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Janiszewska-Bil D, Czarnota-Nowakowska B, Kuciel-Polczak I, Dobrowolski D, Grabarek BO, Lyssek-Boroń A, Wylęgała E, Wierzbowska J. Assessment of Changes in Cap and Residual Stromal Thickness Values during a 6-Month Observation after Refractive Lenticule Extraction Small Incision Lenticule Extraction. J Clin Med 2024; 13:2148. [PMID: 38610913 PMCID: PMC11012741 DOI: 10.3390/jcm13072148] [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: 02/29/2024] [Revised: 04/02/2024] [Accepted: 04/04/2024] [Indexed: 04/14/2024] Open
Abstract
Background: In this study, the changes in corneal cap and residual stromal thickness (RST) values during a 180-day observation period after refractive lenticule extraction small incision lenticule extraction (ReLEx SMILE) were assessed. Methods: Fifty patients underwent ReLEx SMILE using the VisuMax 500 femtosecond laser, with corneal imaging conducted pre and post procedure via anterior segment optical coherence tomography (AS-OCT). Cap thickness in the center and 1.5 mm from the center in four meridians was measured at various intervals. Results: The results showed a significant decrease in cap thickness 180 days post procedure compared to earlier intervals (p < 0.05). Similarly, RST decreased gradually and significantly post procedure (p < 0.05). Notably, changes in cap thickness within the central 1.5 mm area were more dynamic than RST changes during the 6-month observation period following SMILE. Conclusions: The corneal cap thickness measured with swept-source AS-OCT within the central 1.5 mm area underwent more dynamic changes than the residual stromal thickness during the 6-month observation following SMILE.
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Affiliation(s)
- Dominika Janiszewska-Bil
- Department of Ophthalmology, Trauma Centre, St. Barbara Hospital, 41-200 Sosnowiec, Poland; (I.K.-P.); (D.D.); (A.L.-B.)
- Optegra Clinic in Katowice, 40-101 Katowice, Poland
- Collegium Medicum, WSB University, 41-300 Dabrowa Gornicza, Poland;
| | | | - Izabela Kuciel-Polczak
- Department of Ophthalmology, Trauma Centre, St. Barbara Hospital, 41-200 Sosnowiec, Poland; (I.K.-P.); (D.D.); (A.L.-B.)
| | - Dariusz Dobrowolski
- Department of Ophthalmology, Trauma Centre, St. Barbara Hospital, 41-200 Sosnowiec, Poland; (I.K.-P.); (D.D.); (A.L.-B.)
- Clinical Department of Ophthalmology, Faculty of Medical Sciences in Zabrze, Medical University of Silesia, 40-760 Katowice, Poland;
- Department of Ophthalmology, District Railway Hospital, 40-760 Katowice, Poland
| | | | - Anita Lyssek-Boroń
- Department of Ophthalmology, Trauma Centre, St. Barbara Hospital, 41-200 Sosnowiec, Poland; (I.K.-P.); (D.D.); (A.L.-B.)
- Optegra Clinic in Katowice, 40-101 Katowice, Poland
- Optegra Clinic in Krakow, 30-347 Krakow, Poland
| | - Edward Wylęgała
- Clinical Department of Ophthalmology, Faculty of Medical Sciences in Zabrze, Medical University of Silesia, 40-760 Katowice, Poland;
- Department of Ophthalmology, District Railway Hospital, 40-760 Katowice, Poland
| | - Joanna Wierzbowska
- Department of Ophthalmology, Central Clinical Hospital of the Ministry of National Defense, Military Institute of Medicine in Warsaw, 04-141 Warsaw, Poland
- Optegra Clinic in Warszawa, 02-366 Warszawa, Poland
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Wang L, Shen M, Shi C, Zhou Y, Chen Y, Pu J, Chen H. EE-Net: An edge-enhanced deep learning network for jointly identifying corneal micro-layers from optical coherence tomography. Biomed Signal Process Control 2022. [DOI: 10.1016/j.bspc.2021.103213] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Elsawy A, Gregori G, Eleiwa T, Abdel-Mottaleb M, Shousha MA. Pathological-Corneas Layer Segmentation and Thickness Measurement in OCT Images. Transl Vis Sci Technol 2020; 9:24. [PMID: 33173606 PMCID: PMC7594599 DOI: 10.1167/tvst.9.11.24] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 09/22/2020] [Indexed: 11/26/2022] Open
Abstract
Purpose The purpose of this study was to propose a new algorithm for the segmentation and thickness measurement of pathological corneas with irregular layers using a two-stage graph search and ray tracing. Methods In the first stage, a graph, with only gradient edge-cost, is used to segment the air-epithelium and endothelium-aqueous boundaries. In the second stage, a graph, with gradient, directional, and multiplier edge-cost, is used to correct segmentation. The optical coherence tomography (OCT) image is flattened using the air-epithelium boundary and a graph search is used to segment the epithelium-Bowman's and Bowman's-stroma boundaries. Then, the OCT image is flattened using the endothelium-aqueous boundary and a graph search is used to segment the Descemet's membrane. Ray tracing is used to correct the inter-boundary distances, then the thickness is measured using the shortest distance. The proposed algorithm was trained and evaluated using 190 OCT images manually segmented by trained operators. Results The mean and standard deviation of the unsigned errors of the algorithm-operator and inter-operator were 0.89 ± 1.03 and 0.77 ± 0.68 pixels in segmentation and 3.62 ± 3.98 and 2.95 ± 2.52 µm in thickness measurement. Conclusions Our proposed algorithm can produce accurate segmentation and thickness measurements compared with the manual operators. Translational Relevance Our algorithm could be potentially useful in the clinical practice.
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Affiliation(s)
- Amr Elsawy
- Bascom Palmer Eye Institute, Miller School of Medicine, University of Miami, Miami, FL, USA
- Electrical and Computer Engineering, University of Miami, Miami, FL, USA
| | - Giovanni Gregori
- Bascom Palmer Eye Institute, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Taher Eleiwa
- Bascom Palmer Eye Institute, Miller School of Medicine, University of Miami, Miami, FL, USA
- Ophthalmology Department, Benha Faculty of Medicine, Egypt
| | | | - Mohamed Abou Shousha
- Bascom Palmer Eye Institute, Miller School of Medicine, University of Miami, Miami, FL, USA
- Electrical and Computer Engineering, University of Miami, Miami, FL, USA
- Biomedical Engineering, University of Miami, Miami, FL, USA
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4
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Atalay E, Yu DJ, Nongpiur ME. When to use anterior segment optical coherence tomography. EXPERT REVIEW OF OPHTHALMOLOGY 2020. [DOI: 10.1080/17469899.2020.1767596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Eray Atalay
- Department of Ophthalmology, Eskisehir Osmangazi University Faculty of Medicine, Turkey
| | - Daryle Jason Yu
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
| | - Monisha Esther Nongpiur
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
- Duke-NUS Medical School, Singapore, Singapore
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5
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Rashdan H, Shah M, Robertson DM. The frequency of non-pathologically thin corneas in young healthy adults. Clin Ophthalmol 2019; 13:1123-1135. [PMID: 31371912 PMCID: PMC6628863 DOI: 10.2147/opth.s188935] [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: 09/27/2018] [Accepted: 01/16/2019] [Indexed: 11/23/2022] Open
Abstract
Purpose: Measurement of normal corneal thickness and corneal epithelial thickness is important in keratorefractive surgery, glaucoma, following extended contact lens wear, and in patients with corneal disease. Clinically, a central corneal thickness less than 500 µm is considered to be moderately-to-extremely thin. The purpose of this study was to compare biological differences in patients with clinically thin compared to normal corneal thickness values in healthy young adults using Fourier domain optical coherence tomography. Patients and methods: In total, 168 eyes from 84 patients aged 19-38 years were scanned using an Avanti optical coherence tomographer. To eliminate circadian effects on corneal thickness, all patients were scanned within a 4-hour window. Corneal thickness was measured across the central 6 mm of the cornea. Total central corneal thickness, corneal epithelial thickness, and corneal stromal thickness were compared between males and females and tested for correlations with age, use of systemic hormones, degree of myopia, and corneal curvature. Results: The average central corneal thickness for males and females was 540.5±32.0 μm and 525.2±33.0 μm, respectively (P=0.020). Thirty-eight eyes had corneal thickness measurements below 500 µm; 12% (6 eyes) from males and 28% (16 eyes) from females (P=0.008). All women with corneas below 500 μm were bilaterally thin. This finding differed for men. Corneal thinning was not associated with age, use of systemic hormones, or degree of myopia. Females had steeper keratometry (K) readings (P=0.01 for flat K, P=0.002 for steep K) than males. No differences in layer offset values between normal thickness corneas and thin corneas were evident, suggesting that the reduced thickness was not pathological. Conclusion: The results of this study indicate that a subpopulation of healthy young adults have non-pathologically thin corneas, well below 500 μm; and that these thinner corneas are more frequent in females. This underscores the importance of accurate corneal thickness measurements prior to keratorefractive surgery and when evaluating intraocular pressure in glaucoma.
