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Llorens-Quintana C, Pavlatos E, Thaware O, Gupta S, Gradin D, Romfh D, Li Y, Huang D. Accuracy of OCT-derived net corneal astigmatism measurement. J Cataract Refract Surg 2022; 48:267-274. [PMID: 34326282 PMCID: PMC8792105 DOI: 10.1097/j.jcrs.0000000000000766] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 07/21/2021] [Indexed: 01/29/2023]
Abstract
PURPOSE To assess the repeatability and accuracy of corneal astigmatism measurement with a spectral-domain optical coherence tomography (OCT) system (Avanti, Optovue) and compare them with Scheimpflug imaging (Pentacam HR, Oculus) and swept-source optical biometry (IOLMaster 700, Carl Zeiss Meditec AG). SETTING Casey Eye Institute, Oregon Health & Science University, Portland, Oregon. DESIGN Prospective cross-sectional observational study. METHODS 60 pseudophakic eyes with monofocal nontoric intraocular lens that previously had refractive surgery were analyzed. To assess accuracy, simulated keratometry (SimK) and net corneal astigmatism, obtained from each device, were compared with subjective manifest refraction astigmatism. Repeatability for corneal astigmatism was assessed for OCT and Pentacam HR by the coefficient of repeatability from 3 repeated measures. RESULTS Compared with manifest refraction, SimK readings produced with-the-rule astigmatic bias that was reduced for net astigmatism for the 3 devices. Except for OCT net astigmatism, all instruments significantly overestimated the magnitude of the astigmatism (linear mixed-effects model [LMM], P < .05). OCT net astigmatism showed the highest accuracy for manifest astigmatism prediction with the smaller 95% confidence ellipse for the mean difference vector. OCT net mean absolute difference was 0.57 diopters (D), significantly smaller than that of the other modalities (LMM, P < .05). Net corneal astigmatism measured with OCT showed the best repeatability (coefficient of repeatability = 0.29 D). CONCLUSIONS OCT has the capability to measure net corneal astigmatism with higher precision and accuracy than Pentacam HR Scheimpflug imaging and IOLMaster 700 swept-source optical biometry in postrefractive subjects.
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Affiliation(s)
- Clara Llorens-Quintana
- From the Casey Eye Institute and Department of Ophthalmology, Oregon Health and Science University, Portland, Oregon
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Xu G, Wu G, Du Z, Zhu S, Guo Y, Yu H, Hu Y. Distribution of White-to-White Corneal Diameter and Anterior Chamber Depth in Chinese Myopic Patients. Front Med (Lausanne) 2021; 8:732719. [PMID: 34869427 PMCID: PMC8639187 DOI: 10.3389/fmed.2021.732719] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 10/22/2021] [Indexed: 11/13/2022] Open
Abstract
Purpose: To investigate the distribution of white-to-white (WTW) corneal diameter and anterior chamber depth (ACD) in Chinese myopia patients. Methods: This was a cross-sectional observational study conducted at five ophthalmic centers. Anterior segment biometry was performed in 7,893 eyes of the 7,893 myopic patients using Pentacam, and the WTW and ACD were recorded. The distribution patterns of WTW and ACD were evaluated and the correlation between WTW and ACD was analyzed statistically. Results: There were 4416 (55.95%) males and 3477 (44.05%) females. The age of the study population was 25.14 ± 5.41 years. Distribution of WTW was slightly positively skewed (Skewness = 0.0076, Kurtosis = 0.3944, KS P = 0.020) with a mean of 11.65 ± 0.38 mm and a 95% normal range of 10.91-12.39 mm. A significant difference in WTW was found among different myopia groups (P < 0.001). The ACD was normally distributed (Skewness = 0.899, Kurtosis = 0.027, KS P = 0.086). The mean ACD was 3.25 ± 0.26 mm and the 95% normal range of was 2.74-3.75 mm. A significant difference in ACD was also found among different myopia groups (P = 0.030). There was a significant correlation between WTW and ACD (r = 0.460, P < 0.001). Conclusions: In our study, 95% of the Chinese myopic patients had a WTW within 10.91-12.39 mm and an ACD within 2.74-3.75 mm. ACD and WTW were significantly different among different myopia, gender and age groups. WTW was positively correlated with ACD.
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Affiliation(s)
- Guihua Xu
- Department of Ophthalmology, Huizhou Municipal Central Hospital, Huizhou, China
| | - Guanrong Wu
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Zijing Du
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Shanqing Zhu
- Aier Institute of Refractive Surgery, Refractive Surgery Center, Guangzhou Aier Eye Hospital, Guangzhou, China
| | - Yunxiang Guo
- Aier Institute of Refractive Surgery, Refractive Surgery Center, Guangzhou Aier Eye Hospital, Guangzhou, China
| | - Honghua Yu
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Yijun Hu
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,Aier Institute of Refractive Surgery, Refractive Surgery Center, Guangzhou Aier Eye Hospital, Guangzhou, China.,Aier School of Ophthalmology, Central South University, Changsha, China
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Biometric Measurement of Anterior Segment: A Review. SENSORS 2020; 20:s20154285. [PMID: 32752014 PMCID: PMC7435894 DOI: 10.3390/s20154285] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 07/22/2020] [Accepted: 07/29/2020] [Indexed: 12/12/2022]
Abstract
Biometric measurement of the anterior segment is of great importance for the ophthalmology, human eye modeling, contact lens fitting, intraocular lens design, etc. This paper serves as a comprehensive review on the historical development and basic principles of the technologies for measuring the geometric profiles of the anterior segment. Both the advantages and drawbacks of the current technologies are illustrated. For in vivo measurement of the anterior segment, there are two main challenges that need to be addressed to achieve high speed, fine resolution, and large range imaging. One is the motion artefacts caused by the inevitable and random human eye movement. The other is the serious multiple scattering effects in intraocular turbid media. The future research perspectives are also outlined in this paper.
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Núñez MX, Henriquez MA, Escaf LJ, Ventura BV, Srur M, Newball L, Espaillat A, Centurion VA. Consensus on the management of astigmatism in cataract surgery. Clin Ophthalmol 2019; 13:311-324. [PMID: 30809088 PMCID: PMC6376888 DOI: 10.2147/opth.s178277] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
This project was aimed at achieving consensus on the management of astigmatism during cataract surgery by ophthalmologists from Latin America using modified Delphi technique. Relevant peer-reviewed literature was identified, and 21 clinical research questions associated with the definition, classification, measurement, and treatment of astigmatism during cataract surgery were formulated. Twenty participants were divided into seven groups, and each group was assigned three questions to which they had to respond in written form, after thoroughly reviewing the literature. The assigned questions with corresponding responses by each group were discussed with other participants in round 4 – presentation of findings. The consensus was achieved if approval was obtained from at least 80% of participants. The present paper provides several agreements and recommendations for management of astigmatism during cataract surgery, which could potentially minimize the variability in practice patterns and help ophthalmologists adopt optimal practices for cataract patients with astigmatism and improve patient satisfaction.
