Detection of Post-Laser Vision Correction Ectasia with a new Combined Biomechanical Index


Vinciguerra, Riccardo, Ambrosio, Renato, Elsheikh, Ahmed, Farhad, Hafezi, Kang, David Sung Yong, Kermani, Omid, Koh, Shizoka, Lu, Nanji, Padmanabhan, Prema, Roberts, Cynthia et al (show 4 more authors) (2021) Detection of Post-Laser Vision Correction Ectasia with a new Combined Biomechanical Index. Journal of Cataract and Refractive Surgery, 47 (10). pp. 1314-1318.

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Abstract

<h4>Purpose</h4>To validate and evaluate the use of a new biomechanical index known as the Corvis biomechanical index-laser vision correction (CBI-LVC) as a method for separating stable post-LVC eyes from post-LVC eyes with ectasia.<h4>Setting</h4>10 clinics from 9 countries.<h4>Design</h4>Retrospective, multicenter, clinical study.<h4>Methods</h4>The study was designed with 2 purposes: to develop the CBI-LVC, which combines dynamic corneal response (DCR) parameters provided by a high-speed dynamic Scheimpflug camera (CorVis ST; OCULUS Optikgeräte GmbH) 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 and arclength, deformation amplitude ratio of 2 mm, and A1 arclength in millimeters. 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 percentage of the database was used for training the software and 20% for validation.<h4>Results</h4>736 eyes of 736 patients were included (685 stable LVC and 51 post-LVC ectasia). The receiver operating characteristic curve analysis showed an area under the curve of 0.991 when applying CBI-LVC in the validation dataset and 0.998 in the training dataset. A cutoff of 0.2 was able to separate stable LVC from ectasia with a sensitivity of 93.3% and a specificity of 97.8%.<h4>Conclusions</h4>The CBI-LVC was highly sensitive and specific in distinguishing stable from ectatic post-LVC eyes. Using CBI-LVC in routine practice, along with topography and tomography, can aid the early diagnosis of post-LVC ectasia and allow intervention prior to visually compromising progression.

Item Type: Article
Uncontrolled Keywords: Cornea, Humans, Keratoconus, Dilatation, Pathologic, Corneal Topography, Retrospective Studies, Elasticity, Biomechanical Phenomena
Divisions: Faculty of Science and Engineering > School of Engineering
Depositing User: Symplectic Admin
Date Deposited: 14 Jun 2022 07:47
Last Modified: 18 Jan 2023 21:00
DOI: 10.1097/j.jcrs.0000000000000629
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3156055

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