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Affiliation(s)
- Hannah Rashdan
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Manali Shah
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
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6
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Wang SB, Cornish EE, Grigg JR, McCluskey PJ. Anterior segment optical coherence tomography and its clinical applications. Clin Exp Optom 2019; 102:195-207. [PMID: 30635934 DOI: 10.1111/cxo.12869] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 11/05/2018] [Accepted: 11/29/2018] [Indexed: 11/29/2022] Open
Abstract
Anterior segment optical coherence tomography (AS-OCT) has become one of the cornerstones of non-contact imaging modalities for assessing such structures as the cornea, anterior chamber angle, aqueous outflow pathway, sclera, and ocular surface structures. As such, it has a broad range of clinical applications, which have been independently reported in the literature. This paper aims to present a review of extant literature on the utility of AS-OCT and its efficacy in clinical applications, and to evaluate the quality of available evidence. The following databases were searched from inception to 24 June 2018: Medline via Ovid, Cochrane Central Register of Controlled Trials, PubMed, World Health Organization International Clinical Trials Registry Platform, EMBASE, and CINAHL. Bibliographies of identified papers were hand searched. Inclusion criteria: articles describing or assessing the use of OCT for visualising the AS. The authors excluded studies without an identified primary outcome variable. One author independently selected studies, extracted data, and assessed for risk of bias using PRISMA guidelines. This review included 82 studies, of which there were 11 cohort studies, 37 case series, 10 case studies, 21 comparative observational studies, and three non-systematic review articles. Primary outcome variables included anterior chamber angle, angle opening distance, angle recess area, trabecular iris angle, trabecula-iris space area, corneal thickness, tear meniscus height, tear meniscus area, tear meniscus volume, and the morphology of AS structures, including the ocular surface, blebs, flaps, and graft sites. This review attempts to encompass the breadth and depth of evidence for AS-OCT in the arena of diagnostics, therapeutics, and prognostics. At the same time, it brings to light the dearth of high-level evidence on this topic, suggesting the important role of randomised controlled trials and meta-analyses for the future validation of this technology.
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Affiliation(s)
- Sarah B Wang
- Faculty of Medicine and Health, Save Sight Institute, The University of Sydney, Sydney Eye Hospital, Sydney, New South Wales, Australia
| | - Elisa E Cornish
- Faculty of Medicine and Health, Save Sight Institute, The University of Sydney, Sydney Eye Hospital, Sydney, New South Wales, Australia.,Sydney Eye Hospital Foundation, Sydney Eye Hospital, Sydney, New South Wales, Australia.,Sydney Eye Hospital, Sydney, New South Wales, Australia
| | - John R Grigg
- Faculty of Medicine and Health, Save Sight Institute, The University of Sydney, Sydney Eye Hospital, Sydney, New South Wales, Australia
| | - Peter J McCluskey
- Faculty of Medicine and Health, Save Sight Institute, The University of Sydney, Sydney Eye Hospital, Sydney, New South Wales, Australia
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7
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Ang M, Baskaran M, Werkmeister RM, Chua J, Schmidl D, Aranha dos Santos V, Garhöfer G, Mehta JS, Schmetterer L. Anterior segment optical coherence tomography. Prog Retin Eye Res 2018; 66:132-156. [DOI: 10.1016/j.preteyeres.2018.04.002] [Citation(s) in RCA: 216] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 02/20/2018] [Accepted: 04/04/2018] [Indexed: 02/03/2023]
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8
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Dawood YF, Al Hassany U, Issa AF. Temporal and Spatial Flap Variability in Laser In-Situ Keratomileusis by Optical Coherence Tomography. J Ophthalmic Vis Res 2017; 12:368-373. [PMID: 29090044 PMCID: PMC5644401 DOI: 10.4103/jovr.jovr_173_16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Purpose: To study changes in flap thickness made with two different microkeratome heads across different corneal locations using anterior segment optical coherence tomography (OCT). Methods: In this prospective, non-randomized, consecutive case series, subjects who had their laser in-situ keratomileusis (LASIK) flaps made using 90 μm (MSU90) or 130 μm (MSU130) disposable M2 microkeratome heads were examined using OCT. The measurements were performed at three locations (central and 2.5 mm to either side) at 1 day, 1 week, and 1 month postoperatively. Results: The central flap thickness was 123 ± 15, 130 ± 14, and 127 ± 13 μm, respectively, at 1 day, 1 week, and 1 month postoperatively in the MSU90 group (41 eyes) and 142 ± 20, 147 ± 19, and 143 ± 15 μm, respectively, in the MSU130 group (47 eyes). At 1 month, peripheral flap thickness was 161 ± 17 and 159 ± 13 μm, respectively, at 2.5 mm to the right and left of corneal center in the MSU90 group. The corresponding figures were 170 ± 14 and 167 ± 13 μm, respectively, in the MSU130 group. There was a statistically significant difference between the two groups at all locations (P < 0.001). No statistically significant change in flap thickness was detected in either group at any assessment time. There was a partial positive correlation (after controlling for preoperative manifest refractive spherical equivalent) between central flap thickness and preoperative ultrasound central pachymetry (r = 0.739, P = 0.036) in the MSU90 group but not in the MSU130 group. Conclusion: Using OCT, changes in flap thickness were minimal in the first month after LASIK. Flap thickness correlated strongly with central corneal thickness if a 90 μm head was used.
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Affiliation(s)
- Yousif Farhan Dawood
- Department of Ophthalmology, College of Medicine, University of Anbar, Anbar, Iraq.,Department of Ophthalmology, Ibn Al Haitham Teaching Eye Hospital, Baghdad, Iraq
| | | | - Ammar F Issa
- Department of Ophthalmology, Ibn Al Haitham Teaching Eye Hospital, Baghdad, Iraq.,Jenna Ophthalmic Center, Baghdad, Iraq.,Dr Sulaiman Al Habib Medical Center, Dubai, UAE
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9
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Catalan-Lopez S, Portas-Ferradas AM, Cadarso-Suarez L, Rodriguez-Rodriguez A. Small Incision Lenticule Extraction (SMILE) as Re-treatment for a Thick LASIK Flap. J Refract Surg 2016; 32:718-720. [PMID: 27722762 DOI: 10.3928/1081597x-20160603-03] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 05/19/2016] [Indexed: 11/20/2022]
Abstract
PURPOSE To report the case of a residual refractive error after LASIK for moderate myopia successfully re-treated several years later using the small incision lenticule extraction (SMILE) technique. METHODS Case report. RESULTS Following LASIK, the patient showed a central flap thickness of 269 microns, whereas residual stromal bed thickness under the flap was 210 microns. SMILE was performed within the flap. In this less invasive surgical procedure, the residual stromal bed is not manipulated and ablation is conducted on the existing flap. At 6 months of follow-up, visual and anatomical outcomes were satisfactory. Uncorrected distance visual acuity was 20/20 and refractive error was +0.75 -0.50 × 30°. CONCLUSIONS In selected patients with a thick flap and thin residual stromal bed after LASIK, SMILE as re-treatment may be a good option. [J Refract Surg. 2016;32(10):718-720.].
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10
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Applications of Anterior Segment Optical Coherence Tomography in Cornea and Ocular Surface Diseases. J Ophthalmol 2016; 2016:4971572. [PMID: 27721988 PMCID: PMC5046038 DOI: 10.1155/2016/4971572] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 07/31/2016] [Indexed: 11/29/2022] Open
Abstract
Optical coherence tomography (OCT) is a noncontact technology that produces high-resolution cross-sectional images of ocular tissues. Anterior segment OCT (AS-OCT) enables the precise visualization of anterior segment structure; thus, it can be used in various corneal and ocular surface disorders. In this review, the authors will discuss the application of AS-OCT for diagnosis and management of various corneal and ocular surface disorders. Use of AS-OCT for anterior segment surgery and postoperative management will also be discussed. In addition, application of the device for research using human data and animal models will be introduced.
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11
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Obtaining Thickness Maps of Corneal Layers Using the Optimal Algorithm for Intracorneal Layer Segmentation. Int J Biomed Imaging 2016; 2016:1420230. [PMID: 27247559 PMCID: PMC4876237 DOI: 10.1155/2016/1420230] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 03/11/2016] [Accepted: 04/06/2016] [Indexed: 11/18/2022] Open
Abstract
Optical Coherence Tomography (OCT) is one of the most informative methodologies in ophthalmology and provides cross sectional images from anterior and posterior segments of the eye. Corneal diseases can be diagnosed by these images and corneal thickness maps can also assist in the treatment and diagnosis. The need for automatic segmentation of cross sectional images is inevitable since manual segmentation is time consuming and imprecise. In this paper, segmentation methods such as Gaussian Mixture Model (GMM), Graph Cut, and Level Set are used for automatic segmentation of three clinically important corneal layer boundaries on OCT images. Using the segmentation of the boundaries in three-dimensional corneal data, we obtained thickness maps of the layers which are created by these borders. Mean and standard deviation of the thickness values for normal subjects in epithelial, stromal, and whole cornea are calculated in central, superior, inferior, nasal, and temporal zones (centered on the center of pupil). To evaluate our approach, the automatic boundary results are compared with the boundaries segmented manually by two corneal specialists. The quantitative results show that GMM method segments the desired boundaries with the best accuracy.