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Affiliation(s)
- Maria X Núñez
- Unit of Cornea, Cataract and Refractive Surgery, Grupo de Investigacion Vision Sana, Clinica de Oftalmología de Cali, Universidad Javeriana, Cali, Colombia,
| | - Maria A Henriquez
- Department of Cataract, Department of Research, Oftalmosalud Instituto de Ojos, Lima, Peru
| | - Luis J Escaf
- Clinica Oftalmologica del Caribe (Cofca), Universidad Javeriana, Barranquilla, Colombia
| | - Bruna V Ventura
- Department of Cataract, Altino Ventura Foundation, HOPE Eye Hospital, Recife, Brazil
| | - Miguel Srur
- Centro de la Visión, Filial Clínica Las Condes, Universidad de Los Andes, Santiago de Chile, Chile
| | | | - Arnaldo Espaillat
- Cataract and refractive surgery service, Espaillat Cabral Institute, Santo Domingo, Dominican Republic
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Comparison of Color Light-Emitting Diode Corneal Topographer and Dual Rotating Scheimpflug-Placido Topographer. J Ophthalmol 2018; 2018:6764805. [PMID: 30687546 PMCID: PMC6327256 DOI: 10.1155/2018/6764805] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Revised: 12/01/2018] [Accepted: 12/09/2018] [Indexed: 11/17/2022] Open
Abstract
Purpose To compare measurements of anterior and posterior keratometric values, using a color light-emitting diode corneal topographer and a dual rotating Scheimpflug-Placido topographer. Methods Anterior and posterior corneal index measurements were performed using a color light-emitting diode corneal topographer (Cassini) and a dual rotating Scheimpflug-Placido topographer (Galilei G4) and then compared. The paired t-test, intraclass correlation coefficients (ICCs), and Bland-Altman plots were used to evaluate the agreement between measurements. Results Sixty postrefractive surgery eyes and 60 normal eyes were evaluated. Both the color light-emitting diode corneal topographer and the dual rotating Scheimpflug-Placido topographer provided highly repeatable corneal measurements (ICC > 0.969). The agreement levels between the 2 devices for anterior corneal power, astigmatism magnitude, and J0 and J45 values were ICC > 0.906 for the total group. However, the ICC values for posterior corneal power, astigmatism magnitude, and J0 and J45 values were lower than 0.681 for the total group. Conclusions The anterior keratometric values obtained by the color light-emitting diode corneal topographer and the dual rotating Scheimpflug-Placido topographer showed high agreement levels, but the posterior keratometric values showed lower agreement levels.
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Martin R. Cornea and anterior eye assessment with slit lamp biomicroscopy, specular microscopy, confocal microscopy, and ultrasound biomicroscopy. Indian J Ophthalmol 2018; 66:195-201. [PMID: 29380757 PMCID: PMC5819094 DOI: 10.4103/ijo.ijo_649_17] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Current corneal assessment technologies make the process of corneal evaluation extremely fast and simple, and several devices and technologies show signs that help in identification of different diseases thereby, helping in diagnosis, management, and follow-up of patients. The purpose of this review is to present and update readers on the evaluation of cornea and ocular surface. This first part reviews a description of slit lamp biomicroscopy (SLB), endothelial specular microscopy, confocal microscopy, and ultrasound biomicroscopy examination techniques and the second part describes the corneal topography and tomography, providing up-to-date information on the clinical recommendations of these techniques in eye care practice. Although the SLB is a traditional technique, it is of paramount importance in clinical diagnosis and compulsory when an eye test is conducted in primary or specialist eye care practice. Different techniques allow the early diagnosis of many diseases, especially when clinical signs have not yet become apparent and visible with SLB. These techniques also allow for patient follow-up in several clinical conditions or diseases, facilitating clinical decisions and improving knowledge regarding the corneal anatomy.
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Affiliation(s)
- Raul Martin
- Departamento de Física Teórica, Atómica y Óptica, Universidad de Valladolid; Instituto Universitario de Oftalmobiología Aplicada, Universidad de Valladolid; School of Optometry, IOBA Eye Institute, University of Valladolid, 47011 Valladolid, Spain; Faculty of Health and Human Sciences, Plymouth University, PL6 8BH Plymouth, United Kingdom
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Fan R, Chan TCY, Prakash G, Jhanji V. Applications of corneal topography and tomography: a review. Clin Exp Ophthalmol 2018; 46:133-146. [DOI: 10.1111/ceo.13136] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 12/10/2017] [Accepted: 12/14/2017] [Indexed: 12/25/2022]
Affiliation(s)
- Rachel Fan
- Faculty of Medicine; The University of Hong Kong; Hong Kong
| | - Tommy CY Chan
- Department of Ophthalmology & Visual Sciences; The Chinese University of Hong Kong; Hong Kong
| | - Gaurav Prakash
- NMC Eye Care; NMC Specialty Hospital; Abu Dhabi United Arab Emirates
| | - Vishal Jhanji
- Department of Ophthalmology & Visual Sciences; The Chinese University of Hong Kong; Hong Kong
- Department of Ophthalmology; University of Pittsburgh School of Medicine; Pittsburgh Pennsylvania USA
- Centre for Eye Research Australia; University of Melbourne; Melbourne Victoria Australia
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Yap TE, Archer TJ, Gobbe M, Reinstein DZ. Comparison of Central Corneal Thickness Between Fourier-Domain OCT, Very High-Frequency Digital Ultrasound, and Scheimpflug Imaging Systems. J Refract Surg 2016; 32:110-6. [PMID: 26856428 DOI: 10.3928/1081597x-20151223-01] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 11/10/2015] [Indexed: 11/20/2022]
Abstract
PURPOSE To compare corneal thickness measurements between three imaging systems. METHODS In this retrospective study of 81 virgin and 58 post-laser refractive surgery corneas, central and minimum corneal thickness were measured using optical coherence tomography (OCT), very high-frequency digital ultrasound (VHF digital ultrasound), and a Scheimpflug imaging system. Agreement between methods was analyzed using mean differences (bias) (OCT - VHF digital ultrasound, OCT - Scheimpflug, VHF digital ultrasound - Scheimpflug) and Bland-Altman analysis with 95% limits of agreement (LoA). RESULTS Virgin cornea mean central corneal thickness was 508.3 ± 33.2 µm (range: 434 to 588 µm) for OCT, 512.7 ± 32.2 µm (range: 440 to 587 µm) for VHF digital ultrasound, and 530.2 ± 32.6 µm (range: 463 to 612 µm) for Scheimpflug imaging. OCT and VHF digital ultrasound showed the closest agreement with a bias of -4.37 µm, 95% LoA ±12.6 µm. Least agreement was between OCT and Scheimpflug imaging with a bias of -21.9 µm, 95% LoA ±20.7 µm. Bias between VHF digital ultrasound and Scheimpflug imaging was -17.5 µm, 95% LoA ±19.0 µm. In post-laser refractive surgery corneas, mean central corneal thickness was 417.9 ± 47.1 µm (range: 342 to 557 µm) for OCT, 426.3 ± 47.1 µm (range: 363 to 563 µm) for VHF digital ultrasound, and 437.0 ± 48.5 µm (range: 359 to 571 µm) for Scheimpflug imaging. Closest agreement was between OCT and VHF digital ultrasound with a bias of -8.45 µm, 95% LoA ±13.2 µm. Least agreement was between OCT and Scheimpflug imaging with a bias of -19.2 µm, 95% LoA ±19.2 µm. Bias between VHF digital ultrasound and Scheimpflug imaging was -10.7 µm, 95% LoA ±20.0 µm. No relationship was observed between difference in central corneal thickness measurements and mean central corneal thickness. Results were similar for minimum corneal thickness. CONCLUSIONS Central and minimum corneal thickness was measured thinnest by OCT and thickest by Scheimpflug imaging in both groups. A clinically significant bias existed between Scheimpflug imaging and the other two modalities.
