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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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de Andrade Ramos L, Seullner Brandão CV, Arce CG, Micheline L, Gordon Gandolfi M, Padovani C. Simulated keratometry and central corneal thickness measured in cats by autokeratometer, ultrasonic pachymeter, and Galilei G6™. Vet Ophthalmol 2022; 26:128-134. [PMID: 36383444 DOI: 10.1111/vop.13039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 11/01/2022] [Accepted: 11/02/2022] [Indexed: 11/17/2022]
Abstract
OBJECTIVE The aims of this study were to compare the central corneal thickness (CCT) measured by an ultrasonic pachymeter (SP-100, Tomey, Japão) versus the Galilei G6™ (Ziemer Ophthalmics System AG, Port, Switzerland) and to compare the simulated keratometry (SimK) measured by an autokeratometer (KM 500 Nidek) versus the Galilei G6™. ANIMAL STUDIED Eighteen mixed-breed cats, 10 males, and eight females, aged between 18 and 48 months, were evaluated (n = 36 eyes). PROCEDURE(S) The cats were manually restrained using a blanket. The operator held the autokeratometer close to the eye and measured the SimK. Next, one anesthetic eye drop was applied; the operator lightly touched the corneal using the ultrasound pachymeter and measured the CCT. At another moment, the cats were sedated using meperidine and xylazine and then evaluated using the Galilei. Student's t-test was employed to perform the statistical analyzes. RESULTS Considering the CCT, the ultrasound pachymeter provided mean ± SD of 623.03 ± 48.17 μm and the Galilei 617.34 ± 53.38 μm. The autokeratometer produced a SimK of 38.20 ± 0.84D (8.84 ± 0.20 mm) and the Galilei 38.37 ± 0.83D (8.80 ± 0.19 mm). The CCT and SimK did not differ statistically regardless of the device used. CONCLUSION To the best of the authors' knowledge, this is the first work to compare the CCT measured by the Galilei versus the ultrasonic pachymeter and to compare the SimK measured by the Galilei versus the keratometer in cats. No statistical difference was found considering the CCT and the SimK measured by the different devices.
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Affiliation(s)
- Leticia de Andrade Ramos
- Department of Veterinary Surgery and Animal Reproduction, School of Veterinary Medicine and Animal Science São Paulo State University ‐ UNESP São Paulo Brazil
| | - Cláudia Valéria Seullner Brandão
- Department of Veterinary Surgery and Animal Reproduction, School of Veterinary Medicine and Animal Science São Paulo State University ‐ UNESP São Paulo Brazil
| | - Carlos Guillermo Arce
- Contact Lens, Cornea, Refractive Surgery, Research & Technology Sectors Ophthalmologic Hospital and Eye Bank of Sorocaba São Paulo Brazil
| | - Laura Micheline
- Department of Veterinary Surgery and Animal Reproduction, School of Veterinary Medicine and Animal Science São Paulo State University ‐ UNESP São Paulo Brazil
| | - Micaella Gordon Gandolfi
- Department of Veterinary Surgery and Animal Reproduction, School of Veterinary Medicine and Animal Science São Paulo State University ‐ UNESP São Paulo Brazil
| | - Carlos Roberto Padovani
- Department of Biostatistics, Bioscience Institute São Paulo State University ‐ UNESP São Paulo Brazil
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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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Avetisov SE, Gridin VN, Bubnova IA, Lebedev AS, Novikov IA. [Prospects for early detection of keratoconus based on systems built for computer-assisted diagnostics of structural changes in the cornea]. Vestn Oftalmol 2022; 138:100-106. [PMID: 35234428 DOI: 10.17116/oftalma2022138011100] [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: 11/17/2022]
Abstract
The article is devoted to the problem of diagnosing subclinical keratoconus (KK). The need to identify early signs of KK is primarily associated with the potential for the development of iatrogenic keratoectasia in cases of underdiagnosis of the disease when determining the conditions for laser keratorefractive surgery involving a decrease in the thickness of the cornea. Today generally accepted algorithms for early computer-assisted diagnosis of KK are mainly based on the analysis of various morphometric parameters of the cornea, reflecting changes in its shape and thickness induced by structural abnormalities. Direct detection of structural changes in the cornea characteristic of early KK requires the use of high-tech imaging methods that are not always applicable in everyday clinical practice. The promising approach proposed in this study is based on the fact that a digital image of a corneal «slice» obtained using serial analyzers such as the Scheimpflug camera widely used in clinical practice provides indirect information about the structure of the epithelial layer, the local thickening of which takes place in the initial stages KK. It is this criterion that underlies the proposed system of computer-assisted diagnosis of KK. The carried out studies have shown the high sensitivity of this algorithm, and its specificity can be increased by involving the known diagnostic indicators of KK.
