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Salgado RMPC, Torres PFAAS, Marinho AAP. Pupil versus 1st Purkinje capsulotomy centration with femtosecond laser: Long term outcomes with a sinusoidal trifocal lens. JOURNAL OF BIOPHOTONICS 2024; 17:e202300446. [PMID: 38414335 DOI: 10.1002/jbio.202300446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 12/01/2023] [Accepted: 01/28/2024] [Indexed: 02/29/2024]
Abstract
PURPOSE To assess the role of femtosecond laser-assisted capsulotomy centration in the long-term intraocular positioning of a multifocal intraocular lens. DESIGN Prospective comparative study. METHODS A total of 60 eyes of 30 patients underwent femtosecond laser-assisted Refractive Lens Exchange (RLE). For every patient, capsulotomy centration was randomly performed according to pupil centre (PC) in one eye and first Purkinje reflex (FPR) in the other. The intraocular lens (IOL) positioning, visual acuities, spherical equivalent, internal aberrometry and quality of vision were assessed and compared at 3 years' follow-up between groups (PC and FPR). RESULTS Intraocular lens positioning showed a statistically significant difference between groups, with a closer centration to the visual axis in the FPR patients (p < 0.001). Internal aberrometry showed higher values in the PC capsulotomy centration group (p < 0.01). CONCLUSIONS FPR centered capsulotomy is associated to a closer centration of the IOL to the visual axis.
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Affiliation(s)
- Ramiro M P C Salgado
- Departamento de Oftalmologia do Hospital da Arrábida, Hospital de Santo António, Centro Hospitalar e Universitário do Porto, Portugal
| | - Paulo F A A S Torres
- Departamento de Oftalmologia do Hospital da Prelada, Universidade do Porto, Portugal
| | - António A P Marinho
- Departamento de Oftalmologia do Hospital da Luz Arrábida, Universidade do Porto, Portugal
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Stern B, Chowers I, Ben-Eli H. Effect of mydriasis on chord mu value in cataract surgery candidates. Eur J Ophthalmol 2024; 34:759-765. [PMID: 37849296 PMCID: PMC11067402 DOI: 10.1177/11206721231207470] [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: 06/15/2023] [Accepted: 09/26/2023] [Indexed: 10/19/2023]
Abstract
PURPOSE This study investigates the relationship between pupil size during biometry examinations and the chord mu value in candidates for cataract surgery. METHODS Retrospective analysis of ocular biometry measurements was performed on consecutive cataract surgery candidates above 50 years of age, examined between 2018 and 2020 at a single tertiary referral center. Statistical analysis assessed the association between pupil size and the chord mu value. The population was categorized into groups based on pupil size, and an analysis was conducted on the barycenter positions of the iris and pupil center for each group. RESULTS The analysis included 2877 patients. A weak positive correlation was observed between the chord mu value and pupil size using Pearson's test (r = 0.160, p < 0.01). Group stratification by pupil size indicated temporal and inferior shifts in pupil center barycenter as pupil size increased, reflecting asymmetrical pupil dilation during mydriasis. A moderate positive correlation between the chord mu value and chord alpha value was identified (Pearson's test, r = 0.641, p < 0.01). As expected, no correlation was found between chord alpha value and pupil size. CONCLUSIONS Chord mu values were higher in patients with mydriatic pupils, likely due to asymmetric pupil dilation and center displacement. Evaluating chord mu values requires considering pupil status and conducting biometry under standardized lighting to prevent misinterpretation caused by pharmacological dilation. This caution is crucial to avoid erroneously excluding eligible patients from multifocal IOL implants. Alternatively, the chord alpha value could serve as a more appropriate alternative in such scenarios.
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Affiliation(s)
- Benjamin Stern
- Department of Ophthalmology, Hadassah Medical Organization and Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Itay Chowers
- Department of Ophthalmology, Hadassah Medical Organization and Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Hadas Ben-Eli
- Department of Ophthalmology, Hadassah Medical Organization and Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
- Department of Optometry and Vision Science, Hadassah Academic College, Jerusalem, Israel
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Foo VHX, Liu YC, Ang M, Htoon HM, Ting DSJ, Mehta JS. Comparative Study of Primary SMILE, SMILE Enhancement, and Femtosecond Laser-Assisted LASIK on Higher Order Aberrations and Corneal Densitometry. J Refract Surg 2024; 40:e291-e303. [PMID: 38717083 DOI: 10.3928/1081597x-20240314-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
PURPOSE To compare differences in corneal densitometry (CD) and higher order aberrations (HOAs) in eyes that underwent small incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) for the treatment of myopia and myopic astigmatism at postoperative months 3, 6, and 12, and to evaluate their changes in a separate cohort of eyes after SMILE enhancement. METHODS In this prospective, randomized, paired-eye clinical trial, consecutive eligible participants were randomized to undergo SMILE or FS-LASIK in either eye. Main outcome measures were CD and HOAs preoperatively and at 3, 6, and 12 months postoperatively. A separate cohort of consecutive patients who had SMILE and underwent enhancement were also included for comparison. RESULTS For CD, no significant differences were found between SMILE and FS-LASIK up to month 12. For HOA measured by wavefront aberrometry, both SMILE and FS-LASIK had an increase in total root mean square (RMS) HOAs, spherical aberration (SA), and vertical coma up to month 12. SMILE had an additional increase in vertical quatrefoil, and FS-LASIK had an increase in horizontal coma at month 12. FS-LASIK had higher SA than SMILE, whereas SMILE had higher vertical quatrefoil than FS-LASIK at month 12. Central and posterior zone CD had significantly decreased after SMILE enhancement compared to after primary SMILE up to 2 years after enhancement. RMS HOAs, lower order aberrations, and SA were all increased after SMILE enhancement compared to after primary SMILE. CONCLUSIONS SMILE induced lower SA but higher vertical quatrefoil than FS-LASIK at 1 year. Both SMILE and FS-LASIK had similar increases in RMS HOAs and vertical coma up to 1 year. There were no differences in CD between both groups. SMILE enhancement additionally had decreased central and posterior CD but greater RMS HOAs and SA compared to primary SMILE. [J Refract Surg. 2024;40(5):e291-e303.].