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Repeatability and comparability of corneal power and corneal astigmatism obtained from a point-source color light-emitting diode topographer, a Placido-based corneal topographer, and a low-coherence reflectometer. J Cataract Refract Surg 2016; 41:2242-50. [PMID: 26703301 DOI: 10.1016/j.jcrs.2015.11.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 03/09/2015] [Accepted: 03/18/2015] [Indexed: 11/20/2022]
Abstract
PURPOSE To assess the repeatability and agreement of corneal power and astigmatism obtained from the Cassini point-source color light-emitting diode (LED) topographer, Humphrey Atlas 9000 Placido-based corneal topographer, and Lenstar LS-900 low-coherence reflectometer in normal eyes. SETTING Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA. DESIGN Evaluation of diagnostic test or technology. METHODS Consecutively enrolled patients with normal corneas were enrolled. Three sets of measurements were obtained using the color-LED topographer, the Placido topographer, and the reflectometer. Vector analysis was used in the astigmatism analysis. The repeatability was evaluated using the within-subject standard deviation, coefficient of variation (CoV), and intraclass correlation coefficient (ICC). Agreement was verified using Bland-Altman plots. The paired Student t test was used to assess statistical significance. RESULTS Thirty-two eyes (32 patients) were evaluated. All devices provided highly repeatable corneal power and astigmatism measurements (ICC > 0.9) except for the Placido topographer with regard to J45 (ICC = 0.721). The color-LED topographer and the reflectometer obtained similar mean values of corneal power, astigmatism magnitude, J0, and J45 (P > .05), which was also true when comparing the color-LED topographer and the Placido topographer, except for the mean corneal power (P = .0007). The Bland-Altman plots showed a wide data spread for all analyzed variables. CONCLUSIONS The color-LED topographer provided highly repeatable corneal power and astigmatism measurements. Even though it obtained values similar to those of the reflectometer and the Placido topographer, the wide data spread discourages their interchangeable use to assess corneal power and astigmatism. FINANCIAL DISCLOSURE Drs. Wang, Koch, and Weikert are consultants to Ziemer USA, Inc. Dr. Koch is a consultant to Abbott Medical Optics, Inc., Alcon Surgical, Inc., and i-Optics, Corp. Drs. Ventura and Al-Mohtaseb have no financial or proprietary interest in any material or method mentioned.
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Comparative Evaluation of the Corneal and Anterior Chamber Parameters Derived From Scheimpflug Imaging in Arab and South Asian Normal Eyes. Cornea 2016. [PMID: 26203755 DOI: 10.1097/ico.0000000000000544] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To evaluate the differences in the normal corneal and anterior segment Scheimpflug parameters in Arab and South Asian eyes. METHODS This hospital-based study was performed at a cornea and refractive surgery service in Abu Dhabi. A total of 600 consecutive normal candidates of South Asian (group 1, n = 300) and Arab (group 2, n = 300) origins underwent Scheimpflug imaging (Sirius; Costruzione Strumenti Oftalmici, Italy). One eye was randomly selected for evaluation. RESULTS The age and sex distributions in both groups were comparable. The pachymetric variables were statistically higher in group 2 (group 2 vs. group 1, 544.3 ± 32.2 μm vs. 535.1 ± 31.4 μm for central corneal thickness, 541.0 ± 32.6 μm vs. 531.9 ± 31.5 μm for minimum corneal thickness, 571.7 ± 43.2 μm vs. 558.1 ± 42.3 μm for apical thickness, and 58.1 ± 4.2 vs. 57.3 ± 4.3 mm³ for the corneal volume; P < 0.05). The anterior chamber volume (group 2 vs. group 1: 166.4 ± 16.4 vs. 161.6 ± 20.5 mm³) and angle (group 2 vs. group 1: 44.6 ± 6.2 vs. 43.5 ± 5.8 degrees) were also higher for group 2 (P < 0.05). Central corneal curvature and apical corneal curvature (apex K) were higher in group 1 (P < 0.05) with comparable astigmatism. The flat keratometry (K), steep K, and apex K were 43.6 ± 2.2 diopters (D), 44.9 ± 1.8 D, and 45.7 ± 1.8 D for group 1, and 43.1 ± 2.2 D, 44.5 ± 2 D, and 45.2 ± 1.9 D for group 2. The effect size (Cohen d) for significant parameters ranged from 0.2 to 0.3. CONCLUSIONS Normal eyes of Arab ethnicity tend to have statistically thicker and flatter corneas and less-crowded anterior segments than those of the South Asian counterparts. These epidemiological differences have a mild to moderate biological effect size (Cohen d), but they should be considered when evaluating these eyes for anterior segment or corneal procedures.
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Ma XY, Zhu D, Zou J, Zhang WJ, Cao YL. Comparison of ultrasound biomicroscopy and spectral-domain anterior segment optical coherence tomography in evaluation of anterior segment after laser peripheral iridotomy. Int J Ophthalmol 2016; 9:417-23. [PMID: 27158613 DOI: 10.18240/ijo.2016.03.16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 07/13/2015] [Indexed: 11/23/2022] Open
Abstract
AIM To quantitatively assess narrow anterior chamber angle using spectral-domain anterior segment optical coherence tomography (SD-AS-OCT) and ultrasound biomicroscopy (UBM), and to evaluate the correlations and consistency between SD-AS-OCT and UBM. METHODS Fifty-five eyes from 40 patients were examined. Patients were diagnosed with primary angle-closure glaucoma (PACG) remission (11 eyes from 8 patients), primary angle closure (PAC, 20 eyes from 20 patients) and PAC suspect (24 eyes from 12 patients). Each eye was examined by SD-AS-OCT and UBM after laser peripheral iridotomy (LPI). The measurements of SD-AS-OCT were angle open distance (AOD), anterior chamber angle (ACA), trabecular iris angle (TIA), and trabecular iris space area (TISA). UBM measurements were AOD and TIA. Correlations of AOD500 and TIA500 between UBM and AS-OCT were assessed. All parameters were analysed by SPSS 16.0 and MedCalc. RESULTS ACA, TIA and AOD measured by SD-AS-OCT reached a maximum at the temporal quadrant and minimum at the nasal quadrant. TISA reached the maximum at the inferior and minimum at the superior quadrant. Group parameters of AOD500 and AOD750 showed a linear positive correlation, and AOD750 had less variability. UBM outcomes of AOD500 and TIA500 were significantly smaller than those of SD-AS-OCT. The results of the two techniques were correlated at the superior, nasal and inferior quadrants. CONCLUSION Both UBM and SD-AS-OCT are efficient tools for follow-up during the course of PACG. We recommended using parameters at 750 µm anterior to the sclera spur for the screening and follow-up of PACG and PAC. The two methods might be alternatives to each other.