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Affiliation(s)
- S E Avetisov
- Research Institute of Eye Diseases, Moscow, Russia.,I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
| | - V N Gridin
- Center of Information Technologies in Design Russian Academy of Sciences, Odintsovo, Russia
| | - I A Bubnova
- Research Institute of Eye Diseases, Moscow, Russia.,Center of Information Technologies in Design Russian Academy of Sciences, Odintsovo, Russia
| | - A S Lebedev
- Center of Information Technologies in Design Russian Academy of Sciences, Odintsovo, Russia
| | - I A Novikov
- Research Institute of Eye Diseases, Moscow, Russia.,Center of Information Technologies in Design Russian Academy of Sciences, Odintsovo, Russia
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Pérez-Rueda A, Jiménez-Rodríguez D, Castro-Luna G. Diagnosis of Subclinical Keratoconus with a Combined Model of Biomechanical and Topographic Parameters. J Clin Med 2021; 10:2746. [PMID: 34206580 PMCID: PMC8269366 DOI: 10.3390/jcm10132746] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 06/14/2021] [Accepted: 06/17/2021] [Indexed: 01/01/2023] Open
Abstract
This study sought to develop a diagnostic model with aberrometry and biomechanical variables for subclinical keratoconus. The design was a cross-sectional study. The topographic data were obtained with a rotating Scheimpflug camera (Pentacam HR), and biomechanical data were obtained with Corvis ST. The study included 81 eyes distributed in 61 healthy corneas and 20 subclinical keratoconus (SCKC), defined as eyes with suspicious topographic findings, normal slit-lamp examination, and a manifestation of keratoconus. Analyses of the topographic and biomechanical data were performed, and a classifying model of SCKC was elaborated. The model for the diagnosis of SCKC includes posterior coma to 90°, Ambrósio's Relational Thickness in the horizontal profile (ARTh), and velocity when the air pulse is off (A2 velocity). The sensitivity was 89.5%, specificity 96.7%, accuracy 94.9%, and precision 89.5%. The area under the curve (AUC) of the receiver operating characteristic (ROC) curve for the model was 0.951. Diagnosis of subclinical keratoconus depends on the aberrometry variable posterior coma to 90° and the biomechanical variables A2 velocity and ARTh.
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Affiliation(s)
- Antonio Pérez-Rueda
- Department of Ophthalmology, Torrecárdenas University Hospital, 04009 Almería, Spain;
| | - Diana Jiménez-Rodríguez
- Department of Nursing, Physiotherapy and Medicine, University of Almería, 04120 Almería, Spain;
| | - Gracia Castro-Luna
- Department of Nursing, Physiotherapy and Medicine, University of Almería, 04120 Almería, Spain;
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Peris-Martínez C, Díez-Ajenjo MA, García-Domene MC, Pinazo-Durán MD, Luque-Cobija MJ, del Buey-Sayas MÁ, Ortí-Navarro S. Evaluation of Intraocular Pressure and Other Biomechanical Parameters to Distinguish between Subclinical Keratoconus and Healthy Corneas. J Clin Med 2021; 10:1905. [PMID: 33924937 PMCID: PMC8125335 DOI: 10.3390/jcm10091905] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 04/17/2021] [Accepted: 04/25/2021] [Indexed: 12/13/2022] Open
Abstract
(1) Purpose: To assess the main corneal response differences between normal and subclinical keratoconus (SCKC) with a Corvis® ST device. (2) Material and Methods: We selected 183 eyes of normal patients, of a mean age of 33 ± 9 years and 16 eyes of patients with SCKC of a similar mean age. We measured best corrected visual acuity (BCVA) and corneal topography with a Pentacam HD device to select the SCKC group. Biomechanical measurements were performed using the Corvis® ST device. We carried out a non-parametric analysis of the data with SPSS software (Wilcoxon signed rank-test). (3) Results: We found statistically significant differences between the control and SCKC groups in some corneal biomechanical parameters: first and second applanation time (p = 0.05 and p = 0.02), maximum deformation amplitude (p = 0.016), highest concavity radius (p = 0.007), and second applanation length and corneal velocity ((p = 0.039 and p = 0.016). (4) Conclusions: Our results show that the use of normalised biomechanical parameters provided by noncontact tonometry, combined with a discriminant function theory, is a useful tool for detecting subclinical keratoconus.
