Corneal Biomechanics in Ectatic Diseases: Refractive Surgery Implications
Renato Ambrósio, Jr1, 2, 3, 4, 5, *, Fernando Faria Correia6, 7, 8, Bernardo Lopes1, 2, 3, 4, 5, Marcella Q. Salomão1, 2, 3, 4, 5, Allan Luz3, 4, 5, Daniel G. Dawson9, Ahmed Elsheikh10, 11, Riccardo Vinciguerra12, Paolo Vinciguerra12, 13, Cynthia J. Roberts14
Identifiers and Pagination:Year: 2017
Issue: Suppl-1, M2
First Page: 176
Last Page: 193
Publisher Id: TOOPHTJ-11-176
Article History:Received Date: 13/02/2017
Revision Received Date: 16/05/2017
Acceptance Date: 15/06/2017
Electronic publication date: 31/07/2017
Collection year: 2017
open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: https://creativecommons.org/licenses/by/4.0/legalcode. This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Ectasia development occurs due to a chronic corneal biomechanical decompensation or weakness, resulting in stromal thinning and corneal protrusion. This leads to corneal steepening, increase in astigmatism, and irregularity. In corneal refractive surgery, the detection of mild forms of ectasia pre-operatively is essential to avoid post-operative progressive ectasia, which also depends on the impact of the procedure on the cornea.
The advent of 3D tomography is proven as a significant advancement to further characterize corneal shape beyond front surface topography, which is still relevant. While screening tests for ectasia had been limited to corneal shape (geometry) assessment, clinical biomechanical assessment has been possible since the introduction of the Ocular Response Analyzer (Reichert Ophthalmic Instruments, Buffalo, USA) in 2005 and the Corvis ST (Oculus Optikgeräte GmbH, Wetzlar, Germany) in 2010. Direct clinical biomechanical evaluation is recognized as paramount, especially in detection of mild ectatic cases and characterization of the susceptibility for ectasia progression for any cornea.
The purpose of this review is to describe the current state of clinical evaluation of corneal biomechanics, focusing on the most recent advances of commercially available instruments and also on future developments, such as Brillouin microscopy.