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Affiliation(s)
- Xiao-Yun Ma
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Tissue Engineering, National Tissue Engineering Center of China, Shanghai 200011, China; Department of Ophthalmology, Shanghai Guanghua Integrative Medicine Hospital, Shanghai 200052, China
| | - Dan Zhu
- Department of Ophthalmology, Shanghai Guanghua Integrative Medicine Hospital, Shanghai 200052, China
| | - Jun Zou
- Department of Ophthalmology, Shanghai Tenth People's Hospital, Tongji University, Shanghai 200072, China
| | - Wen-Jie Zhang
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Tissue Engineering, National Tissue Engineering Center of China, Shanghai 200011, China
| | - Yi-Lin Cao
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Tissue Engineering, National Tissue Engineering Center of China, Shanghai 200011, China
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Ventura BV, Wang L, Ali SF, Koch DD, Weikert MP. Comparison of corneal power, astigmatism, and wavefront aberration measurements obtained by a point-source color light-emitting diode-based topographer, a Placido-disk topographer, and a combined Placido and dual Scheimpflug device. J Cataract Refract Surg 2016; 41:1658-71. [PMID: 26432123 DOI: 10.1016/j.jcrs.2014.11.051] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 11/07/2014] [Accepted: 11/09/2014] [Indexed: 10/23/2022]
Abstract
PURPOSE To evaluate and compare the performance of a point-source color light-emitting diode (LED)-based topographer (color-LED) in measuring anterior corneal power and aberrations with that of a Placido-disk topographer and a combined Placido and dual Scheimpflug device. SETTING Cullen Eye Institute, Baylor College of Medicine, Houston, Texas USA. DESIGN Retrospective observational case series. METHODS Normal eyes and post-refractive-surgery eyes were consecutively measured using color-LED, Placido, and dual-Scheimpflug devices. The main outcome measures were anterior corneal power, astigmatism, and higher-order aberrations (HOAs) (6.0 mm pupil), which were compared using the t test. RESULTS There were no statistically significant differences in corneal power measurements in normal and post-refractive surgery eyes and in astigmatism magnitude in post-refractive surgery eyes between the color-LED device and Placido or dual Scheimpflug devices (all P > .05). In normal eyes, there were no statistically significant differences in 3rd-order coma and 4th-order spherical aberration between the color-LED and Placido devices and in HOA root mean square, 3rd-order coma, 3rd-order trefoil, 4th-order spherical aberration, and 4th-order secondary astigmatism between the color-LED and dual Scheimpflug devices (all P > .05). In post-refractive surgery eyes, the color-LED device agreed with the Placido and dual-Scheimpflug devices regarding 3rd-order coma and 4th-order spherical aberration (all P > .05). CONCLUSIONS In normal and post-refractive surgery eyes, all 3 devices were comparable with respect to corneal power. The agreement in corneal aberrations varied. FINANCIAL DISCLOSURE Drs. Wang, Koch, and Weikert are consultants to Ziemer Ophthalmic Systems AG. Dr. Koch is a consultant to Abbott Medical Optics, Inc., Alcon Surgical, Inc., and i-Optics Corp.
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Affiliation(s)
- Bruna V Ventura
- From the Cullen Eye Institute (Ventura, Wang, Ali, Koch, Weikert), Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA; Altino Ventura Foundation (Ventura), Recife, and the Department of Ophthalmology (Ventura), Federal University of São Paulo, São Paulo, Brazil.
| | - Li Wang
- From the Cullen Eye Institute (Ventura, Wang, Ali, Koch, Weikert), Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA; Altino Ventura Foundation (Ventura), Recife, and the Department of Ophthalmology (Ventura), Federal University of São Paulo, São Paulo, Brazil
| | - Shazia F Ali
- From the Cullen Eye Institute (Ventura, Wang, Ali, Koch, Weikert), Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA; Altino Ventura Foundation (Ventura), Recife, and the Department of Ophthalmology (Ventura), Federal University of São Paulo, São Paulo, Brazil
| | - Douglas D Koch
- From the Cullen Eye Institute (Ventura, Wang, Ali, Koch, Weikert), Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA; Altino Ventura Foundation (Ventura), Recife, and the Department of Ophthalmology (Ventura), Federal University of São Paulo, São Paulo, Brazil
| | - Mitchell P Weikert
- From the Cullen Eye Institute (Ventura, Wang, Ali, Koch, Weikert), Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA; Altino Ventura Foundation (Ventura), Recife, and the Department of Ophthalmology (Ventura), Federal University of São Paulo, São Paulo, Brazil
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Consistency of Corneal Sublayer Thickness Measurements using Fourier-Domain Optical Coherence Tomography after Phacoemulsification. Eur J Ophthalmol 2016; 26:540-545. [DOI: 10.5301/ejo.5000776] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/10/2016] [Indexed: 11/20/2022]
Abstract
Purpose To assess the reliability of corneal epithelial thickness (CET), nonepithelial central corneal thickness (NECCT), and central corneal thickness (CCT) measurements using Cirrus high-definition optical coherence tomography (HD-OCT) in patients who did and did not undergo cataract surgery. Methods Forty patients who underwent uneventful phacoemulsification and 40 healthy participants were recruited to evaluate the intraobserver repeatability and interobserver reproducibility of CET, NECCT, and CCT measurements using Cirrus HD-OCT. To analyze repeatability, one examiner obtained 5 consecutive scans in each participant; for interobserver reproducibility, another examiner randomly obtained another scan. Within-subject standard deviation, coefficient of variation (CV), limits of agreement, and intraclass correlation coefficient (ICC) data were obtained. Results For intraobserver repeatability, the intrasession CV (CVw) and ICC values of the CET in the operated and nonoperated groups were 3.7% and 0.80 and 3.8% and 0.73, respectively; for NECCT, 0.7% and 0.98 and 0.8% and 0.97; and for CCT, 0.6% and 0.99 and 0.7% and 0.98. For interobserver reproducibility, the CVw and ICC values for the CET in the operated and nonoperated groups were 2.6% and 0.82 and 2.3% and 0.62, respectively; for NECCT, 0.7% and 0.98 and 0.5% and 0.98; and for CCT, 0.5% and 0.99 and 0.4% and 0.99. Conclusions The corneal sublayer thickness can be measured reliably using Cirrus HD-OCT in patients who underwent cataract surgery and elderly participants; however, the CET consistency is poorer than the NECCT. Corneal epithelial thickness modifications exceeding 4% reflect true thickness changes instead of random error variations using HD-OCT.