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12
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Zhao MH, Wu Q, Jia LL, Hu P. Changes in central corneal thickness and refractive error after thin-flap laser in situ keratomileusis in Chinese eyes. BMC Ophthalmol 2015. [PMID: 26220189 PMCID: PMC4517627 DOI: 10.1186/s12886-015-0083-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Refractive stability is influenced by alterations in corneal curvature and corneal thickness after laser in situ keratomileusis (LASIK). The aim of this study was to analyze the changes of central corneal thickness (CCT) and refractive error following thin-flap LASIK surgery in Chinese eyes. METHODS One hundred and fifty-eight myopic patients (302 eyes) who underwent thin-flap LASIK surgery were prospectively evaluated. CCT was measured by non-contact specular microscopy before, and 1 day, 1 week, and 1, 3, and 6 months following surgery. Age, refractive error, and optic zone diameter were also recorded. RESULTS Preoperatively, the mean CCT was 531.6 ± 24.3 μm. At 1 day, 1 week, and 1, 3, and 6 months after surgery, mean CCTs were 431.4 ± 38.4 μm, 422.6 ± 3 7.8 μm, 427.2 ± 38.0 μm, 434.4 ± 38.2 μm, and 435.6 ± 38.0 μm, respectively. Significant changes were detected in CCT values at each time point after thin-flap LASIK treatment (P < 0.05). The mean preoperative spherical equivalent (SE) was -5.73 ± 2.30 diopters (D). At 1 day, 1 week, and 1, 3, and 6 months after surgery, it was 0.26 ± 0.58 D, 0.54 ± 0.52 D, 0.49 ± 0.53 D, 0.45 ± 0.49 D, and 0.37 ± 0.42 D, respectively. The spherical equivalent refraction at 6 months postsurgery was close to the predicted value (0.34 ± 0.30 D). The changes in CCT within 6 months (4.06 ± 9.99 μm) were negatively correlated with age, preoperative refractive error, and optical zone diameter, respectively (r = -0.180, P < 0.05; r = -0.187, P < 0.001; r = -0.171, P < 0.05, respectively). No significant correlation was found between CCT changes and SE changes at different time points, postoperatively. CONCLUSIONS CCTs decreased significantly at 1 day after surgery, and continued to decline at 1 week after surgery, then increased over time. From postoperative 1 week, SE over time continually shifted to the myopic side.
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Affiliation(s)
- Ming-Hui Zhao
- Department of Ophthalmology, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai,, 200233, China.
| | - Qiang Wu
- Department of Ophthalmology, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai,, 200233, China.
| | - Li-Li Jia
- Department of Ophthalmology, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai,, 200233, China.
| | - Ping Hu
- Department of Ophthalmology, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai,, 200233, China.
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Xu Z, Shen M, Hu L, Zhuang X, Peng M, Hu D, Liu J, Wang J, Qu J, Lu F. The Impact of Flap Creation Methods for Sub-Bowman's Keratomileusis (SBK) on the Central Thickness of Bowman's Layer. PLoS One 2015; 10:e0124996. [PMID: 25938492 PMCID: PMC4418749 DOI: 10.1371/journal.pone.0124996] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 03/19/2015] [Indexed: 11/20/2022] Open
Abstract
Purpose To determine the impact of flap creation methods for sub-Bowman’s keratomileusis (SBK) on central Bowman’s layer thickness. Methods SBK flaps were made by Moria microkeratome for 20 subjects and by femtosecond (FEMTO) laser for 21 subjects. Corneal sublayer thicknesses were measured by ultra-high resolution optical coherence tomography before SBK and at 1 day, 1 week, 2 weeks, and 1 month afterwards. Each subject was imaged twice on each visit. Thicknesses of central epithelium, Bowman’s layer, flap, and total cornea were calculated using a custom-made automated image processing algorithm. The repeatability of sublayer thickness measurements was tested by the intraclass correlation coefficient (ICC) and by the coefficient of repeatability (CoR) at 1 week post-SBK. Results ICCs of the Moria and FEMTO groups were ≥0.959 and ≥0.961 respectively for all sublayer measurements. The segmentation CoRs were less than 6.78% and 5.63% respectively. For both groups, microdistortions were present in the epithelium and Bowman’s layer after SKB. The flap thickness of the Moria group was 9.8 μm (95% confidence interval: 4.8 – 14.8μm) thinner than the FEMTO group one day after SBK (independent samples t-test, P < 0.05). Bowman’s layer became thicker by 1.6 ± 1.1 μm and 1.7 ± 1.6 μm one day post-SBK for the Moria and FEMTO groups (repeated ANOVA, P < 0.05) and then remained stable. Corneal and sublayer thickness were similar between the two groups. Conclusions Central Bowman’s layer thickness increased 1 day post-SBK. Flap creation by Moria microkeratome and femtosecond laser did not have significantly different impacts on Bowman’s layer thickness following SBK. Trial Registration Chinese Clinical Trial Registry (ChiCTR) NO: ChiCTR-OCH-14004525
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Affiliation(s)
- Zhe Xu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Meixiao Shen
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Liang Hu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Xiran Zhuang
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Mei Peng
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Di Hu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Jing Liu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Jianhua Wang
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami, Miami, FL, United States of America
| | - Jia Qu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Fan Lu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
- * E-mail:
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14
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Zhang C, Che J, Yu J, Yu L, Yu D, Zhao G. Using femtosecond laser to create customized corneal flaps for patients with low and moderate refractive error differing in corneal thickness. PLoS One 2015; 10:e0121291. [PMID: 25807232 PMCID: PMC4373722 DOI: 10.1371/journal.pone.0121291] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 01/29/2015] [Indexed: 11/19/2022] Open
Abstract
This study is designed to evaluate the visual outcomes, accuracy, and predictability of corneal flaps with different thicknesses created by 60-kHz femtosecond laser according to different corneal thicknesses in the patients with low and moderate refractive error. A total of 182 eyes were divided according to the central corneal thickness (470 μm-499 μm in Group A, 500 μm-549 μm in Group B, and 550 μm-599 μm in Group C) and underwent femtosecond laser-assisted LASIK for a target corneal flap thickness (100 μm for Group A, 110 μm for Group B, and 120 μm for Group C). Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and refractive status were examined. The flap thickness of each eye was measured by anterior segment optical coherence tomography (AS-OCT) on 30 points at 1-month follow-up to assess the accuracy and predictability. Postoperatively, at least 75% of eyes had a UDVA of 20/16 or better, less than 2% of eyes lost one line, over 30% of eyes gained one or more lines in CDVA, at least 95% of eyes had astigmatism of less than 0.25 D, all eyes achieved a correction within ± 1.00 D from the target spherical equivalent refraction. The visual and refractive outcomes did not differ significantly in all groups (P >0.05). The mean flap thickness was 100.36 ± 4.32 μm (range: 95-113 μm) in Group A, 111.64 ± 3.62 μm (range: 108-125 μm) in Group B, and 122.32 ± 2.88 μm (range: 112-128 μm) in Group C. The difference at each measured point among the three groups was significant (P < 0.05). The accuracy and predictability were satisfactory in all three groups. In conclusion, this customized treatment yielded satisfactory clinical outcomes with accurate and predictable flap thickness for patients with low and moderate refractive error.
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Affiliation(s)
- Chi Zhang
- Department of Ophthalmology, The First People’s Hospital of Foshan, Foshan, Guangdong, China
| | - Jingbin Che
- Department of Ophthalmology, People’s Hospital of Laiwu, Laiwu, Shandong, China
| | - Jianhong Yu
- Department of Ophthalmology, The First People’s Hospital of Foshan, Foshan, Guangdong, China
| | - Linli Yu
- Department of Ophthalmology, The First People’s Hospital of Foshan, Foshan, Guangdong, China
| | - Dan Yu
- Department of Ophthalmology, The First People’s Hospital of Foshan, Foshan, Guangdong, China
| | - Gangping Zhao
- Department of Ophthalmology, The First People’s Hospital of Foshan, Foshan, Guangdong, China
- * E-mail:
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Clinical applications of anterior segment optical coherence tomography. J Ophthalmol 2015; 2015:605729. [PMID: 25821589 PMCID: PMC4363581 DOI: 10.1155/2015/605729] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Accepted: 02/21/2015] [Indexed: 11/18/2022] Open
Abstract
Anterior segment optical coherence tomography (AS-OCT) was recently developed and has become a crucial tool in clinical practice. AS-OCT is a noncontact imaging device that provides the detailed structure of the anterior part of the eyes. In this review, the author will discuss the various clinical applications of AS-OCT, such as the normal findings, tear meniscus measurement, ocular surface disease (e.g., pterygium, pinguecula, and scleromalacia), architectural analysis after cataract surgery, post-LASIK keratectasia, Descemet's membrane detachment, evaluation of corneal graft after keratoplasty, corneal deposits (corneal dystrophies and corneal verticillata), keratitis, anterior segment tumors, and glaucoma evaluation (angle assessment, morphological analysis of the filtering bleb after trabeculectomy, or glaucoma drainage device implantation surgery). The author also presents some interesting cases demonstrated via AS-OCT.
