Detection of postlaser vision correction ectasia with a new combined biomechanical index. Issue 10 (October 2021)

• Record Type: Journal Article
• Authors: Vinciguerra, Riccardo; Ambrósio, Renato; Elsheikh, Ahmed; Hafezi, Farhad; Yong Kang, David Sung; Kermani, Omid; Koh, Shizuka; Lu, Nanji; Padmanabhan, Prema; Roberts, Cynthia J.; Taneri, Suphi; Trattler, William; Eliasy, Ashkan; Jum, Ikhyun; Lopes, Bernardo; Padmanaban, Vasanthi; Rosetta, Pietro; Rost, Anika; Torres-Netto, Emilio A.; Vinciguerra, Paolo
• Is Part Of: Journal of cataract and refractive surgery. Volume 47:Issue 10(2021)
• Page Start: 1314
• Page End: 1318
• Publication Date: 2021-10
• Subjects: 617.7
• DOI: 10.1097/j.jcrs.0000000000000629
• Languages: English
• ISSNs: 0886-3350

Abstract

Abstract : Corneal biomechanics evaluation post-LVC was able to accurately separate stable patients from those with ectasia after LVC. Abstract : Purpose: 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. Setting: 10 clinics from 9 countries. Design: Retrospective, multicenter, clinical study. Methods: 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. Results: 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%. Conclusions: 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.