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Williams D, Zheng Y, Davey PG, Bao F, Shen M, Elsheikh A. Reconstruction of 3D surface maps from anterior segment optical coherence tomography images using graph theory and genetic algorithms. Biomed Signal Process Control 2016. [DOI: 10.1016/j.bspc.2015.11.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Reliability of Pentacam HR Thickness Maps of the Entire Cornea in Normal, Post-Laser In Situ Keratomileusis, and Keratoconus Eyes. Am J Ophthalmol 2016; 162:74-82.e1. [PMID: 26556008 DOI: 10.1016/j.ajo.2015.11.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Revised: 11/03/2015] [Accepted: 11/03/2015] [Indexed: 11/21/2022]
Abstract
PURPOSE To measure the repeatability and reproducibility of Pentacam HR system thickness maps for the entire cornea in normal, post-laser in situ keratomileusis (post-LASIK), and keratoconus (KC) eyes. DESIGN Reliability study. METHODS Sixty normal subjects (60 eyes), 30 post-LASIK subjects (60 eyes), and 14 KC patients (27 eyes) were imaged with the Pentacam HR system by 2 well-trained operators. For pachymetry the cornea was divided into 4 zones: a central zone (2-mm diameter) and concentric pericentral zone (2-5 mm), transitional zone (5-7 mm), and peripheral zone (7-10 mm). The 3 concentric zones were subdivided into 8 sectors. Intraobserver repeatability and interobserver reproducibility of entire corneal thickness maps were tested by the repeatability and reproducibility coefficients, intraclass correlation coefficients, coefficient of variation, and 95% limits of agreement. RESULTS From central to peripheral zones, the precision of corneal thickness measurements became gradually smaller. Central zone repeatability and reproducibility were the best in the normal, post-LASIK, and KC groups. The peripheral superior sectors showed poorer repeatability and reproducibility for all subjects. The intraobserver repeatability and interobserver reproducibility for all zones were ≤19.3 μm, ≤22.1 μm, and ≤20.7 μm, in the normal, post-LASIK, and KC groups, respectively. The intraobserver and interobserver coefficients of variation for all zones were ≤1.3%, ≤1.6%, and ≤1.6% for all 3 groups. CONCLUSIONS Pentacam HR system pachymetry of the entire cornea provided good precision in normal, post-LASIK, and KC corneas. Thickness measurements in the peripheral cornea should be interpreted with caution in abnormal corneas after surgery or with diseases.
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Mi H, Tan N, Ang M, Htoon HM, Mehta JS. Comparison of anterior and posterior topographic analysis between 3 imaging systems. J Cataract Refract Surg 2015; 41:2533-45. [DOI: 10.1016/j.jcrs.2015.05.039] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 05/19/2015] [Accepted: 05/25/2015] [Indexed: 11/16/2022]
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Park CY, Lee JK, Zhang C, Chuck RS. New Details of the Human Corneal Limbus Revealed With Second Harmonic Generation Imaging. Invest Ophthalmol Vis Sci 2015; 56:6058-66. [PMID: 26393473 DOI: 10.1167/iovs.15-16783] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To report novel findings of the human corneal limbus by using second harmonic generation (SHG) imaging. METHODS Corneal limbus was imaged by using an inverted two-photon excitation fluorescence microscope. Laser (Ti:Sapphire) was tuned at 850 nm for two-photon excitation. Backscatter signals of SHG and autofluorescence (AF) were collected through a 425/30-nm emission filter and a 525/45-emission filter, respectively. Multiple, consecutive, and overlapping image stacks (z-stack) were acquired for the corneal limbal area. RESULTS Two novel collagen structures were revealed by SHG imaging at the limbus: an anterior limbal cribriform layer and presumed anchoring fibers. Anterior limbal cribriform layer is an intertwined reticular collagen architecture just beneath the limbal epithelial niche and is located between the peripheral cornea and Tenon's/scleral tissue. Autofluorescence imaging revealed high vascularity in this structure. Central to the anterior limbal cribriform layer, radial strands of collagen were found to connect the peripheral cornea to the limbus. These presumed anchoring fibers have both collagen and elastin and were found more extensively in the superficial layers than deep layer and were absent in very deep limbus near Schlemm's canal. CONCLUSIONS By using SHG imaging, new details of the collagen architecture of human corneal limbal area were elucidated. High resolution images with volumetric analysis revealed two novel collagen structures.
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Affiliation(s)
- Choul Yong Park
- Department of Ophthalmology, Dongguk University, Ilsan Hospital, Goyang, Kyunggido, South Korea 2Department of Ophthalmology and Visual Sciences, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, United States
| | - Jimmy K Lee
- Department of Ophthalmology and Visual Sciences, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, United States
| | - Cheng Zhang
- Department of Ophthalmology and Visual Sciences, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, United States
| | - Roy S Chuck
- Department of Ophthalmology and Visual Sciences, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, United States
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Randleman JB, Lynn MJ, Perez-Straziota CE, Weissman HM, Kim SW. Comparison of central and peripheral corneal thickness measurements with scanning-slit, Scheimpflug and Fourier-domain ocular coherence tomography. Br J Ophthalmol 2015; 99:1176-81. [PMID: 25824260 DOI: 10.1136/bjophthalmol-2014-306340] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 03/08/2015] [Indexed: 11/03/2022]
Abstract
PURPOSE To compare central, regional and relational corneal thickness values obtained with multiple technologies in normal patients and to determine their equivalence and interchangeability. METHODS Retrospective analysis of 100 eyes from 50 patients evaluated by ultrasound pachymetry (Pachette II), scanning-slit (Orbscan II), Scheimpflug (Pentacam HR) and spectral-domain ocular coherence tomography (OCT) (RTVue-100) obtained as average values (OCT-A) and point measurements (OCT-P). Measurements included central corneal thickness (CCT) for all technologies and thinnest corneal thickness for scanning-slit, Scheimpflug and OCT. Peripheral thickness measurements were obtained at the 3 mm radius in the superior (S), nasal (N), inferior (I) and temporal (T) regions. RESULTS CCT values were: 563.9±36.1μ ultrasound, 570.9±36.1μ scanning-slit, 552.8±33.8μ Scheimpflug, 550.5±32.7μ (OCT-A), 549.4±32.7μ (OCT-P). Ultrasound and scanning-slit were significantly different from each other (p<0.0001), and both were significantly different from all other devices (p<0.0001), while Scheimpflug was similar to OCT-A and OCT-P (p=0.4). Differences between CCT and thinnest corneal thickness were significantly different from all technologies except scanning-slit and OCT-A. For peripheral values, almost all locations' measurements were significantly different from one another (p<0.0001). Superior-inferior values and ratios were also significantly different from one another for almost all devices with no consistent patterns detectible. CONCLUSIONS There are significant clinically relevant differences between regional and relational thickness measurements obtained with ultrasound, scanning-slit, Scheimpflug and OCT devices. Screening metrics devised for one system do not appear directly applicable to other measurement systems.
