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Urban B, Bakunowicz-Łazarczyk A. Refractive Surgery in Myopic Children. J Clin Med 2024; 13:4311. [PMID: 39124578 PMCID: PMC11313164 DOI: 10.3390/jcm13154311] [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: 05/14/2024] [Revised: 07/15/2024] [Accepted: 07/22/2024] [Indexed: 08/12/2024] Open
Abstract
In this paper, we summarize the current knowledge on refractive surgery performed in the myopic pediatric population. We describe the main concerns about refractive surgery in myopic children and the indications for refractive surgery in this age group. We present a range of surgical procedures that are being used for the management of unilateral/bilateral myopia in children: corneal refractive surgery (PRK, LASEK, LASIK, FS-LASIK and SMILE) and intraocular refractive surgery (phakic intraocular lens implantation, refractive lens exchange or clear lens extraction), with both their advantages and drawbacks. We also describe the various complications and measures to prevent them.
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Affiliation(s)
- Beata Urban
- Department of Pediatric Ophthalmology and Strabismus, Medical University of Bialystok, Waszyngtona 17, 15-274 Bialystok, Poland;
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Yücekul B, Förster A, Dick HB, Taneri S. Detecting Keratoconus in Adolescents with Anterior Segment Optical Coherence Tomography. J Ophthalmol 2024; 2024:6655217. [PMID: 38881564 PMCID: PMC11178420 DOI: 10.1155/2024/6655217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 04/26/2024] [Accepted: 05/25/2024] [Indexed: 06/18/2024] Open
Abstract
Purpose Assessing the applicability of an algorithm developed for keratoconus detection in adolescents. This algorithm relies on optical coherence tomography (OCT) and incorporates features related to corneal pachymetric and epithelial thickness alterations. Methods We retrospectively reviewed charts of patients under the age of 18 and divided them into four groups according to the Belin-Ambrosio display (Pentacam): normal, manifest, and subclinical keratoconus, as well as very asymmetric eye with normal topography and tomography (VAE-NTT). Corneal and epithelial thickness maps (Cirrus 5000 HD-OCT, Carl Zeiss Meditec, Germany) were evaluated by a human grader. In the first step, if at least one of four parameters (pachymetry minimum (pachy min), pachy minimum-median (min-med), pachy superonasal-inferotemporal (SN-IT), or epithelial (epi SN-IT)) exceeded its cut-off value, the eye was considered as suspect. In the second step, the combined presence of coincident thinning of total cornea and epithelium as well as concentric epithelial thinning lead to the diagnosis of keratoconus. Receiver operating characteristic (ROC) curves were generated to determine area under the curve (AUC), sensitivity, and specificity for the parameters. Results The study involved 19 pediatric patients diagnosed with keratoconus, comprising 29 manifest keratoconic eyes, 3 eyes with subclinical keratoconus, and 5 VAE-NTT eyes. In addition, 22 eyes from 11 normal adolescents were included in the analysis. The AUC values of parameters in step 1 were 0.889 for pachy min, 0.997 for pachy min-med, 0.893 for pachy SN-IT, and 0.998 for epi SN-IT. When both steps were performed, this algorithm captured all manifest and subclinical pediatric keratoconic eyes. When all eyes of the keratoconus patients were combined, step 1 had 97.3% sensitivity and step 2 had 100% specificity. Conclusion Using this OCT-based approach in adolescents yielded a high level of agreement with the current gold standard, tomography. Using them together, potentially also with other examinations may improve the diagnostic accuracy of KC in the pediatric population. Integration of this approach into the software of the device to facilitate automated evaluations is desired.
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Affiliation(s)
- Burcu Yücekul
- Haseki Training and Research Hospital, Department of Ophthalmology, Istanbul, Türkiye
| | - Anika Förster
- Zentrum für Refraktive Chirurgie, Augenzentrum am St. Franziskus Hospital, Münster, Germany
| | | | - Suphi Taneri
- Zentrum für Refraktive Chirurgie, Augenzentrum am St. Franziskus Hospital, Münster, Germany
- Ruhr University Bochum, Eye Clinic, Bochum, Germany
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Wu W, Wang Y, Chen J, Zhang F. The biomechanical proteins different between low myopic corneas and moderate to high myopic corneas in human. Cont Lens Anterior Eye 2024; 47:102134. [PMID: 38472014 DOI: 10.1016/j.clae.2024.102134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 02/20/2024] [Accepted: 03/01/2024] [Indexed: 03/14/2024]
Abstract
PURPOSE To explore the biomechanical proteins different between low myopic corneas and moderate to high myopic corneas. METHODS A total of 27 myopic corneas were used for the Tandem Mass Tag (TMT) proteomics analysis. Differentially expressed proteins (DEPs) were clustered with fold changes > 1.20 or < 0.83 and p < 0.05. Proteins and Proteins Interactions (PPIs) were conducted to find hub proteins; Uniprot database was to screen proteins with biomechanical functions, and Parallel Reaction Monitoring (PRM) was performed to verify the TMT results. Pearson analysis was used to reveal the correlations between myopic degrees and biomechanical proteins. The Immunofluorescence (IF) staining was used to observe the protein distributions. RESULTS In total, 34 DEPs were observed between moderate myopic corneas and low myopic corneas; 103 DEPs were observed between high myopic corneas and low myopic corneas, 20 proteins overlapped. The PPIs analysis showed keratin 2, keratins 10 and PRSS1 were hub proteins. The Uniprot function analysis suggested keratin 2 and keratin 10 exhibited biomechanical functions. The PRM demonstrated keratin 2 and keratin 10 levels were significantly lower in moderate and high myopic corneas, which was consistent with the TMT proteomics results. IF staining also demonstrated keratin 2 and keratin 10 were less distributed in moderate and high myopic corneas than in low myopic corneas. CONCLUSIONS The levels of biomechanical proteins keratin 2 and keratin 10 are significantly lower in moderate and high myopic corneas than in low myopic corneas.
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Affiliation(s)
- Wenjing Wu
- Beijing Tongren Eye Center, Beijing Tongren Hospital of Capital Medical University, Beijing, China, No. 1, Dongjiaomin Lane, Dongcheng District, Beijing 100730, China
| | - Yan Wang
- Tianjin Eye Hospital, Tianjin Ophthalmology and Visual Science Key Laboratory, Nankai University Eye Hospital, Nankai University Eye Institute, Tianjin, China, No 4. Gansu Rd, Heping District, Tianjin 300020, China
| | - Jingyi Chen
- Tianjin Eye Hospital, Tianjin Ophthalmology and Visual Science Key Laboratory, Nankai University Eye Hospital, Nankai University Eye Institute, Tianjin, China, No 4. Gansu Rd, Heping District, Tianjin 300020, China
| | - Fengju Zhang
- Beijing Tongren Eye Center, Beijing Tongren Hospital of Capital Medical University, Beijing, China, No. 1, Dongjiaomin Lane, Dongcheng District, Beijing 100730, China.
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Moshirfar M, Pandya S, Zhang S, Stoakes IM, Ayesha A, Hoopes PC. AvaGen Genetic Testing versus Ocular Screening Assessments Including the Keratoconus Severity Score (KSS) and Randleman Ectasia Risk Score System (ERSS) in Refractive Surgery Candidates. Clin Ophthalmol 2024; 18:1245-1255. [PMID: 38737593 PMCID: PMC11088376 DOI: 10.2147/opth.s452128] [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: 12/15/2023] [Accepted: 04/15/2024] [Indexed: 05/14/2024] Open
Abstract
Purpose To determine whether the AvaGen (AG) Genetic Eye Test provided additional information for screening for the presence of keratoconus (KC) and assessing KC risk in refractive surgery candidates, as compared to the Keratoconus Severity Score (KSS) and Randleman Ectasia Risk Score System (ERSS). Methods This retrospective study analyzed patients seeking refractive surgery at an eye clinic in the United States between January 2022 and July 2023. The inclusion criteria encompassed those with a family history of KC, positive KC indices, or both. Corneal evaluations and demographic information were recorded and analyzed. KSS and ERSS criteria were utilized to evaluate postoperative KC and ectasia risk, respectively. Patients were categorized on how the AG genetic test compared to KSS and ERSS criteria. Clinicians assessed topographic indices, criteria scoring, and AG testing to deliver a definitive surgical recommendation. Results Among the 19 patients evaluated for ectasia risk, AG testing showed lower KC risk than ocular screening in three patients (15.8%), equal risk in three patients (15.8%), and higher risk in 13 patients (68.4%). The mean AG scores were 45.7 ± 7.0, 49.0 ± 3.46, and 61 ± 13.0 for these respective categories. The most frequently identified KC risk genes were ADAMTS18, COL2A1, and COL4A1. The AG test modified the physician's recommendation for refractive surgery in nine cases (47.4%). Conclusion Despite the promising application of AG testing for assessing KC risk, further research and development are needed to enhance its applicability for screening refractive surgery candidates, in addition to standard ocular screening approaches.
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Affiliation(s)
- Majid Moshirfar
- Hoopes Vision Research Center, Hoopes Vision, Draper, UT, USA
- John A. Moran Eye Center, University of Utah School of Medicine, Salt Lake City, UT, USA
- Utah Lions Eye Bank, Murray, UT, USA
| | - Shreya Pandya
- University of Louisville School of Medicine, Louisville, KY, USA
| | - Stephanie Zhang
- University of Arizona College of Medicine-Phoenix, Phoenix, AZ, USA
| | - Isabella M Stoakes
- Hoopes Vision Research Center, Hoopes Vision, Draper, UT, USA
- Pacific Northwest University of Health Sciences, Yakima, WA, USA
| | - Azraa Ayesha
- University of Utah School of Medicine, Salt Lake City, UT, USA
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Ambrósio R, Salomão MQ, Barros L, da Fonseca Filho JBR, Guedes J, Neto A, Machado AP, Lopes BT, Sena N, Esporcatte LPG. Multimodal diagnostics for keratoconus and ectatic corneal diseases: a paradigm shift. EYE AND VISION (LONDON, ENGLAND) 2023; 10:45. [PMID: 37919821 PMCID: PMC10623885 DOI: 10.1186/s40662-023-00363-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Accepted: 10/14/2023] [Indexed: 11/04/2023]
Abstract
Different diagnostic approaches for ectatic corneal diseases (ECD) include screening, diagnosis confirmation, classification of the ECD type, severity staging, prognostic evaluation, and clinical follow-up. The comprehensive assessment must start with a directed clinical history. However, multimodal imaging tools, including Placido-disk topography, Scheimpflug three-dimensional (3D) tomography, corneal biomechanical evaluations, and layered (or segmental) tomography with epithelial thickness by optical coherence tomography (OCT), or digital very high-frequency ultrasound (dVHF-US) serve as fundamental complementary exams for measuring different characteristics of the cornea. Also, ocular wavefront analysis, axial length measurements, corneal specular or confocal microscopy, and genetic or molecular biology tests are relevant for clinical decisions. Artificial intelligence enhances interpretation and enables combining such a plethora of data, boosting accuracy and facilitating clinical decisions. The applications of diagnostic information for individualized treatments became relevant concerning the therapeutic refractive procedures that emerged as alternatives to keratoplasty. The first paradigm shift concerns the surgical management of patients with ECD with different techniques, such as crosslinking and intrastromal corneal ring segments. A second paradigm shift involved the quest for identifying patients at higher risk of progressive iatrogenic ectasia after elective refractive corrections on the cornea. Beyond augmenting the sensitivity to detect very mild (subclinical or fruste) forms of ECD, ectasia risk assessment evolved to characterize the inherent susceptibility for ectasia development and progression. Furthermore, ectasia risk is also related to environmental factors, including eye rubbing and the relational impact of the surgical procedure on the cornea.