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Kim NH, Kim HJ, Cho SC, Han KE. Repeatability and Agreement of Chord Mu between Scheimpflug Tomography and Swept-Source Optical Coherence Tomography. KOREAN JOURNAL OF OPHTHALMOLOGY 2023; 37:510-517. [PMID: 37899279 PMCID: PMC10721399 DOI: 10.3341/kjo.2023.0092] [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: 09/07/2023] [Revised: 10/01/2023] [Accepted: 10/13/2023] [Indexed: 10/31/2023] Open
Abstract
PURPOSE To evaluate repeatability and agreement of chord mu between Scheimpflug tomography (Pentacam HR) and sweptsource optical coherence tomography-based optical biometer (IOLMaster 700). METHODS In this retrospective study, 63 eyes from 33 patients were included. Chord mu, X and Y Cartesian distances between the corneal vertex and the pupil center (Px and Py), and the pupil diameter were compared using two instruments. Repeatability was evaluated using intraclass correlation coefficient (ICC), coefficient of variation (CoV), and within-subject standard deviation (Sw). Interdevice agreement was evaluated using paired t-tests and Bland-Altman plots. RESULTS Although Sw values for all parameters were similar between the two devices, CoV values of chord mu and pupil diameter were lower, and ICC values of those parameters were higher, in the IOLMaster 700 than in the Pentacam HR. Chord mu and pupil diameter values were higher in IOLMaster 700 than Pentacam HR (p < 0.01). The width of the 95% limit of agreement was wide for all parameters. CONCLUSIONS IOLMaster 700 showed better repeatability than Pentacam HR in chord mu, Px, Py, and pupil diameter values. Because there were statistically significant differences and a low level of agreement in chord mu and pupil diameter values between the two devices, they cannot be used interchangeably.
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Affiliation(s)
- Na Hyun Kim
- Department of Ophthalmology, Ewha Womans University Mokdong Hospital, Ewha Womans University College of Medicine, Seoul, Korea
| | - Hyun Jin Kim
- Department of Ophthalmology, Ewha Womans University Mokdong Hospital, Ewha Womans University College of Medicine, Seoul, Korea
| | - Soo Chang Cho
- Department of Ophthalmology, Ewha Womans University Mokdong Hospital, Ewha Womans University College of Medicine, Seoul, Korea
| | - Kyung Eun Han
- Department of Ophthalmology, Ewha Womans University Mokdong Hospital, Ewha Womans University College of Medicine, Seoul, Korea
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Fernández J, Burguera N, Rocha-de-Lossada C, Rachwani-Anil R, Rodríguez-Vallejo M. Influence of a multifocal intraocular lens centration and eye angles on light distortion and ocular scatter index. Graefes Arch Clin Exp Ophthalmol 2023; 261:2291-2299. [PMID: 36884063 DOI: 10.1007/s00417-023-06028-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 01/10/2023] [Accepted: 02/04/2023] [Indexed: 03/09/2023] Open
Abstract
PURPOSE To assess how eye axes and multifocal intraocular lens (MIOL) centration may impact the light distortion index (LDI) and ocular scatter index (OSI). METHODS Fifty-eight subjects implanted with the trifocal MIOL Q-Flex M 640PM or Liberty 677MY (Medicontur) were included in this retrospective analysis. The following variables were collected with the Pentacam Wave (Oculus) considering the vertex normal as the coordinates center: chord-mu to the center of the pupil, chord-alpha to the geometrical center of the cornea, and chord-MIOL to the center of the diffractive ring. These measurements were correlated with OSI (HD Analyzer, Visiometrics) and LDI (light distortion analyzer, CEORLab). RESULTS Chord-MIOL centroid was 0.12 mm at 62°, chord-mu was 0.09 mm at 174°, and chord-alpha was 0.38 mm at 188°. A relationship was found between OSI and LDI, rho = 0.58, p < 0.0005). No relationships were found between chord-mu or chord-alpha and the LDI or OSI, neither for the total magnitude, nor the decomposition in orthogonal components (p > 0.05). The LDI was significantly correlated with the temporal centration of the MIOL versus the vertex normal (rho = 0.32, p = 0.02). CONCLUSIONS As opposed to what has been previously described, the temporal centration of the MIOL was related to a decrease in the LDI. Future studies with extreme values of the included variables are required to establish cut-offs for considering these variables as exclusion criteria in the implantation of a MIOL.
