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Al Bdour M, Sabbagh HM, Jammal HM. Multi-modal imaging for the detection of early keratoconus: a narrative review. EYE AND VISION (LONDON, ENGLAND) 2024; 11:18. [PMID: 38730479 PMCID: PMC11088107 DOI: 10.1186/s40662-024-00386-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 04/21/2024] [Indexed: 05/12/2024]
Abstract
Keratoconus is a common progressive corneal disorder that can be associated with significant ocular morbidity. Various corneal imaging techniques have been used for the diagnosis of established cases. However, in the early stages of the disease, which include subclinical keratoconus and forme fruste keratoconus, detection of such cases can be challenging. The importance of detecting such cases is very important because early intervention can halt disease progression, improve visual outcomes and prevent postrefractive surgery ectasia associated with performing corneal refractive procedures in such patients. This narrative review aimed to examine several established and evolving imaging techniques for the detection of early cases of keratoconus. The utilization of combinations of these techniques may further increase their diagnostic ability.
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Affiliation(s)
- Muawyah Al Bdour
- Department of Ophthalmology, School of Medicine, The University of Jordan, Amman, Jordan
| | - Hashem M Sabbagh
- The National Center for Diabetes Endocrinology and Genetics (NCDEG), Amman, Jordan
| | - Hisham M Jammal
- Department of Ophthalmology, Faculty of Medicine, Jordan University of Science and Technology, PO Box 3030, Irbid, 22110, Jordan.
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Huo Y, Chen X, Xie R, Li J, Wang Y. Longitudinal Analysis of Corneal Biomechanics of Suspect Keratoconus: A Prospective Case-Control Study. Bioengineering (Basel) 2024; 11:420. [PMID: 38790289 PMCID: PMC11118031 DOI: 10.3390/bioengineering11050420] [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: 03/12/2024] [Revised: 04/11/2024] [Accepted: 04/24/2024] [Indexed: 05/26/2024] Open
Abstract
BACKGROUND To evaluate the corneal biomechanics of stable keratoconus suspects (Stable-KCS) at 1-year follow-up and compare them with those of subclinical keratoconus (SKC). METHODS This prospective case-control study included the eyes of 144 patients. Biomechanical and tomographic parameters were recorded (Corvis ST and Pentacam). Patients without clinical signs of keratoconus in both eyes but suspicious tomography findings were included in the Stable-KCS group (n = 72). Longitudinal follow-up was used to evaluate Stable-KCS changes. Unilateral keratoconus contralateral eyes with suspicious tomography were included in the SKC group (n = 72). T-tests and non-parametric tests were used for comparison. Multivariate general linear models were used to adjust for confounding factors for further analysis. Receiver operating characteristic (ROC) curves were used to analyze the distinguishability. RESULTS The biomechanical and tomographic parameters of Stable-KCS showed no progression during the follow-up time (13.19 ± 2.41 months, p > 0.05). Fifteen biomechanical parameters and the Stress-Strain Index (SSI) differed between the two groups (p < 0.016). The A1 dArc length showed the strongest distinguishing ability (area under the ROC = 0.888) between Stable-KCS and SKC, with 90.28% sensitivity and 77.78% specificity at the cut-off value of -0.0175. CONCLUSIONS The A1 dArc length could distinguish between Stable-KCS and SKC, indicating the need to focus on changes in the A1 dArc length for keratoconus suspects during the follow-up period. Although both have abnormalities on tomography, the corneal biomechanics and SSI of Stable-KCS were stronger than those of SKC, which may explain the lack of progression of Stable-KCS.
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Affiliation(s)
- Yan Huo
- School of Medicine, Nankai University, Tianjin 300071, China; (Y.H.); (X.C.); (R.X.)
| | - Xuan Chen
- School of Medicine, Nankai University, Tianjin 300071, China; (Y.H.); (X.C.); (R.X.)
| | - Ruisi Xie
- School of Medicine, Nankai University, Tianjin 300071, China; (Y.H.); (X.C.); (R.X.)
| | - Jing Li
- School of Medicine, Northwest University, Xi’an 710199, China;
| | - Yan Wang
- School of Medicine, Nankai University, Tianjin 300071, China; (Y.H.); (X.C.); (R.X.)
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin 300070, China
- Nankai Eye Institute, Nankai University, Tianjin 300071, China
- Tianjin Eye Hospital, Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Institute, Nankai University Affiliated Eye Hospital, Tianjin 300020, China
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Huo Y, Chen X, Song J, Li J, Hou J, Jhanji V, Li S, Wu G, Tian C, Liu Y, Wang Y. Corneal Biomechanical Properties to Predict Prognosis of Abnormal Tomographic Corneas: A Prospective Cohort Study. Am J Ophthalmol 2024; 259:185-196. [PMID: 38211780 DOI: 10.1016/j.ajo.2024.01.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 01/03/2024] [Accepted: 01/05/2024] [Indexed: 01/13/2024]
Abstract
PURPOSE To analyze the corneal biomechanical properties in patients with abnormal corneal tomography (ACT) and predict their stability using the biomechanical stability index (BSI). DESIGN Prospective cohort study. METHODS Setting: Multicenter study. STUDY POPULATION This study included 385 eyes of 278 patients with stable ACT (n = 70), subclinical keratoconus (SKC, n = 65), keratoconus (n = 65), normal controls (NL, n = 142). Forty-three eyes with first-visit ACT were included in a separate cohort (follow-up ACT group). OBSERVATION PROCEDURE Tomographical and biomechanical parameters (Pentacam and Corvis ST) were recorded. MAIN OUTCOME MEASURES Nonparametric tests were used for comparison. Logistic regression was employed to introduce BSI to separate stable ACT and SKC accurately. An independent dataset of 43 first-visit ACT eyes was followed up for 1 year to validate BSI's accuracy and positive and negative predictive values (PPV, NPV). RESULTS The tomographical and biomechanical parameters in patients with Stable ACT remained stable over the follow-up period (12.73 ± 2.57 months, P > .05). Stable ACT had 12/14 biomechanical parameters different (P < .05) from SKC but not different from NL (P > .05). With a cut-off value of 0.585, BSI demonstrated the strongest ability to distinguish between stable ACT and SKC (area under the receiver operating characteristic curve = 0.991), with 93.85% sensitivity and 97.14% specificity. During the 1-year follow-up of 43 eyes (follow-up ACT group), 30 remained stable. The accuracy, PPV, and NPV of the BSI were 95.35%, 100%, and 93.75%, respectively. CONCLUSIONS Biomechanical properties of patients with stable abnormal tomography corneas were stronger than SKC and close to normal corneas, which may explain the reason for tomographic stability. The BSI may be useful for predicting disease progression in patients with ACT and the possible management of corneal cross-linking at the first visit.