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Affiliation(s)
- Renato Ambrósio
- Department of Ophthalmology, Federal University the State of Rio de Janeiro (UNIRIO), Rio de Janeiro, Brazil.
- Department of Ophthalmology, Federal University of São Paulo, São Paulo, Brazil.
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil.
- Rio Vision Hospital, Rua Prudente de Moraes, 1276, Rio de Janeiro, RJ, 22420-042, Brazil.
- Brazilian Study Group of Artificial Intelligence and Corneal Analysis - BrAIN, Rio de Janeiro & Maceió, Brazil.
| | - Marcella Q Salomão
- Department of Ophthalmology, Federal University of São Paulo, São Paulo, Brazil
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil
- Rio Vision Hospital, Rua Prudente de Moraes, 1276, Rio de Janeiro, RJ, 22420-042, Brazil
- Brazilian Study Group of Artificial Intelligence and Corneal Analysis - BrAIN, Rio de Janeiro & Maceió, Brazil
- Benjamin Constant Institute, Rio de Janeiro, Brazil
| | - Lorena Barros
- Department of Ophthalmology, Federal University the State of Rio de Janeiro (UNIRIO), Rio de Janeiro, Brazil
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil
- Rio Vision Hospital, Rua Prudente de Moraes, 1276, Rio de Janeiro, RJ, 22420-042, Brazil
| | - João Batista R da Fonseca Filho
- Department of Ophthalmology, Federal University the State of Rio de Janeiro (UNIRIO), Rio de Janeiro, Brazil
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil
- Rio Vision Hospital, Rua Prudente de Moraes, 1276, Rio de Janeiro, RJ, 22420-042, Brazil
| | - Jaime Guedes
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil
| | - Alexandre Neto
- Department of Ophthalmology, Federal University the State of Rio de Janeiro (UNIRIO), Rio de Janeiro, Brazil
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil
| | - Aydano P Machado
- Department of Ophthalmology, Federal University of São Paulo, São Paulo, Brazil
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil
- Brazilian Study Group of Artificial Intelligence and Corneal Analysis - BrAIN, Rio de Janeiro & Maceió, Brazil
- Computing Institute, Federal University of Alagoas, Maceió, Brazil
| | - Bernardo T Lopes
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil
- Brazilian Study Group of Artificial Intelligence and Corneal Analysis - BrAIN, Rio de Janeiro & Maceió, Brazil
- Department of Ophthalmology, Alder Hey Children's Hospital, Liverpool, L12 2AP, UK
| | - Nelson Sena
- Department of Ophthalmology, Federal University the State of Rio de Janeiro (UNIRIO), Rio de Janeiro, Brazil
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil
- Rio Vision Hospital, Rua Prudente de Moraes, 1276, Rio de Janeiro, RJ, 22420-042, Brazil
| | - Louise Pellegrino Gomes Esporcatte
- Department of Ophthalmology, Federal University of São Paulo, São Paulo, Brazil
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil
- Rio Vision Hospital, Rua Prudente de Moraes, 1276, Rio de Janeiro, RJ, 22420-042, Brazil
- Brazilian Study Group of Artificial Intelligence and Corneal Analysis - BrAIN, Rio de Janeiro & Maceió, Brazil
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Ma G, Cai J, Zhong R, He W, Ye H, Duvvuri C, Song C, Feng J, An L, Qin J, Huang Y, Xu J, Twa MD, Lan G. Corneal Surface Wave Propagation Associated with Intraocular Pressures: OCT Elastography Assessment in a Simplified Eye Model. Bioengineering (Basel) 2023; 10:754. [PMID: 37508781 PMCID: PMC10376591 DOI: 10.3390/bioengineering10070754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 06/18/2023] [Accepted: 06/21/2023] [Indexed: 07/30/2023] Open
Abstract
Assessing corneal biomechanics in vivo has long been a challenge in the field of ophthalmology. Despite recent advances in optical coherence tomography (OCT)-based elastography (OCE) methods, controversy remains regarding the effect of intraocular pressure (IOP) on mechanical wave propagation speed in the cornea. This could be attributed to the complexity of corneal biomechanics and the difficulties associated with conducting in vivo corneal shear-wave OCE measurements. We constructed a simplified artificial eye model with a silicone cornea and controllable IOPs and performed surface wave OCE measurements in radial directions (54-324°) of the silicone cornea at different IOP levels (10-40 mmHg). The results demonstrated increases in wave propagation speeds (mean ± STD) from 6.55 ± 0.09 m/s (10 mmHg) to 9.82 ± 0.19 m/s (40 mmHg), leading to an estimate of Young's modulus, which increased from 145.23 ± 4.43 kPa to 326.44 ± 13.30 kPa. Our implementation of an artificial eye model highlighted that the impact of IOP on Young's modulus (ΔE = 165.59 kPa, IOP: 10-40 mmHg) was more significant than the effect of stretching of the silicone cornea (ΔE = 15.79 kPa, relative elongation: 0.98-6.49%). Our study sheds light on the potential advantages of using an artificial eye model to represent the response of the human cornea during OCE measurement and provides valuable insights into the impact of IOP on wave-based OCE measurement for future in vivo corneal biomechanics studies.
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Affiliation(s)
- Guoqin Ma
- School of Mechatronic Engineering and Automation, Foshan University, Foshan 528000, China
| | - Jing Cai
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan 528000, China
| | - Rijian Zhong
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan 528000, China
| | - Weichao He
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan 528000, China
| | - Haoxi Ye
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan 528000, China
| | | | - Chengjin Song
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan 528000, China
| | - Jinping Feng
- Institute of Engineering and Technology, Hubei University of Science and Technology, Xianning 437100, China
| | - Lin An
- Weiren Meditech Co., Ltd., Foshan 528000, China
| | - Jia Qin
- Weiren Meditech Co., Ltd., Foshan 528000, China
| | - Yanping Huang
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan 528000, China
- Weiren Meditech Co., Ltd., Foshan 528000, China
| | - Jingjiang Xu
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan 528000, China
- Weiren Meditech Co., Ltd., Foshan 528000, China
| | - Michael D Twa
- College of Optometry, University of Houston, Houston, TX 77204, USA
| | - Gongpu Lan
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan 528000, China
- Weiren Meditech Co., Ltd., Foshan 528000, China
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Lan G, Twa MD, Song C, Feng J, Huang Y, Xu J, Qin J, An L, Wei X. In vivo corneal elastography: A topical review of challenges and opportunities. Comput Struct Biotechnol J 2023; 21:2664-2687. [PMID: 37181662 PMCID: PMC10173410 DOI: 10.1016/j.csbj.2023.04.009] [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: 02/14/2023] [Revised: 04/07/2023] [Accepted: 04/12/2023] [Indexed: 05/16/2023] Open
Abstract
Clinical measurement of corneal biomechanics can aid in the early diagnosis, progression tracking, and treatment evaluation of ocular diseases. Over the past two decades, interdisciplinary collaborations between investigators in optical engineering, analytical biomechanical modeling, and clinical research has expanded our knowledge of corneal biomechanics. These advances have led to innovations in testing methods (ex vivo, and recently, in vivo) across multiple spatial and strain scales. However, in vivo measurement of corneal biomechanics remains a long-standing challenge and is currently an active area of research. Here, we review the existing and emerging approaches for in vivo corneal biomechanics evaluation, which include corneal applanation methods, such as ocular response analyzer (ORA) and corneal visualization Scheimpflug technology (Corvis ST), Brillouin microscopy, and elastography methods, and the emerging field of optical coherence elastography (OCE). We describe the fundamental concepts, analytical methods, and current clinical status for each of these methods. Finally, we discuss open questions for the current state of in vivo biomechanics assessment techniques and requirements for wider use that will further broaden our understanding of corneal biomechanics for the detection and management of ocular diseases, and improve the safety and efficacy of future clinical practice.
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Affiliation(s)
- Gongpu Lan
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan, Guangdong 528000, China
- Weiren Meditech Co., Ltd., Foshan, Guangdong 528000, China
| | - Michael D Twa
- College of Optometry, University of Houston, Houston, TX 77204, United States
| | - Chengjin Song
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan, Guangdong 528000, China
| | - JinPing Feng
- Institute of Engineering and Technology, Hubei University of Science and Technology, Xianning, Hubei 437100, China
| | - Yanping Huang
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan, Guangdong 528000, China
- Weiren Meditech Co., Ltd., Foshan, Guangdong 528000, China
| | - Jingjiang Xu
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan, Guangdong 528000, China
- Weiren Meditech Co., Ltd., Foshan, Guangdong 528000, China
| | - Jia Qin
- Weiren Meditech Co., Ltd., Foshan, Guangdong 528000, China
| | - Lin An
- Weiren Meditech Co., Ltd., Foshan, Guangdong 528000, China
| | - Xunbin Wei
- Biomedical Engineering Department, Peking University, Beijing 100081, China
- International Cancer Institute, Peking University, Beijing 100191, China
- Institute of Medical Technology, Peking University Health Science Center, Beijing 100191, China
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Wang Q, Fan L, Zhou Q. The best choice for low and moderate myopia patients incapable for corneal refractive surgery: implantation of a posterior chamber phakic intraocular lens. Int Ophthalmol 2023; 43:575-581. [PMID: 35984557 PMCID: PMC9971141 DOI: 10.1007/s10792-022-02459-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Accepted: 07/31/2022] [Indexed: 11/28/2022]
Abstract
PURPOSE This study aims to evaluate the early clinical outcomes of central hole phakic posterior chamber intraocular lens(ICLV4c) implantation for low and moderate myopia correction. METHODS This retrospective clinical study included 27 patients(47 eyes)who underwent ICLV4c implantation to correct myopia with spherical equivalent (SE) between - 1.75D and -6.0D. The uncorrected visual acuity (UCVA), intraocular pressure(IOP), central anterior chamber depth (ACD), vault, and endothelial cell density (ECD) were evaluated after surgery. RESULTS At one year follow-up, the postoperative UCVA of patients was higher than the preoperative CDVA and showed a stable trend. There was no significant difference in ECD (p > 0.05) one month after the surgery, the vault was 0.77 ± 0.32 mm, which decreased to 0.63 ± 0.26 mm after one year of surgery. Similarly, ACD was 3.24 ± 0.25 mm in the preoperative, which decreased significantly to 2.05 ± 0.39 mm at one month, while rose to 2.2 ± 0.39 mm at one year after surgery. There was no significant correlation between IOP and ACD and vault at one month and one year after surgery. The correlation coefficient between ACD and vault was found to be - 0.72 at one month after surgery, while the same -0.71 after one year. One patient developed visual fatigue, one with glare, and while no other complications were observed with the rest of the patients. CONCLUSION The ICL implantation is a safe, effective and stable method to correct low and moderate myopia, and may be a good alternative for patients with low and moderate myopia who cannot undergo corneal refractive surgery.