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Affiliation(s)
- Cristina Peris-Martínez
- FISABIO Oftalmología Médica (FOM), Anterior Segment and Cornea and External Eye Diseases Unit, Bifurcación Pío Baroja-General Avilés, 12, E-46015 Valencia, Spain; (C.P.-M.); (M.A.D.-A.); (M.C.G.-D.); (M.J.L.-C.)
- Surgery Department, Ophthalmology, School of Medicine, University of Valencia, Av. Blasco Ibáñez, 15, E-46010 Valencia, Spain;
- Aviño Peris Eye Clinic, Avinguda de l’Oest, 34, E-46001 Valencia, Spain
| | - María Amparo Díez-Ajenjo
- FISABIO Oftalmología Médica (FOM), Anterior Segment and Cornea and External Eye Diseases Unit, Bifurcación Pío Baroja-General Avilés, 12, E-46015 Valencia, Spain; (C.P.-M.); (M.A.D.-A.); (M.C.G.-D.); (M.J.L.-C.)
- Optics, Optometry and Vision Sciences Department, School of Physics, University of Valencia, Dr. Moliner, 50, E-46100 Valencia, Spain
| | - María Carmen García-Domene
- FISABIO Oftalmología Médica (FOM), Anterior Segment and Cornea and External Eye Diseases Unit, Bifurcación Pío Baroja-General Avilés, 12, E-46015 Valencia, Spain; (C.P.-M.); (M.A.D.-A.); (M.C.G.-D.); (M.J.L.-C.)
- Optics, Optometry and Vision Sciences Department, School of Physics, University of Valencia, Dr. Moliner, 50, E-46100 Valencia, Spain
| | - María Dolores Pinazo-Durán
- Surgery Department, Ophthalmology, School of Medicine, University of Valencia, Av. Blasco Ibáñez, 15, E-46010 Valencia, Spain;
| | - María José Luque-Cobija
- FISABIO Oftalmología Médica (FOM), Anterior Segment and Cornea and External Eye Diseases Unit, Bifurcación Pío Baroja-General Avilés, 12, E-46015 Valencia, Spain; (C.P.-M.); (M.A.D.-A.); (M.C.G.-D.); (M.J.L.-C.)
- Optics, Optometry and Vision Sciences Department, School of Physics, University of Valencia, Dr. Moliner, 50, E-46100 Valencia, Spain
| | | | - Susana Ortí-Navarro
- Optics, Optometry and Vision Sciences Department, School of Physics, University of Valencia, Dr. Moliner, 50, E-46100 Valencia, Spain
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Coelho RP, Messias A. Phacoemulsification with big-bubble deep anterior lamellar keratoplasty: Variant of the triple procedure. J Cataract Refract Surg 2019; 45:1064-1066. [DOI: 10.1016/j.jcrs.2019.04.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 04/01/2019] [Accepted: 04/02/2019] [Indexed: 10/26/2022]
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Valdez-García JE, Hernandez-Camarena JC, Lozano-Ramírez JF, Zavala J, Loya-García D, Merayo-Lloves J. Correlation of age, corneal curvature and spherical equivalent with central corneal thickness. REVISTA MEXICANA DE OFTALMOLOGÍA 2017. [DOI: 10.1016/j.mexoft.2016.05.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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Swierkowska J, Gajecka M. Genetic factors influencing the reduction of central corneal thickness in disorders affecting the eye. Ophthalmic Genet 2017; 38:501-510. [DOI: 10.1080/13816810.2017.1313993] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
| | - Marzena Gajecka
- Institute of Human Genetics, Polish Academy of Sciences, Poznan, Poland
- Department of Genetics and Pharmaceutical Microbiology, Poznan University of Medical Sciences, Poznan, Poland
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Kovács I, Miháltz K, Kránitz K, Juhász É, Takács Á, Dienes L, Gergely R, Nagy ZZ. Accuracy of machine learning classifiers using bilateral data from a Scheimpflug camera for identifying eyes with preclinical signs of keratoconus. J Cataract Refract Surg 2016; 42:275-83. [PMID: 27026453 DOI: 10.1016/j.jcrs.2015.09.020] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 09/19/2015] [Accepted: 09/30/2015] [Indexed: 12/20/2022]
Abstract
PURPOSE To describe the topographic and tomographic characteristics of normal fellow eyes of unilateral keratoconus cases and to evaluate the accuracy of machine learning classifiers in discriminating healthy corneas from the normal fellow corneas. SETTING Department of Ophthalmology, Semmelweis University, Budapest, Hungary. DESIGN Retrospective case-control study. METHODS Patients with bilateral keratoconus (keratoconus group), clinically and according to the keratoconus indices of the Pentacam HR Scheimpflug camera; normal fellow eyes of patients with unilateral keratoconus (fellow-eye group); and eyes of refractive surgery candidates (control group) were compared. Tomographic data, topographic