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Affiliation(s)
- J Bradley Randleman
- Department of Ophthalmology, Emory University, Atlanta, Georgia, USA Emory Vision, Emory Eye Center, Atlanta, Georgia, USA
| | - Michael J Lynn
- Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA
| | | | | | - Sang Woo Kim
- Department of Ophthalmology, University of Ulsan College of Medicine, Ulsan, South Korea
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Lockwood JC, Randleman JB. Toric intraocular lens rotation to optimize refractive outcome despite appropriate intraoperative positioning. J Cataract Refract Surg 2015; 41:878-83. [PMID: 25754381 DOI: 10.1016/j.jcrs.2015.02.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 12/31/2014] [Accepted: 12/31/2014] [Indexed: 11/27/2022]
Abstract
UNLABELLED We present 3 eyes of 2 patients who benefitted from toric intraocular lens (IOL) rotation despite appropriate intraoperative positioning. In each case, preoperative astigmatism measurements were obtained by manual keratometry, partial coherence interferometry, and corneal topography. In Case 1, a dramatic shift in corneal topography occurred after surgery, resulting in the need to rotate the toric IOL to maximize the refractive outcome. In Case 2 (both eyes), no significant change in topography occurred, but IOL rotation was required to maximize the refractive outcome despite appropriate IOL alignment based on preoperative measurements. Using an online toric IOL calculator, it was determined that rotation of the IOL would result in significantly improved astigmatic outcomes. At the final evaluation 2 months after IOL rotation, the residual manifest astigmatism was 0.50 diopter (D) in Case 1 and 0 D (right eye) and 0.75 D (left eye) in Case 2. Use of the toric IOL online calculator maximized the uncorrected visual and refractive outcomes. FINANCIAL DISCLOSURE Neither author has a financial or proprietary interest in any material or method mentioned.
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Affiliation(s)
- James C Lockwood
- From Emory University School of Medicine (Lockwood, Randleman), the Department of Ophthalmology (Randleman), Emory University, and Emory Vision at the Emory Eye Center (Randleman), Atlanta, Georgia, USA
| | - J Bradley Randleman
- From Emory University School of Medicine (Lockwood, Randleman), the Department of Ophthalmology (Randleman), Emory University, and Emory Vision at the Emory Eye Center (Randleman), Atlanta, Georgia, USA.
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Williams D, Zheng Y, Bao F, Elsheikh A. Fast segmentation of anterior segment optical coherence tomography images using graph cut. EYE AND VISION 2015; 2:1. [PMID: 26605357 PMCID: PMC4657268 DOI: 10.1186/s40662-015-0011-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 01/11/2015] [Indexed: 10/11/2023]
Abstract
Background Optical coherence tomography (OCT) is a non-invasive imaging system that can be used to obtain images of the anterior segment. Automatic segmentation of these images will enable them to be used to construct patient specific biomechanical models of the human eye. These models could be used to help with treatment planning and diagnosis of patients. Methods A novel graph cut technique using regional and shape terms was developed. It was evaluated by segmenting 39 OCT images of the anterior segment. The results of this were compared with manual segmentation and a previously reported level set segmentation technique. Three different comparison techniques were used: Dice’s similarity coefficient (DSC), mean unsigned surface positioning error (MSPE), and 95% Hausdorff distance (HD). A paired t-test was used to compare the results of different segmentation techniques. Results When comparison with manual segmentation was performed, a mean DSC value of 0.943 ± 0.020 was achieved, outperforming other previously published techniques. A substantial reduction in processing time was also achieved using this method. Conclusions We have developed a new segmentation technique that is both fast and accurate. This has the potential to be used to aid diagnostics and treatment planning.
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Affiliation(s)
- Dominic Williams
- Ocular Biomechanics and Biomaterials Group, School of Engineering, University of Liverpool, Brownlow Hill, Liverpool, L69 3GH UK ; Department of Eye and Vision Science, University of Liverpool, 3rd Floor, UCD Building, Daulby Street, Liverpool, L69 3GA UK
| | - Yalin Zheng
- Department of Eye and Vision Science, University of Liverpool, 3rd Floor, UCD Building, Daulby Street, Liverpool, L69 3GA UK
| | - Fangjun Bao
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, No. 270, Xueyuanxi Road, Wenzhou City, Zhejiang Province 325027 China
| | - Ahmed Elsheikh
- Ocular Biomechanics and Biomaterials Group, School of Engineering, University of Liverpool, Brownlow Hill, Liverpool, L69 3GH UK
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Randleman JB, Akhtar J, Lynn MJ, Ambrósio R, Dupps WJ, Krueger RR, Klyce SD. Comparison of objective and subjective refractive surgery screening parameters between regular and high-resolution Scheimpflug imaging devices. J Cataract Refract Surg 2014; 41:286-94. [PMID: 25537685 DOI: 10.1016/j.jcrs.2014.06.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 06/24/2014] [Accepted: 06/26/2014] [Indexed: 11/29/2022]
Abstract
PURPOSE To compare objective and subjective metrics from regular and high-resolution Scheimpflug devices (Pentacam) to determine their equivalence and interchangeability for refractive surgery screening. SETTING Emory Vision at Emory University, Atlanta, Georgia, USA. DESIGN Retrospective comparative case series. METHODS Eyes of consecutive screened refractive surgery patients were evaluated with high-resolution and regular Scheimpflug devices. Objective parameters evaluated included keratometry (K) values, central corneal thickness (CCT), and device-generated keratoconus screening indices. Masked expert reviewers subjectively graded images as normal, suspicious, or abnormal. RESULTS One hundred eyes of 50 patients were evaluated. The mean K values were not significantly different (anterior K: high resolution 1.21 diopters [D] ± 1.13 (SD) versus regular 1.15 ± 1.16 D, P = 0.73; posterior K: 0.34 ± 0.23 D versus regular 0.35 ± 0.23 D, P = .67). The mean CCT was significantly thinner in the high-resolution group (514.7 ± 26.6 μm versus 527.6 ± 27.6 μm (P < .0001) with limits of agreement of -12.9 to +17.5 μm. Most keratoconus screening indices were more suspicious with the high-resolution device than with the regular device except the indices of height asymmetry and height deviation. Subjectively, 60% of cases received the same score, high resolution was more suspicious in 28% of cases, and regular was more suspicious in 12% of cases; there was only slight subjective agreement between technologies (κ = 0.26 to 0.31). CONCLUSIONS Regular and high-resolution Scheimpflug imaging devices generated different objective values and significantly different subjective interpretations with poor inter-reviewer agreement. The high-resolution device provided a more conservative overall output. For refractive surgical screening, the 2 devices are not interchangeable. FINANCIAL DISCLOSURE Proprietary or commercial disclosures are listed after the references.