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Affiliation(s)
- Joaquín Fernández
- Qvision, Department of Ophthalmology, VITHAS Almería Hospital, 04120, Almería, Spain
| | - Noemí Burguera
- Qvision, Department of Ophthalmology, VITHAS Almería Hospital, 04120, Almería, Spain
| | - Carlos Rocha-de-Lossada
- Qvision, Department of Ophthalmology, VITHAS Almería Hospital, 04120, Almería, Spain
- Hospital Regional Universitario de Málaga, Plaza del Hospital Civil, S/N, 29009, Málaga, Spain
- Departamento de Cirugía, Área de Oftalmología, Universidad de Sevilla, Doctor Fedriani, S/N, 41009, Sevilla, Spain
| | - Rahul Rachwani-Anil
- Hospital Norte de Málaga, Avenida Poeta Muñoz Rojas, S/N, Antequera, 29200, Málaga, Spain
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Shouchane-Blum K, Reitblat O, Dadon J, Bahar I, Sella R. Evaluating Changes in Apparent Chord Mu after Pharmacological Pupil Dilatation. Ophthalmic Res 2023; 66:921-927. [PMID: 37231882 DOI: 10.1159/000530905] [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: 01/16/2023] [Accepted: 04/24/2023] [Indexed: 05/27/2023]
Abstract
INTRODUCTION Preoperative measurements of apparent chord mu length above 0.6 mm have been associated with higher risks for photic phenomena after cataract surgery with multifocal intraocular lenses (MFIOLs). METHODS This retrospective study evaluated patients scheduled for elective cataract surgery at a single tertiary medical center between 2021 and 2022. Pupil diameter and apparent chord mu length were analyzed for eyes with biometry measurements from IOLMaster 700 (Carl Zeiss Meditec, AG) under photopic light conditions, before and after pharmacological pupil dilatation. Exclusion criteria were visual acuity worse than 20/100, prior intraocular surgery, refractive surgery, iris-related procedures, or pupil abnormalities affecting dilatation. Apparent chord mu lengths before and after pupil dilatation were compared. In addition, multivariate linear regression analysis, using a stepwise method, was conducted to assess possible predictors of apparent chord values. RESULTS Included were 87 eyes of 87 patients. Mean chord mu length increased after pupillary dilatation from 0.32 ± 0.17 mm to 0.41 ± 0.17 mm for right eyes (p < 0.001) and from 0.29 ± 0.16 mm to 0.40 ± 0.22 mm for left eyes (p < 0.001). Seven eyes (8.0%) had an apparent chord mu of 0.6 mm and above pre-dilatation. Fourteen eyes (16.1%) with an apparent chord mu under 0.6 mm pre-dilatation had apparent chord mu of 0.6 mm or above post-dilatation. CONCLUSION Apparent chord mu length significantly increases after pharmacological pupillary dilatation. Pupil size and dilatation status should always be considered during patient selection for a planned MFIOL using apparent chord mu length as a reference marker.
