Riccardo Vinciguerra1, Renato Ambrósio, Ahmed Elsheikh, Farhad Hafezi, David Sung Yong Kang, Omid Kermani, Shizuka Koh, Nanji Lu, Prema Padmanabhan, Cynthia J Roberts, Suphi Taneri, William Trattler, Paolo Vinciguerra. 1. Humanitas San Pio X Hospital, Milan, Italy The School of Engineering, University of Liverpool, Liverpool, United Kingdom Department of Ophthalmology, the Federal University of the State of Rio de Janeiro (UNIRIO), Rio de Janeiro, Brazil Department of Ophthalmology, the Federal University of São Paulo (UNIFESP), São Paulo, Brazil Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, 100083, China NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, UK ELZA Institute, Dietikon/Zurich, Switzerland Faculty of Medicine, University of Geneva, Geneva, Switzerland USC Roski Eye Institute, Miller School of Medicine, Los Angeles, CA School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China Eyereum Eye Clinic, Seoul, Korea Augenklinik am Neumarkt, Cologne, Germany Department of Ophthalmology, Osaka University Graduate School of Medicine, Osaka, Japan School of Medicine and Health Sciences, University of Antwerp, Wilrijk, Belgium Emmetropia Mediterranean Eye Institute, Heraklion, Greece Department of Cornea & Refractive Surgery, Medical Research Foundation, Chennai, India Department of Ophthalmology & Visual Science, Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA Center for Refractive Surgery Muenster, Hohenzollernring 70, Muenster, Germany University Eye-Clinic, Ruhr-University, Bochum, Germany Eye Care, Miami, FL, USA Humanitas University, Department of Biomedical Sciences, Via Rita Levi Montalcini 4, 20090 Pieve Emanuele, Milan, Italy Humanitas Clinical and Research Center - IRCCS, via Manzoni 56, 20089 Rozzano (Mi) Italy.
Abstract
PURPOSE: To validate and evaluate the use of a new biomechanical index known as the CBI-LVC (Corvis Biomechanical Index-Laser Vision Correction) as a method for separating stable post-LVC eyes from post-LVC eyes with ectasia. SETTING: Patients were included from 10 clinics/9 countries. DESIGN: Retrospective, multi-center, clinical study. METHODS: The study was designed with two purposes: to develop the CBI-LVC, which combines dynamic corneal response parameters (DCR) provided by a high-speed Scheimpflug camera (Corvis ST, Oculus, Germany) and then to evaluate its ability to detect post-LVC ectasia. The CBI-LVC includes Integrated Inverse Radius, Applanation 1(A1) Velocity, A1-Deflection Amplitude, Highest Concavity-dArc Length, Deformation Amplitude ratio-2mm, and A1-ArcLength mm. Logistic regression with Wald forward stepwise approach was used to identify the optimal combination of DCRs to create the CBI-LVC, and then separate stable from LVC-induced ectasia. Eighty percent of the database was used for training the software and 20% for validation. RESULTS: 736 eyes of 736 patients were included (685 stable LVC, and 51 post-LVC ectasia). The ROC curve analysis showed an AUC of 0.991 when applying CBI-LVC in the validation dataset and 0.998 in the training dataset. A cut-off of 0.2 was able to separate stable LVC from ectasia with a sensitivity of 93.3% and a specificity of 97.8%. CONCLUSIONS: The CBI-LVC was highly sensitive and specific in distinguishing stable from ectatic post-LVC eyes. We suggest using CBI-LVC in routine practice, along with topography and tomography, to aid the early diagnosis of post-LVC ectasia and allow intervention prior to visually compromising progression.
PURPOSE: To validate and evaluate the use of a new biomechanical index known as the CBI-LVC (Corvis Biomechanical Index-Laser Vision Correction) as a method for separating stable post-LVC eyes from post-LVC eyes with ectasia. SETTING:Patients were included from 10 clinics/9 countries. DESIGN: Retrospective, multi-center, clinical study. METHODS: The study was designed with two purposes: to develop the CBI-LVC, which combines dynamic corneal response parameters (DCR) provided by a high-speed Scheimpflug camera (Corvis ST, Oculus, Germany) and then to evaluate its ability to detect post-LVC ectasia. The CBI-LVC includes Integrated Inverse Radius, Applanation 1(A1) Velocity, A1-Deflection Amplitude, Highest Concavity-dArc Length, Deformation Amplitude ratio-2mm, and A1-ArcLength mm. Logistic regression with Wald forward stepwise approach was used to identify the optimal combination of DCRs to create the CBI-LVC, and then separate stable from LVC-induced ectasia. Eighty percent of the database was used for training the software and 20% for validation. RESULTS: 736 eyes of 736 patients were included (685 stable LVC, and 51 post-LVC ectasia). The ROC curve analysis showed an AUC of 0.991 when applying CBI-LVC in the validation dataset and 0.998 in the training dataset. A cut-off of 0.2 was able to separate stable LVC from ectasia with a sensitivity of 93.3% and a specificity of 97.8%. CONCLUSIONS: The CBI-LVC was highly sensitive and specific in distinguishing stable from ectatic post-LVC eyes. We suggest using CBI-LVC in routine practice, along with topography and tomography, to aid the early diagnosis of post-LVC ectasia and allow intervention prior to visually compromising progression.
Authors: Riccardo Vinciguerra; Robert Herber; Yan Wang; Fengju Zhang; Xingtao Zhou; Ji Bai; Keming Yu; Shihao Chen; Xuejun Fang; Frederik Raiskup; Paolo Vinciguerra Journal: Front Med (Lausanne) Date: 2022-02-25