Corneal biomechanical properties assessed by corneal visualization Scheimpflug technology (Corvis ST): comparison between both eyes of patients with unilateral keratoconus and with normal controls

Session Details

Session Title: Corneal Biomechanics

Session Date/Time: Tuesday 13/09/2016 | 16:30-18:00

Paper Time: 16:30

Venue: Auditorium C6

First Author: : P.Padmanabhan INDIA

Co Author(s): :    S. Mahadik   S. Rachapalle Reddi                 

Abstract Details

Purpose:

To compare various biomechanical parameters measured by Corvis ST between both eyes of patients diagnosed with unilateral keratoconus(KC), the contralateral eye being termed forme fruste keratoconus (FFKC) and to compare them in turn with normal controls.

Setting:

Department of Cornea & Refractive Surgery Medical Research Foundation, Sankara Nethralaya 18 College Road, Chennai - 600 006 Tamil Nadu, INDIA

Methods:

This is an observational comparative case control study. Study eyes: Both eyes of patients with unilateral keratoconus. Control eyes: Right eye of refractive surgery candidates who did not develop ectasia for at least 2 years following Lasik. All patients underwent detailed ophthalmic examination, corneal topography, tomography and biomechanical properties measured by Corvis ST (Oculus, Germany). Corvis ST research software specifies 35 biomechanical parameters. Using single and multivariate logistic regression models, we identified parameters with significant difference between the 3 groups.

Results:

A total of 152eyes of 126patients were studied. 26eyes with KC, 26 contralateral eyes (FFKC) and 100 age-and sex-matched control eyes. The significant predictors for KC vs FFKC were A1 time, A1 deflection amplitude and HCdArc-length. Receiver operating characteristic(ROC) curve was constructed for the overall model with area under curve(AUC) 0.947(p<0.005). The significant predictors for KC vs normal were A1 time, HC deflection area and HCdArc-length and the AUC for the overall model was 0.853(p<0.005). The significant predictors for FFKC vs normal were A1 time, A2 deformation amplitude and A2dArc-length and the AUC for the overall model was 0.863(p<0.005).

Conclusions:

Based on a multivariate logistic regression, certain biomechanical properties can distinguish keratoconus from FFKC and normal eyes, using the Corvis ST. A1 time was identified as a parameter that can be used across all groups as a differentiating measure.

Financial Disclosure:

NONE