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Demirci H, Steen DW. Limitations in imaging common conjunctival and corneal pathologies with fourier-domain optical coherence tomography. Middle East Afr J Ophthalmol 2014; 21:220-4. [PMID: 25100905 PMCID: PMC4123273 DOI: 10.4103/0974-9233.134673] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Purpose: To describe the limitations of Fourier-domain optical coherence tomography (OCT) in imaging common conjunctival and corneal pathology. Materials and Methods: Retrospective, single-center case series of 40 patients with conjunctival and cornea pathology. Results: Fourier-domain OCT imaged laser in situ keratomileusis (LASIK) flaps in detail, including its relation to other corneal structures and abnormalities. Similarly, in infectious or degenerative corneal disorders, Fourier-domain OCT successfully showed the extent of infiltration or material deposition, which appeared as hyper-reflective areas. In cases with pterygium, the underlying cornea could not be imaged. All cases of common conjunctival pathologies, such as nevus or pinguecula, were successfully imaged in detail. Nevi, scleritis, pterygium, pinguecula, and subconjunctival hemorrhage were hyper-reflective lesions, while cysts and lymphangiectasia were hyporeflective. The details of the underlying sclera were not uniformly imaged in conjunctival pathologies. Fourier-domain OCT imaged the trabeculectomy bleb in detail, whereas the details of structures of the anterior chamber angle were not routinely visualized in all cases. Conclusions: Light scatter through vascularized, densely inflamed, or thick lesions limits the imaging capabilities of Fourier-domain anterior segment OCT.
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Affiliation(s)
- Hakan Demirci
- Department of Ophthalmology and Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, USA
| | - Daniel W Steen
- Department of Ophthalmology, Henry Ford Hospital, Detroit, Michigan, USA
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Reinstein DZ, Archer TJ, Gobbe M. Small incision lenticule extraction (SMILE) history, fundamentals of a new refractive surgery technique and clinical outcomes. EYE AND VISION (LONDON, ENGLAND) 2014; 1:3. [PMID: 26605350 PMCID: PMC4604118 DOI: 10.1186/s40662-014-0003-1] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 08/13/2014] [Indexed: 11/30/2022]
Abstract
This review summarizes the current status of the small incision lenticule extraction (SMILE) procedure. Following the early work by Sekundo et al. and Shah et al., SMILE has become increasingly popular. The accuracy of the creation of the lenticule with the VisuMax femtosecond laser (Carl Zeiss Meditec) has been verified using very high-frequency (VHF) digital ultrasound and optical coherence tomography (OCT). Visual and refractive outcomes have been shown to be similar to those achieved with laser in situ keratomileusis (LASIK), notably in a large population reported by Hjortdal, Vestergaard et al. Safety in terms of the change in corrected distance visual acuity (CDVA) has also been shown to be similar to LASIK. It was expected that there would be less postoperative dry eye after SMILE compared to LASIK because the anterior stroma is disturbed only by the small incision, meaning that the anterior corneal nerves should be less affected. A number of studies have demonstrated a lower reduction and faster recovery of corneal sensation after SMILE than LASIK. Some studies have also used confocal microscopy to demonstrate a lower decrease in subbasal nerve fiber density after SMILE than LASIK. The potential biomechanical advantages of SMILE have been modeled by Reinstein et al. based on the non-linearity of tensile strength through the stroma. Studies have reported a similar change in Ocular Response Analyzer (Reichert) parameters after SMILE and LASIK, however, these have previously been shown to be unreliable as a representation of corneal biomechanics. Retreatment options after SMILE are discussed. Tissue addition applications of the SMILE procedure are also discussed including the potential for cryo-preservation of the lenticule for later reimplantation (Mohamed-Noriega, Angunawela, Lim et al.), and a new procedure referred to as endokeratophakia in which a myopic SMILE lenticule is implanted into a hyperopic patient (Pradhan et al.). Finally, studies reporting microdistortions in Bowman's layer and corneal wound healing responses are also described.
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Affiliation(s)
- Dan Z Reinstein
- />London Vision Clinic, 138 Harley Street, London, W1G 7LA UK
- />Department of Ophthalmology, Columbia University Medical Center, New York, NY USA
- />Centre Hospitalier National d’Ophtalmologie, Paris, France
| | | | - Marine Gobbe
- />London Vision Clinic, 138 Harley Street, London, W1G 7LA UK
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Malandrini A, Martone G, Canovetti A, Menabuoni L, Balestrazzi A, Fantozzi C, Lenzetti C, Fantozzi M. Morphologic study of the cornea by in vivo confocal microscopy and optical coherence tomography after bifocal refractive corneal inlay implantation. J Cataract Refract Surg 2014; 40:545-57. [PMID: 24680518 DOI: 10.1016/j.jcrs.2013.08.057] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 08/24/2013] [Accepted: 08/27/2013] [Indexed: 11/17/2022]
Abstract
PURPOSE To evaluate the biocompatibility of the Flexivue Microlens intracorneal inlay based on healing of corneal wounds and analysis of corneal structural features using in vivo confocal microscopy (IVCM) and anterior segment optical coherence tomography (AS-OCT). SETTING Ophthalmology Department, Misericordia e Dolce Hospital, Prato, Italy. DESIGN Case series. METHODS The intracorneal inlay was inserted in a stromal pocket created in the nondominant eye of emmetropic presbyopic patients using a femtosecond laser. In vivo confocal microscopy and AS-OCT examinations were performed preoperatively and 1, 6, and 12 months postoperatively. RESULTS The mean follow-up was 7.6 months. In the early postoperative period, IVCM showed intense cellular activity in the stroma around the inlay, edema, inflammation, and degenerative material deposition but normal regularity after 12 months. Anterior segment OCT showed a regular planar shape of the corneal pocket in all eyes. The mean of the side-cut angles was 30.7 degrees. The mean difference between the measured and planned pocket depth was 9.77 μm. At 1 month, hyperreflective areas beneath the inlay and microfolds were observed in 21 of the 52 eyes. After 12 months, the anterior segment profile was regular and interface pocket reflectivity decreased over time. Six patients had inlay removal postoperatively (3 before 6 months; 3 before 12 months); after removal, IVCM and AS-OCT showed clear corneas without signs of irregularity. CONCLUSION In vivo confocal microscopy and AS-OCT analysis showed that the inlay elicited a low-level wound-healing response in its immediate vicinity with no alteration in the corneal structures. FINANCIAL DISCLOSURE Dr. M. Fantozzi is a member of the Presbia medical advisory board. No other author has a financial or proprietary interest in any material or method mentioned.
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Affiliation(s)
- Alex Malandrini
- From the Department of Ophthalmology (Malandrini, Canovetti, Menabuoni, C. Fantozzi, M. Fantozzi, Lenzetti), Misericordia e Dolce Hospital, Prato, and the Department of Ophthalmology (Martone, Balestrazzi), University of Siena, Siena, Italy.
| | - Gianluca Martone
- From the Department of Ophthalmology (Malandrini, Canovetti, Menabuoni, C. Fantozzi, M. Fantozzi, Lenzetti), Misericordia e Dolce Hospital, Prato, and the Department of Ophthalmology (Martone, Balestrazzi), University of Siena, Siena, Italy
| | - Annalisa Canovetti
- From the Department of Ophthalmology (Malandrini, Canovetti, Menabuoni, C. Fantozzi, M. Fantozzi, Lenzetti), Misericordia e Dolce Hospital, Prato, and the Department of Ophthalmology (Martone, Balestrazzi), University of Siena, Siena, Italy
| | - Luca Menabuoni
- From the Department of Ophthalmology (Malandrini, Canovetti, Menabuoni, C. Fantozzi, M. Fantozzi, Lenzetti), Misericordia e Dolce Hospital, Prato, and the Department of Ophthalmology (Martone, Balestrazzi), University of Siena, Siena, Italy
| | - Angelo Balestrazzi
- From the Department of Ophthalmology (Malandrini, Canovetti, Menabuoni, C. Fantozzi, M. Fantozzi, Lenzetti), Misericordia e Dolce Hospital, Prato, and the Department of Ophthalmology (Martone, Balestrazzi), University of Siena, Siena, Italy
| | - Chiara Fantozzi
- From the Department of Ophthalmology (Malandrini, Canovetti, Menabuoni, C. Fantozzi, M. Fantozzi, Lenzetti), Misericordia e Dolce Hospital, Prato, and the Department of Ophthalmology (Martone, Balestrazzi), University of Siena, Siena, Italy
| | - Chiara Lenzetti
- From the Department of Ophthalmology (Malandrini, Canovetti, Menabuoni, C. Fantozzi, M. Fantozzi, Lenzetti), Misericordia e Dolce Hospital, Prato, and the Department of Ophthalmology (Martone, Balestrazzi), University of Siena, Siena, Italy
| | - Marco Fantozzi
- From the Department of Ophthalmology (Malandrini, Canovetti, Menabuoni, C. Fantozzi, M. Fantozzi, Lenzetti), Misericordia e Dolce Hospital, Prato, and the Department of Ophthalmology (Martone, Balestrazzi), University of Siena, Siena, Italy
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Li P, Johnstone M, Wang RK. Full anterior segment biometry with extended imaging range spectral domain optical coherence tomography at 1340 nm. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:046013. [PMID: 24752381 PMCID: PMC3993014 DOI: 10.1117/1.jbo.19.4.046013] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 03/24/2014] [Indexed: 05/11/2023]
Abstract
We demonstrate an extended-imaging-range anterior-segment optical coherence tomography (eAS-OCT) system for the biometric assessment of full AS in human eye. This newly developed eAS-OCT operating at 1340-nm wavelength band is simultaneously capable of an imaging speed of 120 kHz A-line scan rate, an axial resolution of 7.2 μm, and an extended imaging range of up to 16 mm in air. Imaging results from three healthy subjects and one subject with a narrow-angle demonstrate the instrument's utility. With this system, it can provide anatomical dimensions of AS, including central corneal thickness, anterior chamber width, anterior chamber depth, crystalline lens vault, crystalline lens thickness, angle opening distance (AOD500/AOD750), and the area described by the trabecular-iris space (TISA500/TISA750) at 500/750 μm. We also use eAS-OCT to image and quantify dynamic functional changes of the AS in response to a light stimulus that induces physiological pupillary changes as well as accommodative efforts that induce lens changes. The results show that the described eAS-OCT is able to provide full anatomical biometry for AS and is useful for the studies where the dynamic response of AS compartment to certain stimulus is required.