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Affiliation(s)
- Yan Huo
- School of Medicine (Y.H., X.C., S.L., Y.L., Y.W.), Nankai University, Tianjin, China
| | - Xuan Chen
- School of Medicine (Y.H., X.C., S.L., Y.L., Y.W.), Nankai University, Tianjin, China
| | - Jiaxin Song
- Clinical College of Ophthalmology (J.S., G.W., C.T., Y.W.), Tianjin Medical University, Tianjin, China
| | - Jing Li
- Shanxi Eye Hospital (J.L.), Xi'an People's Hospital, Xi'an, China
| | - Jie Hou
- Jinan Mingshui Eye Hospital (J.H.), Ji'nan, Shandong, China
| | - Vishal Jhanji
- Department of Ophthalmology (V.J.), University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Shuangcheng Li
- School of Medicine (Y.H., X.C., S.L., Y.L., Y.W.), Nankai University, Tianjin, China
| | - Guoxi Wu
- Clinical College of Ophthalmology (J.S., G.W., C.T., Y.W.), Tianjin Medical University, Tianjin, China
| | - Caixia Tian
- Clinical College of Ophthalmology (J.S., G.W., C.T., Y.W.), Tianjin Medical University, Tianjin, China
| | - Yutong Liu
- School of Medicine (Y.H., X.C., S.L., Y.L., Y.W.), Nankai University, Tianjin, China
| | - Yan Wang
- School of Medicine (Y.H., X.C., S.L., Y.L., Y.W.), Nankai University, Tianjin, China; Clinical College of Ophthalmology (J.S., G.W., C.T., Y.W.), Tianjin Medical University, Tianjin, China; Tianjin Eye Hospital, Tianjin Key Lab of Ophthalmology and Visual Science (Y.W.), Tianjin Eye Institute, Nankai University Affiliated Eye Hospital, Tianjin, China; Nankai Eye Institute (Y.W.), Nankai University, Tianjin, China.
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Kuo AN, Cortina MS, Greiner MA, Li JY, Miller DD, Shtein RM, Veldman PB, Yin J, Kim SJ, Shen JF. Advanced Corneal Imaging in Keratoconus: A Report by the American Academy of Ophthalmology. Ophthalmology 2024; 131:107-121. [PMID: 37855776 DOI: 10.1016/j.ophtha.2023.07.030] [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: 05/22/2023] [Revised: 07/31/2023] [Accepted: 07/31/2023] [Indexed: 10/20/2023] Open
Abstract
PURPOSE To review the published literature on the diagnostic capabilities of the newest generation of corneal imaging devices for the identification of keratoconus. METHODS Corneal imaging devices studied included tomographic platforms (Scheimpflug photography, OCT) and functional biomechanical devices (imaging an air impulse on the cornea). A literature search in the PubMed database for English language studies was last conducted in February 2023. The search yielded 469 citations, which were reviewed in abstract form. Of these, 147 were relevant to the assessment objectives and underwent full-text review. Forty-five articles met the criteria for inclusion and were assigned a level of evidence rating by the panel methodologist. Twenty-six articles were rated level II, and 19 articles were rated level III. There were no level I evidence studies of corneal imaging for the diagnosis of keratoconus found in the literature. To provide a common cross-study outcome measure, diagnostic sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) were extracted. (A perfect diagnostic test that identifies all cases properly has an AUC of 1.0.) RESULTS: For the detection of keratoconus, sensitivities for all devices and parameters (e.g., anterior or posterior corneal curvature, corneal thickness) ranged from 65% to 100%. The majority of studies and parameters had sensitivities greater than 90%. The AUCs ranged from 0.82 to 1.00, with the majority greater than 0.90. Combined indices that integrated multiple parameters had an AUC in the mid-0.90 range. Keratoconus suspect detection performance was lower with AUCs ranging from 0.66 to 0.99, but most devices and parameters had sensitivities less than 90%. CONCLUSIONS Modern corneal imaging devices provide improved characterization of the cornea and are accurate in detecting keratoconus with high AUCs ranging from 0.82 to 1.00. The detection of keratoconus suspects is less accurate with AUCs ranging from 0.66 to 0.99. Parameters based on single anatomic locations had a wide range of AUCs. Studies with combined indices using more data and parameters consistently reported high AUCs. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
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Affiliation(s)
- Anthony N Kuo
- Duke Eye Center, Duke University Medical Center, Durham, North Carolina
| | - Maria S Cortina
- Department of Ophthalmology and Visual Science, University of Illinois College of Medicine, Chicago, Illinois
| | - Mark A Greiner
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine and Institute for Vision Research, University of Iowa, Iowa City, Iowa
| | - Jennifer Y Li
- University of California, Davis Eye Center, University of California, Davis, California
| | - Darby D Miller
- Department of Ophthalmology, Mayo Clinic, Jacksonville, Florida
| | - Roni M Shtein
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
| | - Peter B Veldman
- Department of Ophthalmology and Visual Sciences, The University of Chicago, Chicago, Illinois
| | - Jia Yin
- Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts
| | - Stephen J Kim
- Department of Ophthalmology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Joanne F Shen
- Department of Ophthalmology, Mayo Clinic, Scottsdale, Arizona.
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Niazi S, Jiménez-García M, Findl O, Gatzioufas Z, Doroodgar F, Shahriari MH, Javadi MA. Keratoconus Diagnosis: From Fundamentals to Artificial Intelligence: A Systematic Narrative Review. Diagnostics (Basel) 2023; 13:2715. [PMID: 37627975 PMCID: PMC10453081 DOI: 10.3390/diagnostics13162715] [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: 05/24/2023] [Revised: 07/21/2023] [Accepted: 07/26/2023] [Indexed: 08/27/2023] Open
Abstract
The remarkable recent advances in managing keratoconus, the most common corneal ectasia, encouraged researchers to conduct further studies on the disease. Despite the abundance of information about keratoconus, debates persist regarding the detection of mild cases. Early detection plays a crucial role in facilitating less invasive treatments. This review encompasses corneal data ranging from the basic sciences to the application of artificial intelligence in keratoconus patients. Diagnostic systems utilize automated decision trees, support vector machines, and various types of neural networks, incorporating input from various corneal imaging equipment. Although the integration of artificial intelligence techniques into corneal imaging devices may take time, their popularity in clinical practice is increasing. Most of the studies reviewed herein demonstrate a high discriminatory power between normal and keratoconus cases, with a relatively lower discriminatory power for subclinical keratoconus.
