Posters

The corneal deformation parameters and IOP measurements of post corneal transplant eyes by a Scheimpflug-based tono-pachymeter

Poster Details

First Author: P.Mandal UK

Co Author(s):                        

Abstract Details

Purpose:

To evaluate the differences in intraocular pressure (IOP) and corneal biomechanical parameters of normal eyes and eyes that have undergone corneal surgery.

Setting:

Birmingham and Midland Eye Centre, City Hospital, Dudley Road, Birmingham, B18 7QH, United Kingdom.

Methods:

This prospective comparative study involved 142 eyes divided into four groups: control (70), post-PK (19), post -DSAEK (26) and post-DALK (27). IOP was measured with both the Goldmann tonometer (GAT) and the Corvis ST (CST). The CST biomechanical response of the cornea was measured, covering the following parameters: time to reach applanation (AT), length of the flattened segment in a Scheimpflug image (AL), and velocity of the corneal movement during applanation (AV), highest concavity time (HCT), deformation amplitude (HdA), distance between bending points of the cornea (HpD) and concave radius of curvature (HcR).

Results:

Mean CST IOP was 1mmHg lower than GAT IOP in post-PK and post-DSAEK eyes, post-DALK eyes were 2mmHg higher than normal eyes. During the highest corneal concavity phase, the post-DALK group had a significantly higher HCT (mean difference 0.53±0.13s) and HdA (mean difference 0.11±0.30mm) whilst the HcR was lower compared to normal subjects (mean difference 0.52±0.32mm). HCT of post-DSEK subjects was also noted to be higher (mean difference 0.53±0.13s) than normal subjects. Post-PK subjects showed no significant difference compared to normal subjects except for HcR, which was lower than normal eyes.

Conclusions:

Each group displayed a different effect on all the CST parameters during different corneal deformation phase. The most affected corneal biomechanical parameter is during highest corneal concavity phase.

Financial Disclosure:

NONE