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Affiliation(s)
- Peng Li
- University of Washington, Department of Bioengineering, Seattle, Washington 98195
| | - Murray Johnstone
- University of Washington, Department of Ophthalmology, Seattle, Washington 98104
| | - Ruikang K. Wang
- University of Washington, Department of Bioengineering, Seattle, Washington 98195
- University of Washington, Department of Ophthalmology, Seattle, Washington 98104
- Address all correspondence to: Ruikang K. Wang, E-mail:
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Hurmeric V, Yoo SH, Mutlu FM. Optical coherence tomography in cornea and refractive surgery. EXPERT REVIEW OF OPHTHALMOLOGY 2014. [DOI: 10.1586/eop.12.28] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Reinstein DZ, Archer TJ, Gobbe M. Accuracy and Reproducibility of Cap Thickness in Small Incision Lenticule Extraction. J Refract Surg 2013; 29:810-5. [DOI: 10.3928/1081597x-20131023-02] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 07/15/2013] [Indexed: 11/20/2022]
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Kymionis GD, Kontadakis GA, Grentzelos MA, Panagopoulou SI, Stojanovic N, Kankariya VP, Henderson BA, Pallikaris IG. Thin-flap laser in situ keratomileusis with femtosecond-laser technology. J Cataract Refract Surg 2013; 39:1366-71. [DOI: 10.1016/j.jcrs.2013.03.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Revised: 03/09/2013] [Accepted: 03/11/2013] [Indexed: 10/26/2022]
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The morphology of corneal cap and its relation to refractive outcomes in femtosecond laser small incision lenticule extraction (SMILE) with anterior segment optical coherence tomography observation. PLoS One 2013; 8:e70208. [PMID: 23940547 PMCID: PMC3734027 DOI: 10.1371/journal.pone.0070208] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Accepted: 06/17/2013] [Indexed: 11/22/2022] Open
Abstract
Purpose To investigate the morphology of corneal caps in femtosecond laser small incision lenticule extraction (SMILE) and its relation to the refractive outcomes. Methods A prospective study of fifty-four corneal caps created with VisuMax femtosecond laser were examined using an Fourier-domain optical coherence tomography at 1 day, 1 week, 1 month and 6 months after SMILE. The cap thickness at nine points on each of the four meridians (0°, 45°, 90°, 135°) and the diameter were measured. Cap morphology, changes over time and its correlation with refractive outcomes were assessed. Results The mean achieved central cap thickness were (108.74±5.06) µm at 6 months and (107.32±4.81 ) µm at 1 month postoperatively, significantly thinner than that at 1 day (110.81±7.95) µm and 1 week (109.58±7.48 ) µm (P<0.05). The mean diameter on 0° meridian was (7.61±0.07) mm, significantly larger than that on 90° meridian (7.57±0.06) mm (P = 0.001). Cap morphology showed good regularity, except that the differences of points in two pairs were significant at 1 day postoperatively. The uniformity was consistent over time and the central cap thickness was thinner than those in the paracentral and peripheral areas. The refractive outcomes stabilized within 1 month. Uncorrected distance visual acuity (UDVA) was correlated to the central cap thickness at 1 day and 1 week (both rs = 0.33, p<0.05). The uniformity index was correlated with UDVA (rs = 0.34, p<0.05) and corrected distance visual acuity (rs = 0.32, p<0.05) at 1 week postoperatively. Conclusions Corneal caps of SMILE are predictable with good reproducibility, regularity and uniformity. Cap morphology might have a mild effect on refractive outcomes in the early stage. Further study should focus on the impact on the visual quality.
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Corneal Sublayers Thickness Estimation Obtained by High-Resolution FD-OCT. Int J Biomed Imaging 2013; 2013:989624. [PMID: 23818895 PMCID: PMC3684120 DOI: 10.1155/2013/989624] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 05/21/2013] [Indexed: 11/17/2022] Open
Abstract
This paper presents a novel processing technique which can be applied to corneal in vivo images obtained with optical coherence tomograms across the central meridian of the cornea. The method allows to estimate the thickness of the corneal sublayers (Epithelium, Bowman's layer, Stroma, Endothelium, and whole corneal thickness) at any location, including the center and the midperiphery, on both nasal and temporal sides. The analysis is carried out on both the pixel and subpixel scales to reduce the uncertainty in thickness estimations. This technique allows quick and noninvasive assessment of patients. As an example of application and validation, we present the results obtained from the analysis of 52 healthy subjects, each with 3 scans per eye, for a total of more than 300 images. Particular attention has been paid to the statistical interpretation of the obtained results to find a representative assessment of each sublayer's thickness.
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Zhang J, Zhou Y, Zhai C, Tian L. Comparison of 2 femtosecond lasers for laser in situ keratomileusis flap creation. J Cataract Refract Surg 2013; 39:922-7. [DOI: 10.1016/j.jcrs.2013.01.042] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Revised: 01/04/2013] [Accepted: 01/05/2013] [Indexed: 11/26/2022]
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Shetty R, Malhotra C, D'Souza S, Wadia K. WaveLight FS200 vs Hansatome LASIK: intraoperative determination of flap characteristics and predictability by hand-held bioptigen spectral domain ophthalmic imaging system. J Refract Surg 2013; 28:S815-20. [PMID: 23447894 DOI: 10.3928/1081597x-20121005-01] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To intraoperatively determine and compare the characteristics and predictability of LASIK flaps made by the WaveLight FS200 femtosecond laser (Alcon Laboratories Inc) and Hansatome (Bausch & Lomb) microkeratome using a hand-held spectral domain ophthalmic imaging system (Bioptigen Inc). METHODS Sixty eyes from 30 patients undergoing bilateral LASIK were prospectively evaluated. Patients were divided into two equal groups to undergo flap creation with either 100-microm femtosecond laser flaps (FS flap group) or 120-microm microkeratome flaps (MK flap group). Flap thickness was measured intraoperatively after creation of the flap but prior to lifting using the hand-held probe of the spectral domain imaging system. Geometry of the flap edge and smoothness of the stromal bed after lifting the flap was also evaluated in all cases. RESULTS Mean difference between planned and achieved flap thickness in the paracentral region was 2.84 +/- 3.16 mm for the FS flap group and 11.33 +/- 10.27 mm for the MK flap group, whereas in the periphery, it was 5.72 +/- 3.26 mm in the FS flap group and 24.67 +/- 10.35 mm in the MK flap group. The differences between groups were statistically significant (P < 0.001, Kruskal-Wallis test). The edges of the flaps were vertical in the FS flap group and the stromal bed was smoother, whereas in the MK flap group, the edges were more sloping and the stromal bed more irregular. CONCLUSIONS The WaveLight FS200 femtosecond laser is able to produce planar flaps with a high degree of predictability between the desired and achieved flap thickness. The ability to study the flap characteristics intraoperatively (when flap edema and stromal bed hydration changes have not yet occurred) with the hand-held probe of the Bioptigen imaging system ensures greater accuracy than measurements done postoperatively using other anterior segment optical coherence tomography prototypes.
