ELP change had a positive correlation with IOL rotation (R2 = 0.383; p = 0.006), and the postoperative refractive astigmatic change had a positive correlation with ELP change (R2 = 0.272; p = 0.027) and IOL rotation (R2 = 0.272; p = 0.0001) from week 1 to month 3. CONCLUSION ELP change can influence toric IOL rotation and increase residual astigmatism after toric IOL implantation.
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Affiliation(s)
- Kyung-Sun Na
- Department of Ophthalmology and Visual Science, Catholic University of Korea College of Medicine, Seoul, South Korea
| | - Dohyeon An
- Department of Ophthalmology and Visual Science, Catholic University of Korea College of Medicine, Seoul, South Korea
| | - Hyun Seung Kim
- Department of Ophthalmology and Visual Science, Catholic University of Korea College of Medicine, Seoul, South Korea
| | - Eun Chul Kim
- Department of Ophthalmology and Visual Science, Catholic University of Korea College of Medicine, Seoul, South Korea.
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Kim J, Park J, Jo Y. Investigation of the myopic outcomes of the newer intraocular lens power calculation formulas in Korean patients with long eyes. Sci Rep 2024; 14:12558. [PMID: 38822089 PMCID: PMC11143184 DOI: 10.1038/s41598-024-63334-y] [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: 03/02/2024] [Accepted: 05/28/2024] [Indexed: 06/02/2024] Open
Abstract
This study investigated the underlying causes of the myopic outcomes of the optic-based newer formulas (Barrett Universal II, EVO 2.0, Kane, Hoffer-QST and PEARL-DGS) in long Korean eyes with Alcon TFNT intraocular lens (IOL) implantation. Postoperative data from 3100 randomly selected eyes of 3100 patients were analyzed to compare the reference back-calculated effective lens positions (ELPs) based on the Haigis formula using conventional axial length (AL) and Cooke-modified AL (CMAL) with the predicted ELP of each single- and triple-optimized Haigis formula applied to AL- and CMAL. Contrary to the AL-applied Haigis formula, the predicted ELP curve of the CMAL-applied, single-optimized Haigis formula, simulating the methods of the newer formulas, exhibited a significant upward deviation from the back-calculated ELP in long eyes. The relationship between the AL and anterior chamber depth in our long-eyed population differed from that in the base population of the PEARL-DGS formula. The myopic outcomes in long eyes appeared to stem from the substantial overestimation of the postoperative IOL position with AL modification, leading to the implantation of inappropriately higher-powered IOLs. This discrepancy may be attributed to the ethnic differences in ocular biometrics, particularly the relatively smaller anterior segment in East Asian patients with long AL.
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Affiliation(s)
- Jinchul Kim
- Department of Ophthalmology, Miracle Eye Clinic, 115-gil, Teheran-ro, Gangnam-gu, Seoul, 06134, Korea.
| | - Joonsung Park
- Department of Ophthalmology, Miracle Eye Clinic, 115-gil, Teheran-ro, Gangnam-gu, Seoul, 06134, Korea
| | - Yoonjung Jo
- Department of Ophthalmology, Miracle Eye Clinic, 115-gil, Teheran-ro, Gangnam-gu, Seoul, 06134, Korea
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Langenbucher A, Hoffmann P, Cayless A, Wendelstein J, Szentmáry N. Evaluation of corneal power from an AS-OCT thick lens model and ray tracing: reliability of the keratometer index. J Cataract Refract Surg 2024; 50:360-368. [PMID: 37962174 DOI: 10.1097/j.jcrs.0000000000001363] [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: 07/27/2023] [Accepted: 11/07/2023] [Indexed: 11/15/2023]
Abstract
PURPOSE To investigate and compare different strategies of corneal power calculations using keratometry, paraxial thick lens calculations and ray tracing. SETTING Tertiary care center. DESIGN Retrospective single-center consecutive case series. METHODS Using a dataset with 9780 eyes of 9780 patients from a cataractous population the corneal front (Ra/Qa) and back (Rp/Qp) surface radius/asphericity, central corneal thickness (CCT), and entrance pupil size (PUP) were recorded using the Casia 2 tomographer. Beside keratometry with the Zeiss (PK Z ) and Javal (PK J ) keratometer index, a thick lens paraxial formula (PG) and ray tracing (PR) was implemented to extract corneal power for pupil sizes from 2 mm to 5 mm in steps of 1 mm and PUP. RESULTS With PUP PK Z /PK J overestimates the paraxial corneal power PG in around 97%/99% of cases and PR in around 80% to 85%/99%. PR is around 1/6 or 5/6 diopters (D) lower compared with PK Z or PK J . For a 2 mm pupil PR is around 0.20/0.91 D lower compared with PK Z /PK J and for a 5 mm pupil PR is comparable with PK Z (around 0.03 D lower) but around 0.70 to 0.75 D lower than PK J . CONCLUSIONS "True" values of corneal power are mostly required in lens power calculations before cataract surgery, and overestimation of corneal power could induce trend errors in refractive outcome with axial length and lens power if compensated with the effective lens position.
