Posters

In vivo measurement of corneal material properties using dynamic Scheimpflug analyser

Poster Details

First Author: A.Elsheikh UK

Co Author(s):    R. Vinciguerra   A. Eliasy                 

Abstract Details

Purpose:

This study aims to provide an estimate, obtained in vivo, of the biomechanical behaviour of corneal tissue that would be suitable for customisation of several treatments such as refractive surgery, use of corneal implants and application of cross-linking in eyes with keratoconus.

Setting:

Clinical data collected from the Vincieye Clinic in Milan, Italy and the research conducted at Biomechanical Engineering Group, School of Engineering, University of Liverpool.

Methods:

The study relied on numerical models of full eye globes subjected to both intraocular pressure (IOP) and the air pressure of the CorVis ST. The models enabled consideration of wide ranges of ocular topography, thickness profiles, IOP values and material behaviour trends, and led to predictions of corneal deformation and CorVis output parameters. These results enabled the development of an algorithm providing a material behaviour estimate (tangent modulus, Et), which was applied to 158 healthy eyes, and the Et estimates obtained were checked against the results of inverse analysis of the same eyes.

Results:

The mean age of participants was 39.9±16.7 (7-81) years, central corneal thickness (CCT) was 543.8±29.4 (454-621) mm, and CorVis IOP was 15±2.6 (9.5-29) mmHg. The study showed that the Et estimates provided by the new algorithm were significantly similar to those obtained via inverse analysis of the same eyes (p=657). The Et estimates were also checked for dependence on CCT, IOP and age, and while they were not dependant on CCT (p=0.599) and IOP (p=0.281), they were significantly correlated with age (P < 0.01).

Conclusions:

The assessment of corneal biomechanics in-vivo has been impossible using current technology. The new method developed in this study promises to provide accurate estimate of the tissue’s biomechanical behaviour, which could make a step change in our ability to customise treatments for individual patients’ needs.

Financial Disclosure:

None