data, and keratoconus indices were measured in both eyes using the Scheimpflug camera. Receiver operating characteristic (ROC) analysis was used to assess the performance of automated classifiers trained on bilateral data as well as individual parameters to discriminate fellow eyes of patients with keratoconus from control eyes. RESULTS Keratometry, elevation, and keratoconus indices values were significantly higher and pachymetry values were significantly lower in keratoconus eyes than in fellow eyes of unilateral keratoconus cases (P < .001). These fellow eyes had significantly higher keratometry, elevation, and keratoconus index values and significantly lower pachymetry values than control eyes (P < .001). Automated classifiers trained on bilateral data of index of height decentration had higher accuracy than the unilateral single parameter in discriminating fellow eyes of patients with keratoconus from control eyes (area under ROC 0.96 versus 0.88). CONCLUSION Automatic classifiers trained on bilateral data were better than single parameters in discriminating fellow eyes of patients with unilateral keratoconus with preclinical signs of keratoconus from normal eyes. FINANCIAL DISCLOSURE No author has a financial or proprietary interest in any material or method mentioned.
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Affiliation(s)
- Illés Kovács
- From the Department of Ophthalmology (Kovács, Kránitz, Juhász, Takács, Dienes, Gergely, Nagy), Semmelweis University, Budapest, Hungary; the Karl Landsteiner Institute of Process Optimization and QM in Cataract Surgery (Mihált), Vienna, Austria.
| | - Kata Miháltz
- From the Department of Ophthalmology (Kovács, Kránitz, Juhász, Takács, Dienes, Gergely, Nagy), Semmelweis University, Budapest, Hungary; the Karl Landsteiner Institute of Process Optimization and QM in Cataract Surgery (Mihált), Vienna, Austria
| | - Kinga Kránitz
- From the Department of Ophthalmology (Kovács, Kránitz, Juhász, Takács, Dienes, Gergely, Nagy), Semmelweis University, Budapest, Hungary; the Karl Landsteiner Institute of Process Optimization and QM in Cataract Surgery (Mihált), Vienna, Austria
| | - Éva Juhász
- From the Department of Ophthalmology (Kovács, Kránitz, Juhász, Takács, Dienes, Gergely, Nagy), Semmelweis University, Budapest, Hungary; the Karl Landsteiner Institute of Process Optimization and QM in Cataract Surgery (Mihált), Vienna, Austria
| | - Ágnes Takács
- From the Department of Ophthalmology (Kovács, Kránitz, Juhász, Takács, Dienes, Gergely, Nagy), Semmelweis University, Budapest, Hungary; the Karl Landsteiner Institute of Process Optimization and QM in Cataract Surgery (Mihált), Vienna, Austria
| | - Lóránt Dienes
- From the Department of Ophthalmology (Kovács, Kránitz, Juhász, Takács, Dienes, Gergely, Nagy), Semmelweis University, Budapest, Hungary; the Karl Landsteiner Institute of Process Optimization and QM in Cataract Surgery (Mihált), Vienna, Austria
| | - Róbert Gergely
- From the Department of Ophthalmology (Kovács, Kránitz, Juhász, Takács, Dienes, Gergely, Nagy), Semmelweis University, Budapest, Hungary; the Karl Landsteiner Institute of Process Optimization and QM in Cataract Surgery (Mihált), Vienna, Austria
| | - Zoltán Z Nagy
- From the Department of Ophthalmology (Kovács, Kránitz, Juhász, Takács, Dienes, Gergely, Nagy), Semmelweis University, Budapest, Hungary; the Karl Landsteiner Institute of Process Optimization and QM in Cataract Surgery (Mihált), Vienna, Austria
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Lago MA, Rupérez MJ, Monserrat C, Martínez-Martínez F, Martínez-Sanchis S, Larra E, Díez-Ajenjo MA, Peris-Martínez C. Patient-specific simulation of the intrastromal ring segment implantation in corneas with keratoconus. J Mech Behav Biomed Mater 2015; 51:260-8. [PMID: 26275488 DOI: 10.1016/j.jmbbm.2015.07.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 07/14/2015] [Accepted: 07/22/2015] [Indexed: 10/23/2022]
Abstract