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Affiliation(s)
- Sana Niazi
- Translational Ophthalmology Research Center, Tehran University of Medical Sciences, Tehran P.O. Box 1336616351, Iran;
| | - Marta Jiménez-García
- Department of Ophthalmology, Antwerp University Hospital (UZA), 2650 Edegem, Belgium
- Department of Medicine and Health Sciences, University of Antwerp, 2000 Antwerp, Belgium
| | - Oliver Findl
- Department of Ophthalmology, Vienna Institute for Research in Ocular Surgery (VIROS), Hanusch Hospital, 1140 Vienna, Austria
| | - Zisis Gatzioufas
- Department of Ophthalmology, University Hospital Basel, 4031 Basel, Switzerland;
| | - Farideh Doroodgar
- Translational Ophthalmology Research Center, Tehran University of Medical Sciences, Tehran P.O. Box 1336616351, Iran;
- Negah Aref Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran P.O. Box 1544914599, Iran
| | - Mohammad Hasan Shahriari
- Department of Health Information Technology and Management, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran P.O. Box 1971653313, Iran
| | - Mohammad Ali Javadi
- Ophthalmic Research Center, Labbafinezhad Hospital, Shahid Beheshti University of Medical Sciences, Tehran P.O. Box 19395-4741, Iran
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Flockerzi E, Xanthopoulou K, Munteanu C, Daas L, Langenbucher A, Seitz B. The Biomechanical E-Staging: In Vivo Biomechanics in Keratoconus. Klin Monbl Augenheilkd 2023; 240:761-773. [PMID: 37348512 DOI: 10.1055/a-2079-1740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/24/2023]
Abstract
Belin's ABCD keratoconus classification system allows keratoconus staging based on the criteria of anterior (A) and posterior (B) corneal curvature, thinnest corneal thickness (C), and best spectacle-corrected visual acuity (D). These parameters also provide a progression assessment, but do not take corneal biomechanics into account. The analysis of corneal biomechanics by the Corvis ST (Oculus, Wetzlar, Germany) allows for separation of healthy and keratoconus corneas, based on the Corvis Biomechanical Index (CBI) and the Tomographic Biomechanical Index (TBI). As Corvis ST measurements are highly reliable and are independent of keratoconus severity, a biomechanical parameter was developed for keratoconus corneas based on the linear term of the CBI. This provides biomechanical keratoconus staging. The Corvis Biomechanical Factor (CBiF) is the basis for the introduction of the biomechanical E-staging, which augments the ABCD classification to the ABCDE classification, thus including the cornerstone of corneal biomechanics. This article highlights strengths and limitations of the ABCDE classification. "Unilateral keratoconus" supposedly turns out to be mostly a snapshot of a highly asymmetric keratectasia. Regular astigmatism is sometimes an important differential diagnosis to keratectasia and may be difficult to differentiate from it. Furthermore, the use of the biomechanical E-staging in daily practice for progression assessment of keratoconus and after its treatment by corneal cross-linking or implantation of intracorneal ring segments will be demonstrated and discussed.
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Affiliation(s)
- Elias Flockerzi
- Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes und Medizinische Fakultät der Universität des Saarlandes, Homburg, Deutschland
| | - Kassandra Xanthopoulou
- Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes und Medizinische Fakultät der Universität des Saarlandes, Homburg, Deutschland
| | - Cristian Munteanu
- Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes und Medizinische Fakultät der Universität des Saarlandes, Homburg, Deutschland
| | - Loay Daas
- Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes und Medizinische Fakultät der Universität des Saarlandes, Homburg, Deutschland
| | - Achim Langenbucher
- Institut für Experimentelle Ophthalmologie, Universitätsklinikum des Saarlandes und Medizinische Fakultät der Universität des Saarlandes, Homburg, Deutschland
| | - Berthold Seitz
- Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes und Medizinische Fakultät der Universität des Saarlandes, Homburg, Deutschland
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Feldman RM, Kim G, Chuang AZ, Shiraishi A, Okamoto K, Tsukamoto M. Comparison between the CASIA SS-1000 and Pentacam in measuring corneal curvatures and corneal thickness maps. BMC Ophthalmol 2023; 23:10. [PMID: 36604657 PMCID: PMC9814456 DOI: 10.1186/s12886-023-02768-w] [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: 05/31/2022] [Accepted: 01/02/2023] [Indexed: 01/06/2023] Open
Abstract
PURPOSE To compare the intra-device repeatability and inter-device reproducibility between two anterior segment imaging instruments, the CASIA SS-1000 (Tomey Corp., Nagoya, Japan) and Pentacam (OCULUS, Arlington, WA) in measuring anterior segment parameters. METHODS Single-center, prospective clinical trial. Participants ≥20 years of age were included. One eye was randomly selected, each imaged by three CASIA SS-1000 devices and three Pentacam devices by three different examiners. Each photographer operated a pair of devices, one CASIA SS-1000 and one Pentacam. The image order for each participant was determined by a random permutation table. Three images were taken from each device. A total of 18 images were taken for each eye. Ratios of the standard deviations, referenced as (CASIA/Pentacam), were calculated to compare the repeatability and reproducibility of the two imaging instruments. RESULTS In all, 66 participants with a mean age of 46.4 years (±21.7) were enrolled in the study. All repeatability ratios and intra-device variability were less than 1 (anterior corneal curvature: flat = 0.86, steep = 0.85; posterior corneal curvature: flat = 0.43, steep = 0.61; and map: thinnest = 0.22; central = 0.24, 2 mm = 0.26, 4 mm = 0.27, and 6 mm = 0.30). All reproducibility ratios, which measure the inter-device variability, were less than 1 (anterior corneal curvature: flat = 0.58, steep = 0.73; posterior corneal curvature: flat = 0.25, steep = 0.31; and pachymetry map: thinnest = 0.20; central = 0.20; 2 mm = 0.20; 4 mm = 0.19; and 6 mm = 0.22). A ratio of less than 1 indicates that the CASIA SS-1000 has more consistent measurements. CONCLUSIONS The CASIA SS-1000 was found to have better repeatability and reproducibility compared to the Pentacam for both corneal curvature and pachymetry maps. This greater consistency may require further study to determine whether the decreased variability can be translated into improved clinical results.