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Affiliation(s)
- Rohit Shetty
- Narayana Nethralaya Eye Hospital, Bangalore, India
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Sayegh RR, Pineda R. Practical Applications of Anterior Segment Optical Coherence Tomography Imaging Following Corneal Surgery. Semin Ophthalmol 2012; 27:125-32. [DOI: 10.3109/08820538.2012.707274] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Role of optical coherence tomography on corneal surface laser ablation. J Ophthalmol 2012; 2012:676740. [PMID: 23050122 PMCID: PMC3461297 DOI: 10.1155/2012/676740] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 08/22/2012] [Indexed: 11/17/2022] Open
Abstract
This paper focuses on reviewing the roles of optical coherence tomography (OCT) on corneal surface laser ablation procedures. OCT is an optical imaging modality that uses low-coherence interferometry to provide noninvasive cross-sectional imaging of tissue microstructure in vivo. There are two types of OCTs, each with transverse and axial spatial resolutions of a few micrometers: the time-domain and the fourier-domain OCTs. Both have been increasingly used by refractive surgeons and have specific advantages. Which of the current imaging instruments is a better choice depends on the specific application. In laser in situ keratomileusis (LASIK) and in excimer laser phototherapeutic keratectomy (PTK), OCT can be used to assess corneal characteristics and guide treatment decisions. OCT accurately measures central corneal thickness, evaluates the regularity of LASIK flaps, and quantifies flap and residual stromal bed thickness. When evaluating the ablation depth accuracy by subtracting preoperative from postoperative measurements, OCT pachymetry correlates well with laser ablation settings. In addition, OCT can be used to provide precise information on the morphology and depth of corneal pathologic abnormalities, such as corneal degenerations, dystrophies, and opacities, correlating with histopathologic findings.
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Tay E, Li X, Chan C, Tan DT, Mehta JS. Refractive lenticule extraction flap and stromal bed morphology assessment with anterior segment optical coherence tomography. J Cataract Refract Surg 2012; 38:1544-51. [DOI: 10.1016/j.jcrs.2012.05.030] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Revised: 05/15/2012] [Accepted: 05/17/2012] [Indexed: 11/29/2022]
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Wong MHY, Chew A, Htoon HM, Lee BH, Cheng J, Liu J, Tan DT, Mehta JS. Reproducibility of Corneal Graft Thickness measurements with COLGATE in patients who have undergone DSAEK (Descemet Stripping Automated Endothelial Keratoplasty). BMC Med Imaging 2012; 12:25. [PMID: 22853647 PMCID: PMC3443444 DOI: 10.1186/1471-2342-12-25] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Accepted: 07/17/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The CorneaL GrAft Thickness Evaluation (COLGATE) system was recently developed to facilitate the evaluation of corneal graft thickness from OCT images. Graft thickness measurement can be a surrogate indicator for detecting graft failure or success. The purpose of this study was to determine the reproducibility of the COLGATE system in measuring DSAEK graft area between two observers. METHODS This was a prospective case series in which 50 anterior segment OCT images of patients who had undergone DSAEK in either eye were analysed. Two observers (MW, AC) independently obtained the image analysis for the graft area using both semi automated and automated method. One week later, each observer repeated the analysis for the same set of images. Bland-Altman analysis was performed to analyze inter and intra observer agreement. RESULTS There was strong intraobserver correlation between the 2 semi automated readings obtained by both observers. (r = 0.936 and r = 0.962). Intraobserver ICC for observer 1 was 0.936 (95% CI 0.890 to 0.963) and 0.967 (95% CI 0.942 to 0.981) for observer 2. Likewise, there was also strong interobserver correlation (r = 0.913 and r = 0.969). The interobserver ICC for the first measurements was 0.911 (95% CI 0.849 to 0.949) and 0.968 (95% CI 0.945 to 0.982) for the second. There was statistical difference between the automatic and the semi automated readings for both observers (p = 0.006, p = 0.003). The automatic readings gave consistently higher values than the semi automated readings especially in thin grafts. CONCLUSION The analysis from the COLGATE programme can be reproducible between different observers. Care must be taken when interpreting the automated analysis as they tend to over estimate measurements.
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Affiliation(s)
- Melissa H Y Wong
- Singapore National Eye Centre (SNEC), 11 Third Hospital Avenue, 168751, SNEC, Singapore
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Study of anterior chamber aqueous tube shunt by fourier-domain optical coherence tomography. J Ophthalmol 2012; 2012:189580. [PMID: 22778909 PMCID: PMC3388420 DOI: 10.1155/2012/189580] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 05/07/2012] [Indexed: 11/23/2022] Open
Abstract
Purpose. This cross-sectional, observational study used Fourier-domain optical coherence tomography (OCT) to examine the position, patency, and the interior entrance site of anterior chamber (AC) aqueous tube shunts. Methods. The OCT, slitlamp biomicroscopy, and gonioscopy findings of 23 eyes of 18 patients with AC shunts were collected and compared. Results. OCT images demonstrated the shunt position and patency in all 23 eyes, and the details of the AC entrance in 16 eyes. The position of the tube varied, with the majority (14/23) on the surface of the iris. The exact position of the AC entrance relative to Schwalbe's line (SL) could be determined in 9 eyes (posterior to SL in 7 eyes, anterior in 2 eyes). At the AC entrance, growth of fibrous scar tissue was present between the tube and the corneal endothelium in all 16 eyes in which the entrance could be clearly visualized. It's a new finding that could not be visualized by slitlamp examination or lower resolution OCT. Conclusion. Compared to slitlamp examination, Fourier-domain OCT of AC tube shunts provided more detailed anatomic information regarding the insertion level relative to SL, scar tissue between the tube and the corneal endothelium, and patency of the tube opening.
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Reinstein DZ, Gobbe M, Archer TJ. Anterior Segment Biometry: A Study and Review of Resolution and Repeatability Data. J Refract Surg 2012; 28:509-20. [DOI: 10.3928/1081597x-20120620-02] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 05/04/2012] [Indexed: 11/20/2022]
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Zhang XX, Zhong XW, Wu JS, Wang Z, Yu KM, Liu Q, Yang B. Corneal flap morphological analysis using anterior segment optical coherence tomography in laser in situ keratomileusis with femtosecond lasers versus mechanical microkeratome. Int J Ophthalmol 2012; 5:69-73. [PMID: 22553758 DOI: 10.3980/j.issn.2222-3959.2012.01.14] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Accepted: 01/28/2012] [Indexed: 11/02/2022] Open
Abstract
AIM To assess and compare the flap morphology using anterior segment optical coherence tomography (AS-OCT) in laser in situ keratomileusis (LASIK) with Femto LDV femtosecond lasers versus Hansatome mechanical Microkeratome. METHODS AS-OCT (Visante) was used to compare 1 month postoperatively the morphology of the flaps created with Femto LDV femtosecond lasers or Hansatome Microkeratome. The intended flap thickness was 110µm and 160µm respectively. The thickness of twenty-five points across each flap, which were 0mm, 1.5mm, 2.5mm, and 3.5mm to the corneal vertex on the horizontal, vertical, 45° and 135° meridian respectively, was evaluated. RESULTS One month postoperative, the central flap thickness in the Femto LDV group was 107.43±4.70µm, while 125.90±17.50µm in the Hansatome group. The difference between the actual and the expected flap thickness was 5.61±3.84µm and 31.52±12.27µm, respectively. The Hansatome group had presented a statistically significant result (P<0.001). Flap morphology showed a more regular planar shape in the Femto LDV group and a meniscus shape in the Hansatome group. CONCLUSION AS-OCT is a direct and fast procedure to assess the flap morphology. The morphology by AS-OCT showed that the flaps created with Femto LDV femtosecond laser were more accurate and regular than the flaps created with Hansatome microkeratome.
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Affiliation(s)
- Xiao-Xiao Zhang
- Zhongshan Ophthalmic Center and State Key Laboratory of Ophthalmology, Sun Yat-sen University, Guangzhou 510060, Guangdong Province, China
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Correlation of Straylight and Visual Acuity in Long-Term Follow-up of Manual Descemet Stripping Endothelial Keratoplasty. Cornea 2012; 31:380-6. [DOI: 10.1097/ico.0b013e31823f8ab7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Hahn P, Migacz J, O'Connell R, Maldonado RS, Izatt JA, Toth CA. The use of optical coherence tomography in intraoperative ophthalmic imaging. Ophthalmic Surg Lasers Imaging Retina 2012; 42 Suppl:S85-94. [PMID: 21790116 DOI: 10.3928/15428877-20110627-08] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Accepted: 04/05/2011] [Indexed: 02/01/2023]
Abstract
Optical coherence tomography (OCT) has transformed diagnostic ophthalmic imaging but until recently has been limited to the clinic setting. The development of spectral-domain OCT (SD-OCT), with its improved speed and resolution, along with the development of a handheld OCT scanner, enabled portable imaging of patients unable to sit in a conventional tabletop scanner. This handheld SD-OCT unit has proven useful in examinations under anesthesia and, more recently, in intraoperative imaging of preoperative and postoperative manipulations. Recently, several groups have pioneered the development of novel OCT modalities, such as microscope-mounted OCT systems. Although still immature, the development of these systems is directed toward real-time imaging of surgical maneuvers in the intraoperative setting. This article reviews intraoperative imaging of the posterior and anterior segment using the handheld SD-OCT and recent advances toward real-time microscope-mounted intrasurgical imaging.