PURPOSE The purpose of this study was the simulation of the implantation of intrastromal corneal-ring segments for patients with keratoconus. The aim of the study was the prediction of the corneal curvature recovery after this intervention. METHODS Seven patients with keratoconus diagnosed and treated by implantation of intrastromal corneal-ring segments were enrolled in the study. The 3D geometry of the cornea of each patient was obtained from its specific topography and a hyperelastic model was assumed to characterize its mechanical behavior. To simulate the intervention, the intrastromal corneal-ring segments were modeled and placed at the same location at which they were placed in the surgery. The finite element method was then used to obtain a simulation of the deformation of the cornea after the ring segment insertion. Finally, the predicted curvature was compared with the real curvature after the intervention. RESULTS The simulation of the ring segment insertion was validated comparing the curvature change with the data after the surgery. Results showed a flattening of the cornea which was in consonance with the real improvement of the corneal curvature. The mean difference obtained was of 0.74 mm using properties of healthy corneas. CONCLUSIONS For the first time, a patient-specific model of the cornea has been used to predict the outcomes of the surgery after the intrastromal corneal-ring segments implantation in real patients.
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Affiliation(s)
- M A Lago
- Departamento de Sistemas Informáticos y Computación, Universitat Politècnica de València, Camino de Vera s/n, 46022 València, Spain
| | - M J Rupérez
- Departamento de Ingeniería Mecánica y Construcción, Universitat Jaume I, Av. de Vicent Sos Baynat, s/n, 12071 Castelló de la Plana, Spain.
| | - C Monserrat
- Departamento de Sistemas Informáticos y Computación, Universitat Politècnica de València, Camino de Vera s/n, 46022 València, Spain
| | - F Martínez-Martínez
- Center for Machine Perception, Departament of Cybernetics, Czech Technical University in Prague, Karlovo namesti 13, Prague, Czech Republic
| | - S Martínez-Sanchis
- Departamento de Sistemas Informáticos y Computación, Universitat Politècnica de València, Camino de Vera s/n, 46022 València, Spain
| | - E Larra
- AJL Ophtalmics, Ferdinand Zeppelin Kalea, Vitoria-Gasteiz 01510, Miñano, Araba, Spain
| | - M A Díez-Ajenjo
- Clínica Optométrica Fundació Lluís Alcanyís, Universitat de València, C/ Guardia Civil, 22 Cantonera amb C/ Vicente Barrera, 46020 València, Spain
| | - C Peris-Martínez
- Fisabio Oftalmológica Médica, Bifurcación Pío Baroja-general Aviles, S/N, 46015 València, Spain
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Dependability of posterior-segment spectral domain optical coherence tomography for measuring central corneal thickness. Cornea 2015; 33:1219-24. [PMID: 25211358 DOI: 10.1097/ico.0000000000000253] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE The aim of this study was to assess the intersession and interobserver reliability of central corneal thickness (CCT) measurements using a posterior-segment spectral domain optical coherence tomography (SD-OCT). METHODS Sixty patients were examined with a posterior-segment SD-OCT system (Topcon 3D-OCT). To analyze intersession reproducibility, 1 examiner measured CCT in 60 eyes 2 times 1 week apart, and to study interobserver reproducibility, a second examiner obtained another measurement during the first session. Within-subject reproducibility, coefficient of reproducibility (CR), and intraclass correlation coefficients (ICC) were calculated. Agreement between Topcon 3D OCT and ultrasound pachymetry (USP) was also assessed. RESULTS Posterior-segment SD-OCT showed an intersession reproducibility of 12.7 μm (CR = 2.4%) and an excellent ICC (0.96). No systematic difference between sessions was found (average difference, 1.7 μm; P = 0.15). We found no significant bias between observers (mean difference, -1.5 μm; P = 0.29). The interobserver reproducibility was 16.4 μm (CR = 3.1%), and the ICC was 0.94. Topcon 3D OCT CCT values were lower than USP readings (mean difference, 7.6 ± 8.1 μm; 95% confidence interval, 9.9-5.3 μm; P < 0.001). CONCLUSIONS With a commercially available retinal SD-OCT system, reliable intersession and interobserver CCT measurements can be feasibly obtained. The criteria for a significant change, which would be the one exceeding the reproducibility, indicate that intersession and interobserver variations in CCT of more than 13 and 16 μm, respectively, may reflect true corneal change with this particular device. These estimates should help investigators and clinicians differentiate actual CCT modification from measurement random error. The slight CCT underestimation with respect to USP is within the range of other OCT devices.