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Affiliation(s)
- Robert M. Feldman
- grid.267308.80000 0000 9206 2401Ruiz Department of Ophthalmology and Visual Science, McGovern Medical School at The University of Texas Health Science Center at Houston (UTHealth), 6400 Fannin St., Suite #1800, Houston, TX 77030 USA
| | - Gene Kim
- grid.267308.80000 0000 9206 2401Ruiz Department of Ophthalmology and Visual Science, McGovern Medical School at The University of Texas Health Science Center at Houston (UTHealth), 6400 Fannin St., Suite #1800, Houston, TX 77030 USA ,Department of Ophthalmology, Dell Medical School, Austin, TX USA
| | - Alice Z. Chuang
- grid.267308.80000 0000 9206 2401Ruiz Department of Ophthalmology and Visual Science, McGovern Medical School at The University of Texas Health Science Center at Houston (UTHealth), 6400 Fannin St., Suite #1800, Houston, TX 77030 USA
| | - Atsushi Shiraishi
- grid.255464.40000 0001 1011 3808Department of Ophthalmology, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime Japan
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Huo Y, Chen X, Cao H, Li J, Hou J, Wang Y. Biomechanical properties analysis of forme fruste keratoconus and subclinical keratoconus. Graefes Arch Clin Exp Ophthalmol 2022; 261:1311-1320. [PMID: 36441226 DOI: 10.1007/s00417-022-05916-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 10/22/2022] [Accepted: 11/16/2022] [Indexed: 11/29/2022] Open
Abstract
PURPOSE To analyze the biomechanical properties of the eye in patients with unilateral keratoconus with normal (forme fruste keratoconus [FFKC]) or abnormal topography (subclinical keratoconus [SKC]). METHODS This study included 153 eyes of 153 participants, including 95 eyes of patients with unilateral keratoconus, and 58 eyes of 58 healthy controls. Contralateral eyes with unilateral keratoconus were divided into two groups according to clinical manifestations and global consensus: FFKC (n = 30) and SKC (n = 65). The biomechanical characteristics were analyzed using non-parametric tests; further analysis thereof was performed after adjusting for confounding factors (i.e., intraocular pressure, age, and corneal thickness). Receiver operating characteristic curve (ROC) was used to analyze the ability of the biomechanical parameters to distinguish FFKC from SKC. RESULTS Statistically significant differences between the FFKC and SKC groups were found in 9 of the 18 corneal biomechanical parameters analyzed using non-parametric tests. After adjusting for confounding factors, the multivariate analysis still revealed significant statistical differences in A1-time (P = 0.017), integrated radius (IR) (P = 0.024), and tomographic and biomechanical index (TBI, P < 0.001) between the FFKC and SKC groups. Stiffness parameter at first applanation (SP-A1) (Area under ROC [AUROC] = 0.765) demonstrated the strongest distinguishing ability, except for TBI (AUROC = 0.858) and Corvis Biomechanical Index (AUROC = 0.849), however, there was no statistically significant difference in SP-A1 (P = 0.366) between FFKC and SKC. CONCLUSIONS Biomechanical parameters A1-time and IR have a high diversity between FFKC and SKC, besides TBI, and may reflect more subtle changes in corneal biomechanical properties (BPs) preceding SP-A1. The BPs of SKC are weaker than FFKC, which might be a basic and clue for the classification and diagnosis of the severity of early keratoconus in terms of biomechanics.
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Henriquez MA, Hadid M, Moctezuma C, Izquierdo L, Binder PS. The false positive rates for detecting keratoconus and potential ectatic corneal conditions when evaluating astigmatic eyes with Scheimpflug Technology. Eur J Ophthalmol 2022; 32:2532-2546. [PMID: 35313744 DOI: 10.1177/11206721221081467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE To quantify the false positive rates for keratoconus (KC) and potential ectatic corneal conditions in highly astigmatism eyes when using published parameters/indices obtained from the Pentacam and Galilei units. SETTING Oftalmosalud Instituto de Ojos, Lima, Peru. DESIGN Prospective cohort study. METHODS 67 consecutive eyes with corneal astigmatism > 1.5 D, with a minimum follow ups of 36 months after an uneventful LASIK procedure were included. Indices for KC and other potential ectatic corneal conditions (subclinical KC, forme fruste KC, suspect KC) were obtained using the Pentacam and Galilei Scheimpflug cameras. MAIN OUTCOME MEASURES The false positive rates for KC and potential ectatic corneal conditions were measured. Cut off values provided by previous studies and company-based parameters were used to assess the rate of false positivity. RESULTS The range of false positive rates for a KC diagnosis depending on the lowest and highest cutoff values were: index of height decentration (61% - 1%), index of surface variance (76% - 0%), Posterior elevation (55% - 0%), maximum Ambrosio Relational thickness (100% - 13%), Belin Ambrosio enhanced ectasia display total deviation value (100% - 4%), Average pachymetric progression index (69% - 3%), Pachymetry at the thinnest point (58% - 1%), CSI Center Surround Index (100%), Differential sector index (51%). CONCLUSION The false positive rates for KC and ectatic corneal conditions vary dramatically depending on the cut-off values used. Some indexes used for diagnosis of potential ectatic corneal conditions are inaccurate in normal, highly astigmatic eyes.
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Affiliation(s)
- Maria A Henriquez
- Research Department, 568280Oftalmosalud Institute of Eyes, Av. Javier Prado Este 1142, San Isidro, Lima 27, Perú
| | - Marta Hadid
- Research Department, 568280Oftalmosalud Institute of Eyes, Av. Javier Prado Este 1142, San Isidro, Lima 27, Perú
| | - Cristobal Moctezuma
- Research Department, 568280Oftalmosalud Institute of Eyes, Av. Javier Prado Este 1142, San Isidro, Lima 27, Perú
| | - Luis Izquierdo
- Research Department, 568280Oftalmosalud Institute of Eyes, Av. Javier Prado Este 1142, San Isidro, Lima 27, Perú
| | - Perry S Binder
- 481087Gavin Herbert Eye Institute, University of California, Irvine, California, USA
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Flockerzi E, Vinciguerra R, Belin MW, Vinciguerra P, Ambrósio R, Seitz B. Correlation of the Corvis Biomechanical Factor with tomographic parameters in keratoconus. J Cataract Refract Surg 2022; 48:215-221. [PMID: 34321407 DOI: 10.1097/j.jcrs.0000000000000740] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 06/27/2021] [Indexed: 11/25/2022]
Abstract
PURPOSE To investigate the relationship between corneal biomechanics and keratoconus (KC) severity as described by tomographic parameters. SETTING University-based German ophthalmology department. DESIGN Retrospective cross-sectional study. METHODS A total of 448 KC corneas of the Homburg Keratoconus Center and 112 healthy corneas (448+112 patients) were examined by Pentacam high-resolution and Corneal Visualization Scheimpflug Technology (Pentacam HR and Corvis ST). The KC population included a wide spectrum of disease severity based on Belin's ABCD classification. Linear regression analysis was performed between the linear term of the Corvis Biomechanical Index (CBI) (CBI beta) and the tomographic values anterior radius of curvature (ARC), posterior radius of curvature (PRC), and thinnest corneal thickness (TCT). A linear transformation of the CBI beta was performed to provide an intuitive scaling, which was referred to as the Corvis Biomechanical Factor (CBiF = -0.24294226 × CBI beta + 6.02). This scaling adjusted the CBI beta to the same scale as posterior corneal curvature (PRC). RESULTS There was a high correlation of the CBI beta and its modification, the CBiF, with TCT (Pearson, r = -0.775), ARC (r = -0.835), and PRC (r = -0.839) in the KC population (P < .001). In the control corneas, the correlation between the CBI beta and ARC was weak (r = -0.216, P = .022), not significant (PRC, r = -0.146, P = .125), or moderate (TCT, r = -0.628, P < .001). CONCLUSIONS The linear term of the CBI was highly associated with KC severity as defined by corneal tomography. The CBiF represents a new scale based on biomechanical characteristics in KC, which could serve as a basis for a biomechanical KC classification in the future.