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Affiliation(s)
- Paul Hahn
- Departments of Ophthalmology and Biomedical Engineering, Duke University, Durham, North Carolina, USA
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Repeatability of intraoperative central corneal and residual stromal thickness measurement using a handheld ultrasound pachymeter. J Cataract Refract Surg 2011; 38:278-82. [PMID: 22133548 DOI: 10.1016/j.jcrs.2011.08.037] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Revised: 06/13/2011] [Accepted: 08/13/2011] [Indexed: 11/24/2022]
Abstract
PURPOSE To determine and compare the repeatability of intraoperative central corneal thickness (CCT) and residual stromal bed thickness measurements using a handheld ultrasound (US) pachymeter. SETTING London Vision Clinic, London, United Kingdom. DESIGN Comparative evaluation of a diagnostic test or technology. METHODS This study comprised eyes that had laser in situ keratomileusis retreatment by flap lift in which handheld US pachymetry (Corneo-Gage Plus 50 MHz) had been performed intraoperatively. In each case, 5 consecutive measurements were obtained centrally immediately before and after the flap was lifted. The within-eye repeatability was calculated as the standard deviation of the 5 repeated measurements for the CCT measurements and the central residual stromal thickness (RST) measurements. RESULTS The study evaluated 134 eyes (79 patients). The mean CCT was 467 μm ± 40 (SD) (range 393 to 577 μm). The repeatability of CCT measurements was 6.83 μm, the coefficient of repeatability was 13.40 μm, and the coefficient of variation (CoV) was 1.46%. The mean central RST was 335 ± 46 μm (range 259 to 465 μm). The repeatability of central RST measurements was 4.91 μm, the coefficient of repeatability was 9.62 μm, and the CoV was 1.46%. CONCLUSION The repeatability of intraoperative handheld US pachymetry was similar between measurements of CCT and measurements of central RST; the CoV was 1.46% in both cases.
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Reinstein DZ, Archer TJ, Gobbe M. Comparison of residual stromal bed thickness measurement among very high-frequency digital ultrasound, intraoperative handheld ultrasound, and optical coherence tomography. J Refract Surg 2011; 28:42-7. [PMID: 21913632 DOI: 10.3928/1081597x-20110825-02] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Accepted: 07/25/2011] [Indexed: 11/20/2022]
Abstract
PURPOSE To compare residual stromal thickness (RST) measurement by three methods: very high-frequency digital ultrasound (VHFDU), intraoperative handheld ultrasound (US), and optical coherence tomography (OCT). METHODS This was a retrospective analysis of 93 eyes (55 patients) that underwent LASIK retreatment by flap lift where VHFDU and OCT measurements were obtained before the retreatment and intraoperative US RST measurement was performed after lifting the flap. Corneal vertex RST measurements for intraoperative US and OCT were compared with the VHFDU measurement. Linear regression and Bland-Altman analysis were performed. RESULTS Mean corneal vertex RST was 327±53 μm for VHFDU, 338±54 μm for intraoperative US, and 326±43 μm for OCT. Mean difference between VHFDU and intraoperative US was 11±11 μm (range: -12 to 46 μm). Mean difference between VHFDU and OCT was -2±23 μm (range: -53 to 57 μm). The coefficient of determination (R(2)) was 0.96 between VHFDU and intraoperative US and 0.82 between VHFDU and OCT. Intraoperative US was on average 11 μm thicker than VHFDU independent of RST value. Optical coherence tomography was on average thicker than VHFDU for low RST values (250 to 300 μm) and thinner than VHFDU for high RST values (>350 μm). The RST was thicker than VHFDU by >10 μm in 50% and >20 μm in 21% of eyes measured with intraoperative US and by >10 μm in 32% and >20 μm in 18% of eyes measured with OCT. CONCLUSIONS Residual stromal thickness measured by both intraoperative US and OCT was thicker than VHFDU in a significant number of eyes, which could have resulted in retreatment being performed in an eye with insufficient RST.
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Affiliation(s)
- Dan Z Reinstein
- London Vision Clinic, London, United Kingdom. dzr@londonvisionclinic@com
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Murakami Y, Manche EE. Comparison of intraoperative subtraction pachymetry and postoperative anterior segment optical coherence tomography of laser in situ keratomileusis flaps. J Cataract Refract Surg 2011; 37:1879-83. [PMID: 21840682 DOI: 10.1016/j.jcrs.2011.05.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2010] [Revised: 04/17/2011] [Accepted: 05/02/2011] [Indexed: 11/27/2022]
Abstract
PURPOSE To prospectively compare intraoperative subtraction pachymetry flap thickness measurements and postoperative anterior segment optical coherence tomography (AS-OCT) flap thickness measurements in eyes that had laser in situ keratomileusis (LASIK) flap creation with a femtosecond laser or a mechanical microkeratome. SETTING Stanford Eye Laser Center, Stanford University School of Medicine, Stanford, California, USA. DESIGN Comparative case series. METHODS Each patient received wavefront-guided LASIK using an Intralase femtosecond laser in 1 eye and a Hansatome mechanical microkeratome in the fellow eye. Flap morphology was assessed with an ultrasound pachymeter intraoperatively and an AS-OCT system postoperatively at 1 year. RESULTS Thirty-six eyes (18 patients) were enrolled. Intraoperative subtraction pachymetry consistently underestimated mechanical microkeratome flap thickness compared with postoperative AS-OCT (P<.001). There was no significant difference between intraoperative subtraction pachymetry and postoperative AS-OCT measurements for femtosecond flaps (P=.38). The overall mean variation in flap thickness (ie, mean deviation from targeted flap thickness) was 2.6 μm (range 3 to 11 μm) with the femtosecond laser and 14.2 μm (range 17 to 52 μm) with the mechanical microkeratome (P<.001). Postoperative AS-OCT measurements showed femtosecond flaps had a planar configuration and mechanical microkeratome flaps had a meniscus-shaped configuration. CONCLUSIONS The femtosecond laser created more uniformly planar flaps than the mechanical microkeratome as measured by intraoperative subtraction pachymetry and postoperative AS-OCT. Postoperative AS-OCT measurements varied less than intraoperative subtraction pachymetry measurements for mechanical microkeratome flaps. FINANCIAL DISCLOSURE Neither author has a financial or proprietary interest in any material or method mentioned.
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Affiliation(s)
- Yohko Murakami
- Department of Ophthalmology, Stanford University School of Medicine, Stanford, California 94304, USA
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Yao P, Xu Y, Zhou X. Comparison of the predictability, uniformity and stability of a laser in situ keratomileusis corneal flap created with a VisuMax femtosecond laser or a Moria microkeratome. J Int Med Res 2011; 39:748-58. [PMID: 21819705 DOI: 10.1177/147323001103900306] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
This prospective study compared the predictability, uniformity and stability of laser in situ keratomileusis corneal flap thickness created by a femtosecond laser or a classic microkeratome. Twenty-five femtosecond laser (VisuMax, Carl Zeiss Meditec) flaps and 38 microkeratome (Moria M3) flaps were measured using anterior segment optical coherence tomography at 1 week, 1 month and 6 months postoperatively. Flap thickness at seven points on each of the four meridians was calculated. At 6 months, VisuMax flaps showed better prediction than Moria flaps for central flap thickness. The standard deviation within individual flaps was smaller for VisuMax flaps and their index of symmetry was better. The mean thicknesses among the four eccentricities in the VisuMax flaps were the same, while Moria flaps were thicker at the 3-mm radius compared with the centre. The VisuMax femtosecond laser created corneal flaps with better predictability and uniformity, and similar reproducibility and stability, compared with the microkeratome.
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Affiliation(s)
- P Yao
- Myopia Key Laboratory of the Health Ministry, Eye and ENT Hospital of Fudan University, Shanghai, China
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Reinstein DZ, Archer TJ, Gobbe M. LASIK Flap Thickness Profile and Reproducibility of the Standard vs Zero Compression Hansatome Microkeratomes: Three-Dimensional Display with Artemis VHF Digital Ultrasound. J Refract Surg 2011; 27:417-26. [DOI: 10.3928/1081597x-20101110-01] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2010] [Accepted: 09/15/2010] [Indexed: 11/20/2022]
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LaRocca F, Chiu SJ, McNabb RP, Kuo AN, Izatt JA, Farsiu S. Robust automatic segmentation of corneal layer boundaries in SDOCT images using graph theory and dynamic programming. BIOMEDICAL OPTICS EXPRESS 2011; 2:1524-38. [PMID: 21698016 PMCID: PMC3114221 DOI: 10.1364/boe.2.001524] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Revised: 05/06/2011] [Accepted: 05/10/2011] [Indexed: 05/19/2023]
Abstract
Segmentation of anatomical structures in corneal images is crucial for the diagnosis and study of anterior segment diseases. However, manual segmentation is a time-consuming and subjective process. This paper presents an automatic approach for segmenting corneal layer boundaries in Spectral Domain Optical Coherence Tomography images using graph theory and dynamic programming. Our approach is robust to the low-SNR and different artifact types that can appear in clinical corneal images. We show that our method segments three corneal layer boundaries in normal adult eyes more accurately compared to an expert grader than a second grader-even in the presence of significant imaging outliers.