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Affiliation(s)
- Achim Langenbucher
- From the Department of Experimental Ophthalmology, Saarland University, Homburg/Saar, Germany (Langenbucher, Wendelstein); Augen- und Laserklinik Castrop-Rauxel, Castrop-Rauxel, Germany (Hoffmann); School of Physical Sciences, The Open University, Milton Keynes, United Kingdom (Cayless); Department of Ophthalmology, Johannes Kepler University Linz, Linz, Austria (Wendelstein); Dr. Rolf M. Schwiete Center for Limbal Stem Cell and Aniridia Research, Saarland University, Homburg/Saar, Germany (Szentmáry); Department of Ophthalmology, Semmelweis-University, Budapest, Hungary (Szentmáry)
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Kim J, Park J, Jo Y. Comparison of the formula accuracy for calculating multifocal intraocular lens power: a single center retrospective study in Korean patients. Sci Rep 2024; 14:4462. [PMID: 38396107 PMCID: PMC10891126 DOI: 10.1038/s41598-024-54889-x] [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: 11/17/2023] [Accepted: 02/18/2024] [Indexed: 02/25/2024] Open
Abstract
This study evaluated the accuracy of newer formulas (Barrett Universal II, EVO 2.0, Kane, Hoffer QST, and PEARL-DGS) and the Haigis formula in Korean patients with the Alcon TFNT multifocal intraocular lens. In total, 3100 randomly selected eyes of 3100 patients were retrospectively reviewed. After constant optimization, the standard deviation (SD) of the prediction error was assessed for the entire group, and the root mean square error was compared for short and long axial length (AL) subgroup analysis. The Cooke-modified AL (CMAL) was experimentally applied to the Haigis formula. All the newer formulas performed well, but they did not significantly outperform the Haigis formula. In addition, all the newer formulas exhibited significant myopic outcomes (- 0.23 to - 0.29 diopters) in long eyes. Application of the CMAL to the Haigis formula with single constant optimization produced similar behavior and higher correlation with the newer formulas. The CMAL-applied triple-optimized Haigis formula yielded a substantially smaller SD, even superior to the Barrett and Hoffer QST formulas. The AL modification algorithms such as the CMAL used in newer formulas to cope with optical biometry's overestimation of the AL in long eyes seemed to overcompensate, particularly in the long eyes of the East Asian population.
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Affiliation(s)
- Jinchul Kim
- Department of Ophthalmology, Miracle Eye Clinic, Teheran-ro, Gangnam-gu, Seoul, 06134, South Korea.
| | - Joonsung Park
- Department of Ophthalmology, Miracle Eye Clinic, Teheran-ro, Gangnam-gu, Seoul, 06134, South Korea
| | - Yoonjung Jo
- Department of Ophthalmology, Miracle Eye Clinic, Teheran-ro, Gangnam-gu, Seoul, 06134, South Korea
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Ting DSJ, Gatinel D, Ang M. Cataract surgery after corneal refractive surgery: preoperative considerations and management. Curr Opin Ophthalmol 2024; 35:4-10. [PMID: 37962882 DOI: 10.1097/icu.0000000000001006] [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: 11/15/2023]
Abstract
PURPOSE OF REVIEW Corneal refractive surgery (CRS) is one of the most popular eye procedures, with more than 40 million cases performed globally. As CRS-treated patients age and develop cataract, the number of cases that require additional preoperative considerations and management will increase around the world. Thus, we provide an up-to-date, concise overview of the considerations and outcomes of cataract surgery in eyes with previous CRS, including surface ablation, laser in-situ keratomileusis (LASIK), and small-incision lenticule extraction (SMILE). RECENT FINDINGS Challenges associated with accurate biometry in eyes with CRS have been mitigated recently through total keratometry, ray tracing, intraoperative aberrometry, and machine learning assisted intraocular lens (IOL) power calculation formulas to improve prediction. Emerging studies have highlighted the superior performance of ray tracing and/or total keratometry-based formulas for IOL power calculation in eyes with previous SMILE. Dry eye remains a common side effect after cataract surgery, especially in eyes with CRS, though the risk appears to be lower after SMILE than LASIK (in the short-term). Recent presbyopia-correcting IOL designs such as extended depth of focus (EDOF) IOLs may be suitable in carefully selected eyes with previous CRS. SUMMARY Ophthalmologists will increasingly face challenges associated with the surgical management of cataract in patients with prior CRS. Careful preoperative assessment of the ocular surface, appropriate use of IOL power calculation formulas, and strategies for presbyopia correction are key to achieve good clinical and refractive outcomes and patient satisfaction. Recent advances in CRS techniques, such as SMILE, may pose new challenges for such eyes in the future.
