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Corneal biomechical changes with keratoconus progression and collagen cross-linking

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First Author: A.Eliasy UK

Co Author(s):    B. Lopes   A. Abasss   R. Vinciguerra   R. Herber   A. Elsheikh        

Abstract Details

Purpose:

The aim of this study is to evaluate the change in the cornea’s mechanical stiffness associated with keratoconus progression and following collagen cross-linking treatment.

Setting:

University of Liverpool, Liverpool, UK, Vincieye Clinic, Milan, Italy and Carl Gustav Carus University Hospital Dresden, Dresden, Germany.

Methods:

This multicenter retrospective study comprised patients enrolled at two hospitals in Italy and Germany. The study used Corvis ST (Oculus Optikgeräte GmbH) clinical data collected by the Vincieye Clinic for 239 Healthy and 143 keratoconus (KC) patients. In addition, Corvis ST data were collected by the CLINIC NAME for 21 KC patients before and after collagen cross-linking (CXL) treatment. The Corvis ST data included estimates of the Stress-Strain Index (SSI) – a measure of the cornea’s material stiffness.

Results:

There was no correlation between SSI and the biomechanically-corrected intraocular pressure, bIOP (R= 0.008, p= 0.921) and the central corneal thickness, CCT (R= 0.027, p= 0.750). In contrast, SSI showed strong correlation with age (R= 0.747, p< 0.001). SSI for the healthy group was 1.00±0.20 (0.45 - 1.72) and for the KC group, 0.76±0.22 (0.38 - 2.00). Relative to healthy eyes, the SSI also significantly reduced in Form Fruste KC (0.94±0.20, p< 0.019), Mild KC (0.80±0.23, p< 0.001), Moderate KC (0.72±0.21, p< 0.000) and Severe KC (0.68±0.18, p< 0.001). In the CXL database, the Pre-CXL SSI was 0.62±0.11 (0.42-0.83) and post CXL was 0.74±0.13 (0.44-0.98). Among all cases 82% showed increase in SSI.

Conclusions:

This study showed the ability of SSI to estimate the in-vivo biomechanical stiffness for healthy, KC and cross-linked corneas. This new algorithm has potential to enable customisation of CXL treatment, which would be a significant step towards achieving personalised medicine in ophthalmology.

Financial Disclosure:

... receives consulting fees, retainer, or contract payments from a company producing, developing or supplying the product or procedure presented