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Affiliation(s)
- Qin Wang
- Chongqing Aier Eye Hospital, Chongqing, 400020 China
| | - Lina Fan
- Chongqing Aier Eye Hospital, Chongqing, 400020 China
| | - Qizhi Zhou
- Aier Chongqing Optometry Eye hospital, No. 77, Daping Changjiang Second Road, Yuzhong, Chongqing, 400040, China.
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Zhang X, Ding L, Sun L, Huang Y, Han T, Qian Y, Zhou X. Prognostic Nomograms Predicting Risk of Keratoconus in Very Asymmetric Ectasia: Combined Corneal Tomographic and Biomechanical Assessments. Front Bioeng Biotechnol 2022; 10:839545. [PMID: 35252147 PMCID: PMC8892177 DOI: 10.3389/fbioe.2022.839545] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 01/25/2022] [Indexed: 11/13/2022] Open
Abstract
Purpose: The aim of the study was to develop and validate a prognostic nomogram for subclinical keratoconus diagnosis using corneal tomographic and biomechanical integration assessments.Design: This is a retrospective case–control study.Methods:Setting: The study was carried out in a hospital setting. Patients: The study included patients with very asymmetric ectasia (VAE) and normal controls. Patients with VAE had defined clinical ectasia in one eye and normal topography (VAE-NT) in the fellow eye, and VAE-NT eyes were selected for analysis. VAE-NT was defined as stratified stage 0 using the ABCD keratoconus grading system. The normal control group was selected from corneal refractive surgery candidates at our clinic, and the right eye was enrolled. Observation Procedures: Scheimpflug-based corneal tomography (Pentacam) and corneal biomechanical assessment (Corvis ST) were performed. Main Outcome Measures: We performed multiple logistic regression analysis and constructed a simple nomogram via the stepwise method. The receiver operating characteristic (ROC) curve and discrimination and calibration of prognostic nomogram were performed by 500 bootstrap resamplings to assess the determination and clinical value, respectively.Results: A total of 59 VAE-NT and 142 normal eyes were enrolled. For differentiating normal and VAE-NT eyes, the values of specificity, sensitivity, and area under the ROC (AUROC) were 0.725, 0.610, and 0.713 for tomographic parameters, 0.886, 0.632, and 0.811 for biomechanical parameters, and 0.871, 0.754, and 0.849 for combined parameters, respectively. Combined parameters showed better predictability than separated tomographic or biomechanical parameters.Conclusion: Our nomogram developed with combined tomographic and biomechanical parameters demonstrated a plausible, capable, and widely implementable tool to predict risk of keratoconus. The identification of at-risk patients can provide advanced strategies to epitomize ectasia susceptibility.
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Affiliation(s)
- Xiaoyu Zhang
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Shanghai, China
- Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Lan Ding
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Shanghai, China
- Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Ling Sun
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Shanghai, China
- Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Yangyi Huang
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Shanghai, China
- Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Tian Han
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Shanghai, China
- Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Yishan Qian
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Shanghai, China
- Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
- *Correspondence: Yishan Qian, ; Xingtao Zhou,
| | - Xingtao Zhou
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Shanghai, China
- Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
- *Correspondence: Yishan Qian, ; Xingtao Zhou,
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10
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Rajabi S, Asharlous A, Riazi A, Khabazkhoob M, Moalej A. Differences and Limits of Agreement among Pentacam, Corvis-ST, and IOL-Master 700 Optical Biometric Devices regarding Central Corneal Thickness Measurements. J Curr Ophthalmol 2022; 34:44-49. [PMID: 35620377 PMCID: PMC9128434 DOI: 10.4103/joco.joco_96_21] [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: 03/27/2021] [Revised: 07/07/2021] [Accepted: 07/09/2021] [Indexed: 11/24/2022] Open
Abstract
Purpose: To investigate the differences and limits of agreement in measuring corneal thickness using Pentacam, Corvis, and intraocular lens (IOL)-Master 700 devices. Methods: This study was conducted on 37 right eyes of 21 males and 16 females (n = 37) with a mean age of 52.11 ± 6.30 years. The central corneal thickness was measured using three optical biometric devices, including Pentacam, Corvis, and IOL-Master 700. The inclusion criteria were normal eyes without any ophthalmological abnormalities, history of ocular pathology, or ocular surgery. The data obtained from these three devices were compared two by two. The correlation and agreement limits among them were analyzed using statistical techniques. Results: The mean standard deviation differences between Pentacam and Corvis, Pentacam and IOL-Master 700, as well as Corvis and IOL-Master 700 regarding the corneal thickness measurement, were 22.13 ± 8.05, 7.91 ± 8.02, and 14.21 ± 9.85 μm, respectively, which were statistically significant (P < 0.0001). Based on the investigation of the limits of agreement according to the Bland Altman method, the corresponding values between Pentacam and Corvis, Pentacam and IOL-Master 700, and Corvis and IOL-Master 700 were -16.2 to +15.4, -15.8 to +16.3, and -20.1 to +20.0 μm, respectively. Furthermore, the correlation coefficients of the measurements obtained by Pentacam and Corvis, Pentacam and IOL-Master 700, as well as Corvis and IOL-Master 700 were determined 0.957, 0.964, and 0.948, respectively (P < 0.0001). Conclusion: The results from this study indicate that the interchangeable use of these three devices is not appropriate due to statistically significant differences and broad limits of agreement among the three devices, especially between Corvis and IOL-Master 700.
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Affiliation(s)
- Sattar Rajabi
- Department of Optometry, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran
| | - Amir Asharlous
- Department of Optometry, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran
| | - Abbas Riazi
- Department of Optometry, Iran University of Medical Sciences, Tehran, Iran
| | - Mehdi Khabazkhoob
- Department of Basic Sciences, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Alireza Moalej
- Internal Medical Clinic, Bank Melli Hospital, Tehran, Iran
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11
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Chameettachal S, Puranik CJ, Veluthedathu MN, Chalil NB, John R, Pati F. Thickening of Ectatic Cornea through Regeneration Using Decellularized Corneal Matrix Injectable Hydrogel: A Strategic Advancement to Mitigate Corneal Ectasia. ACS APPLIED BIO MATERIALS 2021; 4:7300-7313. [PMID: 35006959 DOI: 10.1021/acsabm.1c00821] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Ectatic corneal diseases are a group of eye disorders characterized by progressive thinning and outward bulging of the cornea, resulting in vision impairment. A few attempts have been made to use cornea-derived extracellular matrix hydrogels for corneal tissue engineering; however, no studies have investigated its application in corneal ectasia. In this study, we have first developed an animal surgical model that mimics a few specific phenotypes of ectatic cornea. Later, we investigated the potential of decellularized cornea matrix hydrogels (dCMH) from both human and bovine sources in increasing the thickness of the cornea in the developed surgical model. Our data advocate that surgical stromal depletion can be followed to establish ectatic models and can also provide information on the biocompatibility of materials, its integration with native stroma, degradation over time, and tissue remodeling. We observed that dCMH from both sources could integrate with ectatic thin corneal stroma and helps in regaining the thickness by regenerating a reasonably functional and transparent stroma; however, no significant difference was spotted between the dCMH made from human and bovine corneal tissue sources. Hence, this study is a promising step toward developing a non-invasive technique for the treatment of corneal ectasia by using dCMH.
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Affiliation(s)
- Shibu Chameettachal
- Department of Biomedical Engineering, Indian Institute of Technology Hyderabad, Kandi, Sangareddy Hyderabad, Telangana 502284, India
| | - Charuta J Puranik
- Oculus Regenerus Eye Care and Research Center, Nanalnagar, Hyderabad, Telangana 500008, India
| | - Mohamed Nijas Veluthedathu
- Department of Biomedical Engineering, Indian Institute of Technology Hyderabad, Kandi, Sangareddy Hyderabad, Telangana 502284, India
| | - Najathulla Bhagavathi Chalil
- Department of Materials Science and Metallurgical Engineering, Indian Institute of Technology Hyderabad, Kandi, Sangareddy , Hyderabad, Telangana 502284, India
| | - Renu John
- Department of Biomedical Engineering, Indian Institute of Technology Hyderabad, Kandi, Sangareddy Hyderabad, Telangana 502284, India
| | - Falguni Pati
- Department of Biomedical Engineering, Indian Institute of Technology Hyderabad, Kandi, Sangareddy Hyderabad, Telangana 502284, India
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12
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Ormonde S. Refractive surgery for keratoconus. Clin Exp Optom 2021; 96:173-82. [DOI: 10.1111/cxo.12051] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Revised: 01/31/2013] [Accepted: 02/03/2013] [Indexed: 11/28/2022] Open
Affiliation(s)
- Sue Ormonde
- Department of Ophthalmology, University of Auckland, Auckland, New Zealand,
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13
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Lan G, Aglyamov S, Larin KV, Twa MD. In vivo human corneal natural frequency quantification using dynamic optical coherence elastography: Repeatability and reproducibility. J Biomech 2021; 121:110427. [PMID: 33873114 DOI: 10.1016/j.jbiomech.2021.110427] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 03/20/2021] [Accepted: 03/29/2021] [Indexed: 12/14/2022]
Abstract
Reliable and quantitative assessment of corneal biomechanics is important for the detection and treatment of corneal disease. The present study evaluates the repeatability and reproducibility of a novel optical coherence tomography (OCT)-based elastography (OCE) method for in vivo quantification of corneal natural frequency in 20 normal human eyes. Sub-micron corneal oscillations were induced by repeated low-force (13 Pa) microliter air pulses at the corneal apex and were observed by common-path phase-sensitive OCT imaging adjacent to a measurement region of 1-6.25 mm2. Corneal natural frequencies were quantified using a single degree of freedom model based on the corneal oscillations. Corneal natural frequencies ranged from 234 to 277 Hz (coefficient of variation: 3.2%; n = 286 for a 2.5 × 2.5 mm2 area; time: 28.6 s). The same natural frequencies can be acquired using a smaller sampling size (n = 9 for 1 mm2) and a shorter time (0.9 s). Spatial distribution and local changes in natural frequencies can be distinguished using denser sampling (e.g., 26 × 41 points for 2.5 × 5 mm2). This novel optical method demonstrates highly repeatable and reliable in vivo measurements of human corneal natural frequencies. While further studies are required to fully characterize anatomical and structural dependencies, this method may be complementary to the current OCE methods used to estimate Young's modulus from strain- or shear-wave-based measurements for the quantitative determination of corneal biomechanics.
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Affiliation(s)
- Gongpu Lan
- Foshan University, School of Physics and Optoelectronic Engineering, Foshan, Guangdong 528000, China
| | - Salavat Aglyamov
- University of Houston, Mechanical Engineering, Houston, TX 77204, United States
| | - Kirill V Larin
- University of Houston, Biomedical Engineering, Houston, TX 77204, United States
| | - Michael D Twa
- University of Houston, College of Optometry, Houston, TX 77204, United States.