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Comparison of central corneal thickness, thinnest corneal thickness, anterior chamber depth, and simulated keratometry using galilei, Pentacam, and Sirius devices. Cornea 2014; 33:582-6. [PMID: 24763122 DOI: 10.1097/ico.0000000000000119] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE The aim was to evaluate the agreement in the central corneal thickness (CCT), thinnest corneal thickness (TCT), anterior chamber depth (ACD), and mean simulated keratometry (simK) measurements using Pentacam, Galilei, and Sirius Scheimpflug systems in normal eyes. METHODS Anterior segment measurements were performed with Pentacam, Galilei, and Sirius devices in 32 healthy subjects. The right eye of each participant was selected. Measurements obtained with the 3 systems were compared using repeated-measures analysis of variance and Bonferroni multiple comparisons test. RESULTS Analysis of variance determined a significant difference in the anterior segment measurements of CCT, TCT, ACD, and simK between the 3 devices (P < 0.001). Pairwise comparisons of CCT and TCT measurements were significantly different except for the comparison between Pentacam and Sirius. All pairwise comparisons for ACD were statistically significant. The pairwise comparison results for simK values showed that the Galilei and Sirius systems demonstrated better agreement with each other than with Pentacam. CONCLUSIONS The results of this study suggest that the Pentacam, Galilei, and Sirius Scheimpflug systems should not be accepted as interchangeable for CCT, TCT, ACD, and simK in healthy subjects.
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Evaluation of intereye corneal asymmetry in patients with keratoconus. A scheimpflug imaging study. PLoS One 2014; 9:e108882. [PMID: 25296183 PMCID: PMC4189959 DOI: 10.1371/journal.pone.0108882] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2014] [Accepted: 08/26/2014] [Indexed: 11/19/2022] Open
Abstract
Purpose To assess the correlation between keratoconus severity and intereye asymmetry of pachymetric data and posterior elevation values and to evaluate their combined accuracy in discriminating normal corneas from those with keratoconus. Methods This study included 97 patients: 65 subjects with bilateral normal corneas (NC) and 32 with keratoconus (KC). Central corneal thickness (CCT), thinnest corneal thickness (ThCT) and posterior elevation (PE) at the thinnest point of the cornea were measured in both eyes using Scheimpflug imaging. Intereye asymmetry and its correlation with keratoconus severity were calculated for each variable. The area under the receiver operating characteristic curve (AUROC) was used to compare predictive accuracy of different variables for keratoconus. Results In normal eyes, intereye differences were significantly lower compared with the keratoconus eyes (p<0.001, for CCT, ThCT and PE). There was a significant exponential correlation between disease severity and intereye asymmetry of steep keratometry (r2 = 0.55, p<0.001), CCT (r2 = 0.39, p<0.001), ThCT (r2 = 0.48, p<0.001) and PE (r2 = 0.64, p<0.001). After adjustment for keratoconus severity, asymmetry in thinnest pachymetry proved to be the best parameter to characterize intereye corneal asymmetry in keratoconus. This variable had high accuracy and significantly better discriminating ability (AUROC: 0.99) for KC than posterior elevation (AUROC: 0.96), ThCT (AUROC: 0.94) or CCT (AUROC: 0.92) alone. Conclusions There is an increased intereye asymmetry in keratometry, pachymetry and posterior corneal elevation values in keratoconic patients compared to subjects with normal corneas. Keratoconus patients with more severe disease are also more asymmetric in their disease status which should be taken into account during clinical care.
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Evaluation of pachymetric measurements with scheimpflug photography-based system and optical coherence tomography pachymetry at different stages of keratoconus. J Ophthalmol 2014; 2014:719205. [PMID: 25143828 PMCID: PMC4129168 DOI: 10.1155/2014/719205] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 07/07/2014] [Indexed: 11/18/2022] Open
Abstract
The aim of this study was to compare the central and peripheral pachymetric measurements determined with Sirius system and Visante OCT and evaluate the agreement between them at different stages of keratoconus. Measurements were not significantly different in all patients and subgroups and showed high correlation for the corneal thicknesses of the entire cornea in different stages of keratoconus.
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