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Affiliation(s)
- Karny Shouchane-Blum
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Department of Ophthalmology, Rabin Medical Center, Petah-Tikva, Israel
| | - Olga Reitblat
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Department of Ophthalmology, Rabin Medical Center, Petah-Tikva, Israel
| | - Judith Dadon
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Department of Ophthalmology, Rabin Medical Center, Petah-Tikva, Israel
| | - Irit Bahar
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Department of Ophthalmology, Rabin Medical Center, Petah-Tikva, Israel
| | - Ruti Sella
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Department of Ophthalmology, Rabin Medical Center, Petah-Tikva, Israel
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Yolcu D. Evaluation of angle kappa using the autorefractometer front monitor image. Photodiagnosis Photodyn Ther 2023; 41:103296. [PMID: 36690196 DOI: 10.1016/j.pdpdt.2023.103296] [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: 12/09/2022] [Revised: 01/09/2023] [Accepted: 01/18/2023] [Indexed: 01/22/2023]
Abstract
Purpose The aim of this study was to present a novel angle kappa (k) measurement method and grading scale using the autorefractometer front monitor image. Methods Two hundred sixty eyes of 130 subjects were included in the study. All eyes were evaluated using the front monitor image from an autorefractometer (ARFMI) (Canon, RK-F1, Japan). The distance from the center of the pupil to the visual axis on the ARFMI was measured using Image J software (http://rsbweb.nih.gov/ij). Sixty eyes of 30 subjects were evaluated using the Lens Star 900 (Haag-Streit AG, Koeniz, Switzerland), and Lens Star 900 angle-k values were compared with autorefractometer measurements to analyze the reliability of the method. Factors that may influence angle-k value were analyzed, and an ARFMI angle-k grading scale was developed and presented in the study. Results The mean ARFMI angle-k was 0.41 ± 0.22 mm, and the Lens Star 900 angle-k was 0.38 ± 0.24 mm. The Pearson correlation test was used to evaluate the reliability of the method, and there was a statistically significant positive correlation between the two methods (r: 0.628, p < 0.001). The mean ARFMI angle-k was higher in old and adult subjects when compared with young subjects, and the difference was statistically significant (p: 0.02 and p: 0.04, respectively). According to the ARFMI analysis, old subjects had narrow and nasally decentralized pupils when compared with young subjects, and the difference was statistically significant (p < 0.00 and p < 0.03, respectively). According to the ARFMI angle-k grading scale, 36.1% of subjects were grade 1, 38.3% were grade 2 on the x axis, and 58.5% were grade 1 on the y axis. Conclusions A novel angle-k measurement method and grading scale is presented in this study. In addition, the factors influencing the ARFMI angle-k and pupillary properties obtained from the ARFMI are evaluated. According to the results, angle-k and pupil properties may be evaluated using an easily evaluable, cost-effective device, which is present in every ophthalmic clinic.
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Affiliation(s)
- Demet Yolcu
- University of Health Sciences, Abdurrahman Yurtaslan Oncology Training and Research Hospital, Department of Ophthalmology, Ankara, Turkey.
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Reliability and agreement of apparent chord mu measurements between static and dynamic evaluations. J Cataract Refract Surg 2023; 49:21-28. [PMID: 36573762 DOI: 10.1097/j.jcrs.0000000000001036] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 07/26/2022] [Indexed: 12/28/2022]
Abstract
PURPOSE To assess the repeatability and agreement of Cartesian coordinates and the length of apparent chord mu and pupil diameter measurements during static (Galilei G4) and dynamic (Topolyzer Vario) evaluations. SETTING IOBA-Eye Institute, Valladolid, Spain. DESIGN Case series. METHODS 3 consecutive measurements per scenario (Galilei G4 and Topolyzer Vario under low mesopic and photopic conditions) were performed by the same clinician. The intrasession repeatability was assessed using the within-subject SD (Sw), the precision, the coefficient of variation, and the intraclass correlation coefficient (ICC). The agreement was analyzed using repeated-measures analysis of variance and the Bland-Altman method. RESULTS Thirty-seven healthy participants were recruited. The Sw values for chord mu parameters and pupil diameter ranged from 0.01 to 0.03 and 0.08 to 0.21, respectively. The ICC was ≥0.89 for all parameters. Galilei G4 and Topolyzer Vario under low mesopic and photopic conditions provided significantly different measures of apparent chord mu length (0.23 ± 0.11 mm, 0.30 ± 0.10 mm, and 0.25 ± 0.11 mm, respectively, P ≤ .02), X-coordinate (-0.18 ± 0.12 mm, -0.27 ± 0.11 mm, and -0.21 ± 0.12 mm, respectively, P < .001), and pupil diameter (3.38 ± 0.50 mm, 6.29 ± 0.60 mm, and 3.04 ± 0.41 mm, respectively, P < .001). Y-coordinate values obtained by Galilei G4 and Topolyzer Vario under low mesopic conditions were significantly different (0.06 ± 0.13 mm vs 0.03 ± 0.11 mm, respectively, P = .02), in contrast to Galilei G4 and Topolyzer Vario under photopic conditions (0.05 ± 0.13 mm, P = .82) and both illumination conditions of Topolyzer Vario (P ≥ .23). CONCLUSIONS Galilei G4 and Topolyzer Vario provide consistent measurements of apparent chord mu Cartesian coordinates and length, as well as pupil diameter; however, the measurements are not interchangeable. Ophthalmic surgeons should consider these findings when planning customized intraocular lens implantation and refractive surgery procedures.