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Kang H, Qian X, Chen R, Wodnicki R, Sun Y, Li R, Li Y, Shung KK, Chen Z, Zhou Q. 2-D Ultrasonic Array-Based Optical Coherence Elastography. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2021; 68:1096-1104. [PMID: 33095699 PMCID: PMC8106462 DOI: 10.1109/tuffc.2020.3033304] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Acoustic radiation force optical coherence elastography (ARF-OCE) has been successfully implemented to characterize the biomechanical properties of soft tissues, such as the cornea and the retina, with high resolution using single-element ultrasonic transducers for ARF excitation. Most currently proposed OCE techniques, such as air puff and ARF, have less capability to control the spatiotemporal information of the induced region of deformation, resulting in limited accuracy and low temporal resolution of the shear wave elasticity imaging. In this study, we propose a new method called 2-D ultrasonic array-based OCE imaging, which combines the advantages of 3-D dynamic electronic steering of the 2-D ultrasonic array and high-resolution optical coherence tomography (OCT). The 3-D steering capability of the 2-D array was first validated using a hydrophone. Then, the combined 2-D ultrasonic array OCE system was calibrated using a homogenous phantom, followed by an experiment on ex vivo rabbit corneal tissue. The results demonstrate that our newly developed 2-D ultrasonic array-based OCE system has the capability to map tissue biomechanical properties accurately, and therefore, has the potential to be a vital diagnostic tool in ophthalmology.
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Nair A, Singh M, Aglyamov S, Larin KV. Heartbeat optical coherence elastography: corneal biomechanics in vivo. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-200338LR. [PMID: 33624461 PMCID: PMC7901857 DOI: 10.1117/1.jbo.26.2.020502] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 01/19/2021] [Indexed: 05/02/2023]
Abstract
SIGNIFICANCE Mechanical assessment of the cornea can provide important structural and functional information regarding its health. Current clinically available tools are limited in their efficacy at measuring corneal mechanical properties. Elastography allows for the direct estimation of mechanical properties of tissues in vivo but is generally performed using external excitation force. AIM To show that heartbeat optical coherence elastography (Hb-OCE) can be used to assess the mechanical properties of the cornea in vivo. APPROACH Hb-OCE was utilized to detect Hb-induced deformations in the rabbit cornea in vivo without the need for external excitation. Furthermore, we demonstrate how this technique can distinguish corneal stiffness between untreated (UT) and crosslinked (CXL) tissue. RESULTS Our results demonstrate that stiffness changes in the cornea can be detected using only the Hb-induced deformations in the cornea. Additionally, we demonstrate a statistically significant difference in strain between the UT and CXL corneas. CONCLUSIONS Hb-OCE may be an effective tool for assessing the mechanical properties of the cornea in vivo without the need for external excitation. This tool may be effective for clinical assessment of corneal mechanical properties because it only requires optical coherence tomography imaging and data processing.
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Affiliation(s)
- Achuth Nair
- University of Houston, Department of Biomedical Engineering, Houston, Texas, United States
| | - Manmohan Singh
- University of Houston, Department of Biomedical Engineering, Houston, Texas, United States
| | - Salavat Aglyamov
- University of Houston, Department of Mechanical Engineering, Houston, Texas, United States
| | - Kirill V. Larin
- University of Houston, Department of Biomedical Engineering, Houston, Texas, United States
- Address all correspondence to Kirill V. Larin,
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Lan G, Aglyamov SR, Larin KV, Twa MD. In Vivo Human Corneal Shear-wave Optical Coherence Elastography. Optom Vis Sci 2021; 98:58-63. [PMID: 33394932 PMCID: PMC7774819 DOI: 10.1097/opx.0000000000001633] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 09/24/2020] [Indexed: 01/01/2023] Open
Abstract
SIGNIFICANCE A novel imaging technology, dynamic optical coherence elastography (OCE), was adapted for clinical noninvasive measurements of corneal biomechanics. PURPOSE Determining corneal biomechanical properties is a long-standing challenge. Elasticity imaging methods have recently been developed and applied for clinical evaluation of soft tissues in cancer detection, atherosclerotic plaque evaluation, surgical guidance, and more. Here, we describe the use of dynamic OCE to characterize mechanical wave propagation in the human cornea in vivo, thus providing a method for clinical determination of corneal biomechanical properties. METHODS High-resolution phase-sensitive optical coherence tomography imaging was combined with microliter air-pulse tissue stimulation to perform dynamic elasticity measurements in 18 eyes of nine participants. Low-pressure (0.1 mmHg), spatiotemporally discreet (150 μm, 800 μs) tissue stimulation produced submicron-scale tissue deformations that were measured at multiple positions over a 1-mm2 area. Surface wave velocity was measured and used to determine tissue stiffness. Elastic wave propagation velocity was measured and evaluated as a function of IOP and central corneal thickness. RESULTS Submicron corneal surface displacement amplitude (range, 0.005 to 0.5 μm) responses were measured with high sensitivity (0.24 nm). Corneal elastic wave velocity ranged from 2.4 to 4.2 m/s (mean, 3.5; 95% confidence interval, 3.2 to 3.8 m/s) and was correlated with central corneal thickness (r = 0.64, P < .001) and IOP (r = 0.52, P = .02). CONCLUSIONS Phase-sensitive optical coherence tomography imaging combined with microliter air-pulse mechanical tissue stimulation has sufficient detection sensitivity to observe submicron elastic wave propagation in corneal tissue. These measurements enable in vivo corneal stiffness determinations that will be further studied for use with disease detection and for monitoring clinical interventions.
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Affiliation(s)
- Gongpu Lan
- School of Physics and Optoelectronic Engineering, Foshan University, Foshan, Guangdong, China
- University of Houston College of Optometry, Houston, Texas
| | | | - Kirill V. Larin
- Department of Biomedical Engineering, University of Houston, Houston, Texas
| | - Michael D. Twa
- University of Houston College of Optometry, Houston, Texas
- School of Optometry, University of Alabama at Birmingham, Birmingham, Alabama
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Abstract
Purpose. To examine the outcomes of keratorefractive surgeries in keratoconus suspect patients. Methods. This study included 192 keratoconus suspects (351 eyes), treated with photorefractive keratectomy (PRK) (211 eyes), Lasik (96 eyes), and Femto-Lasik (44 eyes) surgeries in an eye clinic. The best spectacle-corrected visual acuity (BSCVA) and subjective refraction were evaluated preoperatively and postoperatively (three months and five years after the procedure). The Orbscan II topography system was also used preoperatively and five years after the procedure. Results. The patients’ mean age was 31.6 ± 5.49 years (range: 21–47 years) in the last follow-up. There was no significant difference between the preoperative and postoperative mean values of BSCVA in any of the surgical methods (
= 0.49). The mean spherical equivalent, cylindrical power, corneal curvature, the thinnest corneal thickness, and the central corneal thickness decreased significantly in the last follow-up (
< 0.001). Four patients (3.50%) in the PRK group and one patient (1.85%) in the Lasik group needed glasses in the last follow-up. Eleven cases of corneal ectasia were detected in the last follow-up (six eyes of four patients [2.84%] and five eyes of four patients [5.20%] in the PRK and Lasik groups, respectively). Conclusion. In the present study, the high risk of postoperative ectasia was detected in keratoconus suspects following PRK and Lasik surgeries. According to the results, it can be concluded that Femto-Lasik surgery provides better outcomes than Lasik and PRK. Overall, the surgical criteria are suggested to be evaluated case by case, and the patients must be followed up over time to assess the corneal topography and refraction stability.
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Nair A, Singh M, Aglyamov SR, Larin KV. Heartbeat OCE: corneal biomechanical response to simulated heartbeat pulsation measured by optical coherence elastography. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:1-9. [PMID: 32372574 PMCID: PMC7199791 DOI: 10.1117/1.jbo.25.5.055001] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 04/24/2020] [Indexed: 05/04/2023]
Abstract
SIGNIFICANCE It is generally agreed that the corneal mechanical properties are strongly linked to many eye diseases and could be used to assess disease progression and response to therapies. Elastography is the most notable method of assessing corneal mechanical properties, but it generally requires some type of external excitation to induce a measurable displacement in the tissue. AIM We present Heartbeat Optical Coherence Elastography (Hb-OCE), a truly passive method that can measure the elasticity of the cornea based on intrinsic corneal displacements induced by the heartbeat. APPROACH Hb-OCE measurements were performed in untreated and UV-A/riboflavin cross-linked porcine corneas ex vivo, and a distinct difference in strain was detected. Furthermore, a partially cross-linked cornea was also assessed, and the treated and untreated areas were similarly distinguished. RESULTS Our results suggest that Hb-OCE can spatially map displacements in the cornea induced by small fluctuations in intraocular pressure, similar to what is induced by the heartbeat. CONCLUSIONS The described technique opens the possibility for completely passive and noncontact in vivo assessment of corneal stiffness.
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Affiliation(s)
- Achuth Nair
- University of Houston, Department of Biomedical Engineering, Houston, Texas, United States
| | - Manmohan Singh
- University of Houston, Department of Biomedical Engineering, Houston, Texas, United States
| | - Salavat R. Aglyamov
- University of Houston, Department of Mechanical Engineering, Houston, Texas, United States
| | - Kirill V. Larin
- University of Houston, Department of Biomedical Engineering, Houston, Texas, United States
- Address all correspondence to Kirill V. Larin, E-mail:
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Koh S, Ambrósio R, Inoue R, Maeda N, Miki A, Nishida K. Detection of Subclinical Corneal Ectasia Using Corneal Tomographic and Biomechanical Assessments in a Japanese Population. J Refract Surg 2019; 35:383-390. [PMID: 31185104 DOI: 10.3928/1081597x-20190417-01] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 04/15/2019] [Indexed: 01/03/2023]
Abstract
PURPOSE To test the detection of subclinical corneal ectasia using integrated Scheimpflug tomography and biomechanical assessment in a Japanese population. METHODS This prospective, case-control study included 23 patients with very asymmetric ectasia (VAE) and 70 normal controls. Patients with VAE had defined clinical ectasia in one eye and a fellow eye with normal topography (VAE-NT). Objective topography for confirming normal topography in VAE-NT cases included having 0% similarity and 0% severity derived from Placido-disk based topography. Scheimpflug-based corneal tomography and corneal biomechanical assessment were performed. The Belin/Ambrósio Enhanced Ectasia Deviation index (BAD-D), Corvis Biomechanical Index (CBI), and Tomographic Biomechanical Index (TBI) were compared and their discriminating ability for detecting ectasia was assessed. RESULTS For differentiating normal and VAE-NT eyes, the areas under the receiver operating curve for the BAD-D, CBI, and TBI were 0.668, 0.660, and 0.751, respectively. The TBI cut-off of 0.259 provided 52.17% sensitivity and 88.57% specificity. Fourteen VAE-NT cases (60.9%) were abnormal in at least one of the criteria of the BAD-D > 1.60 (39.1%), CBI > 0.5 (26.1%), or TBI > 0.29 (43.5%). Conversely, nine VAE-NT cases (39.1%) exhibited normal values for the BAD-D, CBI, and TBI. CONCLUSIONS In the current study, 40% of VAE-NT eyes were classified as normal by the BAD-D, CBI, and TBI. Although some of these cases may truly represent unilateral ectasia, further advances are needed to enhance ectasia detection and characterize the susceptibility for ectasia progression. [J Refract Surg. 2019;35(6):383-390.].