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Affiliation(s)
- Darren S J Ting
- Birmingham and Midland Eye Centre, Birmingham
- Academic Unit of Ophthalmology, Institute of Inflammation and Ageing, University of Birmingham
- Academic Ophthalmology, School of Medicine, University of Nottingham, Nottingham, UK
| | - Damien Gatinel
- Department of Anterior Segment and Refractive Surgery, Rothschild Foundation Hospital, Paris, France
| | - Marcus Ang
- Singapore National Eye Centre, Singapore Eye Research Institute
- Duke-NUS Medical School, National University of Singapore, Singapore, Singapore
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Savage DE, Pantanelli SM. An update on intraocular lens power calculations in eyes with previous laser refractive surgery. Curr Opin Ophthalmol 2024; 35:34-43. [PMID: 37820078 DOI: 10.1097/icu.0000000000001004] [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: 10/13/2023]
Abstract
PURPOSE OF REVIEW There is an ever-growing body of research regarding intraocular lens (IOL) power calculations following photorefractive keratectomy (PRK), laser-assisted in-situ keratomileusis (LASIK), and small-incision lenticule extraction (SMILE). This review intends to summarize recent data and offer updated recommendations. RECENT FINDINGS Postmyopic LASIK/PRK eyes have the best refractive outcomes when multiple methods are averaged, or when Barrett True-K is used. Posthyperopic LASIK/PRK eyes also seem to do best when Barrett True-K is used, but with more variable results. With both aforementioned methods, using measured total corneal power incrementally improves results. For post-SMILE eyes, the first nontheoretical data favors raytracing. SUMMARY Refractive outcomes after cataract surgery in eyes with prior laser refractive surgery are less accurate and more variable compared to virgin eyes. Surgeons may simplify their approach to IOL power calculations in postmyopic and posthyperopic LASIK/PRK by using Barrett True-K, and employing measured total corneal power when available. For post-SMILE eyes, ray tracing seems to work well, but lack of accessibility may hamper its adoption.
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Affiliation(s)
- Daniel E Savage
- Department of Ophthalmology, David and Ilene Flaum Eye Institute
- Center for Visual Science, University of Rochester, Rochester, New York
| | - Seth M Pantanelli
- Department of Ophthalmology, Penn State College of Medicine, Hershey, Pennsylvania, USA
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Gatinel D, Debellemanière G, Saad A, Rampat R, Wallerstein A, Gauvin M, Malet J. A Simplified Method to Minimize Systematic Bias of Single-Optimized Intraocular Lens Power Calculation Formulas. Am J Ophthalmol 2023; 253:65-73. [PMID: 37150337 DOI: 10.1016/j.ajo.2023.05.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 05/01/2023] [Accepted: 05/01/2023] [Indexed: 05/09/2023]
Abstract
PURPOSE To provide a simplified method to optimize lens constants to zero the mean prediction error (ME) of an intraocular lens (IOL) calculation formula, without the need to program the formula itself, by exploring the influence of IOL and corneal power on the refractive impact of variations in effective lens position. DESIGN Theoretical development of an optimized formula and retrospective clinical evaluation on documented datasets. METHODS Retrospective data from 8878 patients with cataracts with pre- and postoperative measurements available using 4 IOL models and 6 IOL power calculation formulas were examined. A schematic eye model was used to study the impact of small variations in effective lens position (ELP) on the postoperative spherical equivalent (SE) refraction. The impact of keratometry (K) and IOL power (P) on SE was investigated. A theoretical thick lens model was used to devise a formula to zero the average prediction error of an IOL power calculation formula. This was achieved by incrementing the predicted ELP, which could then be translated into an increment in the IOL constant. This method was tested on documented real-life postoperative datasets, using different IOL models and single-constant optimized IOL calculation formulas. RESULTS For small variations in ELP, there was an exponential relationship between IOL power and the resultant postoperative refractive variation. The ELP adjustment necessary to zero the ME equated to a ratio between the ME and the mean of the following expression: 0.0006*(P2+2K*P) on the considered datasets. The accuracy of the values obtained using this formula was confirmed on documented postoperative datasets, and on published and nonpublished formulas. CONCLUSION The proposed method allows surgeons without special expertise to optimize an IOL constant to nullify the ME on a documented dataset without coding the different formulas. The influence of individual eyes is proportional to the squared power of the implanted IOL.