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Koc H, Kaya F. Pupil barycenter configuration in patients with myopia and hyperopia. Int Ophthalmol 2022; 42:3441-3447. [PMID: 35583683 DOI: 10.1007/s10792-022-02343-0] [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: 02/18/2021] [Accepted: 04/18/2022] [Indexed: 10/18/2022]
Abstract
PURPOSE To compare the apparent chord mu between hyperopia and myopia cases and investigate the usefulness of iris barycenter configurations as an alternative for performing kappa angle distance calculations. METHODS This prospective study evaluated 394 eyes of 197 patients classified into two groups according to their spherical equivalent values: the myopic (mean spherical equivalent refraction ≤ - 0.50 D) and the hyperopia group (mean spherical equivalent refraction ≥ + 0.50 D). The two groups were further subdivided according to severity (myopic group: mild, ≤ - 0.50 and ≤ - 3.00 D; moderate, < - 3.00 and ≤ - 6.00 D; severe, < - 6.00 D; hyperopic group: mild, ≥ + 0.50 and ≤ + 2.00 D; moderate, > + 2.00 and ≤ + 4.00 D; severe, > + 4.00 D). The pupil and iris barycenter distance measurements and other parameters were obtained through optical low-coherence reflectometry. RESULTS Of the 197 patients, 109 (55.3%) were female and 88 (44.7%) were male individuals; their ages ranged from 7 to 60 years (mean, 35.16 ± 14.75 years). The average pupil barycenter distances were 0.38 ± 0.15 and 0.21 ± 0.11 mm in hyperopia and myopia patients, respectively (p < 0.01). Corneal and lens thickness measurements were higher in hyperopia patients (p < 0.01, p < 0.01, respectively), whereas anterior chamber depth and pupil diameter measurements were higher in myopia patients (p < 0.01, p < 0.01, respectively). No significant difference in astigmatism or white-to-white measurements was observed between hyperopia and myopia patients (p > 0.05). CONCLUSION The measurements for the apparent chord mu of the pupil and iris barycenter origins were higher in hyperopic than in myopic cases.
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Affiliation(s)
- Haci Koc
- Ophthalmology Department, Private Adatip Hospital, Sakarya, Turkey.
| | - Faruk Kaya
- Ophthalmology Department, Istanbul Medipol University, Istanbul, Turkey
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Langenbucher A, Szentmáry N, Cayless A, Weisensee J, Wendelstein J, Hoffmann P. Translation model for CW chord to angle Alpha derived from a Monte-Carlo simulation based on raytracing. PLoS One 2022; 17:e0267028. [PMID: 35576202 PMCID: PMC9109904 DOI: 10.1371/journal.pone.0267028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 03/31/2022] [Indexed: 11/18/2022] Open
Abstract
Background The Chang-Waring chord is provided by many ophthalmic instruments, but proper interpretation of this chord for use in centring refractive procedures at the cornea is not fully understood. The purpose of this study is to develop a strategy for translating the Chang-Waring chord (position of pupil centre relative to the Purkinje reflex PI) into angle Alpha using raytracing techniques. Methods The retrospective analysis was based on a large dataset of 8959 measurements of 8959 eyes from 1 clinical centre, using the Casia2 anterior segment tomographer. An optical model based on: corneal front and back surface radius Ra and Rp, asphericities Qa and Qp, corneal thickness CCT, anterior chamber depth ACD, and pupil centre position (X-Y position: PupX and PupY), was defined for each measurement. Using raytracing rays with an incident angle IX and IY the CW chord (CWX and CWY) was calculated. Using these data, a multivariable linear model was built up in terms of a Monte-Carlo simulation for a simple translation of incident ray angle to CW chord. Results Raytracing allows for calculation of the CW chord CWX/CWY from biometric measures and the incident ray angle IX/IY. In our dataset mean values of CWX = 0.32±0.30 mm and CWY = -0.10±0.26 mm were derived for a mean incident ray angle (angle Alpha) of IX = -5.02±1.77° and IY = 0.01±1.47°. The raytracing results could be modelled with a linear multivariable model, and the effect sizes for the prediction model for CWX are identified as Ra, Qa, Rp, CCT, ACD, PupX, PupY, IX, and for CWY they are Ra, Rp, PupY, and IY. Conclusion Today the CW chord can be directly measured with any biometer, topographer or tomographer. If biometric measures of Ra, Qa, Rp, CCT, ACD, PupX, PupY are available in addition to the CW chord components CWX and CWY, a prediction of angle Alpha is possible using a simple matrix operation.
