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Detection of post-laser vision correction ectasia with a new combined biomechanical index: CBI-LVC

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First Author: R.Vinciguerra ITALY

Co Author(s):    R. Ambrosio   A. Elsheikh   C. Roberts   P. Vinciguerra           

Abstract Details

Purpose:

To evaluate the ability of a new Biomechanical Index (CBI-LVC), developed using dynamic corneal response parameters (DCR) provided by a high-speed Scheimpflug camera (CorVis ST, Oculus, Wetzlar, Germany) to separate stable eyes post laser vision correction (LVC) from ectasia post-LVC.

Setting:

Retrospective, Multicentre, Clinical Study

Methods:

Patient: 736 eyes of 736 patients were included (685 stable LVC, and 51 post-LVC ectasia) in 10 clinics on 4 continents. Logistic regression was used to create the CBI-LVC aimed to separate stable from LVC-induced ectasia. Eighty percent of the database was used for training and 20% for validation. Main Outcome Measures: values of DCRs, Area Under the Curve (AUC), sensitivity and specificity.

Results:

The CBI-LVC included Integrated Inverse Radius, Applanation 1(A1) Velocity, A1-Deflection Amplitude, Highest Concavity-dArcLength, Deformation Amplitude ratio-2mm and A1-ArcLengthmm. 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 accurately 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.

Financial Disclosure:

... receives consulting fees, retainer, or contract payments from a company producing, developing or supplying the product or procedure presented