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Affiliation(s)
- Elias Flockerzi
- From the Department of Ophthalmology, Saarland University Medical Center, Homburg, Germany (Flockerzi, Seitz); Humanitas San Pio X Hospital, Milan, Italy (Vinciguerra); School of Engineering, University of Liverpool, Liverpool, United Kingdom (Vinciguerra); Department of Ophthalmology & Vision Science, University of Arizona, Tucson, Arizona (Belin); Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, Milan, Italy (Vinciguerra); Humanitas Clinical and Research Center, IRCCS, Rozzano (Mi), Italy (Vinciguerra); Department of Ophthalmology, Federal University of the State of Rio de Janeiro, Rio de Janeiro, Brazil (Ambrósio)
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11
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Santodomingo-Rubido J, Carracedo G, Suzaki A, Villa-Collar C, Vincent SJ, Wolffsohn JS. Keratoconus: An updated review. Cont Lens Anterior Eye 2022; 45:101559. [PMID: 34991971 DOI: 10.1016/j.clae.2021.101559] [Citation(s) in RCA: 159] [Impact Index Per Article: 79.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 11/23/2021] [Accepted: 12/12/2021] [Indexed: 02/06/2023]
Abstract
Keratoconus is a bilateral and asymmetric disease which results in progressive thinning and steeping of the cornea leading to irregular astigmatism and decreased visual acuity. Traditionally, the condition has been described as a noninflammatory disease; however, more recently it has been associated with ocular inflammation. Keratoconus normally develops in the second and third decades of life and progresses until the fourth decade. The condition affects all ethnicities and both sexes. The prevalence and incidence rates of keratoconus have been estimated to be between 0.2 and 4,790 per 100,000 persons and 1.5 and 25 cases per 100,000 persons/year, respectively, with highest rates typically occurring in 20- to 30-year-olds and Middle Eastern and Asian ethnicities. Progressive stromal thinning, rupture of the anterior limiting membrane, and subsequent ectasia of the central/paracentral cornea are the most commonly observed histopathological findings. A family history of keratoconus, eye rubbing, eczema, asthma, and allergy are risk factors for developing keratoconus. Detecting keratoconus in its earliest stages remains a challenge. Corneal topography is the primary diagnostic tool for keratoconus detection. In incipient cases, however, the use of a single parameter to diagnose keratoconus is insufficient, and in addition to corneal topography, corneal pachymetry and higher order aberration data are now commonly used. Keratoconus severity and progression may be classified based on morphological features and disease evolution, ocular signs, and index-based systems. Keratoconus treatment varies depending on disease severity and progression. Mild cases are typically treated with spectacles, moderate cases with contact lenses, while severe cases that cannot be managed with scleral contact lenses may require corneal surgery. Mild to moderate cases of progressive keratoconus may also be treated surgically, most commonly with corneal cross-linking. This article provides an updated review on the definition, epidemiology, histopathology, aetiology and pathogenesis, clinical features, detection, classification, and management and treatment strategies for keratoconus.
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Affiliation(s)
| | - Gonzalo Carracedo
- Department of Optometry and Vision, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Asaki Suzaki
- Clinical Research and Development Center, Menicon Co., Ltd., Nagoya, Japan
| | - Cesar Villa-Collar
- Department of Pharmacy, Biotechnology, Nutrition, Optics and Optometry, Faculty of Biomedical and Health Sciences, Universidad Europea de Madrid, Madrid, Spain
| | - Stephen J Vincent
- Contact Lens and Visual Optics Laboratory, School of Optometry and Vision Science, Centre for Vision and Eye Research, Queensland University of Technology, Brisbane, Australia
| | - James S Wolffsohn
- School of optometry, Health and Life Sciences, Aston University, Birmingham B4 7ET, United Kingdom
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12
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Wang Q, Yu F, Feng Z, Li W, Li N, Du X, Zhao X, Li S, Yuan J. Changes in Anterior and Posterior Corneal Elevation in Patients With Allergic Conjunctivitis. Front Med (Lausanne) 2021; 8:788302. [PMID: 34901095 PMCID: PMC8653911 DOI: 10.3389/fmed.2021.788302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Accepted: 11/03/2021] [Indexed: 01/31/2023] Open
Abstract
Purpose: To evaluate corneal elevation changes in patients with allergic conjunctivitis (AC) and to analyze their correlations with ocular allergy signs and corneal biomechanical alterations. Methods: Thirty patients (30 eyes) with AC and twenty normal subjects (20 eyes) were included in this prospective study. All participants underwent a complete ocular examination, including corneal tomography by Pentacam and corneal biomechanics evaluation by Corvis ST. AC patients were evaluated for their eye rubbing frequency and ocular allergic signs. Results: The elevation at the thinnest location (TE) and the central location (CE), the elevation difference at the thinnest location (TED) and the central location (CED), and the mean value of elevation difference in the central 4 mm zoom (MED) of both the anterior and posterior corneal surface were significantly higher in the AC group than in the normal group (p < 0.05 for all). In AC patients, only anterior corneal elevation parameters were positively correlated with eye rubbing frequency and ocular allergy sign severity (p < 0.05 for all), while the tomography and biomechanical index (TBI) was positively correlated with the elevation parameters of both the anterior and posterior corneal surfaces (p < 0.05 for all). Conclusion: AC patients carry an increased risk of corneal ectasia. Posterior corneal elevation parameters are sensitive and reliable predictors of keratoconus (KC) risk in AC patients. Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT04299399, identifier [NCT04299399].
