Posters

Evaluation of corneal biomechanical parameters after corneal cross-linking for keratoconus using ocular response analyzer and Corvis ST

Poster Details

First Author: M. Sedaghat IRAN, ISLAMIC REPUBLIC OF

Co Author(s):    M. Deldar   M. Kiarudi                 

Abstract Details

Purpose:

With the advent of the Ocular Response Analyzer (ORA) and corneal visualization scheimpflug technology (CorVis ST), a simple and reliable way for the evaluation of a series of biomechanical factors of the cornea in clinical settings have been provided. The aim of this study was to analyze ocular biomechanical properties before and one year after corneal collagen cross-linking (CXL) using the ORA and CorVis ST devices.

Setting:

Prospective, non-randomized trial from the comprehensive clinic of a tertiary eye care center between February 2015 and February 2016

Methods:

Eighty six eyes of 43 patients with keratoconus (KC) underwent CXL were recruited (mean age: 21.5±4.8 years). Corneal hysteresis (CH) and corneal resistance factor (CRF) parameters were obtained while the patient was sitting on a chair in front of the ORA device. Deformation amplitude (DA) , Radius of curvature (RoC) and peak distance (PD) were assessed using CorVis ST device . After CXL, the patients were followed for one year and all the measurements with two devices were repeated. Preoperative and post operative variables were analyzed for differences by paired student’s t-tests using measurements with the highest waveform scores.

Results:

The mean of preoperative CH and CRF were 8.7 ±1.4 and 7.3± 1.7. The mean of preoperative PD, RoC and DA were 5.0± 0.5, 5.7± 1.1 and 13.3± 1.5. The mean of final CH and CRF were 8.9± 1.5 and 7.4 ±1.8. The final PD, RoC and DA were 5.2 ±0.29, 6.0± 0.8 and 1.1± 0.12. Non-significant differences were detected between pre and postoperative CH and CRF measurements in KC eyes (p = 0.167 and p = 0.479). Significant differences were found among pre and postoperative CorVis ST device parametres; PD, RoC and DA (p= 0.002, p<0.001, p<0.001 respectively).

Conclusions:

The parameters of CorVis ST device better shows the biomechanical changes produced by CXL than ORA.

Financial Disclosure:

NONE