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Affiliation(s)
- Francesco LaRocca
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, US
| | - Stephanie J. Chiu
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, US
| | - Ryan P. McNabb
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, US
| | - Anthony N. Kuo
- Department of Ophthalmology, Duke University Medical Center, Durham, NC 27710, USA
| | - Joseph A. Izatt
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, US
- Department of Ophthalmology, Duke University Medical Center, Durham, NC 27710, USA
| | - Sina Farsiu
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, US
- Department of Ophthalmology, Duke University Medical Center, Durham, NC 27710, USA
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Rosas Salaroli CH, Li Y, Zhang X, Tang M, Branco Ramos JL, Allemann N, Huang D. Repeatability of laser in situ keratomileusis flap thickness measurement by Fourier-domain optical coherence tomography. J Cataract Refract Surg 2011; 37:649-54. [PMID: 21420588 DOI: 10.1016/j.jcrs.2010.10.047] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Revised: 10/21/2010] [Accepted: 10/22/2010] [Indexed: 11/19/2022]
Abstract
PURPOSE To evaluate the repeatability of Fourier-domain optical coherence tomography (OCT) measurements of the thickness of femtosecond laser-created laser in situ keratomileusis (LASIK) flaps. SETTING Doheny Eye Institute, University of Southern California, Los Angeles, California, USA. DESIGN Case series, evaluation of diagnostic technology. METHODS In this consecutive series, Fourier-domain OCT (RTVue) was used to measure flap thickness 1 week after LASIK. Flaps were created with a Pulsion 60 kHz femtosecond laser programmed for 110 μm flap thickness. Each eye was scanned 2 times with a radial pachymetry pattern and 1 time with a horizontal line scan. Flap thicknesses were measured at 6 positions across the corneal flap (ie, ± 0.5 mm, ± 1.5 mm, and ± 2.5 mm from the center on the horizontal and vertical meridians). The within-grader flap thickness repeatability and between-grader reproducibility were calculated by pooled standard deviations (SDs). RESULTS Twenty-one eyes were measured. The mean flap thickness measurements were highly predictable at all positions. Thickness SDs varied from 5.3 to 9.5 μm and uniformity, from 121.7 to 126.5 μm. The within-grader repeatability was 3.3 to 6.4 μm based on the same image measured at different times and 4.7 to 7.4 μm for different images. The between-grader reproducibility was 4.0 to 9.0 μm. There was no statistically significant asymmetry between the nasal side and the temporal side, the superior side and the inferior side, or the pericentral area and the central area of the corneal flap. CONCLUSIONS The femtosecond laser created LASIK flaps with uniform and predictable thicknesses. Fourier-domain OCT gave highly repeatable flap-thickness measurements. FINANCIAL DISCLOSURE Drs. Rosas Salaroli, Zhang, Branco Ramos, and Allemann have no financial or proprietary interest in any material or method mentioned. Additional disclosures are found in the footnotes.
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Affiliation(s)
- Camila Haydée Rosas Salaroli
- Center for Ophthalmic Optics and Lasers, Doheny Eye Institute, and Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
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Gabriele ML, Wollstein G, Ishikawa H, Kagemann L, Xu J, Folio LS, Schuman JS. Optical coherence tomography: history, current status, and laboratory work. Invest Ophthalmol Vis Sci 2011; 52:2425-36. [PMID: 21493951 DOI: 10.1167/iovs.10-6312] [Citation(s) in RCA: 158] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Optical coherence tomography (OCT) imaging has become widespread in ophthalmology over the past 15 years, because of its ability to visualize ocular structures at high resolution. This article reviews the history of OCT imaging of the eye, its current status, and the laboratory work that is driving the future of the technology.
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Affiliation(s)
- Michelle L Gabriele
- Department of Ophthalmology, UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA
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Issa A, Al Hassany U. Femtosecond laser flap parameters and visual outcomes in laser in situ keratomileusis. J Cataract Refract Surg 2011; 37:665-74. [DOI: 10.1016/j.jcrs.2010.10.049] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2010] [Revised: 10/24/2010] [Accepted: 10/27/2010] [Indexed: 11/29/2022]
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46
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Hall RC, Mohamed FK, Htoon HM, Tan DT, Mehta JS. Laser in situ keratomileusis flap measurements: Comparison between observers and between spectral-domain and time-domain anterior segment optical coherence tomography. J Cataract Refract Surg 2011; 37:544-51. [PMID: 21333877 DOI: 10.1016/j.jcrs.2010.10.037] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Revised: 08/31/2010] [Accepted: 10/05/2010] [Indexed: 11/19/2022]
Affiliation(s)
- Reece C Hall
- Singapore National Eye Centre, National University of Singapore, Singapore
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Kim CY, Song JH, Na KS, Chung SH, Joo CK. Factors influencing corneal flap thickness in laser in situ keratomileusis with a femtosecond laser. KOREAN JOURNAL OF OPHTHALMOLOGY 2011; 25:8-14. [PMID: 21350688 PMCID: PMC3039202 DOI: 10.3341/kjo.2011.25.1.8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Accepted: 09/03/2010] [Indexed: 11/23/2022] Open
Abstract
Purpose To evaluate factors responsible for the variability between intended and achieved corneal-flap thickness during femtosecond laser-assisted laser in situ keratomileusis (LASIK). Methods A prospective, nonrandomized, case study was performed on 35 eyes of 18 consecutive patients who underwent LASIK surgery using the 60 kHz femtosecond laser microkeratome. Eyes were assigned to three different thickness groups, with 110-, 120-, or 130-µm cut depths. Anterior segment optical coherence tomography was used to assess the morphology of 35 LASIK flaps at postoperative one week postoperatively. The flap thickness was assessed at seven measuring points across each flap. Patient age, preoperative spherical equivalent, manual keratometry, preoperative central pachymetry, and regional variability of the cornea were evaluated to determine where they influenced the achieved corneal flap thickness. Results Cuttings of all flaps were easily performed without any intraoperative complications. Flap-thickness measurements had a mean of 115.21 ± 4.98 µm (intended thickness, 110 µm), 121.90 ± 5.79 µm (intended, 120 µm), and 134.38 ± 5.04 µm (intended, 130 µm), respectively. There was no significant difference between the 110-µm and 120-µm groups when compared with the 130-µm group (one-way analysis of variance test, p > 0.05). Patients' age, preoperative spherical equivalent, manual keratometry, and preoperative central pachymetry did not affect the achieved flap thickness (Pearson correlations test, p > 0.05). The reproducibility of flap thickness in the central 1.5-mm radius area was more accurate than that in the peripheral 3.0 to 4.0-mm radius area (paired samples t-test, p < 0.05). Conclusions Femtosecond laser-assisted LASIK is likely to reproduce a reliable thickness of the corneal flap, which is independent of corneal shape factors or refractive status. Future studies should focus on variations in corneal biomechanical factors, which may also play an important role in determining flap thickness.
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Affiliation(s)
- Chan Young Kim
- Department of Ophthalmology and Visual Science, Seoul St. Mary's Hospital, The Catholic University of Korea School of Medicine, Seoul, Korea
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Ju WK, Lee JH, Chung TY, Chung ES. Reproducibility of LASIK Flap Thickness Using the Zeiss Femtosecond Laser Measured Postoperatively by Optical Coherence Tomography. J Refract Surg 2011; 27:106-10. [DOI: 10.3928/1081597x-20100428-04] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Accepted: 04/08/2010] [Indexed: 11/20/2022]
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Xu Y, Zhou X, Wang L, Xu H. A morphological study of corneal flap after thin-flap laser-assisted in situ keratomileusis by anterior segment optical coherence tomography. J Int Med Res 2011; 38:1952-60. [PMID: 21226998 DOI: 10.1177/147323001003800608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
This prospective study assessed corneal flap morphology in 115 patients undergoing laser-assisted in situ keratomileusis (LASIK). Flaps were created using the Moria M2 90-μm or KM-5000D 110-μm microkeratomes. Flap thickness was measured using anterior segment optical coherence tomography at seven points in a 7-mm diameter zone 1 h, 1 day, 3 days, 1 week and 1 month after surgery. Flap accuracy, reproducibility, uniformity and changes over time were evaluated. The Moria M2 microkeratome created flaps with less accuracy in the centre than the KM-5000D microkeratome (114.06 ± 6.46 μm vs 128.39 ± 6.79 μm, respectively, at 1 week). For both microkeratomes, flap thickness varied between most of the peripheral areas and the central point. Both microkeratomes created flaps with good central predictability and reproducibility, but high variation and significant deviation from intended thickness were observed in peripheral flap thickness.
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Affiliation(s)
- Y Xu
- Department of Ophthalmology, Eye and ENT Hospital affiliated with Fudan University, Shanghai, China
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50
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Lee SH, Lee JE, Kim JY, Kim MJ, Tchah HW. Comparison of Flap Thickness Measured with Ultrasound Subtraction Method, Direct Method, and Optical Coherence Tomography. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2011. [DOI: 10.3341/jkos.2011.52.5.524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Su Hwan Lee
- Department of Ophthalmology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Joo Eun Lee
- Department of Ophthalmology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Jae Yong Kim
- Department of Ophthalmology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Myung Joon Kim
- Department of Ophthalmology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Hung Won Tchah
- Department of Ophthalmology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
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