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Affiliation(s)
- Qian Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Fei Yu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Ziqing Feng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Weihua Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Naiyang Li
- Eye Center, Zhongshan City People's Hospital, Zhongshan, China
| | - Xinyue Du
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Xuan Zhao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Saiqun Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Jin Yuan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
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Shiga S, Kojima T, Nishida T, Nakamura T, Ichikawa K. Evaluation of CorvisST biomechanical parameters and anterior segment optical coherence tomography for diagnosing forme fruste keratoconus. Acta Ophthalmol 2021; 99:644-651. [PMID: 33326180 DOI: 10.1111/aos.14700] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 09/26/2020] [Accepted: 11/10/2020] [Indexed: 11/27/2022]
Abstract
PURPOSE To investigate the utility of biomechanical property measurements using a Scheimpflug-based tonometer (SBT) and/or anterior segment optical coherence tomography (AS-OCT) for diagnosing forme fruste keratoconus (FFK). METHODS In this retrospective interventional case series, 23 eyes with FFK of 23 consecutive patients and 52 eyes of 52 healthy volunteers who visited our keratoconus outpatient clinic were enrolled. Logistic regression analysis was conducted to determine the causal relationship between FFK diagnosis and each parameter. RESULTS When only SBT was used, the corneal stiffness parameter, stiffness parameter A1 (SP-A1) and the corneal velocity at first applanation were selected as explanatory variables, and sensitivity, specificity and area under the receiver operating characteristic curve (AUROC) were 82.9%, 86.9% and 0.938, respectively. When only AS-OCT parameters were used, the posterior corneal asymmetric component and central corneal thickness were selected, and the sensitivity, specificity and AUROC were 82.6%, 94.2% and 0.893, respectively. When parameters from both methods were used, SP-A1 and the posterior corneal asymmetry component derived from Fourier analysis were selected as explanatory variables, and sensitivity, specificity and AUROC were 91.30%, 90.38% and 0.947, respectively. No significant differences in AUROC were observed between diagnoses using each device and the combination of both devices (AS-OCT versus SBT, p = 0.314; integrated parameters versus AS-OCT, p = 0.081; integrated parameters versus SBT, p = 0.234). CONCLUSION Optimization of SBT and AS-OCT parameters allowed for the diagnosis of FFK at a clinically usable level. Forme fruste keratoconus (FFK) diagnosis integrating biomechanical properties with AS-OCT showed no superiority compared to diagnosis based on a single device.
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Affiliation(s)
| | - Takashi Kojima
- Japanese Red Cross Gifu Hospital Gifu Japan
- Department of Ophthalmology Keio University School of Medicine Tokyo Japan
- Nagoya Eye Clinic Nagoya Japan
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Shanthi S, Aruljyothi L, Balasundaram MB, Janakiraman A, Nirmaladevi K, Pyingkodi M. Artificial intelligence applications in different imaging modalities for corneal topography. Surv Ophthalmol 2021; 67:801-816. [PMID: 34450134 DOI: 10.1016/j.survophthal.2021.08.004] [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: 09/29/2020] [Revised: 08/13/2021] [Accepted: 08/16/2021] [Indexed: 12/26/2022]
Abstract
Interpretation of topographical maps used to detect corneal ectasias requires a high level of expertise. Several artificial intelligence (AI) technologies have attempted to interpret topographic maps. The purpose of this study is to provide a review of AI algorithms in corneal topography from the perspectives of an eye care professional, a biomedical engineer, and a data scientist. A systematic literature review using Web of Science, Pubmed, and Google Scholar was performed from 2010 to 2020 on themes regarding imaging modalities, their parameters, purpose, and conclusions and their samples and performance related to AI in corneal topography. We provide a comprehensive summary of advances in corneal imaging and its applications in AI. Combined metrics from the Dual Scheimpflug and Placido device could be a good starting point to try AI models in corneal imaging systems. The range of area under the receiving operating curve for AI in keratoconus detection and classification was from 0.87 to 1, sensitivity was from 0.89 to 1, and specificity was from 0.82 to 1. A combination of different types of AI applications to corneal ectasia diagnosis is recommended.
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Affiliation(s)
- S Shanthi
- Kongu Engineering College, Erode, Tamil Nadu, India.
| | | | | | | | | | - M Pyingkodi
- Kongu Engineering College, Erode, Tamil Nadu, India
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Differentiating highly asymmetric keratoconus eyes using a combined Scheimpflug/Placido device. J Cataract Refract Surg 2021; 46:1588-1595. [PMID: 32818347 DOI: 10.1097/j.jcrs.0000000000000358] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
PURPOSE To determine the ability to differentiate between normal eyes and clinically unaffected eyes of patients with highly asymmetric keratoconus (AKC) using a Scheimpflug/Placido device. SETTING Tel Aviv Sourasky Medical Center and Enaim Medical Center, Israel. DESIGN Retrospective case-control. METHODS Imaging from a combined Scheimpflug/Placido device (Sirius, C.S.O.) was obtained from 26 clinically unaffected eyes of patients with frank keratoconus in the fellow eye, and 166 eyes from 166 patients with bilaterally normal corneal examinations that underwent uneventful corneal refractive surgery with at least 1 year of follow-up. Receiver operating characteristic curves were produced to calculate the area under the curve, sensitivity, and specificity of 60 metrics, and finally a logistic regression modeling was used to determine optimal variables to differentiate populations. RESULTS The most predictive individual metric able to differentiate between 26 eyes in the case group to 166 eye in the control group was the posterior wall inferior-superior (I-S) ratio, with an receiver operating characteristics (ROC) of 0.862. A combination model of 4 metrics (posterior wall I-S ratio in the central 3 mm, thinnest pachymetry coordinate on the x horizontal axis, posterior asymmetry and asphericity index, corneal volume) yielded an ROC of 0.936, with a sensitivity/specificity pair of 92.3%/87%. Variables related to elevation were not found significant. CONCLUSIONS Using a combination of metrics from a combined Scheimpflug/Placido device, a practical model for discrimination between clinically normal eyes of patients with highly AKC and normal eyes was constructed. Variables related to pachymetry and posterior cornea asymmetry were the most impactful.
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Röck T, Konrad EM, Röck D, Bramkamp M, Blumenstock G, Bartz-Schmidt KU. Successful Regression in Patients with Progressive Keratoconus by Corneal Crosslinking. Klin Monbl Augenheilkd 2021; 238:1229-1235. [PMID: 33607693 DOI: 10.1055/a-1264-7928] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
BACKGROUND Since 2019, corneal collagen crosslinking (CXL) is included in the catalog of procedures covered by statutory health insurance in Germany. CXL is an established ophthalmological procedure for the last 20 years. The aim of this investigation was the measurement of progression before and after CXL. MATERIAL UND METHODS 65 consecutive eyes with progressive keratoconus from 53 patients were included in the retrospective study, which were observed at the University Eye Hospital Tübingen at least two years before and at least two years after CXL. The time of observation took place from October 2009 until March 2018. Parameters of interest had been the best corrected visual acuity (BCVA) and the keratometric values from the elevation maps measured by a Scheimpflug camera. RESULTS 65 eyes of 53 patients had been documented. The study population included 46 (86.8%) male and 7 (13.2%) female subjects. The mean age was 24 ± 8 years. The averaged observation time between the primary consultation and CXL showed 25 ± 15 months. Preoperatively the mean BCVA pointed out in a significant increase (0.13 ± 0.17 [first visit] vs. 0.23 ± 0.22 [preOP], p < 0.0001) while the mean Kmax resulted in a statistically significant increase (46.34 ± 3.33 dpt [first visit] vs. 48.78 ± 4.17 dpt [preOP], p < 0.0001). The mean thinnest point of the cornea showed a significant decrease (490.48 ± 34.23 µm [first visit] vs. 468.62 ± 29.84 µm [preop], p < 0.0001). Postoperatively the mean BCVA resulted in a significant improvement at the 12th postoperative month in comparison to the preoperative measurement (0.23 ± 0.22 [preOP] vs. 0.16 ± 0.14 [12 months], p = 0.04 respectively 0.17 ± 0.17 [24 months], p = 0.0006). The mean Kmax demonstrated in the 12th postoperative month a significant reduction (48.78 ± 4.17 dpt [preOP] vs. 47.91 ± 3.41 dpt [12 months], p = 0.0009 respectively 48 ± 4.56 dpt [24 months], p = 0.0051). The mean thinnest point of the cornea indicated a decrease at the 12th postoperative month (468.62 ± 29.84 µm [preOP] vs. 459.82 ± 35.88 µm [12 months], p = 0.0078 respectively 453.47 ± 43.39 µm [24 months], p = 0.0227). CONCLUSION CXL is a successful procedure for the therapy of progressive keratoconus.