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Affiliation(s)
- Achim Langenbucher
- Department of Experimental Ophthalmology, Universität des Saarlandes, Homburg/Saar, Germany
- * E-mail:
| | - Nóra Szentmáry
- Dr. Rolf M. Schwiete Center for Limbal Stem Cell and Aniridia Research, Universität des Saarlandes, Homburg/Saar, Germany
- Department of Ophthalmology, Semmelweis-University, Budapest, Hungary
| | - Alan Cayless
- School of Physical Sciences, The Open University, Milton Keynes, United Kingdom
| | - Johannes Weisensee
- Department of Experimental Ophthalmology, Universität des Saarlandes, Homburg/Saar, Germany
| | - Jascha Wendelstein
- Department of Experimental Ophthalmology, Universität des Saarlandes, Homburg/Saar, Germany
- Medical Faculty, Johannes Kepler University Linz, Linz, Austria
| | - Peter Hoffmann
- Augen- und Laserklinik Castrop-Rauxel, Castrop-Rauxel, Germany
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Langenbucher A, Szentmáry N, Cayless A, Münninghoff L, Wortmann R, Wendelstein J, Hoffmann P. Translation model for anterior segment tomographic data to corneal spherical aberration derived from a Monte-Carlo simulation based on raytracing. Acta Ophthalmol 2022; 100:e1665-e1674. [PMID: 35233935 DOI: 10.1111/aos.15125] [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: 12/14/2021] [Revised: 01/23/2022] [Accepted: 02/18/2022] [Indexed: 11/30/2022]
Abstract
BACKGROUND Intraocular lenses with a negative aspherical design for correction of corneal spherical aberration (SA) have gained popularity in recent decades. In most cases, a 'one size fits all' concept is followed, where all eyes receive lenses with the same SA correction. The purpose of this study is to develop a strategy based on raytracing using anterior segment tomography data to extract corneal SA and to provide simple multivariable linear models for prediction of corneal SA. METHODS The analysis was based on a large dataset of 8737 measurements of 8737 eyes from 1 clinical centre, using the Casia2 anterior segment tomographer. An optical model based on: corneal front and back surface radius Ra and Rp, asphericities Qa and Qp, corneal thickness CCT, anterior chamber depth ACD, and pupil centre position (X-Y position: PupX and PupY ), was defined for each measurement. Corneal SA was derived using a 6-mm aperture perpendicular to the incident ray and centred on the chief ray, and linear prediction models were derived for SA using biometric data. Cross-validation was used for model performance evaluation. RESULTS Using raytracing, the wavefront error within an aperture (6-mm diameter centred on the intersection of the chief ray with the cornea) was calculated and corneal SA was extracted. After identifying the relevant effect sizes (Ra, Qa, Rp Qp, ACD, PupX and PupY ) using stepwise linear regression, linear mixed-effects models (model 1: all effect sizes, model 2: Ra, Qa, Rp and Qp, model 3: Ra and Qa) were set up on the training data in terms of a Monte-Carlo simulation. On the test data (training data), model 1 with a mean absolute/root-mean-squared prediction error of 0.0095/0.0130 (0.0095/0.0127) performed similarly to model 2 with 0.0097/0.0131 (0.0096/0.0127), and both outperformed model3 with 0.0152/0.0197 (0.0148/0.0190). CONCLUSION Based on the Casia2 anterior segment tomographer, corneal SA could be derived using shape data (curvature and asphericities) of both corneal surfaces (model 2). This information could easily be used for selection of the appropriate negative aspherical lens design in cataract surgery.
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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
- Medical Faculty Johannes Kepler University Linz Linz Austria
| | - Peter Hoffmann
- Augen‐ und Laserklinik Castrop‐Rauxel Castrop‐Rauxel Germany
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Langenbucher A, Szentmáry N, Cayless A, Weisensee J, Wendelstein J, Hoffmann P. Prediction of CW chord as a measure for the eye's orientation axis after cataract surgery from preoperative IOLMaster 700 measurement data. Acta Ophthalmol 2021; 100:e1232-e1239. [PMID: 34850585 DOI: 10.1111/aos.15071] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 09/28/2021] [Accepted: 11/19/2021] [Indexed: 11/27/2022]
Abstract
BACKGROUND The angles alpha and kappa are widely discussed for centring refractive procedures, but they cannot be determined with ophthalmic instruments. The purpose of this study is to investigate the Chang-Waring chord (position of the Purkinje reflex PI relative to the corneal centre) derived from an optical biometer before and after cataract surgery and to study the changes resulting from cataract surgery. METHODS The analysis was based on a large dataset of 1587 complete sets of preoperative and postoperative IOMaster 700 biometry measurements from two clinical centres, each containing: valid data for pupil and corneal centre position, the position of the Purkinje reflex PI originated from a coaxial fixation target, keratometry (K), axial length (AL), anterior chamber depth (ACD), lens thickness (LT), central corneal thickness CCT, and horizontal corneal diameter W2W. The Chang-Waring chord CW was derived from pupil centre and Purkinje reflex PI analysed preoperatively and postoperatively, and a multilinear regression model together with a feedforward neural network algorithm was set up to predict postoperative CW chord from preoperative CW chord, K and biometric distances of the eye. RESULTS The Y component of CW chord shows a slight shift in the inferior direction in both left and right eyes, before and after cataract surgery. The X component shows some shift in the temporal direction, which is more pronounced preoperatively and slightly reduced postoperatively but with a larger variation. The change in CW chord from preoperative to postoperative shows a slight shift in the superior and nasal directions. Our algorithms for prediction of postoperative CW chord using preoperative CW chord, keratometry and biometry as input data performed with a multilinear regression and a feedforward neural network approach were able to reduce the variance, but could not properly predict the postoperative CW chord X and Y components. CONCLUSION The CW chord as the position of the Purkinje reflex PI with respect to the pupil centre can be directly measured with any biometer, topographer or tomographer with a coaxial fixation light. The mean Y component does not differ between right and left eyes or preoperatively and postoperatively, but the mean temporal shift of the X component preoperatively is slightly reduced postoperatively, but with a larger scatter of the values.