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Abstract
Corneal ectasia has emerged as a serious complication of laser vision correction (LVC) procedures since the first report by Seiler in 1998. Thereby, its prevention has become a major concern for refractive surgeons. Ectasia occurs due to biomechanical decompensation of the stroma, which may be related to a severe impact on corneal structure (i.e., attempted treatment for high myopia) or the altered biomechanical properties preoperatively. The current understanding is that a combination from those factors determines stability or ectasia progression after LVC. Abnormal corneal topography has been the most important surrogate for lower biomechanical properties, but novel imaging technologies such as tomography and biomechanical assessment have proven to enhance the ability for detecting mild ectatic disease, such as in the eyes with normal topography from patients with clinical ectasia in the fellow eye. Bohac and associates in a retrospective case series analyzed data from 30,167 eyes from 16,732 documented ten eyes (0.033%) of seven patients that developed post-LASIK ectasia. This data supports the concept that the actual incidence of ectasia has decreased from 0.66% reported by Pallikaris in 2001. This has been the result of major development related to the advanced screening strategies. Nevertheless, mysterious cases of ectasia still challenge the field and stimulated research in this field. Ocular allergy and eye rubbing may be a factor that triggered ectasia in such series. Artificial intelligence (AI) and machine-learning algorithms may play a definitive role for further enhancing ectasia risk assessment. Reporting ectasia after LVC is needed.
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Affiliation(s)
- Renato Ambrósio
- a Department of Ophthalmology , Instituto de Olhos Renato Ambrósio , Rio de Janeiro , Brazil.,b Rio de Janeiro Corneal Tomography and Biomechanics Study Group , Rio de Janeiro , Brazil.,c Department of Ophthalmology , Federal University of São Paulo , São Paulo , Brazil.,d Department of Ophthalmology , Federal University of the State of Rio de Janeiro (UNIRIO) ; Rio de Janeiro , Brazil
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Ferreira-Mendes J, Lopes BT, Faria-Correia F, Salomão MQ, Rodrigues-Barros S, Ambrósio R. Enhanced Ectasia Detection Using Corneal Tomography and Biomechanics. Am J Ophthalmol 2019; 197:7-16. [PMID: 30201341 DOI: 10.1016/j.ajo.2018.08.054] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 08/30/2018] [Accepted: 08/31/2018] [Indexed: 10/28/2022]
Abstract
PURPOSE To test the accuracy of the Tomographic and Biomechanical Index (TBI) for ectasia detection in an independent population from the original study. DESIGN Retrospective case-control study. METHODS Subjects: Patients were grouped according to clinical diagnosis including corneal topography (front-surface curvature): Normal group, including 1 eye randomly selected from 312 patients with normal corneas; Keratoconus group, including 1 eye randomly selected from 118 patients with keratoconus; a nonoperated ectatic eye from 57 patients with very asymmetric ectasia (57 eyes, VAE-E group), and the nonoperated fellow eye with normal topography (57 eyes, VAE-NT group). MAIN OUTCOME MEASURES The ability of TBI to distinguish normal and ectatic corneas; and comparison with other indexes, including the Belin/Ambrósio Deviation Index (BAD-DI) and the Corvis Biomechanical Index (CBI), considering the areas under receiver operating characteristic curves (AUCs). RESULTS The AUC of the TBI was statistically higher than all other tested parameters (DeLong, P < .001). Considering all cases, the cut-off value of 0.335 for the TBI provided a sensitivity of 94.4% and a specificity of 94.9% (AUC = 0.988; 95% confidence interval [CI] 0.982-0.995). Considering the VAE-NT group, optimized TBI cut-off value of 0.295 provided a sensitivity of 89.5% and a specificity of 91.0% (AUC = 0.960; 95% CI 0.937-0.983). CONCLUSION The TBI was more accurate than all parameters tested for differentiating normal from ectatic corneas. The TBI may epitomize ectasia susceptibility and distinguish cases with fruste disease from true unilateral cases among the eyes with normal-topography VAE.
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Enhanced Tomographic Assessment to Detect Corneal Ectasia Based on Artificial Intelligence. Am J Ophthalmol 2018; 195:223-232. [PMID: 30098348 DOI: 10.1016/j.ajo.2018.08.005] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 08/01/2018] [Accepted: 08/02/2018] [Indexed: 12/17/2022]
Abstract
PURPOSE To improve the detection of corneal ectasia susceptibility using tomographic data. DESIGN Multicenter case-control study. METHODS Data from patients from 5 different clinics from South America, the United States, and Europe were evaluated. Artificial intelligence (AI) models were generated using Pentacam HR (Oculus, Wetzlar, Germany) parameters to discriminate the preoperative data of 3 groups: stable laser-assisted in situ keratomileusis (LASIK) cases (2980 patients with minimum follow-up of 7 years), ectasia susceptibility (71 eyes of 45 patients that developed post-LASIK ectasia [PLE]), and clinical keratoconus (KC; 182 patients). Model accuracy was independently tested in a different set of stable LASIK cases (298 patients with minimum follow-up of 4 years) and in 188 unoperated patients with very asymmetric ectasia (VAE); these patients presented normal topography (VAE-NT) in 1 eye and clinically diagnosed ectasia in the other (VAE-E). Accuracy was evaluated with ROC curves. RESULTS The random forest (RF) provided highest accuracy among AI models in this sample with 100% sensitivity for clinical ectasia (KC+VAE-E; cutoff 0.52), being named Pentacam Random Forest Index (PRFI). Considering all cases, the PRFI had an area under the curve (AUC) of 0.992 (94.2% sensitivity, 98.8% specificity; cutoff 0.216), being statistically higher than the Belin/Ambrósio deviation (BAD-D; AUC = 0.960, 87.3% sensitivity, 97.5% specificity; P = .006, DeLong's test). The optimized cutoff of 0.125 provided sensitivity of 85.2% for VAE-NT and 80% for PLE, with 96.6% specificity. CONCLUSION The PRFI enhances ectasia diagnosis. Further integrations with corneal biomechanical parameters and with the corneal impact from laser vision correction are needed for assessing ectasia risk.
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Salomão M, Lopes B, Ambrósio R, Faria-Correia F, Silva-Lopes Í, Azevedo-Wagner A, Tanos FW. Paradigms, Paradoxes, and Controversies on Keratoconus and Corneal Ectatic Diseases. ACTA ACUST UNITED AC 2018. [DOI: 10.5005/jp-journals-10025-1158] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Biomechanical Simulation of Stress Concentration and Intraocular Pressure in Corneas Subjected to Myopic Refractive Surgical Procedures. Sci Rep 2017; 7:13906. [PMID: 29066773 PMCID: PMC5655007 DOI: 10.1038/s41598-017-14293-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 10/05/2017] [Indexed: 11/14/2022] Open
Abstract
Recent advances in the analysis of corneal biomechanical properties remain difficult to predict the structural stability before and after refractive surgery. In this regard, we applied the finite element method (FEM) to determine the roles of the Bowman’s membrane, stroma, and Descemet’s membrane in the hoop stresses of cornea, under tension (physiological) and bending (nonphysiological), for patients who undergo radial keratotomy (RK), photorefractive keratectomy (PRK), laser-assisted in situ keratomileusis (LASIK), or small incision lenticule extraction (SMILE). The stress concentration maps, potential creak zones, and potential errors in intraocular pressure (IOP) measurements were further determined. Our results confirmed that the Bowman’s membrane and Descemet’s membrane accounted for 20% of the bending rigidity of the cornea, and became the force pair dominating the bending behaviour of the cornea, the high stress in the distribution map, and a stretch to avoid structural failure. In addition, PRK broke the central linking of hoop stresses and concentrated stress on the edge of the Bowman’s membrane around ablation, which posed considerable risk of potential creaks. Compared with SMILE, LASIK had a higher risk of developing creaks around the ablation in the stroma layer. Our FEM models also predicted the postoperative IOPs precisely in a conditional manner.
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Ambrósio, Jr R, Correia FF, Lopes B, Salomão MQ, Luz A, Dawson DG, Elsheikh A, Vinciguerra R, Vinciguerra P, Roberts CJ. Corneal Biomechanics in Ectatic Diseases: Refractive Surgery Implications. Open Ophthalmol J 2017; 11:176-193. [PMID: 28932334 PMCID: PMC5585467 DOI: 10.2174/1874364101711010176] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 05/16/2017] [Accepted: 06/15/2017] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Ectasia development occurs due to a chronic corneal biomechanical decompensation or weakness, resulting in stromal thinning and corneal protrusion. This leads to corneal steepening, increase in astigmatism, and irregularity. In corneal refractive surgery, the detection of mild forms of ectasia pre-operatively is essential to avoid post-operative progressive ectasia, which also depends on the impact of the procedure on the cornea. METHOD The advent of 3D tomography is proven as a significant advancement to further characterize corneal shape beyond front surface topography, which is still relevant. While screening tests for ectasia had been limited to corneal shape (geometry) assessment, clinical biomechanical assessment has been possible since the introduction of the Ocular Response Analyzer (Reichert Ophthalmic Instruments, Buffalo, USA) in 2005 and the Corvis ST (Oculus Optikgeräte GmbH, Wetzlar, Germany) in 2010. Direct clinical biomechanical evaluation is recognized as paramount, especially in detection of mild ectatic cases and characterization of the susceptibility for ectasia progression for any cornea. CONCLUSIONS The purpose of this review is to describe the current state of clinical evaluation of corneal biomechanics, focusing on the most recent advances of commercially available instruments and also on future developments, such as Brillouin microscopy.