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Affiliation(s)
- Tobias Röck
- Department für Augenheilkunde, Universitäts-Augenklinik, Eberhard-Karls-Universität Tübingen, Deutschland
| | - Eva-Maria Konrad
- Department für Augenheilkunde, Universitäts-Augenklinik, Eberhard-Karls-Universität Tübingen, Deutschland
| | - Daniel Röck
- Department für Augenheilkunde, Universitäts-Augenklinik, Eberhard-Karls-Universität Tübingen, Deutschland
| | - Matthias Bramkamp
- Abteilung für Allgemeinmedizin, Ruhr-Universität Bochum, Deutschland
| | - Gunnar Blumenstock
- Institut für Medizinische Biometrie, Eberhard-Karls-Universität Tübingen, Deutschland
| | - Karl Ulrich Bartz-Schmidt
- Department für Augenheilkunde, Universitäts-Augenklinik, Eberhard-Karls-Universität Tübingen, Deutschland
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Wang Q, Yu F, Feng Z, Li W, Li N, Du X, Zhao X, Li S, Yuan J. Changes in Anterior and Posterior Corneal Elevation in Patients With Allergic Conjunctivitis. Front Med (Lausanne) 2021; 8:788302. [PMID: 34901095 DOI: 10.3389/fmed.2021b.788302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Accepted: 11/03/2021] [Indexed: 05/22/2023] Open
Abstract
Purpose: To evaluate corneal elevation changes in patients with allergic conjunctivitis (AC) and to analyze their correlations with ocular allergy signs and corneal biomechanical alterations. Methods: Thirty patients (30 eyes) with AC and twenty normal subjects (20 eyes) were included in this prospective study. All participants underwent a complete ocular examination, including corneal tomography by Pentacam and corneal biomechanics evaluation by Corvis ST. AC patients were evaluated for their eye rubbing frequency and ocular allergic signs. Results: The elevation at the thinnest location (TE) and the central location (CE), the elevation difference at the thinnest location (TED) and the central location (CED), and the mean value of elevation difference in the central 4 mm zoom (MED) of both the anterior and posterior corneal surface were significantly higher in the AC group than in the normal group (p < 0.05 for all). In AC patients, only anterior corneal elevation parameters were positively correlated with eye rubbing frequency and ocular allergy sign severity (p < 0.05 for all), while the tomography and biomechanical index (TBI) was positively correlated with the elevation parameters of both the anterior and posterior corneal surfaces (p < 0.05 for all). Conclusion: AC patients carry an increased risk of corneal ectasia. Posterior corneal elevation parameters are sensitive and reliable predictors of keratoconus (KC) risk in AC patients. Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT04299399, identifier [NCT04299399].
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Affiliation(s)
- Qian Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Fei Yu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Ziqing Feng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Weihua Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Naiyang Li
- Eye Center, Zhongshan City People's Hospital, Zhongshan, China
| | - Xinyue Du
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Xuan Zhao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Saiqun Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Jin Yuan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
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Accuracy of the posterior corneal elevation values of Pentacam HR from different reference surfaces in early ectasia diagnosis. Int Ophthalmol 2020; 41:629-638. [PMID: 33095345 DOI: 10.1007/s10792-020-01618-8] [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] [Received: 03/19/2020] [Accepted: 10/05/2020] [Indexed: 10/23/2022]
Abstract
PURPOSE Detecting the accuracy of various posterior elevation (PE) indices of Pentacam HR, and correlating them with some possibly related factors or parameters, in a cohort with early keratoconus (KC). METHODS A cross sectional study that was conducted at Eye World Hospital, Egypt. One hundred and two corneas were enrolled, including two groups; group 1 (50 corneas) having forme fruste or early KC, and group 2 (52 corneas) for healthy controls. Corneas were scanned using Pentacam HR (Oculus, Wetzlar, Germany). The investigated PE parameters were: PE from best fit sphere (BFS), PE from best fit toric ellipsoid (BFTE), PE from exclusion map of Belin Ambrosio's display (BAD), and PE from difference map of BAD. The four PE values were correlated to age, thinnest corneal thickness "TCT," posterior aberrations, and posterior Q value. RESULTS All the investigated indices were significantly different in group 1 compared to group 2 (p < 0.001). Accuracy of PE parameters revealed the highest AUROC for PE from BFTE (AUROC = 0.989, and best cutoff > 4 um with sensitivity 96.00% and specificity 96.15%). PE from difference map was the least accurate. Correlation coefficients showed a significant correlation between all the studied PE parameters and some of the posterior aberrations (root mean square of higher order aberrations, vertical coma, and spherical aberrations), besides a significant correlation with posterior Q value. CONCLUSION PE indices are sensitive detectors of early ectasia. PE from BFTE had the highest deduced AUROC. Alterations in PE values can significantly alter many posterior corneal aberrations and the posterior Q.
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Hao XD, Chen XN, Zhang YY, Chen P, Wei C, Shi WY, Gao H. Multi-level consistent changes of the ECM pathway identified in a typical keratoconus twin's family by multi-omics analysis. Orphanet J Rare Dis 2020; 15:227. [PMID: 32867823 PMCID: PMC7457807 DOI: 10.1186/s13023-020-01512-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 08/13/2020] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Keratoconus (KC) is a common, degenerative disorder of the cornea, and genetic factors play a key role in its development. However, the genetic etiology of KC is still unclear. This study used the family of twins as material, using, for the first time, multi-omics analysis, to systematically display the changes in KC candidate factors in patients at the DNA, RNA, and protein levels. These can evaluate candidate pathogenic factors in depth and lock onto pathogenic targets. RESULTS The twins in this study presented classic phenotypes, clear diagnoses, complete case data, and clinical samples, which are excellent materials for genetically studying KC. Whole-exome sequencing was conducted on both the twins and their parents. Transcriptome sequencing was conducted on proband's and health individual's primary human corneal fibroblast cells. Quantitative Real-time PCR and western blot were used to validate the differential gene expressions between the proband and controls. By integrating genomics, transcriptome, and protein level data, multiple consecutive events of KC were systematically analyzed to help better understand the molecular mechanism and genetic basis of KC. The results showed that the accumulation of rare, micro-effect risk variants was the pathogenic factor in this Chinese KC family. Consistent changes in extracellular matrices (ECMs) at the DNA and RNA levels suggested that ECM related changes play a key role in KC pathogenesis. The major gene variants (WNT16, CD248, COL6A2, COL4A3 and ADAMTS3) may affect the expression of related collagens or ECM proteins, thus reducing the amount of ECM in corneas and resulting in KC. CONCLUSIONS This study, the first to explore the genetic etiology of KC via multi-omics analysis under the polygenetic model, has provided new insights into the genetic mechanisms underlying KC and an effective strategy for studying KC pathogenesis in the future.