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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
| | - Johannes Weisensee
- Department of Experimental Ophthalmology Saarland University Homburg/Saar Germany
| | - Jascha Wendelstein
- Department of Ophthalmology Johannes Kepler University Linz Linz Austria
| | - Peter Hoffmann
- Augen‐ und Laserklinik Castrop‐Rauxel Castrop‐Rauxel Germany
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Rocha-de-Lossada C, Sánchez-González JM, Borroni D, Llorens-Bellés V, Rachwani-Anil R, Torras-Sanvicens J, Romano V, Peraza-Nieves J. Chord Mu (µ) and Chord Alpha (α) Length Changes in Fuchs Endothelial Corneal Dystrophy before and after Descemet Membrane Endothelial Keratoplasty (DMEK) Surgery. J Clin Med 2021; 10:jcm10214844. [PMID: 34768364 PMCID: PMC8584337 DOI: 10.3390/jcm10214844] [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: 08/10/2021] [Revised: 10/14/2021] [Accepted: 10/19/2021] [Indexed: 11/24/2022] Open
Abstract
This paper will evaluate chord mu and alpha length in patients with Fuchs endothelial corneal dystrophy (FECD) and its changes following Descemet membrane endothelial keratoplasty (DMEK). Patients with FECD that underwent DMEK surgery were included in this retrospective study. Scheimpflug Tomography was carried out in order to calculate chord mu and chord alpha lengths prior to surgery and at 3 and 12 months postoperative. This study included 27 eyes from 27 patients. Significant changes in chord mu were observed within the first three months (from 0.47 ± 0.32 to 0.29 ± 0.21 mm, p < 0.01) and remained stable 12 months postoperative (0.30 ± 0.21 mm, p > 0.05). However, chord alpha remained stable throughout the 12 months post surgery (from 0.53 ± 0.19 to 0.49 ± 0.14 mm, p > 0.05). In addition to the pupillary center distance from the corneal center (from 0.35 ± 0.25 to 0.34 ± 0.20 mm, p > 0.05) also remain stable. In FECD patients undergoing DMEK surgery, chord mu length decreased, and chord alpha length remained stable after 12 months of follow-up.
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Affiliation(s)
- Carlos Rocha-de-Lossada
- Department of Ophthalmology, Hospital Clinic de Barcelona Institut Clinic d’Oftalmologia, 08036 Barcelona, Spain; (C.R.-d.-L.); (V.L.-B.); (J.T.-S.); (J.P.-N.)
- Department of Ophthalmology (Qvision), VITHAS Hospital, 04120 Almería, Spain
- Department of Ophthalmology, Hospital Virgen de las Nieves, 18014 Granada, Spain
| | - José-María Sánchez-González
- Department of Physics of Condensed, Optics Area, University of Seville, 41012 Seville, Spain
- Department of Ophthalmology (Tecnolaser Clinic Vision®), Refractive Surgery Centre, 41018 Seville, Spain
- Correspondence:
| | - Davide Borroni
- Department of Doctoral Studies, Riga Stradins University, LV-1007 Riga, Latvia; (D.B.); (V.R.)
- Department of Ophthalmology, Royal Liverpool University Hospital, Liverpool L7 8XP, UK
| | - Víctor Llorens-Bellés
- Department of Ophthalmology, Hospital Clinic de Barcelona Institut Clinic d’Oftalmologia, 08036 Barcelona, Spain; (C.R.-d.-L.); (V.L.-B.); (J.T.-S.); (J.P.-N.)
| | | | - Josep Torras-Sanvicens
- Department of Ophthalmology, Hospital Clinic de Barcelona Institut Clinic d’Oftalmologia, 08036 Barcelona, Spain; (C.R.-d.-L.); (V.L.-B.); (J.T.-S.); (J.P.-N.)
| | - Vito Romano
- Department of Doctoral Studies, Riga Stradins University, LV-1007 Riga, Latvia; (D.B.); (V.R.)
| | - Jorge Peraza-Nieves
- Department of Ophthalmology, Hospital Clinic de Barcelona Institut Clinic d’Oftalmologia, 08036 Barcelona, Spain; (C.R.-d.-L.); (V.L.-B.); (J.T.-S.); (J.P.-N.)