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Affiliation(s)
- J Bradley Randleman
- From the Department of Ophthalmology (Randleman, Akhtar) and the Department of Biostatistics and Bioinformatics (Lynn), Rollins School of Public Health, Emory University, and Emory Vision (Randleman, Akhtar), Emory Eye Center, Atlanta, Georgia, the Cleveland Clinic Cole Eye Institute (Dupps, Krueger), the Department of Biomedical Engineering (Dupps), the Lerner Research Institute and the Transplant Center (Dupps), Surgery Institute, Cleveland Clinic, the Department of Biomedical Engineering (Dupps), Case Western Reserve University, Cleveland, Ohio, the Department of Ophthalmology (Klyce), Mount Sinai School of Medicine, New York, New York, USA; Instituto de Olhos Renato Ambrósio (Ambrósio), Rio de Janeiro Corneal Tomography and Biomechanics Study Group (Ambrósio), Rio de Janeiro, the Department for Ophthalmology of the Federal University of São Paulo (Ambrósio), São Paulo, Brazil.
| | - Jihan Akhtar
- From the Department of Ophthalmology (Randleman, Akhtar) and the Department of Biostatistics and Bioinformatics (Lynn), Rollins School of Public Health, Emory University, and Emory Vision (Randleman, Akhtar), Emory Eye Center, Atlanta, Georgia, the Cleveland Clinic Cole Eye Institute (Dupps, Krueger), the Department of Biomedical Engineering (Dupps), the Lerner Research Institute and the Transplant Center (Dupps), Surgery Institute, Cleveland Clinic, the Department of Biomedical Engineering (Dupps), Case Western Reserve University, Cleveland, Ohio, the Department of Ophthalmology (Klyce), Mount Sinai School of Medicine, New York, New York, USA; Instituto de Olhos Renato Ambrósio (Ambrósio), Rio de Janeiro Corneal Tomography and Biomechanics Study Group (Ambrósio), Rio de Janeiro, the Department for Ophthalmology of the Federal University of São Paulo (Ambrósio), São Paulo, Brazil
| | - Michael J Lynn
- From the Department of Ophthalmology (Randleman, Akhtar) and the Department of Biostatistics and Bioinformatics (Lynn), Rollins School of Public Health, Emory University, and Emory Vision (Randleman, Akhtar), Emory Eye Center, Atlanta, Georgia, the Cleveland Clinic Cole Eye Institute (Dupps, Krueger), the Department of Biomedical Engineering (Dupps), the Lerner Research Institute and the Transplant Center (Dupps), Surgery Institute, Cleveland Clinic, the Department of Biomedical Engineering (Dupps), Case Western Reserve University, Cleveland, Ohio, the Department of Ophthalmology (Klyce), Mount Sinai School of Medicine, New York, New York, USA; Instituto de Olhos Renato Ambrósio (Ambrósio), Rio de Janeiro Corneal Tomography and Biomechanics Study Group (Ambrósio), Rio de Janeiro, the Department for Ophthalmology of the Federal University of São Paulo (Ambrósio), São Paulo, Brazil
| | - Renato Ambrósio
- From the Department of Ophthalmology (Randleman, Akhtar) and the Department of Biostatistics and Bioinformatics (Lynn), Rollins School of Public Health, Emory University, and Emory Vision (Randleman, Akhtar), Emory Eye Center, Atlanta, Georgia, the Cleveland Clinic Cole Eye Institute (Dupps, Krueger), the Department of Biomedical Engineering (Dupps), the Lerner Research Institute and the Transplant Center (Dupps), Surgery Institute, Cleveland Clinic, the Department of Biomedical Engineering (Dupps), Case Western Reserve University, Cleveland, Ohio, the Department of Ophthalmology (Klyce), Mount Sinai School of Medicine, New York, New York, USA; Instituto de Olhos Renato Ambrósio (Ambrósio), Rio de Janeiro Corneal Tomography and Biomechanics Study Group (Ambrósio), Rio de Janeiro, the Department for Ophthalmology of the Federal University of São Paulo (Ambrósio), São Paulo, Brazil
| | - William J Dupps
- From the Department of Ophthalmology (Randleman, Akhtar) and the Department of Biostatistics and Bioinformatics (Lynn), Rollins School of Public Health, Emory University, and Emory Vision (Randleman, Akhtar), Emory Eye Center, Atlanta, Georgia, the Cleveland Clinic Cole Eye Institute (Dupps, Krueger), the Department of Biomedical Engineering (Dupps), the Lerner Research Institute and the Transplant Center (Dupps), Surgery Institute, Cleveland Clinic, the Department of Biomedical Engineering (Dupps), Case Western Reserve University, Cleveland, Ohio, the Department of Ophthalmology (Klyce), Mount Sinai School of Medicine, New York, New York, USA; Instituto de Olhos Renato Ambrósio (Ambrósio), Rio de Janeiro Corneal Tomography and Biomechanics Study Group (Ambrósio), Rio de Janeiro, the Department for Ophthalmology of the Federal University of São Paulo (Ambrósio), São Paulo, Brazil
| | - Ronald R Krueger
- From the Department of Ophthalmology (Randleman, Akhtar) and the Department of Biostatistics and Bioinformatics (Lynn), Rollins School of Public Health, Emory University, and Emory Vision (Randleman, Akhtar), Emory Eye Center, Atlanta, Georgia, the Cleveland Clinic Cole Eye Institute (Dupps, Krueger), the Department of Biomedical Engineering (Dupps), the Lerner Research Institute and the Transplant Center (Dupps), Surgery Institute, Cleveland Clinic, the Department of Biomedical Engineering (Dupps), Case Western Reserve University, Cleveland, Ohio, the Department of Ophthalmology (Klyce), Mount Sinai School of Medicine, New York, New York, USA; Instituto de Olhos Renato Ambrósio (Ambrósio), Rio de Janeiro Corneal Tomography and Biomechanics Study Group (Ambrósio), Rio de Janeiro, the Department for Ophthalmology of the Federal University of São Paulo (Ambrósio), São Paulo, Brazil
| | - Stephen D Klyce
- From the Department of Ophthalmology (Randleman, Akhtar) and the Department of Biostatistics and Bioinformatics (Lynn), Rollins School of Public Health, Emory University, and Emory Vision (Randleman, Akhtar), Emory Eye Center, Atlanta, Georgia, the Cleveland Clinic Cole Eye Institute (Dupps, Krueger), the Department of Biomedical Engineering (Dupps), the Lerner Research Institute and the Transplant Center (Dupps), Surgery Institute, Cleveland Clinic, the Department of Biomedical Engineering (Dupps), Case Western Reserve University, Cleveland, Ohio, the Department of Ophthalmology (Klyce), Mount Sinai School of Medicine, New York, New York, USA; Instituto de Olhos Renato Ambrósio (Ambrósio), Rio de Janeiro Corneal Tomography and Biomechanics Study Group (Ambrósio), Rio de Janeiro, the Department for Ophthalmology of the Federal University of São Paulo (Ambrósio), São Paulo, Brazil
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Yu CQ, Manche EE. A comparison of LASIK flap thickness and morphology between the Intralase 60- and 150-kHz femtosecond lasers. J Refract Surg 2014; 30:827-30. [PMID: 25437481 DOI: 10.3928/1081597x-20141113-04] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2014] [Accepted: 10/02/2014] [Indexed: 11/20/2022]
Abstract
PURPOSE To prospectively compare the achieved thickness and consistency of LASIK flaps created with a 60- and 150-kHz femtosecond laser. METHODS One hundred twenty eyes of 60 patients with myopia were treated with LASIK. One eye had flap created by the Intralase FS 60-kHz femtosecond laser (Abbott Medical Optics, Abbott Park, IL) and the fellow eye was treated with the IntraLase iFS 150-kHz femtosecond laser (Abbott Medical Optics). Eyes were randomized according to ocular dominance. Flap morphology and measurements were taken with anterior segment optical coherence tomography (AS-OCT) at the 1-month postoperative visit. RESULTS AS-OCT showed similar regular planar morphologies in both groups. The mean thickness of the flaps in the FS 60 group was significantly higher than that of the iFS 150 group (105.4 ± 3.9 μm vs 103.9 ± 4.8 μm, P = .009). The mean deviation from targeted flap thickness was not significantly different between the two groups. CONCLUSIONS The Intralase iFS 150-kHz femtosecond laser creates flaps of similar thickness and uniformity to the Intralase FS 60-kHz femtosecond laser.