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Affiliation(s)
- Xiao-Dan Hao
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, 266021, China.,State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Qingdao, 266071, China
| | - Xiu-Nian Chen
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, 266021, China.,State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Qingdao, 266071, China
| | - Yang-Yang Zhang
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Qingdao, 266071, China
| | - Peng Chen
- Department of Human Anatomy, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Chao Wei
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Qingdao, 266071, China
| | - Wei-Yun Shi
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Qingdao, 266071, China.,Shandong Eye Hospital, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, 250021, China
| | - Hua Gao
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Qingdao, 266071, China. .,Shandong Eye Hospital, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, 250021, China.
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Assessment of Corneal Pachymetry Distribution and Morphologic Changes in Subclinical Keratoconus with Normal Biomechanics. BIOMED RESEARCH INTERNATIONAL 2019; 2019:1748579. [PMID: 31828090 PMCID: PMC6885829 DOI: 10.1155/2019/1748579] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 10/24/2019] [Accepted: 11/01/2019] [Indexed: 12/23/2022]
Abstract
Purpose To investigate the pachymetry distribution of central cornea and morphologic changes in subclinical keratoconus with normal biomechanics and determine their potential benefit for the screening of very early keratoconus. Methods This retrospective comparative study was performed in 33 clinically unaffected eyes with normal topography and biomechanics from 33 keratoconus patients with very asymmetric ectasia (VAE-NTB; Corvis Biomechanical Index defined) and 70 truly normal eyes from 70 age-matched subjects. Corneal topographic, tomographic, and biomechanical metrics were measured using Pentacam and Corvis ST. The distance and pachymetry difference between the corneal thinnest point and the apex were defined as DTCP-Apex and DPTCP-Apex, respectively, to evaluate the pachymetry distribution within the central cornea. The discriminatory power of metrics was analysed via the receiver operating characteristic curve. A logistic regression analysis was used to establish predictive models. Results The parameters, DTCP-Apex and DPTCP-Apex, were significantly higher in VAE-NTB than those in normal eyes. For differentiating normal and VAE-NTB eyes, the Belin-Ambrósio deviation (BAD-D) showed the largest area under the curve (AUC; 0.799), followed by ARTmax (0.798), DTCP-Apex (0.771), tomography and biomechanical index (0.760), maximum pachymetry progression index (PPImax, 0.756), DPTCP-Apex (0.753), and back eccentricity (B_Ecc, 0.707) with no statistically significant differences among these AUCs. In the VAE-NTB group, the parameter B_Ecc was significantly and positively correlated with DTCP-Apex (P=0.011) and DPTCP-Apex (P=0.035), whereas the posterior elevation difference had a significant positive association with DPTCP-Apex (P=0.042). A model using the indices DTCP-Apex, B_Ecc, PPImax, and index of height asymmetry demonstrated the highest AUC of 0.846 with 91.43% specificity. Conclusions Abnormal pachymetry distribution within the central cornea and subtle morphologic changes are detectable in subclinical keratoconus with normal biomechanics. This may improve VAE-NTB eyes detection.
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22
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Golan O, Piccinini AL, Hwang ES, De Oca Gonzalez IM, Krauthammer M, Khandelwal SS, Smadja D, Randleman JB. Distinguishing Highly Asymmetric Keratoconus Eyes Using Dual Scheimpflug/Placido Analysis. Am J Ophthalmol 2019; 201:46-53. [PMID: 30721688 DOI: 10.1016/j.ajo.2019.01.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 12/07/2018] [Accepted: 01/22/2019] [Indexed: 12/27/2022]
Abstract
PURPOSE To identify the best metrics or combination of metrics that provide the highest predictive power between normal eyes and the clinically unaffected eye of patients with highly asymmetric keratoconus using data from a Dual Scheimpflug/Placido device. DESIGN Retrospective case-control study. METHODS Combined Dual Scheimpflug/Placido imaging was obtained from the Galilei G4 device (Ziemer Ophthalmic Systems AG, Port, Switzerland) in 31 clinically unaffected eyes with highly asymmetric keratoconus and 178 eyes from 178 patients with bilaterally normal corneal examinations that underwent uneventful LASIK with at least 1 year follow-up. Receiver operating characteristic (ROC) curves were generated to determine area under the curve (AUC), sensitivity, and specificity for 87 metrics, and logistic regression modeling was used to determine optimal variable combinations. RESULTS No individual metric achieved an AUC greater than 0.79. A combined model consisting of 9 metrics yielded an AUC of 0.96, with 90.3% sensitivity and 92.6% specificity. Among those 9 metrics included, 5 related to corneal pachymetry: Opposite Sector Index and Anterior Height BFS Z from the anterior surface, Asphericity and Asymmetry Index, Posterior Height BFS Z, and Posterior Height BFS X from the posterior surface. The strongest variable in the model was the thinnest point location on the horizontal (x) axis. CONCLUSION While individual metrics performed poorly, using a combination of metrics from the combined Dual Scheimpflug/Placido device provided a useful model for differentiating normal corneas from the clinically normal eyes of patients with highly asymmetric keratoconus. Pachymetry values were the most impactful metrics.
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Affiliation(s)
- Oren Golan
- Keck School of Medicine of the University of Southern California, Los Angeles, California, USA; Tel Aviv Souraski Medical Center, Tel Aviv University, Tel Aviv, Israel
| | - Andre L Piccinini
- Keck School of Medicine of the University of Southern California, Los Angeles, California, USA; Sadalla Amin Ghanem Eye Hospital, Joinville, Santa Catarina, Brazil
| | - Eric S Hwang
- Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
| | | | - Mark Krauthammer
- Tel Aviv Souraski Medical Center, Tel Aviv University, Tel Aviv, Israel
| | | | - David Smadja
- Department of Ophthalmology, Shaare Zedek Medical Center, Jerusalem, Israel
| | - J Bradley Randleman
- Keck School of Medicine of the University of Southern California, Los Angeles, California, USA; USC Roski Eye Institute, Los Angeles, California, USA.
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