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Affiliation(s)
- Renato Ambrósio, Jr
- Instituto de Olhos Renato Ambrósio, Rio de Janeiro, Brazil
- VisareRIO, Rio de Janeiro, Brazil
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil
- Brazilian Study Group of Artificial Intelligence and Corneal Analysis - BRAIN, Rio de Janeiro & Maceió, Brazil
- Department of Ophthalmology, Federal University of São Paulo, São Paulo, Brazil
| | - Fernando Faria Correia
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
- Ophthalmology Department, Hospital de Braga, Braga, Portugal
| | - Bernardo Lopes
- Instituto de Olhos Renato Ambrósio, Rio de Janeiro, Brazil
- VisareRIO, Rio de Janeiro, Brazil
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil
- Brazilian Study Group of Artificial Intelligence and Corneal Analysis - BRAIN, Rio de Janeiro & Maceió, Brazil
- Department of Ophthalmology, Federal University of São Paulo, São Paulo, Brazil
| | - Marcella Q. Salomão
- Instituto de Olhos Renato Ambrósio, Rio de Janeiro, Brazil
- VisareRIO, Rio de Janeiro, Brazil
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil
- Brazilian Study Group of Artificial Intelligence and Corneal Analysis - BRAIN, Rio de Janeiro & Maceió, Brazil
- Department of Ophthalmology, Federal University of São Paulo, São Paulo, Brazil
| | - Allan Luz
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil
- Brazilian Study Group of Artificial Intelligence and Corneal Analysis - BRAIN, Rio de Janeiro & Maceió, Brazil
- Department of Ophthalmology, Federal University of São Paulo, São Paulo, Brazil
| | - Daniel G. Dawson
- The University of Florida Department of Ophthalmology, Gainesville, FL, USA
| | - Ahmed Elsheikh
- School of Engineering, University of Liverpool – Liverpool, United Kingdom
- NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, UK
| | - Riccardo Vinciguerra
- Department of Surgical Sciences, Division of Ophthalmology, University of Insubria, Varese, Italy
| | - Paolo Vinciguerra
- Department of Surgical Sciences, Division of Ophthalmology, University of Insubria, Varese, Italy
- Eye Center, Humanitas Clinical and Research Center, Via Manzoni 56, Rozzano (MI) – Italy
| | - Cynthia J. Roberts
- Department of Ophthalmology & Visual Science, Department of Biomedical Engineering, The Ohio State University – Columbus, OH, USA
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Ambrósio R, Lopes BT, Faria-Correia F, Salomão MQ, Bühren J, Roberts CJ, Elsheikh A, Vinciguerra R, Vinciguerra P. Integration of Scheimpflug-Based Corneal Tomography and Biomechanical Assessments for Enhancing Ectasia Detection. J Refract Surg 2017; 33:434-443. [DOI: 10.3928/1081597x-20170426-02] [Citation(s) in RCA: 207] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 04/11/2017] [Indexed: 12/20/2022]
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Subclinical keratoconus detection by pattern analysis of corneal and epithelial thickness maps with optical coherence tomography. J Cataract Refract Surg 2016; 42:284-95. [PMID: 27026454 DOI: 10.1016/j.jcrs.2015.09.021] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 08/22/2015] [Accepted: 09/01/2015] [Indexed: 11/24/2022]
Abstract
PURPOSE To screen for subclinical keratoconus by analyzing corneal, epithelial, and stromal thickness map patterns with Fourier-domain optical coherence tomography (OCT). SETTING Four centers in the United States. DESIGN Cross-sectional observational study. METHODS Eyes of normal subjects, subclinical keratoconus eyes, and the topographically normal eye of a unilateral keratoconus patient were studied. Corneas were scanned using a 26,000 Hz Fourier-domain OCT system (RTVue). Normal subjects were divided into training and evaluation groups. Corneal, epithelial, and stromal thickness maps and derived diagnostic indices, including pattern standard deviation (PSD) variables and pachymetric map-based keratoconus risk scores, were calculated from the OCT data. Area under the receiver operating characteristic curve (AUC) analysis was used to evaluate the diagnostic accuracy of the indices. RESULTS The study comprised 150 eyes of 83 normal subjects, 50 subclinical keratoconus eyes of 32 patients, and 1 topographically normal eye of a unilateral keratoconus patient. Subclinical keratoconus was characterized by inferotemporal thinning of the cornea, epithelium, and stroma. The PSD values for corneal (P < .001), epithelial (P < .001), and stromal (P = .049) thickness maps were all significantly higher in subclinical keratoconic eyes than in the normal group. The diagnostic accuracy was significantly higher for PSD variables (pachymetric PSD, AUC = 0.941; epithelial PSD, AUC = 0.985; stromal PSD, AUC = 0.924) than for the pachymetric map-based keratoconus risk score (AUC = 0.735). CONCLUSIONS High-resolution Fourier-domain OCT could map corneal, epithelial, and stromal thicknesses. Corneal and sublayer thickness changes in subclinical keratoconus could be detected with high accuracy using PSD variables. These new diagnostic variables might be useful in the detection of early keratoconus. FINANCIAL DISCLOSURES Oregon Health and Science University (OHSU) and Drs. Li, Tan, and Huang have a significant financial interest in Optovue, Inc. These potential conflicts have been reviewed and managed by OHSU. Dr. Brass receives research grants from Optovue, Inc. Drs. Chamberlain and Weiss have no financial or proprietary interest in any material or method mentioned.
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Pniakowska Z, Jurowski P. Detection of the early keratoconus based on corneal biomechanical properties in the refractive surgery candidates. Indian J Ophthalmol 2016; 64:109-13. [PMID: 27050343 PMCID: PMC4850803 DOI: 10.4103/0301-4738.179725] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Context: Subclinical keratoconus is contraindication to refractive surgery. The currently used methods of preoperative screening do not always allow differentiating between healthy eyes and those with subclinical keratoconus. Aim: To evaluate biomechanical parameters of the cornea, waveform score (WS), and intraocular pressure (IOP) as potentially useful adjuncts to the diagnostic algorithm for precise detection of the early keratoconus stages and selection of refractive surgery candidates. Settings and Design: Department of Ophthalmology and prospective cross-sectional study. Patients and Methods: Patients enrolled in the study were diagnosed with refractive disorders. We assessed parameters of corneal biomechanics such as corneal hysteresis (CH), corneal resistance factor (CRF), Goldman-correlated IOP (IOPg), corneal compensated IOP, WS, and keratoconus match index (KMI). They were classified into one of three groups based on the predefined KMI range: Group 1 (from 0.352 to 0.757) – 45 eyes, Group 2 (from −0.08 to 0.313) – 52 eyes, and Group 0 - control group (from 0.761 to 1.642) – 80 eyes. Results: In both study groups, IOPg, CRF, and CH were decreased when compared to control (P < 0.0001). In control group, there was positive correlation between CH and KMI (P < 0.05), with no correlations in any of the two study groups. CRF correlated positively with KMI in control (P < 0.0001) and in Group 2 (P < 0.05). Conclusions: CH and CRF, together with WS and IOPg, consist a clinically useful adjunct to detect subclinical keratoconus in patients referred for refractive surgery when based on KMI staging.
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Affiliation(s)
- Zofia Pniakowska
- Department of Ophthalmology and Visual Rehabilitation, Veterans Central Hospital, Lodz, Poland
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Femtosecond Intrastromal Lenticular Implantation Combined With Accelerated Collagen Cross-Linking for the Treatment of Keratoconus--Initial Clinical Result in 6 Eyes. Cornea 2016; 34:1331-9. [PMID: 26252741 DOI: 10.1097/ico.0000000000000539] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To evaluate the initial outcomes of femtosecond intrastromal lenticular implantation (FILI) combined with accelerated collagen cross-linking in patients with progressive keratoconus. METHODS In this interventional, prospective, exploratory case series, patients with progressive keratoconus and contact lens intolerance were included. All eyes underwent femtosecond laser-enabled placement of stromal donor tissue and simultaneous accelerated collagen cross-linking. Follow-up of patients was conducted for a mean period of 190 ± 13 days (range, 177-193 days). RESULTS Six eyes from 6 patients were included in the study. Based on values before and 6 months after the procedure, clinical improvement was noted in uncorrected distance visual acuity (1.06 ± 0.48 logMAR vs. 0.38 ± 0.27 logMAR), corrected distance visual acuity (0.51 ± 0.20 logMAR vs. 0.20 ± 0.24 logMAR), and manifest spherical equivalent (-3.47 ± 1.15 D vs. -1.77 ± 1.7 D). There was flattening of mean keratometry in 3-mm and 5-mm zones by 3.42 ± 2.09 D and 1.70 ± 1.31 D, respectively. Mean pachymetry in the central and midperipheral zones increased by 18.3 ± 7.3 μm and 33.0 ± 8.8 μm, respectively. All eyes had reduction in higher-order aberrations, specifically coma. No eye lost lines of corrected distance visual acuity. No adverse events such as haze, infection, or allogeneic graft rejection were observed. CONCLUSIONS Initial experience with this small number of eyes suggests that the combination of tissue addition and accelerated collagen cross-linking may be a feasible option for low to moderate keratoconus. A larger cohort and longer follow-up are required to validate our results and establish long-term safety and efficacy of the procedure.
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Salouti R, Nowroozzadeh MH, Makateb P, Zamani M, Ghoreyshi M, Melles GRJ. Deep anterior lamellar keratoplasty for keratectasia after laser in situ keratomileusis. J Cataract Refract Surg 2014; 40:2011-8. [PMID: 25457380 DOI: 10.1016/j.jcrs.2014.04.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 03/20/2014] [Accepted: 04/07/2014] [Indexed: 11/15/2022]
Abstract
PURPOSE To assess the efficacy of deep anterior lamellar keratoplasty (DALK) for treating post-LASIK keratectasia. SETTING Poostchi Eye Research Center, Shiraz University of Medical Sciences, Shiraz, Iran. DESIGN Retrospective interventional cases series. METHODS The same surgeon performed all DALK procedures using the Melles manual technique. The preoperative and postoperative corrected distance visual acuity (CDVA), spherical equivalent (SE) refraction, keratometry (K) readings, and endothelial cell profiles were compared. RESULTS The cohort comprised 20 eyes of 18 patients (72% women) with a mean age of 29 years ± 4 (SD). The mean follow-up was 31.8 ± 17.0 months (range 6 to 60 months). The mean Snellen CDVA improved significantly from 20/191 before DALK to 20/23 after DALK (P < .001). The mean of the modulus of SE refraction was 11.9 ± 6.6 diopters (D) and 11.4 ± 4.3 D, respectively (P = .446). The mean K value was 52.2 ± 7.0 D before DALK and 46.0 ± 1.9 D after DALK (P = .001); the mean apical K value, 59.5 ± 5.1 D and 49.9 ± 2.8 D, respectively (P < .001); and the mean keratometric astigmatism, 4.3 ± 2.4 D and 1.9 ± 1.2 D, respectively (P = .003). The endothelial cell profile did not change significantly, and no major complications related to DALK occurred. Twelve eyes had additional refractive procedures to correct residual ametropia. CONCLUSION Deep anterior lamellar keratoplasty using the Melles manual technique was effective and safe in restoring CDVA in patients with post-LASIK keratectasia; however, high residual ametropia was a common finding.