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Affiliation(s)
- Damien Gatinel
- From the Hôpital Fondation Adolphe de Rothschild (D.G., G.D., A.S., R.R., J.M.), Anterior Segment and Refractive Surgery Department, Paris, France.
| | - Guillaume Debellemanière
- From the Hôpital Fondation Adolphe de Rothschild (D.G., G.D., A.S., R.R., J.M.), Anterior Segment and Refractive Surgery Department, Paris, France
| | - Alain Saad
- From the Hôpital Fondation Adolphe de Rothschild (D.G., G.D., A.S., R.R., J.M.), Anterior Segment and Refractive Surgery Department, Paris, France
| | - Radhika Rampat
- From the Hôpital Fondation Adolphe de Rothschild (D.G., G.D., A.S., R.R., J.M.), Anterior Segment and Refractive Surgery Department, Paris, France
| | - Avi Wallerstein
- Department of Ophthalmology and Visual Sciences (A.W., M.G.), McGill University, Montreal, Quebec, Canada; LASIK MD (A.W., M.G.), Montreal, Quebec, Canada
| | - Mathieu Gauvin
- Department of Ophthalmology and Visual Sciences (A.W., M.G.), McGill University, Montreal, Quebec, Canada; LASIK MD (A.W., M.G.), Montreal, Quebec, Canada
| | - Jacques Malet
- From the Hôpital Fondation Adolphe de Rothschild (D.G., G.D., A.S., R.R., J.M.), Anterior Segment and Refractive Surgery Department, Paris, France
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Gatinel D, Debellemanière G, Saad A, Rampat R, Malet J. Theoretical Impact of Intraocular Lens Design Variations on the Accuracy of IOL Power Calculations. J Clin Med 2023; 12:jcm12103404. [PMID: 37240510 DOI: 10.3390/jcm12103404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 04/30/2023] [Accepted: 05/03/2023] [Indexed: 05/28/2023] Open
Abstract
To ascertain the theoretical impact of optical design variations of the intraocular lens (IOL) on the accuracy of IOL power formulas based on a single lens constant using a thick lens eye model. This impact was also simulated before and after optimization. We modeled 70 thick-lens pseudophakic eyes implanted with IOLs of symmetrical optical design and power comprised between 0.50 D and 35 D in 0.5-step increments. Modifications of the shape factor resulting in variations in the anterior and posterior radii of an IOL were made, keeping the central thickness and paraxial powers static. Geometry data from three IOL models were also used. Corresponding postoperative spherical equivalent (SE) were computed for different IOL powers and assimilated to a prediction error of the formula due to the sole change in optical design alone. Formula accuracy was studied before and after zeroization on a uniform and non-uniform realistic IOL power distribution. The impact of the incremental change in optic design variability depended on the IOL power. Design modifications theoretically induce an increase in the standard deviation (SD), Mean Absolute Error (MAE), and Root Mean Square (RMS) of the error. The values of these parameters reduce dramatically after zeroization. While the variations in optical design can affect refractive outcomes, especially in short eyes, the zeroization of the mean error theoretically reduces the impact of the IOL's design and power on the accuracy of IOL power calculation.
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Affiliation(s)
- Damien Gatinel
- Anterior Segment and Refractive Surgery Department, Rothschild Foundation Hospital, 25 Rue Manin, 75019 Paris, France
| | - Guillaume Debellemanière
- Anterior Segment and Refractive Surgery Department, Rothschild Foundation Hospital, 25 Rue Manin, 75019 Paris, France
| | - Alain Saad
- Anterior Segment and Refractive Surgery Department, Rothschild Foundation Hospital, 25 Rue Manin, 75019 Paris, France
| | - Radhika Rampat
- Anterior Segment and Refractive Surgery Department, Rothschild Foundation Hospital, 25 Rue Manin, 75019 Paris, France
| | - Jacques Malet
- Anterior Segment and Refractive Surgery Department, Rothschild Foundation Hospital, 25 Rue Manin, 75019 Paris, France
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