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Espaillat A, Coelho C, Medrano Batista MJ, Perez O. Predictors of Photic Phenomena with a Trifocal IOL. Clin Ophthalmol 2021; 15:495-503. [PMID: 33603327 PMCID: PMC7882435 DOI: 10.2147/opth.s282469] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 12/09/2020] [Indexed: 01/19/2023] Open
Abstract
Aim To assess predictive factors associated with glares and halos in patients undergoing cataract surgery with PanOptix trifocal IOL implantation. Methods Single-center retrospective study. One hundred and forty eyes from 70 patients with cataract were bilaterally implanted with a trifocal PanOptix aspherical diffractive lens between 2017 and 2019 and followed-up for six months. All patients were evaluated for refraction, corneal topography, and aberrometry pre- and post-operatively. Patients were assessed at 1 day, 6 days, 1 and 6 months after surgery. One and six months post-operatively patients were asked to complete a satisfaction questionnaire that included photic phenomena assessment. Main outcome measures were photic phenomena at 1 and 6 months of follow-up. Predictors of photic phenomena at 1 and 6 months were also analyzed. Results A higher corneal coma was associated with more mild halos at 6 months with no association regarding other degrees of severity. The lower the age the higher the glare or halos, the higher the lens thickness and the lower the anterior chamber depth or chord µ the less halos at 1 month. A significant proportion of patients had more none/mild compared to moderate/severe glare and halos both at 1 and 6 months post-operatively. Baseline BCVA was the only predictor of halos at 1 month and glare and halos at 6 months post-surgery. Conclusion On multivariate regression analyses, the only predictor of photic phenomena was baseline visual acuity, suggesting that patients that have a better visual acuity before surgery are more demanding regarding visual outcomes after surgery.
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Affiliation(s)
- Arnaldo Espaillat
- Anterior Segment Department, Instituto Espaillat Cabral, Santo Domingo, Dominican Republic
| | | | | | - Obniel Perez
- Anterior Segment Department, Instituto Espaillat Cabral, Santo Domingo, Dominican Republic
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Nowińska A, Chlasta-Twardzik E, Dembski M, Ulfik-Dembska K, Wylęgała E. Corneal Analysis with Swept Source Optical Coherence Tomography in Patients with Coexisting Cataract and Fuchs Endothelial Corneal Dystrophy. Diagnostics (Basel) 2021; 11:diagnostics11020223. [PMID: 33540847 DOI: 10.3390/diagnostics11020223] [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: 01/09/2021] [Revised: 01/28/2021] [Accepted: 01/29/2021] [Indexed: 11/16/2022] Open
Abstract
This study focused on defining the characteristic features of keratometry and pachymetry elevation maps based on swept source optical coherence tomography (SS OCT) in Fuchs endothelial corneal dystrophy (FECD) eyes with a coexisting cataract. 70 eyes of 35 patients diagnosed with FECD and a coexisting cataract and 70 control eyes were included in this prospective, controlled, observational, cross-sectional study. Features characteristic of intermediately affected eyes included an increased corneal thinnest thickness (CTT) (p = 0.01), 3 and 6 mm asymmetry (p < 0.0001), higher order Fourier indices (p < 0.05 and p ≤ 0.0001, respectively), chord µ, and a posterior Ectasia Screening Index (pESI) (p < 0.01). The lack of agreement between the anterior and posterior elevation map and a significant area of negative values in the posterior map were detected. In advanced FECD eyes, our study additionally revealed decreased posterior keratometry steep (Ks), keratometry flat (Kf), keratometry average (AvgK), eccentricity (Ecc), an increased corneal apex thickness (CAT), and decreased 3 and 6 mm posterior spherical indices (p < 0.0001 for all of the above). Characteristic features of subclinical FECD, independent of the corneal thickness, can be detected by SS OCT and should be considered during the preoperative assessment of patients with a coexisting cataract.
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Affiliation(s)
- Anna Nowińska
- Chair and Clinical Department of Ophthalmology, Faculty of Medical Sciences in Zabrze, Medical University of Silesia, 40-055 Katowice, Poland
- Ophthalmology Department, Railway Hospital, 40-760 Katowice, Poland
| | - Edyta Chlasta-Twardzik
- Chair and Clinical Department of Ophthalmology, Faculty of Medical Sciences in Zabrze, Medical University of Silesia, 40-055 Katowice, Poland
- Ophthalmology Department, Railway Hospital, 40-760 Katowice, Poland
| | - Michał Dembski
- Chair and Clinical Department of Ophthalmology, Faculty of Medical Sciences in Zabrze, Medical University of Silesia, 40-055 Katowice, Poland
- Ophthalmology Department, Railway Hospital, 40-760 Katowice, Poland
| | - Klaudia Ulfik-Dembska
- Chair and Clinical Department of Ophthalmology, Faculty of Medical Sciences in Zabrze, Medical University of Silesia, 40-055 Katowice, Poland
- Ophthalmology Department, Railway Hospital, 40-760 Katowice, Poland
| | - Edward Wylęgała
- Chair and Clinical Department of Ophthalmology, Faculty of Medical Sciences in Zabrze, Medical University of Silesia, 40-055 Katowice, Poland
- Ophthalmology Department, Railway Hospital, 40-760 Katowice, Poland
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Jiang JY, Hodge C, Lawless M. Understanding chord mu through a large population‐based study. Clin Exp Ophthalmol 2020; 48:998-1001. [DOI: 10.1111/ceo.13800] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 05/09/2020] [Indexed: 11/28/2022]
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