A novel clinical method for measuring corneal elasticity in vivo

Session Details

Session Title: Corneal Biomechanics

Session Date/Time: Sunday 15/09/2019 | 16:30-18:00

Paper Time: 17:00

Venue: Free Paper Forum: Podium 4

First Author: : S.McCafferty USA

Co Author(s): :    J. Levine   A. Mccolgin                          

Abstract Details

Purpose:

Validate a simple and quick method for measuring standardised corneal elasticity in live subjects using a multi-centre randomised clinical trial.

Setting:

Multi-centre, randomised, open label clinical trial

Methods:

A modified surface Goldmann (GAT) prism has been shown to correct intraocular pressure (IOP) for central corneal thickness (CCT) and corneal hysteresis (CH) without overall bias. The IOP measurement difference between GAT and a modified prism gives the slope of the force–displacement curve which is a measurement of corneal elasticity. To test this effect, a GAT and a modified surface prism measured IOP on 243 unique eyes, randomised to initial IOP measurement by Goldmann or modified prisms for a total of 1936 IOP measurements. Analysis included a multiple linear regression for CCT and CH correlation in the modified/standard GAT difference.

Results:

The difference in IOP measurements of the standard and modified Goldmann prisms correlated well to CCT particularly in thin (500µm) and thick (600µm) corneas (R2=0.404, p=0.007). Corneal hysteresis (CH) also correlated well to the difference in prism measurements (R2=0.125, p=0.039). The overall mean bias between two prisms was +0.32mmHg in the modified prism (p=0.29).

Conclusions:

Modified surface and standard surface prisms indicated a statistically significant correlation for CCT and CH correlation, without overall bias. The expected correlation to known real-time corneal biomechanical metrics promotes validation that the modified/standard GAT difference is an IOP standardised measurement of relative corneal elasticity. Corneal elasticity is significantly altered with corneal surgical procedures, disease processes and even ocular medications making its measurement a valuable tool predicting ocular health and outcomes.

Financial Disclosure:

has significant investment interest in a company producing, developing or supplying product or procedure presented, research is funded, fully or partially, by a competing company