Posters

Corneal thickness relation versus corneal biomechanical parameters in normal and keratoconic eyes

Poster Details

First Author: N.Burguera-Giménez SPAIN

Co Author(s):    C. Peris-Martínez   M. Díez-Ajenjo   N. Burguera-Giménez              

Abstract Details

Purpose:

To analyze the effect of different corneal thickness in Corneal Biomechanics parameters provided by a non-contact tonometer with a high-speed Scheimpflug-camera (CORVIS® ST, Oculus Optikgeräte GmbH, Wetzlar, Germany) in normal and keratoconus patients.

Setting:

FISABIO Oftalmología Médica, Universidad de Valencia

Methods:

Cross-sectional prospective and non-randomized study in which 48 eyes, 22 control group eyes (CG) and 26 keratoconus group eyes (KG), of 48 patients were enrolled. Uncorrected and corrected logMAR visual acuity, refractive error, anterior and posterior corneal topography with Pentacam® HR (Oculus Optikgeräte GmbH, Wetzlar, Germany) were evaluated. From corneal biomechanical parameters (CORVIS® ST, Oculus Optikgeräte GmbH, Wetzlar, Germany), length and speed of 1st (LA1, SA1) and 2nd applanation (LA2, SA2); Peak distance (PD), Curvature radius (Rc), deformation amplitude (DA); Intraocular Pressure (IOP), biomechanical corrected IOP (bIOP), and Biomechanical Corvis Index (CBI) have been considered.

Results:

KG was divided considering thinnest corneal thickness (TCT); TCT≤490μm and TCT>490μm. CG was distributed in TCT quartiles; TCT≤544μm and TCT>544μm. TCT>544μm in CG have shown no significant decreased values of LA1, LA2, Rc, bIOP. However, statistical significant reduction (p<0.01) of PD, DA and IOP was observed. CBI, SA1 and SA2 parameters were increased compared to TCT≤544μm, but there was statistical significance only in SA1 (p<0.01). TCT>490μm in KG showed an increment in LA1, LA2, Rc, IOP and bIOP and a decreased SA1, SA2, PD, DA and CBI parameters. Statistical significant differences in Rc, PIO, DA and CBI were found.

Conclusions:

Corneal stiffness in healthy and keratoconus subjects change significantly depending on corneal thickness. Higher TCT values in normal eyes have reported an inverse behaviour compared to keratonic eyes. Corneal Biomechanics parameters should be considered as another tool in screening corneal ectasia but taking into account also corneal thickness and keratoconus grade.

Financial Disclosure:

None