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Rozema JJ, Wouters K, Mathysen DGP, Tassignon MJ. Overview of the repeatability, reproducibility, and agreement of the biometry values provided by various ophthalmic devices. Am J Ophthalmol 2014; 158:1111-1120.e1. [PMID: 25128596 DOI: 10.1016/j.ajo.2014.08.014] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 08/08/2014] [Accepted: 08/10/2014] [Indexed: 12/29/2022]
Abstract
PURPOSE To present an overview of the measurement errors for various biometric devices, as well as a meta-analysis of the agreement between biometric devices using the Pentacam, Orbscan, and IOL Master as a reference. DESIGN Meta-analysis of the literature. METHODS The meta-analysis is based on data from 216 articles that compare a total of 24 different devices with the reference devices for the following 9 parameters: mean, steep and flat curvature of the anterior and posterior cornea; central corneal thickness; anterior chamber depth; and axial length. After the weighted average difference between devices has been determined, the "two one-sided t test" was used to test for equivalence between devices within certain thresholds defined by the measurement errors and the influence of these differences on the calculated refraction. RESULTS In only 17 of the 70 comparisons a device was equivalent with the reference device within the thresholds set by the measurement error. More lenient thresholds, based on a change in calculated refraction of ±0.25 diopter, increased this number to a maximum of 25/50 comparisons (excluding pachymetry). High degrees of inconsistency were seen in the reported results, which could partially explain the low agreement between devices. CONCLUSION As a rule, biometry measurements taken by different devices should not be considered equivalent, although several exceptions could be identified. We therefore recommend that clinical studies involving multiple device types treat this as a within-subject variable to avoid bias. The follow-up of individual patients using different devices should be avoided at all times.
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Affiliation(s)
- Jos J Rozema
- Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium; Department of Medicine and Health Science, University of Antwerp, Wilrijk, Belgium.
| | - Kristien Wouters
- Department of Scientific Coordination and Biostatistics, Antwerp University Hospital, Edegem, Belgium; Department of Medicine and Health Science, University of Antwerp, Wilrijk, Belgium
| | - Danny G P Mathysen
- Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium; Department of Medicine and Health Science, University of Antwerp, Wilrijk, Belgium
| | - Marie-José Tassignon
- Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium; Department of Medicine and Health Science, University of Antwerp, Wilrijk, Belgium
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Corneal assessment technologies: Current status. Surv Ophthalmol 2014; 59:599-614. [DOI: 10.1016/j.survophthal.2014.05.001] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 05/15/2014] [Accepted: 05/20/2014] [Indexed: 11/22/2022]
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Hernández-Camarena JC, Chirinos-Saldaña P, Navas A, Ramirez-Miranda A, de la Mota A, Jimenez-Corona A, Graue-Hernández EO. Repeatability, Reproducibility, and Agreement Between Three Different Scheimpflug Systems in Measuring Corneal and Anterior Segment Biometry. J Refract Surg 2014; 30:616-21. [DOI: 10.3928/1081597x-20140815-02] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Quadrantwise Comparison of Lens-Iris Distance in Patients With Pseudoexfoliation Syndrome and Age-matched Controls. J Glaucoma 2014; 25:95-100. [PMID: 25068467 DOI: 10.1097/ijg.0000000000000093] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To perform a quadrantwise comparison of the minimum distance between the posterior iris and the anterior lens in eyes with pseudoexfoliation syndrome (PXS) and age-matched controls. PATIENTS AND METHODS This study was designed as a prospective cross-sectional study. The study population consisted of 60 patients with PXS and 50 age-matched controls. Anterior segment Scheimpflug images of segments 90 to 270, 135 to 315, 180 to 360, and 225 to 45 degrees were exported as high-quality JPEG images (1920 pixels wide, 1048 pixels high; each pixel having a physical dimension of 8.064×8.064 µm) for further evaluation. The images were analyzed by Image J software. Minimum lens-iris distance (MLID) of the superior, inferior, nasal, and temporal quadrants were analyzed and compared between the groups. Anterior chamber depth, anterior chamber angle, pupillary diameter, average of K1 and K2 (Km), and cataract grading system by Scheimpflug imaging [Oculus Pentacam Nucleus Grading System (PNS)] were also assessed. RESULTS The MLIDs of all quadrants in eyes with PXS were shorter than controls and these differences were statistically significant (P<0.05). The shortest distance was recorded in the inferior quadrant followed by the superior, temporal, and nasal quadrants in both groups. Pupillary diameter was the only variable found to be correlated with mean global MLID at a statistically significant level (r=-0.465, P<0.001; adjusted for age, sex, anterior chamber angle, anterior chamber depth, PNS, and Km). CONCLUSION Eyes with PXS manifested with shorter mean MLID than controls.
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Comparison of morphologic features of clear corneal incisions created with a femtosecond laser or a keratome. J Cataract Refract Surg 2014; 40:521-30. [DOI: 10.1016/j.jcrs.2013.11.028] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 11/12/2013] [Accepted: 11/13/2013] [Indexed: 11/24/2022]
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Piñero DP. Technologies for anatomical and geometric characterization of the corneal structure and anterior segment: a review. Semin Ophthalmol 2013; 30:161-70. [PMID: 24175646 DOI: 10.3109/08820538.2013.835844] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Corneal and anterior segment imaging techniques have become a crucial tool in the clinical practice of ophthalmology, with a great variety of applications, such as corneal curvature and pachymetric analysis, detection of ectatic corneal conditions, anatomical study of the anterior segment prior to phakic intraocular lens implantation, or densitometric analysis of the crystalline lens. From the Placido-based systems that allow only a characterization of the geometry of the anterior corneal surface to the Scheimpflug photography-based systems that provide a characterization of the cornea, anterior chamber, and crystalline lens, there is a great variety of devices with the capability of analyzing different anatomical parameters with very high precision. To date, Scheimpflug photography-based systems are the devices providing the more complete analysis of the anterior segment in a non-invasive way. More developments are required in anterior segment imaging technologies in order to improve the analysis of the crystalline lens structure as well as the ocular structures behind the iris in a non-invasive way when the pupil is not dilated.
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Affiliation(s)
- David P Piñero
- Department of Ophthalmology (Oftalmar), Medimar International Hospital , Alicante , Spain
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