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Affiliation(s)
- Ramin Salouti
- From Poostchi Ophthalmology Research Center (Salouti, Nowroozzadeh, Makateb, Ghoreyshi), Shiraz University of Medical Sciences, and Salouti Eye Research Center (Salouti, Zamani, Ghoreyshi), Salouti Eye Clinic, Shiraz, Iran; the Netherlands Institute for Innovative Ocular Surgery (Melles), Rotterdam, the Netherlands
| | - Mohammad H Nowroozzadeh
- From Poostchi Ophthalmology Research Center (Salouti, Nowroozzadeh, Makateb, Ghoreyshi), Shiraz University of Medical Sciences, and Salouti Eye Research Center (Salouti, Zamani, Ghoreyshi), Salouti Eye Clinic, Shiraz, Iran; the Netherlands Institute for Innovative Ocular Surgery (Melles), Rotterdam, the Netherlands
| | - Payam Makateb
- From Poostchi Ophthalmology Research Center (Salouti, Nowroozzadeh, Makateb, Ghoreyshi), Shiraz University of Medical Sciences, and Salouti Eye Research Center (Salouti, Zamani, Ghoreyshi), Salouti Eye Clinic, Shiraz, Iran; the Netherlands Institute for Innovative Ocular Surgery (Melles), Rotterdam, the Netherlands
| | - Mohammad Zamani
- From Poostchi Ophthalmology Research Center (Salouti, Nowroozzadeh, Makateb, Ghoreyshi), Shiraz University of Medical Sciences, and Salouti Eye Research Center (Salouti, Zamani, Ghoreyshi), Salouti Eye Clinic, Shiraz, Iran; the Netherlands Institute for Innovative Ocular Surgery (Melles), Rotterdam, the Netherlands
| | - Maryam Ghoreyshi
- From Poostchi Ophthalmology Research Center (Salouti, Nowroozzadeh, Makateb, Ghoreyshi), Shiraz University of Medical Sciences, and Salouti Eye Research Center (Salouti, Zamani, Ghoreyshi), Salouti Eye Clinic, Shiraz, Iran; the Netherlands Institute for Innovative Ocular Surgery (Melles), Rotterdam, the Netherlands.
| | - Gerrit R J Melles
- From Poostchi Ophthalmology Research Center (Salouti, Nowroozzadeh, Makateb, Ghoreyshi), Shiraz University of Medical Sciences, and Salouti Eye Research Center (Salouti, Zamani, Ghoreyshi), Salouti Eye Clinic, Shiraz, Iran; the Netherlands Institute for Innovative Ocular Surgery (Melles), Rotterdam, the Netherlands
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Alió JL, Soria F, Abbouda A, Peña-García P. Laser in situ keratomileusis for -6.00 to -18.00 diopters of myopia and up to -5.00 diopters of astigmatism: 15-year follow-up. J Cataract Refract Surg 2014; 41:33-40. [PMID: 25465210 DOI: 10.1016/j.jcrs.2014.08.029] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 08/05/2014] [Accepted: 08/19/2014] [Indexed: 10/24/2022]
Abstract
PURPOSE To evaluate the long-term outcomes of laser in situ keratomileusis (LASIK) for high myopia with or without astigmatism. SETTING Vissum Instituto Oftalmologico de Alicante and Miguel Hernandez University, Alicante, Spain. DESIGN Retrospective-prospective case series. METHODS Laser in situ keratomileusis was performed using the Visx 20/20 excimer laser. The minimum follow-up was 15 years. The main outcome measures were uncorrected (UDVA) and corrected (CDVA) distance visual acuities, manifest refraction, and corneal topography. RESULTS This study included 40 patients (40 eyes) with a mean age of 51.08 years ± 6.67 (SD) (range 41 to 60 years) with high myopia (-6.00 to -18.00 diopters [D]). At 15 years, the safety index was 1.23 and the efficacy index, 0.95. During the follow-up, a significant increase in the dioptric power of all keratometric variables was detected (P≤.028, Friedman test), the most notable increase occurring between 3 months and 1 year (P≤.005). At 15 years, 46.15% of the eyes were within ±1.00 D of the attempted spherical equivalent and 64.10% were within ±2.00 D. The UDVA at 15 years was 20/25 or better in 43.59% of eyes and 20/40 or better in 64.10% of eyes. The postoperative CDVA was significantly better than preoperatively (P<.001). The postoperative complications were minor except in 1 eye in which ectasia occurred. CONCLUSIONS Laser in situ keratomileusis for high myopia was safe over the long term. However, significant myopic regression with time was detected. Low preoperative pachymetry and low residual stromal bed were predictors of keratometric regression. FINANCIAL DISCLOSURE No author has a financial or proprietary interest in any material or method mentioned.
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Affiliation(s)
- Jorge L Alió
- From Vissum Instituto Oftalmologico de Alicante (Alió, Soria, Abbouda) and the Division of Ophthalmology (Alió, Peña-García), Universidad Miguel Hernández, Alicante, Spain.
| | - Felipe Soria
- From Vissum Instituto Oftalmologico de Alicante (Alió, Soria, Abbouda) and the Division of Ophthalmology (Alió, Peña-García), Universidad Miguel Hernández, Alicante, Spain
| | - Alessandro Abbouda
- From Vissum Instituto Oftalmologico de Alicante (Alió, Soria, Abbouda) and the Division of Ophthalmology (Alió, Peña-García), Universidad Miguel Hernández, Alicante, Spain
| | - Pablo Peña-García
- From Vissum Instituto Oftalmologico de Alicante (Alió, Soria, Abbouda) and the Division of Ophthalmology (Alió, Peña-García), Universidad Miguel Hernández, Alicante, Spain
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Mita M, Waring GO, Tomita M. High-irradiance accelerated collagen crosslinking for the treatment of keratoconus: Six-month results. J Cataract Refract Surg 2014; 40:1032-40. [DOI: 10.1016/j.jcrs.2013.12.014] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 11/30/2013] [Accepted: 12/08/2013] [Indexed: 10/25/2022]
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Hodge C, Chan C, Sutton G. Investigation of keratoconus in an Australian refractive population. Clin Exp Ophthalmol 2014; 42:796-8. [DOI: 10.1111/ceo.12304] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 02/08/2014] [Indexed: 11/29/2022]
Affiliation(s)
- Chris Hodge
- Vision Eye Institute; Chatswood Sydney New South Wales Australia
- Save Sight Institute; Discipline of Ophthalmology; Sydney Medical School; University of Sydney; Darlington Sydney New South Wales Australia
| | - Colin Chan
- Vision Eye Institute; Chatswood Sydney New South Wales Australia
- Faculty of Science; University of New South Wales; Sydney New South Wales Australia
| | - Gerard Sutton
- Vision Eye Institute; Chatswood Sydney New South Wales Australia
- Save Sight Institute; Discipline of Ophthalmology; Sydney Medical School; University of Sydney; Darlington Sydney New South Wales Australia
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Villavicencio OF, Gilani F, Henriquez MA, Izquierdo L, Ambrósio RR. Independent Population Validation of the Belin/Ambrósio Enhanced Ectasia Display: Implications for Keratoconus Studies and Screening. ACTA ACUST UNITED AC 2014. [DOI: 10.5005/jp-journals-10025-1069] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
ABSTRACT
With advances in technology and imaging, finding diagnostic criteria that are both sensitive and specific for keratoconus while using the latest corneal imaging modalities is paramount. The Belin/Ambrósio enhanced ectasia display final ‘D’ index, tested on an independent population, illustrated excellent false positive rates for refractive screening while eliminating 99% of keratoconus corneas. A false positive rate of 0% is achieved with a final ‘D’ of 2.69, meeting the more stringent criteria for treatment studies.
How to cite this article
Villavicencio OF, Gilani F, Henriquez MA, Izquierdo L Jr, Ambrósio RR Jr, Belin MW. Independent Population Validation of the Belin/Ambrósio Enhanced Ectasia Display:Implications for Keratoconus Studies and Screening. Int J Kerat Ect Cor Dis 2014;3(1):1-8.
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Ramos IC, Correa R, Guerra FP, Trattler W, Belin MW, Klyce SD, Fontes BM, Schor P, Smolek MK, Dawson DG, Chalita MR, Cazal JO, Ruiz M, Randleman JB, Ambrósio R. Variability of Subjective Classifications of Corneal Topography Maps From LASIK Candidates. J Refract Surg 2013; 29:770-5. [DOI: 10.3928/1081597x-20130823-01] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 06/12/2013] [Indexed: 11/20/2022]
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Ambrósio R, Randleman JB. Screening for Ectasia Risk: What Are We Screening For and How Should We Screen For It? J Refract Surg 2013; 29:230-2. [DOI: 10.3928/1081597x-20130318-01] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Comparison of corneal thickness and biomechanical properties between North African and French patients. J Cataract Refract Surg 2013; 39:425-30. [DOI: 10.1016/j.jcrs.2012.09.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 09/14/2012] [Accepted: 09/14/2012] [Indexed: 11/19/2022]
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Ahmadi Hosseini SM, Abolbashari F, Mohidin N. Anterior segment parameters in Indian young adults using the Pentacam. Int Ophthalmol 2013; 33:621-6. [PMID: 23456513 DOI: 10.1007/s10792-013-9747-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 02/20/2013] [Indexed: 11/29/2022]
Abstract
To evaluate Pentacam-Scheimpflug imaging of anterior segment parameters in young Indian adults. In this prospective study 120 eyes of 60 normal Indian subjects with a mean age of 25.93 ± 6.58 years (range 17-39 years) were assessed by Pentacam. Main outcome measures were central corneal thickness (CCT), thinnest corneal thickness (TCT), apex corneal thickness (apex CT), peripheral corneal thickness at 2, 4, 6 and 8 mm from the thinnest point, location of the thinnest pachymetry, corneal volume (CV), anterior chamber depth (ACD), anterior chamber volume (ACV) and anterior chamber angle (ACA). Independent samples t test, dependent samples t test, ANOVA and Pearson correlation test were used for statistical analysis. The mean CCT, TCT, Apex CT and CV were 544.95 ± 35.42, 542 ± 35.19, 545.43 ± 35.45 and 61.64 ± 4.17 μm, respectively. There was a gradual increase in CT from the thinnest point to the periphery. The mean ACD was 3.14 ± 0.33 mm, mean ACV was 177.77 ± 29.02 mm(3), and mean ACA was 39.36° ± 5.42°. There was no significant difference between CCT, TCT and Apex CT. A significant positive correlation was found between CCT and peripheral CT and also between anterior chamber parameters. TCT was mainly located in the inferotemporal and superotemporal zone. No significant difference was found in parameters between the right and left eyes and also between genders. This study provided information about a wide range of parameters in the anterior segment of healthy Indian eyes. These results could be helpful in assessment of patients with corneal diseases, glaucoma and screening for refractive surgeries.
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Affiliation(s)
- Seyed Mahdi Ahmadi Hosseini
- Refractive Errors Research Center, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran,
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Enhanced Screening for Ectasia Susceptibility Among Refractive Candidates: The Role of Corneal Tomography and Biomechanics. CURRENT OPHTHALMOLOGY REPORTS 2013. [DOI: 10.1007/s40135-012-0003-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Ahmadi Hosseini SM, Mohidin N, Abolbashari F, Mohd-Ali B, Santhirathelagan CT. Corneal thickness and volume in subclinical and clinical keratoconus. Int Ophthalmol 2012; 33:139-45. [PMID: 23138667 DOI: 10.1007/s10792-012-9654-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Accepted: 10/10/2012] [Indexed: 11/29/2022]
Abstract
To evaluate corneal thickness and volume in subclinical and clinical keratoconus in Asian population with the aim of discriminating between normal and ectatic cornea. Eyes were placed into one of the following three groups: normal, subclinical, and mild-moderate keratoconus. Pentacam Scheimpflug imaging (Oculus Inc., Wetzlar, Germany) was performed for each participant to record thinnest corneal thickness, central corneal thickness, corneal volume (CV), peripheral corneal thickness (PCT) and percentage thickness increase (PTI) at 2, 4, 6, and 8 mm. The data were exported to SPSS for statistical analysis. Subjects comprised 52 normal, 15 subclinical keratoconus, and 32 mild-moderate clinical keratoconus eyes. Our results indicated that corneal thickness (CT) distribution, PTI, and CV in normal eyes were significantly different compared with subclinical and clinical keratoconus (P < .05). Overall, subclinical group exhibited lower CT distribution and volume, and higher PTI in comparison with normal eyes. However, they showed higher CT distribution and volume, and lower PTI compared with keratoconus group. In addition, there was a smaller change in PCT and PTI from the thinnest point of the cornea to the periphery. The results of the present study indicate that CT parameters and CV were significantly different in normal versus subclinical group and in normal versus keratoconus group. These findings could help clinicians to better discriminate between normal and ectatic cornea.
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Affiliation(s)
- Seyed Mahdi Ahmadi Hosseini
- School of Healthcare Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300, Kuala Lumpur, Malaysia
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Brenner LF, Alió JL, Vega-Estrada A, Baviera J, Beltrán J, Cobo-Soriano R. Clinical grading of post-LASIK ectasia related to visual limitation and predictive factors for vision loss. J Cataract Refract Surg 2012; 38:1817-26. [PMID: 22920505 DOI: 10.1016/j.jcrs.2012.05.041] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 05/23/2012] [Accepted: 05/24/2012] [Indexed: 11/28/2022]
Abstract
PURPOSE To evaluate and characterize the main clinical features of post-laser in situ keratomileusis (LASIK) ectasia, propose a grading system based on visual limitation, and identify predictive factors related to the degree of visual loss. SETTING Vissum Corp., Alicante, Spain. DESIGN Retrospective case series. METHODS This study comprised consecutive eyes with corneal ectasia after LASIK from 1996 to 2010. Main outcomes were post-LASIK ectasia corrected distance visual acuity (CDVA), CDVA loss, spherical equivalent (SE), and the corneal bulge (delta K). These outcomes were correlated with the residual stromal bed, ablation depth, ablation ratio (ablation depth:pachymetry), corneal depth (flap + ablation depth), and corneal ratio (corneal depth:pachymetry) to characterize their role in the severity of the disease. RESULTS The mean post-LASIK ectasia CDVA, CDVA loss, SE, and delta K were 0.20 logMAR ± 0.18 (SD), -0.13 ± 0.15 logMAR, -3.80 ± 3.86 diopters (D), and 4.77 ± 4.23 D, respectively. The ablation ratio had the strongest correlation with post-LASIK ectasia CDVA (ρ = 0.477 and P<.001), whereas the corneal ratio had the strongest correlation with the post-LASIK ectasia SE and delta K (ρ = -0.614 and ρ = 0.453, respectively: P<.001). The ablation ratio was the main predictive factor for post-LASIK ectasia CDVA loss (relative risk, 2.04; P=.049). CONCLUSIONS The grading system based on visual limitation was consistently represented by differences in CDVA loss, SE, and delta K. A high amount of tissue removed by the refractive procedure was associated with greater corneal biomechanical destabilization, increased corneal steepening, and a worse prognosis.
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Affiliation(s)
- Luis F Brenner
- Vissum Instituto Oftalmologico de Alicante, Alicante, Spain
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Li Y, Tan O, Brass R, Weiss JL, Huang D. Corneal epithelial thickness mapping by Fourier-domain optical coherence tomography in normal and keratoconic eyes. Ophthalmology 2012; 119:2425-33. [PMID: 22917888 DOI: 10.1016/j.ophtha.2012.06.023] [Citation(s) in RCA: 243] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 06/13/2012] [Accepted: 06/14/2012] [Indexed: 02/08/2023] Open
Abstract
OBJECTIVE To map the corneal epithelial thickness with Fourier-domain optical coherence tomography (OCT) and to develop epithelial thickness-based variables for keratoconus detection. DESIGN Cross-sectional observational study. PARTICIPANTS One hundred forty-five eyes from 76 normal subjects and 35 keratoconic eyes from 22 patients. METHODS A 26,000-Hz Fourier-domain OCT system with 5-μm axial resolution was used. The cornea was imaged with a Pachymetry + Cpwr scan pattern (6-mm scan diameter, 8 radials, 1024 axial-scans each, repeated 5 times) centered on the pupil. Three scans were obtained at a single visit in a prospective study. A computer algorithm was developed to map the corneal epithelial thickness automatically. Zonal epithelial thicknesses and 5 diagnostic variables, including minimum, superior-inferior (S-I), minimum-maximum (MIN-MAX), map standard deviation (MSD), and pattern standard deviation (PSD), were calculated. Repeatability of the measurements was assessed by the pooled standard deviation. The area under the receiver operating characteristic curve (AUC) was used to evaluate diagnostic accuracy. MAIN OUTCOME MEASURES Descriptive statistics, repeatability, and AUC of the zonal epithelial thickness and diagnostic variables. RESULTS The central, superior, and inferior epithelial thickness averages were 52.3 ± 3.6 μm, 49.6 ± 3.5 μm, and 51.2 ± 3.4 μm in normal eyes and 51.9 ± 5.3 μm, 51.2 ± 4.2 μm, and 49.1 ± 4.3 μm in keratoconic eyes. Compared with normal eyes, keratoconic eyes had significantly lower inferior (P = 0.03) and minimum (P<0.0001) corneal epithelial thickness, greater S-I (P = 0.013), more negative MIN-MAX (P<0.0001), greater MSD (P<0.0001), and larger PSD (P<0.0001). The repeatability of the zonal average, minimum, S-I, and MIN-MAX epithelial thickness variables were between 0.7 and 1.9 μm. The repeatability of MSD was better than 0.4 μm. The repeatability of PSD was 0.02 or better. Among all epithelial thickness-based variables investigated, PSD provided the best diagnostic power (AUC = 1.00). Using an PSD cutoff value of 0.057 alone gave 100% specificity and 100% sensitivity. CONCLUSIONS High-resolution Fourier-domain OCT mapped corneal epithelial thickness with good repeatability in both normal and keratoconic eyes. Keratoconus was characterized by apical epithelial thinning. The resulting deviation from the normal epithelial pattern could be detected with very high accuracy using the PSD variable. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found after the references.
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Affiliation(s)
- Yan Li
- Center for Ophthalmic Optics and Lasers, Casey Eye Institute and Department of Ophthalmology, Oregon Health and Science University, Portland, Oregon 97239, USA.
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Bühren J, Kook D, Kohnen T. [Suitability of various topographic corneal parameters for diagnosis of early keratoconus]. Ophthalmologe 2012; 109:37-44. [PMID: 22274296 DOI: 10.1007/s00347-011-2446-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND For the detection of early stages of keratoconus (KC) several metrics have been developed in recent years. The aim of the study was to assess the suitability of keratometric indices to discriminate between eyes with early and subclinical KC from normal eyes. METHODS From 33 eyes with early KC (group 1), 16 eyes with subclinical KC (group 2) und 121 normal eyes (group 3) the following metrics were computed from axial keratometric data: central keratometry (cK), astigmatism (AST), paracentral inferior-superior keratometric difference (PISD), skew of the steepest axes index (SRAX), the KISA% index, a discriminant function from the KISA% parameters AST, cK, PISD and SRAX (DKISA), corneal C(3) (-1) and a discriminant function from corneal Zernike coefficients (1(st)-7(th) order, pupil diameter 6 mm). The discriminative ability of these metrics between KC and normal eyes was assessed using receiver operating characteristic (ROC) curves and measuring the area under the curve (A (z)ROC). RESULTS Applying the published criteria, the Rabinowitz-McDonnell test (cK and PISD) and KISA% lacked sensitivity. Adjustment of critical values using ROC curve analysis improved the discriminative ability. The PISD (A (z)ROC 1 versus 3: 1, 2 versus 3: 0.947) and C(3) (-1) (A (z)ROC 1 and 0.98, respectively) metrics were the two single parameters with the highest discriminative ability. By weighting KISA parameters and Zernike coefficients with discriminant analyses, 100% of group 1 eyes (DKISA) and 96.7% of group 2 eyes (DA) were correctly classified. CONCLUSION After lowering the critical values the keratometric indices yielded a high discriminative ability for the detection of early KC stages. However, the excellent classification rates for wavefront-based metrics were not achieved.
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Affiliation(s)
- J Bühren
- Klinik für Augenheilkunde, Johann Wolfgang Goethe-Universität, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Deutschland.
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Ambrósio R, Caiado ALC, Guerra FP, Louzada R, Sinha RA, Luz A, Dupps WJ, Belin MW. Novel pachymetric parameters based on corneal tomography for diagnosing keratoconus. J Refract Surg 2011; 27:753-8. [PMID: 21800785 DOI: 10.3928/1081597x-20110721-01] [Citation(s) in RCA: 221] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Accepted: 06/14/2011] [Indexed: 01/01/2023]
Abstract
PURPOSE To describe pachymetric progression indices (PPI) of the Pentacam HR (Oculus Optikgeräte GmbH) and the concept of relational thickness, and to test their accuracy for differentiating keratoconic and normal corneas compared with single-point thickness values. METHODS One hundred thirteen individual eyes randomly selected from 113 normal patients and 44 eyes of 44 patients with keratoconus were studied using the Pentacam HR by acquiring central corneal thickness (CCT), thinnest point (TP), position of the TP and PPI at minimal (PPI Min) and maximal (PPI Max) meridians, and the average (PPI Ave) of all meridians. Relational thickness parameters were calculated as the ratios of TP and CCT and PPI values. Mann-Whitney U test assessed differences in groups for each variable. Receiver operating characteristic (ROC) curves were calculated for all variables and pairwise comparisons were performed. RESULTS Statistically significant differences were noted between normal and keratoconic eyes for all parameters (P<.001), except for horizontal position of TP (P=.79). The best parameters, named Ambrósio's Relational Thickness (ART), were ART-Ave (TP/PPI Ave) and ART-Max (TP/PPI Max) with areas under the ROC curves of 0.987 and 0.983, respectively. The best cutoffs were 424 μm and 339 μm for ART-Ave and ART-Max, respectively. Pachymetric progression indices and ART had a greater area under the curve than TP and CCT (P<.001); TP (0.955) had a greater area under the curve than CCT (0.909; P=.002). CONCLUSIONS Tomographic-derived pachymetric parameters were better able to differentiate normal and keratoconic corneas than single-point pachymetric measurements. Further studies are needed to evaluate the role of tomography in identifying early forms of ectasia as well as ectasia risk among LASIK candidates.
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Angunawela RI, Winkler von Mohrenfels C, Kumar A, O’Brart DP, Marshall J. Live or Let Die: Epithelial Flap Vitality and Keratocyte Proliferation Following LASEK and Epi-LASIK in Human Donor and Porcine Eyes. J Refract Surg 2011; 27:111-8. [DOI: 10.3928/1081597x-20100330-01] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Accepted: 02/04/2010] [Indexed: 11/20/2022]
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